A COMPILATION OF GAS FIELD PRACTICES AND PROCEDURES

by the

Landfill Gas Management Division of the Solid Waste Association of North America (SWANA)

August 2011

SWANA ● 1100 Wayne Avenue, Suite 700, Silver Spring, MD 20910 ● 800-467-9262

FORWARD

This document was prepared by the SWANA Management Division and is based on its professional assessment of current practices and procedures relating to the control, recovery, and utilization of landfill gas. The observations and suggestions in this document should serve as a starting point for readers who are interested in furthering their own knowledge of the subject matter.

SWANA plans to supplement the materials in this report from time to time as warranted by significant breakthroughs in technology and technique. This edition is an update to the original 1985 edition and the 1992 revision.

SWANA, along with its members and chapters, does not assume any liability with respect to the use of, or for damages resulting from the use of, any information, equipment, method, or process discussed in this report. Mere reference to such information, equipment, method, or process does not constitute an endorsement thereof by SWANA or its members and chapters.

John H. Skinner, Ph.D. Executive Director, SWANA August 2011

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Acknowledgment

The following persons are acknowledged as active participants on the Health and Safety Task Force. Their participation and commentary in revision of this document are greatly appreciated.

Mr. Robert Black Mr. Larry S. Carter Mr. George L. Coiner Mr. Steven P. Cooper Mr. Douglas W. Coordes, CIH Ms. Lenda Doane Mr. Michael D. Geyer, P.E. Mr. Clyde N. Moore, P.E. Mr. Richard W. Prosser, P.E. Mr. Jon Shields Mr. Anton Svorinich Mr. Michael E. W. Ward Mr. Mark A. Weisner Mr. Jim Wheeler (Chairman)

The following persons are acknowledged as active participants on the Health and Safety Section Revision and Update Task Force. Their participation and commentary in revision of this document are greatly appreciated.

Mr. Ken Brynda Mr. James A. Chabot, P.E. Mr. Brent L. Dieleman Mr. Scott E. Hill Mr. Ken Kampfen Mr. Mike Knox Mr. Carlo F. Lebron, P.E. Mr. Joseph H. Liserio, CIH, CSP Mr. Chris Marlowe, CIH, QEP Ms. Marcia A. Pincus, P.E. Mr. Gary Pons, CIH, CSP, REA Mr. Michael P. Murphy, P.E. (Chairman)

The following persons are acknowledged as active participants on the Sampling and Analysis Section Revision and Update Task Force. Their participation and commentary in revision of this document is greatly appreciated.

Mr. Kenneth Brynda Mr. Brian Case Mr. Brent L. Dieleman Ms. Anne Germain Mr. Keith Johnson Mr. Ken Kampfen Mr. Mike Knox Mr. Carlo F. Lebron, P.E. Mr. Thomas Lock Mr. Michael P. Murphy, P.E. (Chairman)

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The following persons are acknowledged as active participants on the Material and Equipment Section Revision and Update Task Force. Their participation and commentary in revision of this document is greatly appreciated.

Mr. Brent L. Dieleman Mr. Darrin D. Dillah, Ph.D., P.E. Mr. William M. Held (Chairman) Mr. Michael P. Murphy, P.E. Mr. Ron Wilks

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TABLE OF CONTENTS

SECTION I: HEALTH AND SAFETY

A. Purpose and General Introduction ...... I-1 B. Planning ...... I-9 C. Safety Plans and Programs ...... I-10 D. Hazard Assessment and Identification ...... I-17 E. Safety Equipment ...... I-20 F. Personal Health and Hygiene ...... I-24 G. Landfill Gas-Related Safety Procedures ...... I-25 H. Safety Procedures for Well Drilling and Construction ...... I-27 I. Safety Procedures for Excavation, Trenching and Pipe Installation ...... I-29 J. General Construction/Maintenance ...... I-33 K. Field Sampling for Health and Safety ...... I-34 L. Respiratory Protection ...... I-37 M. Special Conditions ...... I-40 Tables

A-1 Health and Safety Concerns - Landfill Gas Management ...... I-3

A-2 Physiological Response to Various Concentrations of Sulfide ...... I-6

E-1 OSHA Standards for the Use of Personal Protective Equipment ...... I-22

K-1 Exposure Action Levels ...... I-34

L-1 Respiratory Protection Equipment Protection Factors ...... I-38

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SECTION II: LANDFILL GAS MONITORING, SAMPLING, AND ANALYSIS

A. INTRODUCTION ...... II-1 B. FIELD MONITORING ...... II-4 C. FIELD SAMPLING ...... II-19 D. SAMPLE ANALYSIS ...... II-25 E. APPLICABLE REFERENCES AND ANALYTICAL METHODS ...... II-28

Tables

A-1 LANDFILL GAS FIELD INVESTIGATION EQUIPMENT ...... II-2

SECTION III: MATERIALS AND EQUIPMENT

A. INTRODUCTION ...... III-1 B. GAS CONTROL FOR MIGRATION ...... III-2 C. GAS CONTROL FOR ODORS AND SURFACE EMISSIONS ...... III-6 D. GAS RECOVERY ...... III-7

Tables

B-1 DESIRABLE PROPERTIES OF MEMBRANE MATERIALS ...... III-3

Figures Glossary of Health and Safety Acronyms List of Health and Safety Informational Websites References

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SECTION I: HEALTH AND SAFETY

A. PURPOSE AND GENERAL INTRODUCTION

History of SWANA Health and Safety Manual

Over the years, SWANA has strived to provide valuable written resources to its members and to the solid waste industry in general. The predecessor of this document, published in August 1991, contributed significantly to an awareness of health and safety in that earlier audience; as of this writing, hundreds of copies of the manual have been sold. The current version builds on the August 1991 edition and on past volunteer efforts of industry members.

Importance of Health and Safety Related to Landfill Gas Management

Coinciding with the installation and start-up of an active landfill gas collection and control system (LGCCS), the Landfill Manager is often required to hire or assign responsible individuals (Landfill Gas Technicians) to safely operate and maintain the system. Whether operation and maintenance services are provided in-house or by consultants, the Landfill Manager must verify that those selected to perform duties are properly trained and work in compliance with applicable regulations; these may include federal regulations regarding emissions (NSPS 40 CFR 60 Subpart WWW), and local and federal health and safety regulations (OSHA, etc.).

Typical landfill gas contains 30 to 60 percent (CH4), which is explosive at certain gas concentrations (referred to as the explosive limit, typically 5 to 15 percent by volume in air for methane). Methane is also a simple asphyxiant. (H2S) can also be present in landfill gas at potentially dangerous levels, and is often a factor contributing to non-fire-related injuries or deaths associated with landfill gas. Volatile Organic Compounds (VOCs) are also found in landfill gas. Some types of VOCs are carcinogens. Condensate (liquid generated from landfill gas) is perhaps the most difficult medium to characterize regarding its chemical constituents; and although it consists primarily of , condensate may contain sufficient quantities of contaminants to warrant special handling (see Personal Protective Equipment, PPE, in Section E). Depending on the site, condensate may include constituents such as polar organic acids and aldehydes.

Proper operation and management of an LGCCS involves interacting, often day-to-day, with landfill operations. Landfill Gas Technicians travel the same roads as refuse trucks and other associated heavy equipment; they work around active tipping operations, and encounter the same hazards as other landfill staff. Landfill Gas Technicians are exposed to electricity or compressed air or , primarily while operating flare stations and pumps in the field; they may require specific training to become qualified to perform these duties responsibly. Thus, in addition to understanding health and safety issues directly associated with landfill gas management, persons responsible for operating and maintaining an LGCCS must also be aware of, and take part in, all other general safety programs, including safety meetings and training programs related to . Conversely, it is advisable for personnel who work at the landfill, or even those regularly visiting the landfill, to have a general understanding of landfill gas and the landfill’s specific gas management program.

Besides being responsible for regulatory compliance from an environmental perspective, the Landfill Manager must ensure that persons selected for this work are trained to perform required duties safely. Obstacles can occur, however. Landfills sometimes face budgetary constraints

I-1 that limit funds available to address landfill gas management. In many cases, too, management of a landfill gas collection system is performed by two or more personnel with varying degrees of experience. For these reasons, it is critical that Landfill Managers establish Standard Operating Procedures (SOPs) that can document ways to perform common tasks associated with landfill gas management, and programs for addressing unusual situations that could happen during the life of a landfill. SWANA suggests that Landfill Managers become proficient in establishing operating standards for a specific LGCCS, when warranted, and for training the Landfill Manager’s staff.

Entries into confined space entry work are often responsible for critical injuries or deaths associated with landfill gas. While this manual, in part, assists in identifying confined space and recommends avoidance, it is not intended to serve as instruction related to confined space entry. SWANA suggests that SOPs for LGCCSs refrain from addressing confined space entry. Confined space on landfills (leachate vaults, manholes, vessels, etc.) should be labeled as such and secured, with staff instructed about the associated hazards. ONLY PROPERLY TRAINED PERSONNEL SHOULD EVER ENTER A CONFINED SPACE.

Purpose of This Manual

This manual is intended to serve as a reference for the Landfill Manager and landfill personnel, and to assist in the safe management of landfill gas collection and control systems. As described below, the goal of this manual is to refresh, refocus, and reorganize the 1991 edition such that it is not only updated, but clarifies content for those working in the landfill gas industry for the first time.

Refresh - A fresh prospective from a new group of volunteers provides additional insight and updates the document regarding today’s issues and concerns. The writing team that created this document is active in the industry in varying areas, which adds to the quality and credibility of the manual. Furthering this effort, SWANA has insisted that accredited health and safety and legal professionals review the document to ensure that regulatory and liability issues are properly referenced and addressed. A reference is included in the Appendix, identifying internet resources relative to the topic.

Refocus - Primarily due to the overwhelming amount of material that this document could cover, as demonstrated by the 1991 edition, the writing team decided to clearly define the target audience and create a common theme throughout. After several discussions, the writers decided to define the target audience as two groups: new landfill management personnel, and contractors. New management personnel are often burdened with significant responsibilities in a short period of time, requiring condensed, informative, and well-organized content to address responsibilities, of which health and safety is paramount. On the other hand, contractors working on landfills are often unfamiliar with landfill practices, and are frequently required to develop project-specific health and safety manuals for landfill projects. This manual is intended to serve as a reference for both sets of readers.

Reorganize - Reorganization of the manual is a logical means of accomplishing these purposes. The writing team’s goal of building on past work necessitated a condensation of material from the 1991 edition, in a format that creates a more “user-friendly” document. As described below, this “tiered” format, with a significant, well-organized Appendix, provides clearly defined resources and useful information on specific topics.

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Health and Safety Concerns

An initial step in developing this health and safety manual was to identify the range of health and safety concerns likely to be encountered while operating and maintaining a landfill gas management system. Table A-1 contains the results of this exercise. Although concerns specific to flammability characteristics of landfill gas are often paramount in the minds of Landfill Gas Technicians as they perform duties, a key objective of the manual is to stress that equally hazardous health and safety concerns exist in the operating environment, which may not be directly related to managing landfill gas. This wider context for addressing hazards emphasizes the need for cross-training with regard to health and safety in which landfill operational personnel have at least a basic knowledge of the landfill gas management system, and Landfill Gas Technicians participate in all health and safety training programs required for landfill employees.

TABLE A-1

HEALTH AND SAFETY CONCERNS - LANDFILL GAS MANAGEMENT

 Inhalation of landfill gas.  Methane in landfill gas is a simple asphyxiant (displaces , but is not toxic).

 Hazardous components (H2S, etc.).  Exposure to landfill gas.  Explosive (lower and upper explosive limit).  Volatile Organic Compounds (vinyl chloride, etc.).  Fires in the waste fill.  Environment (sun, wind, rain, snow/ice, heat, cold, dust, etc.).  Insects (mosquitoes, ticks, chiggers, bees, etc.).  Poisonous plants (poison ivy, poison oak, poison sumac, etc.).  Animals (bears, snakes, coyotes, rats, etc.).  Landfill activities (heavy equipment, traffic, etc.).  Slip, trip, and fall hazards (vegetation, erosion ruts, debris).  Confined spaces.  Hazardous energy: mechanical, electrical, chemical, gravity, thermal, pneumatic, radiation, and hydraulic.

SWANA warns that the Table A-1 is meant to list common hazards. Hazards not shown on the table can pertain to your specific situation.

Components of a Typical Landfill Gas Collection System

 Well heads.  Lateral collection pipes.  Conveyance pipe (including looped system).

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 Condensate management structures (traps, knockouts, etc.).  Flare station or beneficial use facility.

Equipment and Instruments Typically Required at a Landfill Site

 Typical landfill instruments (manometer, GEM landfill gas analyzer, temp gauge, etc.).

 PPE (steel shank boots, safety vest, hard hat, gloves, insect protection, etc.) (see Section E).

 Communication (radio and/or cell phone).

INHALATION OF LANDFILL GAS

At some point, every Landfill Gas Technician wonders if inhalation of landfill gas will cause bodily harm. Usually, this curiosity happens after exposure has occurred and often is coupled with apprehension (see Section L). H2S is of great concern in dealing with sites that accept large amounts of C&D waste and contain significant amounts of moisture. Death from landfill gas inhalation results mostly from exposure to H2S above 800 ppm, which is possible in some landfills. Exposure to gas can also arise from the repair of leachate or condensate lines. Technicians should be wary of potential hazards arising from gas in these lines.

Notwithstanding the apparent lack of danger, SWANA recommends that exposure to landfill gas be avoided, if at all possible, and believes reasonable precautions can significantly reduce an individual’s contact with gas. Perhaps the most significant characteristic of an active LGCCS, relative to minimizing gas emission and exposure, is the fact that, under normal conditions, the portion of a system upstream of the gas mover (blower compressor, etc.) operates under a vacuum; this, by its nature, brings atmospheric air into the system when the system is breached.

VACUUM IS YOUR FRIEND

All active LGCCSs move gas by inducing a pressure gradient force (through movement also known as convection). Gas follows the path of least resistance toward the source of lower absolute pressure, commonly referred to as (relative) vacuum. The fact that in a well- maintained gas collection system, vacuum is present means that, if there is a small leak, air at a higher pressure will enter the source of the leak, precluding landfill gas from leaking out of that source. A practical example involves sample ports on well heads that have caps rather than valves to seal them between monitoring events. When the cap is removed, air quickly flows into the well as a result of vacuum. If substantial, leaks of this nature will be evident at the flare station in the form of higher oxygen and/or balance gas (as measured with instrumentation); in some cases, enough air can be brought into the system to extinguish the flame at the flare, shutting down the entire system.

Key Point - The source of vacuum in LGCCSs, whether it originates from a flare station or beneficial end-use facility, is a critical component of maintaining a safe working environment. Vacuum not only provides a means of extracting and conveying gas, it ensures that leaks in the system do not emit gas to the atmosphere. Personnel should make sure, at the beginning and throughout a regularly scheduled monitoring event, that the vacuum source is operating and stable.

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Major leaks, or those that cause an unstable flame at the flare or combustion device, may trigger alarms or automatic shutdowns at the flare. For this reason, it is critical to monitor gas constituents at the flare station immediately prior to regular landfill gas collection system monitoring; these constituents should be checked throughout the day to confirm stable operation. It is also important to inform all relevant personnel, especially those stationed on or near the source of the vacuum, that you will be working in the field and that they should not disrupt or adjust the vacuum. When vacuum is lost during a monitoring event, it not only disrupts work, but makes the work environment more dangerous.

Although monitoring an LGCCS that is not under vacuum is not typical practice, portions of the system may from time to time operate under slight positive pressure. As the system ages, header pipes may settle and condensate collect in low spots along a pipe, reducing and sometimes sealing off the flow of gas altogether. If the LGCCS on the other side of this blockage is not influenced by vacuum through another path (e.g., a looped collection header), there will often be a reduction of vacuum such that positive pressure is developed within the gas system components. This pressure could build up enough to cause leaks through mechanical joints (flanges and screw clamps on flex hose, for example) or through the surface cover of the landfill. If not addressed, these areas of the landfill will likely become a source of danger and odor. Liquid collection systems are usually under positive pressure, and can pose a substantial health hazard if lines are being repaired or expanded (see Section D – Liquids Management).

It is important to remember that lost vacuum in a portion of the LGCCS is considered an unusual occurrence that may require a work permit, special equipment, and appropriate expertise to repair. Tier 2 of this manual provides further information on how to respond to these types of situation.

Landfill Gas Components That Are Simple Asphyxiants (Displacing Oxygen, But Not Toxic)

Methane and , which are the primary constituents of typical landfill gas generated by municipal solid waste, are simple asphyxiants in that they are non-toxic but do displace oxygen. Methane and carbon dioxide are odorless. Gas-related odors derive from contaminants in the landfill gas. Asphyxiants are usually defined as follows:

Asphyxiant - A material capable of reducing the level of oxygen in the body to dangerous levels. Simple asphyxiants merely displace air in the environment. This reduces the concentration of oxygen below the normal level of around 21 percent, which can lead to breathing difficulties, unconsciousness or even death (Reference: Physical and Theoretical Chemistry Laboratory, Oxford University).

Key to the ability of any gas (or gases) to displace air is the presence of an enclosed area (or confined space) to trap gas at the source. Build-up of landfill gas is also possible in topographic depressions or trenches on calm days. If conditions are appropriate, gas may displace air within the space, creating an oxygen-deficient atmosphere. As a key point of this document, SWANA stresses that Landfill Gas Technicians should be able to recognize and avoid potential confined space entry at all times. (Further information about confined space is found in Section G.) Note that most injuries and deaths attributed to landfill gas involve personnel entering confined space without proper training and/or equipment (see Appendix I for incidents).

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Hazardous Components in Landfill Gas

As described in more detail in Section D, landfill gas contains major constituents (CH4, O2, N2, and CO2) and trace contaminants that can prove hazardous to on-site personnel. Accuracy and sensitivity in testing for these chemicals will vary, depending on analytical procedures and equipment used during work activities at the landfill. Priority pollutants of chief regulatory concern include various hazardous components of landfill gas. Perhaps the most prominent toxic contaminant in landfill gas that could be present at potentially harmful levels is hydrogen sulfide (H2S). H2S is a colorless, toxic, very flammable gas which, in low concentrations, has an offensive odor described as that of rotten eggs. H2S, however, quickly numbs the olfactory senses (sense of smell), so reliance on detecting an odor can lead to very dangerous conditions, and even cause virtually instant death.

H2S is usually present at some concentration, generally below 100 ppm, in landfill gas. It is unlikely that dangerous concentrations of H2S will develop, except:

 In vaults or other confined spaces where oxygen deficiency may be a hazard.

 In low-lying areas of the landfill.

 If a landfill contains large amounts of sulfate, such as where natural or man-made gypsum is present along with high levels of moisture, very high (lethal) concentrations of H2S could be produced (large amounts of construction debris containing wallboard concentrated in one location would be an example).

Dangerous and unexpected pockets of H2S gas may therefore be encountered under some circumstances. Personnel must be trained for, and remain alert to, these possibilities.

Table A-2 lists physiological responses to H2S that can be encountered during landfill operations.

TABLE A-2

PHYSIOLOGICAL RESPONSE TO VARIOUS CONCENTRATIONS OF HYDROGEN SULFIDE

H S Concentration Response 2 (ppm)

Maximum allowable concentration for prolonged exposure, 8 hours. 10 Slight symptoms possible after several hours. 70-150 IDLH - Level at which exposure is immediately dangerous to life and 100 health. Death possible/probable. Permanent nervous system damage. 400-700 Immediate death. 1,000

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Note: Laboratories are often not able to properly analyze for H2S due to its reactivity. Colorimetric stain tubes (such as Draeger or Sensidyne) diffusion type tube monitoring may be generally adequate. Note that when using diffusion type tubes, some interferants may mask detection of the chemical of interest.

EXPOSURE TO LANDFILL GAS

Perhaps the most prominent concern regarding work around landfill gas is its potential to combust or explode. This concern is well founded in that methane in landfill gas can burn at concentrations as low as 5 percent in air (referred to as the lower explosive limit, or LEL). When the LGCCS is operating normally, the Landfill Gas Technician is rarely exposed to landfill gas at combustible levels (see Vacuum Is Your Friend). Since portions of the system may not be working effectively, however, it is critical to eliminate the use of equipment, tools, instrumentation, flashlights, or any other devices that could serve as ignition sources in a combustible gas mixture.

Landfill Gas Technicians often find it necessary to add or replace sample ports in the landfill gas system. Though the system typically operates under a vacuum, technicians should not assume that vacuum is present without verification—loss of vacuum is often the motive for installing a sample port. The tool most commonly used to install the port is a battery-powered drill. Most such drills are not “intrinsically safe” (see definition below). If portions of the system into which the port is being installed are under pressure (an unusual occurrence), conditions could be ripe for gas to be released from the drilled hole in sufficient quantities to create a flammable mixture, which could then be ignited by sparks from the drill.

Intrinsically safe - Equipment and wiring not capable of releasing sufficient electrical or thermal energy under normal or abnormal conditions to cause ignition of a flammable or combustible atmospheric mixture in its most easily ignitable concentration. NOTE: Other types of explosion safety are also acceptable. Technicians should locate the approval label.

Situations such as these can be remedied with common sense. If vacuum cannot be directly verified, the Landfill Gas Technician should use an intrinsically -safe or hand-operated drill, thus removing the potential source of ignition. When monitoring of the surrounding air is required, a combustible gas analyzer, or preferably a multi-gas meter, should be used to verify that safe concentrations exist. The meter should be activated and remain with the technician whenever the vacuum could be broken.

As safety procedures are developed, they should be recorded in standard work permits and distributed to personnel as necessary (see Section J).

ENVIRONMENT

From a health and safety perspective, physical hazards at landfills are often considered less important than explosive characteristics of landfill gas. But physical hazards are often the source of injuries. Technicians must be trained for and ready to work in this environment.

The landfill environment features all of the hazards associated with an outdoor natural environment, coupled with those found at any large-scale construction site. Landfill Gas Technicians can face weather conditions ranging from extreme cold to extreme heat, and from

I-7 wet to dry. Insects and pests associated with natural environments, including spiders, snakes, or other animals, can also be found on landfills, and on or around gas wells and other components of the landfill gas system. Landfill Gas Technicians should carry sun block, insect repellent, and items such as those that hikers or outdoor enthusiasts use.

In addition to these items, protective clothing, sufficient water, dust protection, and vision protection must be available so that landfill personnel can complete tasks with minimal potential for injury.

Slip, Trip, and Fall Hazards

Landfill Gas Technicians must be constantly aware of where they walk while performing their tasks. Many gas collection wells are located on the landfill’s side slopes. Often, those areas have vegetated cover that may camouflage hazards on the surface, including erosion ruts, construction debris, refuse, and leachate seeps that can impede walking. Landfill Gas Technicians should wear appropriate foot wear such as sturdy hiking boots with steel toes and steel shanks. Additional site-specific equipment, such as crampons, snowshoes, or snake- repellent gaiters, may be required, depending on expected conditions.

Landfill Activities

Many injuries and deaths on landfills are associated with heavy construction and compaction equipment operating on the landfill. Much of this equipment is extremely large, and the operator may have poor visibility. The fatigue of operators who perform repetitive tasks for long periods of time is an additional danger. Landfill Gas Technicians typically constitute one of the smallest features of this environment, and are dwarfed by equipment commonly found there. Landfill Gas Technicians often work in close proximity to heavy equipment when monitoring gas collection wells near the active landfill face, or while sharing the same roads. Single-lane roads with poor visibility (blind corners, hills, etc.) are common, requiring Landfill Gas Technicians to be constantly aware of activities around them as they perform tasks.

Landfill Gas Managers must develop a traffic management plan, essentially a choreography that lets everyone know where they should be and when, for the benefit of all site workers. Equipment operators must be advised when landfill personnel are working near them, and visitors to the landfill must be adequately informed of the dangers. Landfill Gas Technicians must make an effort to remain visible to fellow workers and customers at the landfill. Wearing high-visibility lime-green or fluorescent orange safety vests (see Personal Protective Equipment, PPE) with reflective materials, and staying away from blind spots of large equipment, are recommendations to put into practice. A technician can minimize the time spent in high-traffic areas by carefully planning routes and ensuring that equipment, materials, and tools necessary to complete tasks are being personally carried, that instruments are calibrated, and that batteries (along with spares) are fully charged.

Communication with site workers, especially equipment operators, is an important component of maintaining a safe working environment. This can be accomplished by radio or by using hand signals through which the Landfill Gas Technician verifies that the equipment operator has noticed his or her presence through a confirming hand signal. A daily operations meeting is a good place to advise personnel where you will be working throughout the day.

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B. PLANNING

Employees are required to comply with safety rules and regulations applicable to their activities and conduct. Personnel must be physically able and mentally willing to comply with safety requirements. Managers should organize and plan for contingencies. Planning should include the following:

1. Designate responsibility outlined as follows (a single person may fill more than one of these roles):

a. Principal-in-Charge (engineering company principal, Public Works Director, etc.).

b. Technical/Project Director (Project Principal/Associate/Director, etc.).

c. Safety Officer/Manager (at the office) (Project Manager/Company Safety Manager, Landfill Operations Manager, etc.).

d. Site Safety Coordinator (field) (Project Engineer, Landfill Operations Supervisor, etc.).

2. Verify worker fitness for landfill work. In some situations, certain employees need to be in a medical surveillance program. Physical health examination reports, certified by a licensed and qualified occupational health physician, should state that the worker is fit to wear the required respirator (see Section L).

3. Identify the nearest hospital and emergency notification phone numbers.

4. Prepare (hospital) admissions information, prior to need, for each employee as appropriate.

The following admissions information is often required:

a. Name, address, telephone.

b. Emergency contact information - relationship, telephone, spouse (patient’s).

c. Employer - address, telephone.

d. Insurance company - name, address, telephone, policy holder, policy number.

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C. SAFETY PLANS AND PROGRAMS

A site-specific Health and Safety Plan (HASP) should be developed for each landfill site. This plan should be tailored to both the site and the situation. At a minimum, the HASP should include a site location plan with a map showing directions to the local hospital. The HASP should also provide emergency contact information, a description of responsibilities, and an organizational structure for the site. A brief overview of site work activities covered by the plan; a description of hazards, both physical (e.g., entry into excavations) and chemical (hazard assessment information); and a list of air monitoring/action levels and required PPE should be included. Proper decontamination of equipment and PPE, and disposal of contaminated materials, should be indicated. The HASP should also provide an incident report form for listing deviations or additions that were incorporated into the document, and should include a visitor’s log. The reader should consult OSHA 29 CFR 1910.120 for Site-Specific Plan requirements.

SAFETY MANAGEMENT

At a minimum, the following recommendations should be implemented:

1. Designated safety personnel should be qualified to manage compliance with requirements and safety concerns.

2. Safety procedures set forth in a site-specific HASP should be documented and reviewed with all workers prior to the start of work. The site-specific HASP is required to be maintained at the job site.

3. Scheduled health and safety meetings should be held regularly to review the safety program and the site-specific HASP.

4. Unsafe behaviors should be immediately stopped if discovered, and should be replaced by procedures that protect the health and safety of workers.

5. Required safety equipment must be maintained on site, according to the manufacturer’s recommendations, and should be checked periodically for damage, necessary repairs, and replacement and/or function.

6. If respirators are used, a written respiratory protection program will be required from each employer that describes SOPs governing selection and use of respirators, medical examination and approval, fit testing, respirator inspection, cleaning and disinfecting, repair, and storage. All employees who may be required to wear respirators will be required to be fit tested and trained in their proper use (see Section L).

7. A list containing names and phone numbers of appropriate local authorities (fire department, air quality, etc.) should be part of the site-specific HASP, a copy of which should be maintained at the job site at all times. Included in this list should be a map with directions to the nearest hospital. The site-specific HASP must be readily available to all workers at the site.

8. Contracts for landfill gas testing, construction, or operation should include a requirement that safety procedures, as set forth in the site-specific HASP and the Contractor’s health and safety plan, will be followed by all parties involved in the work.

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OSHA requires that companies develop a general health and safety plan or program (OSHA 1910.120 and OSHA 1926). Work locations such as landfills must also comply with this requirement, since field construction contractors may be working at the landfill sites (activities related to construction are discussed in Sections H and J). General health and safety programs should address the following components, as necessary and appropriate, depending on conditions and state and local laws:

1. Accident Prevention Program (General Safety).

2. Hazard Communication and “Right-to-Know.”

3. Noise Control.

4. Dust Control.

5. Respiratory Protection Program.

6. Confined Space Entry Safety Program.

7. Medical Surveillance (mandatory under certain circumstances; optional in others).

8. Safety Training Program (including hazardous materials and hazardous waste site training).

9. Personnel and Work Environment Monitoring.

10. Records Maintenance (for all of the above).

1. Accident Prevention Program

A written accident prevention program covering general safety issues is a basic building block of an overall health and safety program. The program should contain the company or organization policy, objectives of the program, and assignments of responsibility for health and safety. Availability of resources should also be addressed. Employee training sessions and routine “tailgate” safety meetings are advisable and, in some instances, required.

2. Hazard Communication and “Right-to-Know” Standards

OSHA’s Hazard Communication Standard does not apply to landfill gas, since hazardous chemicals in the gas are not “used” by the operator. However, principles of the standard will serve the best interests of the landfill owner/operator, the landfill gas developer, or the consultant. Hazard communication programs provide a good start for properly informing personnel of the dangers to which they may be exposed. The Hazard Communication Standard does apply to chemicals used in construction and recovery system operation and maintenance activities. The Federal Hazard Communication Standard is covered in 29 CFR Part 1910.1200.

If personnel perform such tasks as constructing or repairing and maintaining PVC landfill gas collection systems, and therefore work with PVC primer and cement, work with these materials is covered under requirements of Hazard Communication and “Right-to-Know” statutes. Material Safety Data Sheets (MSDSs) must be maintained and personnel trained in their use. MSDSs may also be required at landfill gas recovery plants where water treatment or other types of chemicals are a part of the operation.

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Information regarding the constituents of landfill gas (vinyl chloride, methylene chloride, benzene, or toluene) should be included in such programs. It may be impractical to attempt to identify all of these chemicals; only those of special significance, or those found in high enough concentrations to be of concern, should be addressed in detail. For municipal sites, such an approach, while not required by law, would be prudent.

3. Noise Control

Where high levels of noise are present (when, for example, a coworker cannot be heard while speaking in a normal volume from a distance of 3 feet for prolonged periods), a noise control program is typically required. Appropriate use of hearing protection, either ear plugs or ear muffs, or both, should be enforced. OSHA’s Noise Control Standard is covered in 29 CFR Part 1910.95.

4. Dust Control

Typical dust control or mitigation practices require the regular use of a water truck or some other means of dust suppression. Where high levels of dust and particulates may be generated from excavation, drilling, or earthmoving operations, a dust control program, sometimes including fugitive dust monitoring and sampling, is typically required.

5. Respiratory Protection Program

Respiratory protection programs should accomplish the following tasks: a. Hazard identification and assessment. b. Written standard operating procedures. c. Employee training. d. Periodic medical assessment of employees and approval for respirator fitting and use. e. Appropriate respirator selection for a specific job. f. Proper qualitative fitting of respirators to personnel. g. Maintenance and storage of respiratory protection equipment. h. Periodic reevaluation of the program.

Persons involved in the administration of a respiratory protection program should be thoroughly familiar with the Protection Factor (PF) of Air-Purifying Respirators (APRs) used, the Maximum Use Concentration (MUC) of the APRs, determination of the Maximum Use Limitation (MUL) of a respirator, Permissible Exposure Limits (PELs), Threshold Limit Values (TLVs), levels Immediately Dangerous to Life and Health (IDLHs), and other concepts such as warning properties and respirator filter breakthrough. Note that APRs are not permitted for landfill gas work because of inadequate warning properties. Supplied-air respirators are typically used at landfills unless stringent, reliable monitoring for hydrogen sulfide, methane, and carbon dioxide is continuously performed in the breathing zone.

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Specific regulatory requirements for respiratory protection are delineated in CFR 29, Part 1910.134, for general industry, and 29 CFR 1926.103 for the construction industry. Relevant health standards include:

 Federal OSHA PELs, which are legal standards; these are found in 29 CFR 1910.1000, Subpart Z.

 State-published PELs, which often adopt the American Conference of Governmental Industrial Hygienists (ACGIH) TLVs; these standards are usually lower (more stringent) than PELs.

 The current annual edition of "Threshold Limit Values and Biological Exposure Indices," published by the ACGIH. This document contains the often-cited Threshold Limit Value/Time-Weighted-Average (TLV-TWA), Threshold Limit Value/Short-Term Exposure Limit (TLV-STEL), and Ceiling (C) exposure limits.

 National Institute of Occupational Safety and Health (NIOSH) Recommended Exposure Limits (RELs), found in the "NIOSH Pocket Guide to Chemical Hazards" (2005), which is available from the U.S. Government Printing Office and may be downloaded from the NIOSH website at www.cdc.gov/niosh/npg/default.html.

Note that these sources address different lists of chemicals and have different limits for the chemicals that they do address.

Hierarchy of Protection (Engineering Controls)

It is a basic tenet of occupational health that employers must first use whatever engineering controls are available to reduce hazards. If, after instituting controls, conditions still warrant respiratory protection, such protection must be implemented. At an operating landfill, the vacuum system is the primary engineering control. Another example would be application of water spray to prevent fugitive dust emissions.

Medical Assessment for Respirator Use--

Individuals who may be required to use a respirator must see a qualified physician to undergo an occupational physical assessment for proposed respirator use. This is a legal requirement. A physician who is Board-certified in Occupational Health is recommended. There are numerous medical issues that must be addressed by a qualified medical professional, such as diabetes, cardiovascular problems, and the like, which are not readily apparent to the untrained individual.

Respirator Fit Testing--

Respirator fit testing is performed after approval by a qualified physician. Fit testing is intended to verify the seal of a particular brand of respirator to an individual’s face, to demonstrate respirator effectiveness, to instill confidence in respiratory performance, and to allow the individual being tested to experience the physical limitations imposed by the respirator.

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6. Confined Space Entry Program

Many spaces present at landfills, such as manholes or pump stations, may be “confined.” A confined space is defined by OSHA 29 CFR 1910.146 as a space that is large enough and so configured that an employee can bodily enter and perform work; confined space also has limited or restricted means for entry or exit, and is not designed for continuous employee occupancy.

The OSHA Construction Standard 29 CFR 1926.31 defines a confined space as any space that has a limited means of egress, which is subject to the accumulation of toxic or flammable contaminants, or has an oxygen-deficient atmosphere.

Facilities with confined spaces are required by 29 CFR 1910.146 to have a confined space entry program that includes training and written safety procedures for each defined confined space at the facility. Employees that work in or around confined spaces should receive appropriate training, and be familiar with and comply with the facility’s confined space entry program.

During any confined space entry, these general guidelines should be followed:

 Do not enter a confined space until the safety precautions described in the entry permit have been taken. If there is no permit yet, you are not ready to enter.

 Safety precautions that should be observed prior to the start of permit-required confined space work include, but are not limited to, the following:

 Posting a properly completed and approved confined space entry permit outside the confined space.

 Closing and placing locks or tags on any system that may affect the safety of personnel in or around the confined space, such as electrical lines, steam pipes, or pipes containing toxic chemicals.

 Conducting atmospheric monitoring to ensure that the atmosphere inside the confined space does not contain hazardous or explosive gases, and that there is adequate oxygen.

 Ensuring that procedures and equipment for responding to emergencies, such as evacuating personnel or responding to fires, are in place. These include, but are not limited to:

 Posting standby personnel outside the space.

 Posting emergency phone numbers and points of contact in highly visible locations by site telephones.

Equipment required for an emergency can include:

 SCBAs.  Tripod-mounted emergency hoists.  Safety harnesses and lifelines.  Fire extinguishers.

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7. Medical Surveillance

In addition to medical approval for use of respiratory protection equipment, baseline physicals and medical surveillance may be required for work under special circumstances. If exposure to concentrations of specific toxic chemicals such as benzene, vinyl chloride, and asbestos is above action levels, medical surveillance is required by law. Technicians who routinely work directly with landfill gas at municipal landfills should receive routine medical examinations. 29 CFR Part 1910.20 governs access to employee exposure medical records.

8. Safety Training Program

A basic safety training program is usually provided to serve the following functions: a. Teach and inform employees about basic safety concerns. b. Address job-specific hazards likely to be encountered. c. Fulfill certain legal notification and training requirements. d. Heighten employee awareness.

9. Personnel and Work Environment Monitoring

Consistent with the “general duty clause” in the OSHA statute, an employer must monitor employees and/or the work environment whenever a risk for employee exposure is known or can be suspected. Requirements for personnel or work environment monitoring are dependent on the type of work being performed and specific site conditions. Monitoring may or may not be appropriate, depending on the situation, and whether or not it is specifically required by federal, state, or local regulations. Unless it can be demonstrated that monitoring is not required, monitoring should be performed at all times. Air monitoring should be conducted when excavating in refuse or repairing leachate or condensate piping. Consideration should be given to the fact that landfills are subject to changing conditions.

Typically in industrial processes, contaminants or substances that may cause health threats are known and monitoring is straightforward. For certain specific substances of concern, action levels at and above which monitoring must take place are specified by regulation (example: the action level for vinyl chloride is 0.5 parts per million, or ppm). The action level for a given substance is typically set at one half the TLV or OSHA PEL, but may be specified otherwise by regulation. When it is necessary to monitor work on waste sites, more complex issues may be encountered. A thorough site characterization is necessary at the outset of site work for the safety of personnel who will engage in field monitoring, construction, engineering, or landfill gas recovery activities. The monitoring or sampling plan may need to be modified or adjusted, based on findings.

Monitoring or sampling techniques should involve the use of a combustible gas analyzer (CGA), an organic vapor analyzer-flame ionization detector (OVA-FID), and a photo ionization detector (OVA-PID) to monitor total gas concentration in air and estimate the percentage of trace contaminants, based on analytical data. In general, FID instruments, which react too strongly to methane, provide less useful information about toxic vapors, which methane can “mask.” A monitoring or sampling plan should demonstrate an approach with a justifiable rationale, and

I-15 should be scrutinized for statistical validity. The necessity for such monitoring or additional sampling should be determined by an experienced and qualified professional who can evaluate the types of hazards and risks present, and the extent of exposure for the work to be performed. Note: CGA and FID instruments require a minimum of 15 percent oxygen to function correctly.

10. Records Maintenance

Accurate, reproducible, and verifiable records are essential for an effective overall health and safety program. They also provide protection against liability, and preclude situations where compliance cannot be demonstrated. Records should include medical assessment and respirator use approvals, certification of respirator fit test, respirator eyeglass insert information, respirator maintenance records, exposure monitoring data, gas characterization information, etc.

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D. HAZARD ASSESSMENT AND IDENTIFICATION

Identification of hazards to be protected against is a necessary step in the implementation of respiratory and bodily protection. Extreme caution is warranted in dealing with situations where landfill gas is detected within the explosive range, or high concentrations of hydrogen sulfide are present. Other kinds of special hazards are listed in Section H, “Safety Procedures for Well Drilling and Construction.”

A Job Safety Analysis (also known as a Job Task Safety Analysis or Activity Hazard Analysis) is used to identify physical and chemical hazards, appropriate PPE, and safeguards to prevent exposure and injuries from identified hazards. The Job Safety Analysis involves the following elements:

 The steps involved in performing a specific job task.

 The existing or potential safety and health hazards associated with each step of the task.

 The recommended safeguards, action(s), and PPE that will eliminate or reduce the hazards and minimize the risk of occurrence of a workplace injury or illness.

(For guidance on conducting Job Safety Analysis, see OSHA Publication 3071 - Job Hazard Analysis - 2002, http://www.osha.gov/Publications/osha3071.html)

In the case of landfill gas, hazard assessment and identification should include site-specific characterization of the gas. Initial characterization may be performed by gas chromatograph/mass spectrometer. Once chemicals are qualitatively identified, more specific quantitative data should be obtained using a more specific analytical detector for the classes of chemicals in question. The analytical method selected should be capable, at a minimum, of identifying compounds of concern at concentration levels at or below any action levels set for those compounds (i.e., one half the TLV or PEL).

At a minimum, hazard assessment should include characterization of hydrogen sulfide in the landfill gas. H2S has been observed at landfills with large amounts of construction debris (especially gypsum board wastes) at levels exceeding 1,000 ppm, which is well above the IDLH value of 100 ppm for H2S.

Identification of contaminants in landfill gas may be difficult due to the heterogeneous nature of landfills and the dynamic nature of biological decomposition occurring there. Hence, landfill gas composition varies from site to site, as well as throughout a site. An appropriate initial characterization, however, can predict chemicals that are present and their relative concentrations. When characterization is performed, care must be exercised in interpreting results, taking into account the specific limitations of the collection and the analytical methods and hardware used.

In addition to primary landfill gas constituents (CH4, O2, N2, and CO2), trace contaminants are present in landfill gas. There are hundreds to thousands of trace contaminants, most of which are at such low levels that it is impractical to identify all of them. Accuracy and sensitivity to a given class of chemicals will vary, depending on the analytical methods and hardware used. Chemicals that have received the most regulatory scrutiny are volatile priority pollutants. These,

I-17 generally, are the aliphatic, aromatic, cyclical, and chlorinated hydrocarbons. Other classes of chemicals may also be present in landfill gas, in gas condensate from various phases of a recovery process, and in leachate. They may include organic and inorganic acids and bases, sulfur compounds, metals, and metal hydrides.

The following priority pollutants may be found in landfill gas:

Chemical Formula Exposure Limits (PEL, TLV, IDLH1)

Hydrogen Sulfide H2S PEL = 20 ppm (Ceiling - 1971) TLV = 1 ppm (8-hr TWA2, 5 ppm (STEL3) IDLH = 100 ppm

Methyl Mercaptan CH3SH PEL = 0.5 ppm (8-hr TWA), 10 ppm (ceiling) TLV = 0.5 ppm (8-hr TWA) IDLH = 150 ppm

Benzene C6H6 PEL = 1 ppm (8-hr TWA), 5 ppm (STEL) TLV = 0.5 ppm (8-hr TWA), 2.5 ppm (STEL) IDLH = 500 ppm

Chloroethene (Vinyl CH2:CHCl PEL = 1 ppm (8-hr TWA), 5 ppm (STEL) Chloride) TLV = 1 ppm (8-hr TWA)

1,2-Dibromoethane BrCH2CH2Br PEL = 20 ppm (8-hr TWA), 30 ppm (ceiling), (Ethylene Dibromide) 50 ppm (maximum peak above ceiling for 5-minute period in 8 hrs) TLV = A3 carcinogen IDLH= 100 ppm

1,2-Dichloroethane ClCH2CH2Cl PEL = 50 ppm (8-hr TWA), 100 ppm (ceiling), (Ethylene Dichloride) 200 ppm (maximum peak above ceiling for 5-minute period in any 3 hrs) TLV = 10 ppm (8-hr TWA) IDLH = 50 ppm

Dichloromethane CH2Cl PEL = 25 ppm (8-hr TWA), 125 ppm (STEL) (Methylene Chloride) TLV = 50 ppm (8-hr TWA) IDLH = 2,300 ppm

Tetrachloroethylene Cl2C:CCl2 PEL = 100 ppm (8-hr TWA), 200 ppm (ceiling), (Perchloroethylene) 300 ppm (maximum peak above ceiling for 5-minute period in any 3 hrs) TLV = 25 ppm (8-hr TWA), 100 ppm (STEL) IDLH = 150 ppm

Tetrachloromethane CCl4 PEL = 10 ppm (8-hr TWA), 25 ppm (ceiling), (Carbon Tetrachloride) 200 ppm (maximum peak above ceiling for 5- minute period in any 3 hrs)

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Chemical Formula Exposure Limits (PEL, TLV, IDLH1)

TLV = 5 ppm (8-hr TWA), 10 ppm (STEL) IDLH = 200 ppm

1,1,1-Trichloroethane CH3CCl3 PEL = 350 ppm (8-hr TWA) (Methyl Chloroform) TLV = 350 (8-hr TWA), 450 ppm (STEL) IDLH = 700 ppm

Trichloroethylene HClC:CCl2 PEL = 100 ppm (8-hr TWA), 200 ppm (ceiling), 300 ppm (maximum peak above ceiling for 5-minute period in any 2 hrs) TLV = 10 ppm (8-hr TWA), 25 ppm (STEL) IDLH = 1,000 ppm

Trichloromethane CHCl3 PEL = 50 ppm (ceiling) (Chloroform) TLV = 10 ppm (8-hr TWA) IDLH = 500 ppm

1 PEL = Occupational Health and Safety Administration (OSHA) Permissible Exposure Limit, TLV = American Conference of Industrial Hygienists (ACGIH) Threshold Limit Values (guideline), IDLH = Immediately Dangerous to Life and Health based on NIOSH Revised Guidelines. 2 8-hr TWA = Time weighted average for an 8-hr exposure period. 3 STEL = 15-minute Short-term Exposure Limit.

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E. SAFETY EQUIPMENT

Employees at landfill gas sites often perform tasks that require equipment to protect them from chemical and physical hazards that may be encountered. OSHA requires that employers issue such equipment after they assess the nature and extent of potential chemical and physical hazards associated with the work. Regarding the assessment, this section provides guidance to employers whose personnel may be exposed to landfill gas.

Any worker engaged in operating landfill gas facilities should wear the protective safety equipment required on typical industrial or construction work sites, including items listed below. These items are subject to OSHA regulations. Table E-1 (below) shows OSHA standards related to the use of PPE. The relevant national consensus standards are provided in Table K-1 (see Section K):

1. Full-length trousers are recommended.

2. Shirts with sleeves are recommended (short-sleeve shirts are acceptable). Do not use synthetic fabrics, unless they are flame-retardant.

3. ANSI-approved steel-toe and shank footwear are recommended:

a. Safety footwear should cover the ankle and have sturdy tread appropriate for outdoor use and a defined heel.

4. Hardhat:

a. Employees should wear ANSI-approved hard hats during field activities, unless they know there are no potential overhead hazards.

5. ANSI-approved high-visibility vests are recommended.

6. Safety glasses with side shields:

a. Employees should wear safety glasses during field activities, unless they know there are no potential hazards to the eye.

b. Contact lenses may be used in most situations, provided appropriate eye protection such as safety eyewear is also used.

Workers engaged in construction or maintenance of landfill gas facilities should wear the protective safety equipment listed above, plus:

1. Protective gloves:

a. Chemically protective gloves are mandatory while working with wet solid waste or where exposure to leachate or condensate is possible.

b. Glove material should be impermeable to expected contaminants.

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c. Selection of protective materials is dependent on the potential hazards present, and should be based on performance data and recommendations provided by material manufacturers.

d. Because some people can be allergic to rubber products, be prepared to offer alternatives to natural rubber gloves.

2. Hearing protection, depending on noise levels in the work environment:

a. A Hearing Conservation Program should be implemented.

Other protective equipment may include:

1. Chemically protective overalls (Saranex, Tyvek, etc.):

a. In selecting overalls, consideration should be given to such factors as size, durability, chemical compatibility, and heat stress potential.

b. Appropriate sizes of protective garments for large and small individuals should be provided.

2. Steel-toe and shank neoprene boots.

3. Chemically protective gloves (e.g., Viton, neoprene, nitrile).

4. Respiratory protection appropriate to the level of hazard (see Section L and Section C, Item 5).

5. Self-Contained Breathing Apparatus (SCBA), fitted with a pressure-demand type regulator and a 30-minute (minimum) bottle or supplied air system. (This equipment is needed if the concentration of contaminants can change rapidly in the workspace, or if methane, carbon dioxide, or hydrogen sulfide is present at concentrations above action levels, as defined in the HASP.)

The following equipment should be available at the job site in quantities sufficient to cover all anticipated activities:

1. Clean water, soap, and paper towels.

2. First aid kit, eye wash station, stretcher, and blanket.

3. Two fire extinguishers: 20:A-80:BC.

4. “No Smoking” signs. (These are necessary where employees unfamiliar with the operation of landfill gas systems may be present.)

5. For confined space entry equipment requirements, see Section I.

6. Combustible Gas Analyzer (CGA) with oxygen indicator. (As described in Section K, this equipment is operated continuously whenever landfill gas is potentially present in the workspace. Note that the concentration of oxygen must be checked first, since most CGAs

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will not provide a proper reading of combustible gas concentrations in an oxygen-deficient atmosphere.)

7. Hydrogen sulfide indicator. (Hydrogen sulfide may be measured on the same multi-gas tester as combustible gas and oxygen levels. As described in Section K, this instrument should be operated continuously whenever there is a potential for landfill gas to enter the workspace.).

8. Additional monitoring equipment for toxic vapors and aerosols.

9. Barricades and/or barrier tape. (This equipment is necessary where employees unfamiliar with the operation of landfill gas systems may be present.)

10. Covers for excavations that will remain open at the end of the day.

11. Air-moving equipment that can provide ventilation if employees are working in environments with substandard air (trenches, condensate drain pits, etc.).

12. Fire-resistant blanket suitable for extinguishing a small fire or for maintaining body heat of personnel in shock.

13. Construction equipment equipped with vertical exhaust or spark arrestors if located within 2 feet of grade.

14. Flagging, traffic markers, and high-visibility safety vests for use when working around operating equipment or near public roadways.

Employees should utilize protective equipment required by the HASP. Safety items must be inspected before use. Items that contact the body must be cleaned and sanitized, as appropriate, before other employees can use them. Defective or damaged PPE must be taken out of service immediately.

Table E-1 shows OSHA standards related to the use of PPE.

TABLE E-1

OSHA STANDARDS FOR THE USE OF PERSONAL PROTECTIVE EQUIPMENT

Type of Protection Regulation Source

General 29 CFR 1910.132 41 CFR, Part 50-204.7 - General Requirements for Personal Protective Equipment

29 CFR 1910.1000-1045 OSHA Rulemaking

Eye and Face 29 CFR 1910.133(a) ANSI Z87.1 - Eye and Face Protection1

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TABLE E-1

OSHA STANDARDS FOR THE USE OF PERSONAL PROTECTIVE EQUIPMENT

Type of Protection Regulation Source

Noise Exposure 29 CFR 1910.95 41 CFR 50-204.10 and OSHA Rulemaking

Respiratory 29 CFR 1910.134 ANSI Z88.2 - Standard Practice for Respiratory Protection Head 29 CFR 1910.135 ANSI Z89.1 - Safety Requirements for Industrial Head Protection

Foot 29 CFR 1910.136 ASTM F2413-05 - Standard for Foot Protection

Electrical Protective 29 CFR1910.335(a)(2) NFPA 70E - Standard for Electrical Devices Safety in the Workplace

High-Visibility Safety 29 CFR 1926.651(d) ANSI/ISEA 107-2004 - National Apparel Standard for High-Visibility Safety Apparel

1 American National Standards Institute (ANSI), 1430 Broadway, New York, NY 10018.

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F. PERSONAL HEALTH AND HYGIENE

1. Ensuring personal safety and the safety of fellow workers requires that employees remain mentally alert at all times. No alcohol or drugs are permitted. Smoking should be prohibited on the landfill site. No worker should handle excavated solid waste without wearing chemically protective gloves. Parts of the body accidentally exposed to waste, leachate, or condensate should be washed immediately with soap and water. Eating meals on the landfill should be prohibited, and washing of hands prior to eating should be required.

2. Any cut or abrasion that occurs on the landfill should be examined and/or treated immediately by a physician or other licensed health care professional, because the chance of incurring infection while working in this environment is high. A tetanus shot may be recommended for personnel involved in site construction and/or testing activities. Any person who makes contact with fresh waste has a potential to contact bloodborne pathogens. It is recommended these persons participate in a bloodborne pathogen program. Employers should consult medical professionals to determine if hepatitis B immunizations are appropriate.

3. Workers should avoid contact with hazardous plants, or those known or suspected to be hazardous, growing on the landfill.

4. Animals, snakes, spiders, and insects should be avoided. First aid supplies should be maintained and placed in a location readily available to personnel. If unusual flora or fauna are expected, they should be characterized and identified as potential hazards in the site- specific HASP. Note: Expect to find such creatures whenever you open a closed space, such as well casings or portable toilets. Antidotes and/or medication should be maintained for persons with severe allergies.

5. The address, telephone number, and map to the nearest hospital and medical emergency room should be prominently posted. In addition, the telephone number of an ambulance and fire department/rescue unit should be prominently posted and maintained in the site- specific HASP.

6. Workers should wash hands prior to eating, drinking, smoking, or changing clothes.

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G. LANDFILL GAS-RELATED SAFETY PROCEDURES

1. As a general safety rule, work with landfill gas should be performed by a team consisting of a minimum of two people. In situations where hazards are minimal, and where it is necessary to allow an individual to work alone, another responsible person must be aware of the solitary worker’s tasks and scheduled time of completion and return, and, if possible monitor that individual’s progress.

2. When working on (or within 1,000 feet of) an active or completed solid waste landfilled area, workers should be alert to the existence of (or potential for the presence of) landfill gas. Some authorities assume 1,000 feet is the maximum distance that landfill gas will migrate through soil under average conditions. Migration distance, however, may be greater through underground conduits (such as the gravel pack around a leachate pipeline or fractured bedrock), in favorable subsurface soil conditions, or where surface conditions interfere with normal surface venting.

Hazards could be one or more of the following:

a. Spontaneous fires caused by exposed and/or decomposing waste.

b. Fires and explosions in confined or enclosed spaces caused by an accumulation of landfill gas.

c. Oxygen deficiency in topographically low areas, underground trenches, vaults, conduits, and structures because air in these locations was displaced by landfill gas.

d. Other potentially toxic, flammable, or hazardous gases that may be present as constituents of landfill gas, including, but not limited to, hydrogen sulfide (H2S), hydrogen (H2), and other volatile organic compounds (VOCs).

e. Sudden subsidence or collapse of the landfill surface caused by the collapse of subsurface voids, which may be formed by decomposition, poor compaction, or subsurface landfill fires.

3. Confined spaces may be present at landfills (see Confined Space Entry Safety Program in Section C, Item 6).

4. Flammable conditions may be present at landfills. It is not recommended to work where flammable gas levels are above 10 percent of the lower explosive limit (LEL) due to the potential for fire or explosion.

5. Oxygen levels between 19.5 and 23.5 percent are considered acceptable conditions for working. Oxygen concentrations below or above these limits are not acceptable.

6. The Resource Conservation and Recovery Act (RCRA) (40 CFR, Part 257.3-8, Safety) places a limit of 25 percent of the LEL (1.25 percent methane) on the maximum allowable methane concentration in landfill facility structures on or near landfills. OSHA regulations related to flammable or combustible environments may place a more stringent requirement on the maximum concentration allowed in a work environment (i.e., an occupied structure that is not private and residential).

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7. The flammable range (LEL to UEL) for methane is approximately 5 to 15 percent in air at sea level at 25°C. As little as 0.3 millijoule of static electricity is sufficient to cause methane ignition. This is about 1/50th the amount of static electricity accumulated by a person walking across a carpeted floor on a dry day. The specific (vapor) density of methane is 0.6 that of air; in contrast, the specific density of undiluted landfill gas is normally about 1.0 (close to that of air, depending on constituent concentrations). Personnel should not, therefore, automatically assume that because landfill gas contains methane, the mixture is lighter than air and will rise. The behavior of landfill gas varies with its constituent makeup, which also varies.

8. Prior to the entry of workers into an excavation, vault, or below-grade ditch, and routinely during intrusive work into waste, the atmosphere should be tested for explosive conditions, oxygen deficiency, and H2S levels. Air blowers or fans should be available for positive ventilation. APRs with chemical cartridges may be used for gaseous contaminants (but not for hydrogen sulfide, methane, or carbon dioxide) if ALL of the following conditions are met:

a. The oxygen concentration is satisfactory. b. The chemical contaminants have been identified. c. The concentrations have been monitored. d. The cartridges are effective in removing the contaminants. e. All contaminants have good warning properties, or the employer has developed a process of evaluating cartridge service life.

Mechanical filter respirators should be used only for protection against the particulate matter for which they are rated.

A pressure-demand SCBA or supplied air respirator must be used when entering all other areas containing hazardous and/or oxygen-deficient atmospheres.

9. Fires and explosions always require a source of ignition. Smoking should be strictly forbidden anywhere on landfills and surrounding properties and buildings. Non-sparking and/or explosion-proof tools should be used in vaults, trenches, and other enclosed areas. Positive ventilation is required in construction shacks or other temporary or permanent structures on or near a landfill. Temporary structures on the landfill surface should be constructed on blocks or other supports, with a ventilated area under the main floor. Construction equipment should be equipped with a vertical exhaust at least 5 feet above grade and/or with spark arrestors. Other potential ignition sources include cell phones, two-way radios, flashlights, digital cameras, and other powered equipment.

10. Hydrogen sulfide gas is usually present at some concentration, generally below 100 ppm (NIOSH IDLH concentration), in landfill gas. Very high (lethal) concentrations of H2S may be produced where natural or manmade gypsum occurs (including construction debris containing wallboard concentrated in one location), and can interact with high levels of moisture. Dangerous and unexpected pockets of H2S gas may therefore be encountered (Table I-1 lists the physiological responses to this chemical). Personnel must be trained for, and remain alert to, these possibilities.

Given that concentrations of H2S at a landfill can be variable or unknown, APRs are never acceptable in the case of H2S. In situations when high concentrations of H2S are known or suspected, pressure-demand SCBA or supplied air respirators should be used.

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H. SAFETY PROCEDURES FOR WELL DRILLING AND CONSTRUCTION

1. One person representing the landfill owner should be present at all times during construction. That individual will have the responsibility of observing safety procedures, and will be trained in the use of all recommended safety equipment.

2. Smoking should be strictly forbidden anywhere on the landfill.

3. Fire extinguishers should be on hand during drilling (two 20:A-80:BC fire extinguishers are recommended). The drilling crew should be alert to the potential for drill tools to spark against rock or metal, causing fire in or at the top of the bore hole. Landfill gas will typically burn almost invisibly under such circumstances. Fires should be extinguished by covering the boring with soil, using earthmoving equipment. As a contingency before drilling, arrangements should be made to have a loader or equivalent equipment available or on call in case of a borehole fire, along with excess soil that can be used to cover the borehole if a fire should break out.

4. Field personnel should stay away from the edge of any borehole that is 14 inches in diameter or greater until it is fully completed. Due to the typically oxygen-deficient environment “down hole,” an individual who falls into an open borehole, even a short distance, would likely not survive. Workers required to work within 5 feet of the edge of the borehole need to be protected from falling into the opening either by a safety grate, guard rail, tether, or more than one means. Federal fall protection standards should be enforced. It should be determined beforehand under what circumstances individuals working in the vicinity of drilling activities will need to be tethered to a fixed object.

5. No worker should be allowed to work alone at any time near the edge of the well under construction. At least one other worker must be present beyond areas considered to be subject to the possible effects of landfill gas or cave-in. The number of persons working near the borehole should also be limited to the number necessary to accomplish the task, though there should always be sufficient workers present nearby to remove an injured worker or to summon help if it is safe for others to enter the area where the injured worker is located. If the situation appears unsafe, help should be summoned and appropriate measures (PPE, proper tie-downs, etc.) taken before other workers enter the area where an injured worker is located.

6. During drilling, special consideration must be given to the strength of the refuse surrounding the borehole. Refuse may be prone to instability that may cause side wall failure of a borehole at any time. Individuals present at the time of failure could be drawn into an oxygen-deficient environment or buried.

At all times, personnel performing drilling work must remain alert to changing subsurface conditions and signs of impending physical failure, including fissures or cracks on the ground that indicate a failure might occur. It is not uncommon to experience a “hollowing out” effect, which creates a cavity at depths much larger than the boring due to side wall failure “down hole.” This could cause a sudden collapse to happen at the surface. It should be remembered that the drill rig usually exerts a large, vibratory force at the surface in the vicinity of a boring, which may exacerbate borehole wall failure.

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7. Drilling personnel must also remain alert to the potential for encountering subsurface hazards, particularly in older landfills where screening of materials may have been less controlled. Although rare, a variety of hazardous situations have been encountered during drilling in landfills, especially near military or chemical processing facilities. Potential hazards include:

a. Unknown hazardous chemicals in drums or containers. These could contain combustible or explosive, reactive, toxic, or corrosive materials.

b. Military munitions.

c. Asbestos.

d. Compressed gas cylinders (CGCs).

e. Biomedical waste.

f. Radioactive waste.

8. Periodically during well construction, the work area should be monitored for concentrations of methane and hydrogen sulfide. Continuous monitoring is better. Toxic organic compounds may be present and may include vinyl chloride, benzene, and other chemicals that are known to exist within landfills (see Section K).

9. If well construction is not completed by the end of the workday, the hole must be covered with a plate or cover of sufficient size to prevent access to the hole, and must be of sufficient thickness and structural strength to support expected loads. The plate or cover should be placed so that it cannot be removed by persons not authorized to remove the cover. The edges of the cover must be covered with a sufficient quantity of soil to limit the amount of gas escaping. Barricades with caution tape should be placed around the covered hole outside the range of possible cave-ins to prevent unauthorized persons from entering the area.

10. All pipes should be capped at the end of each working day.

11. An exhaust hood can be used to control venting of landfill gas vapors while drilling, to the limit exposure of personnel and the environment to hazards. This is mandatory in some locales.

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I. SAFETY PROCEDURES FOR EXCAVATION, TRENCHING, AND PIPE INSTALLATION

Employees involved in landfill gas operations are likely to work in or around excavations, and are exposed to hazards similar to those faced by construction personnel. Employees should learn to recognize these hazards and to avoid situations that put them, other employees, and contractors at risk. At a minimum, employees and contractors are required to operate in compliance with the trenching and shoring requirements described in OSHA 29 CFR 1926. Employees should be aware of the following safe excavation work practices:

1. Pre-excavation activities:

a. Before excavation, the location of any underground utilities, such as gas, sewer, electricity, and telephone lines, should be determined and marked. In public areas, most states require that operators contact the state’s utility location service. Calling 811 from any location in the USA will connect to the utility location service. On private property, each owner must determine the location of its underground utilities. It may be necessary to use non-intrusive subsurface investigation techniques to identify underground utilities and installations.

b. Excavations should be conducted under the direction of a competent person. OSHA defines “competent person” as an individual who has sufficient training and experience to be able to recognize hazards, and the authority to take corrective action. The competent person should be located on site and:

i. Perform inspections prior to the start of each shift, and as needed throughout the shift, to ensure safe operation.

ii. Remove employees from hazardous areas when there is evidence of possible cave- in.

iii. Identify and correct hazards associated with excavation.

c. Operators may choose to require a permit before excavation occurs. State regulations should be investigated, as standards and requirements vary.

d. Surface encumbrances (buildings, utility poles, pavement, or other structures that may be undermined by excavation) that have the potential to create hazards for employees or to become subject to physical damage must be removed, supported, or neutralized, as necessary, prior to the start of excavation work.

e. The competent person must evaluate soil conditions and determine the shoring or sloping requirements for the trench or excavation, based on soil evaluation:

i. If no attempt is made to determine soil type, excavations must be sloped at an angle not steeper than 1.5 (horizontal) to 1 (vertical) (34 degrees); otherwise, a trench box or other protective system must be used.

ii. For excavations greater than 20 feet (6 m) deep, sloping and/or shoring requirements and systems must be designed by a professional engineer licensed to practice in the state where the work is being performed.

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iii. Smoking is prohibited within 50 feet of trenching and piping. Prohibition of smoking on the entire landfill is recommended.

2. During excavation:

General

a. Do not stand under a live load, including the load of an excavator bucket.

b. No material, including trench spoil, may be stored within 2 feet of the edge of an excavation.

c. Avoid polluting water bodies by placing spoil piles away from the water and preventing the accumulation of spoils on slopes.

d. Remove standing water using pumps, and continuously monitor the water level and pump operation.

e. Place environmentally impacted soils on plastic liners, and cover spoil piles with plastic to prevent further spreading of contamination. Liners and covers should be durable enough for the intended period of storage.

Equipment

a. Unless special precautions are implemented, keep heavy equipment, tools, and individuals more than 10 feet from any power line or exposed electrical distribution component. For lines rated above 30 kilovolts, follow the table in Table A of OSHA Standard 29 CFR 1409.

b. Construction equipment should have a vertical exhaust at least 5 feet above grade and/or spark arrestors.

c. All excavations that are 4 feet deep or deeper must have a ladder for access into the excavation, with no more than 25 feet of lateral travel in any direction. The ladder must extend beyond the top of the excavation by at least 3 feet.

d. When mobile equipment is working near an excavation, and the operator cannot see the edge of the excavation well, a warning system, such as barricades, hand or mechanical signals, or stop logs, should be utilized.

e. Tools, equipment, or heavy machinery should not be placed where they may affect the structural stability of the excavation or can fall into it.

f. If possible, excavations should not be left open when unattended. If an excavation must be kept open, proper covers, fencing, and security should be provided to prevent access to the excavation during non-working hours.

g. Personnel should stand away from vehicles being loaded or unloaded to avoid being struck by spillage or falling materials.

h. The swing radius of excavation equipment should be completely avoided.

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Air Contaminants

a. Monitor air quality during excavation activities at landfill sites. Use forced ventilation, if needed (contaminants of concern and acceptable entry conditions are described in Section K).

b. Provide forced-air ventilation, if needed, to keep concentrations of contaminants of concern below acceptable levels, as described in Section K, Field Sampling for Health and Safety. Calculations of required volumes should be performed by a competent person.

Excavation Collapse

a. The competent person on site must evaluate soil conditions and stability as new soil layers are encountered.

b. The competent person must also inspect the trench or excavation daily before any work occurs in trenches or excavations.

c. All excavations must be barricaded with appropriate barrier tape and other protective devices to protect against falls or other inadvertent entry.

d. All excavations that are 5 feet deep or deeper, and excavations shallower than 5 feet in unstable soil, must be sloped, braced, or shored to prevent cave-ins.

3. Regarding work outside, but in support of, excavation:

a. No worker should work alone, at any time, in or near the excavation. Another worker must be stationed beyond the area considered to be subject to the possible effects of landfill gas. A sufficient number of personnel should always be present to remove an injured or endangered worker and to summon help.

b. No worker may handle excavated solid waste without wearing appropriate work gloves and clothing, selected in accordance with Section E, Safety Equipment.

c. Electrical and electronic equipment used in or near landfill excavations should be explosion-proof or intrinsically safe, and should meet requirements for Class I, Division 1, Group D, in accordance with the National Electric Code (NEC).

d. No welding is permitted in, on, or immediately near the excavation area, unless the on- site competent person determines that methane and other combustible gases are not present in high enough concentrations to be hazardous. Some sites may require a “hot permit” to perform this work.

e. Solvent cleaning, gluing, or bonding of pipe should be performed, to the extent possible, outside the trench. Use of organic vapor respirators and appropriate gloves is recommended for employees who use PVC solvents or cements. Personnel using solvent and cement must be familiar with the appropriate Materials Safety Data Sheets (MSDS) for those products.

I-31 f. As construction progresses, all valves should be closed as installed, to prevent migration of gases through the pipeline and gas collection system. g. All installed pipe, and staged fused sections longer than 40 feet, must be capped when no employees are present, particularly at the end of each workday.

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J. GENERAL CONSTRUCTION/MAINTENANCE

1. When drilling holes through pipe that contains landfill gas under positive pressure, or with methane in excess of the LEL, only explosion-proof electric, compressed air or hand- powered tools should be used.

2. When using alternating-current driven power tools, a portable ground-fault current interrupter (GFCI) should be used.

3. When welding near gas recovery processing equipment, suitable procedures and precautions should be employed, including:

a. Procuring a “hot work” permit (a self-issued serial numbered permit is required in many states).

b. Designating a specific, dedicated individual, by name, for fire watch.

c. Verifying that explosive concentrations of gas are not present (see Section K).

d. Providing adequate fire extinguishers (20:A-80:BC) and fire blankets.

e. Sandbagging all below-grade closed drainage system components.

f. Providing the appropriate purge and inert blanket on process equipment and piping.

Procedures for safe welding and purging of process equipment are available from the American Petroleum Institute (API).

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K. FIELD SAMPLING FOR HEALTH AND SAFETY

1. The engineer or contractor has the responsibility to determine what toxic compounds are present in landfill gas so that the potential level of exposure can be determined and provisions prepared to prevent exposure.

Table K-1 lists suggested action levels for various types of monitoring instruments. Project- specific action levels should be determined for each site, based on tasks to be performed and hazards expected to be encountered.

TABLE K-1

EXPOSURE ACTION LEVELS

Concentration PPE Upgrade Guidelines

Organic Vapor Meter Action Levels (PID)* 0 - 5 ppm Level D 5 - 25 ppm Level C 25 - 500 ppm SCBA >500 ppm Exit area and contact H&S Officer * If you use this action level with an FID instrument, you may have problems resolving the positive artifact methane causes.

Hydrogen Sulfide (H2S) Action Levels 0 - 1 ppm Level D 1 - 5 ppm Level D (minimize duration of exposure) >5 ppm Exit area and contact H&S Officer

Benzene (Single Vapor) Action Levels 0 - 0.5 ppm Level D 0.5 - 10 ppm SCBA >10 ppm Exit area and contact H&S Officer Vinyl Chloride (Single Vapor) Action Levels 0 - 0.5 ppm Level D 0.5 - 10 ppm SCBA >10 ppm Exit area and contact H&S Officer Dust Meter Action Levels 0 - 150 ug/m3 Level D 0.150 - 10 mg/m3 Levels C >10 mg/m3 Exit area and contact H&S Officer

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TABLE K-1

EXPOSURE ACTION LEVELS

Concentration PPE Upgrade Guidelines

Multi-gas Meter Action Levels 0 - 5% of LEL Work continues 10 - 20% of LEL Work continues while competent person investigates >20% of LEL Exit area and contact H&S officer

AIR MONITORING REQUIREMENTS FOR LANDFILL OPERATIONS

1. The following fully functional air monitoring instrumentation must be available at the site for evaluation and characterization of air quality during landfill operations:

a. Hydrogen sulfide chemical reagent diffusion tube indicator or direct reading instrument (preferred).

b. Oxygen analyzer.

c. Combustible gas analyzer (CGA [methane analyzer]).

d. Photo-ionization, flame ionization detector, or other reliable means of measuring total non-methane organic compounds (NMOC), such as benzene and vinyl chloride. This is optional when landfill gas analysis data indicate the possible presence of a specific gas above its respective exposure limit.

2. Employees whose tasks require performance of air monitoring activities must be trained in the use, limitations, calibration, and maintenance of air monitoring equipment. All air monitoring equipment must be calibrated and maintained in accordance with the manufacturer’s instructions.

3. CGAs and other electronic portable monitoring instruments should be rated explosion-proof or intrinsically safe. They should bear labels showing approval by a national testing laboratory, such as Factory Mutual, UL or MSHA, to operate in hazardous atmospheres.

4. Air quality for site and landfill operations should be initially characterized using real-time ambient air monitoring equipment for hydrogen sulfide, volatile organics, and flammable gases. Excavations, trenches, confined spaces, and low-lying areas should be evaluated for oxygen content from outside or above the monitored area.

5. Gas samples should be collected from gas system wells for laboratory analysis to characterize H2S content, especially at landfills with construction and demolition waste. Colorimetric H2S detector tubes can also be a good indicator of H2S content.

6. If ambient air monitoring results indicate significant levels of volatile organic compounds (VOCs >5 ppm above background), a gas sample should be collected prior to beginning

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work, or as soon as possible, and should be analyzed for VOCs by an accredited laboratory (by EPA Methods 8260B/5035 or TO-15). Proper instructions and close coordination with the analytical laboratory are important to properly characterize the gas. Several composite samples will provide a more uniform representation of landfill gas at the site. Several discrete grab samples may, however, provide a better indication of peak concentrations, and show chemicals that would not be indicated in composite samples.

7. A written record of air monitoring activities, which includes calibration data, type, results, and location of monitoring, should be maintained daily.

8. For operations requiring the use of APRs, personal sampling for contaminants of concern should be performed to determine the contaminants of concern, the levels of exposure, and whether the APRs can provide adequate protection. Note that APRs are generally not appropriate for use with landfill gas.

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L. RESPIRATORY PROTECTION

1. Landfill operators and contractors who require employees to wear respirators must develop a written respiratory protection program, in accordance with OSHA 29 CFR 1910.134. The only exception is the voluntary use of disposable dust masks. This mandate describes how the following elements of the program are implemented at a site or during a project:

a. Procedures for selecting respirators to be used in the workplace.

b. Medical evaluations of employees required to use respirators.

c. Fit testing procedures for respirators.

d. Procedures for proper use of respirators in routine and reasonably foreseeable emergency situations.

e. Procedures and schedules for cleaning, disinfecting, storing, inspecting, repairing, discarding, and otherwise maintaining respirators.

f. Procedures to ensure adequate air quality, quantity, and flow of breathing air for supplied air respirators (if used).

g. Training of employees regarding respiratory hazards to which they are potentially exposed during routine and emergency situations.

h. Training of employees regarding proper use of respirators, including putting on and removing the devices, any limitations on their use, and maintenance.

i. Procedures for regularly evaluating the effectiveness of the program.

2. All employees who may be required to wear respirators must be:

a. Trained in the proper use of respirators.

b. Approved by a qualified physician for respirator use, which will usually involve an appropriate physical examination.

c. Covered by and under the jurisdiction of their employer's written respiratory protection program.

d. Trained annually about respiratory program requirements.

e. Individually fit tested, wearing assigned respirators before starting work on projects or at landfill sites. Fit testing must be conducted annually, using OSHA-approved qualitative methods and employing isoamyl acetate with organic vapor cartridges, Bitrex with particulate filter cartridges (P-100), or irritant smoke (stannic chloride) with particulate filter cartridges (P-100). Quantitative methods are more sensitive. Documentation of compliance with these provisions should be maintained.

f. For operations requiring the use of APRs, personal sampling for contaminants of concern should be performed to determine the contaminants of concern, the levels of

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exposure, and whether the APRs can provide adequate protection. Note that APRs are generally not appropriate for use with landfill gas.

3. Persons with interfering facial hair are not permitted in areas where respiratory protection equipment is required (beards are prohibited).

4. All NIOSH procedures and guidelines for respirator selection and use should be adhered to. Only equipment certified by NIOSH on its most recent certified equipment list may be used. APRs with chemical cartridges can only be used for acid gas/organic solvent vapors under the following conditions:

a. If the oxygen concentration is satisfactory. b. If the chemical contaminants have been identified. c. If the concentration levels have been characterized and are being monitored. d. If the chemical filter cartridges are effective in removing contaminants. e. If cartridges are approved for use by NIOSH. f. If contaminants have good warning properties.

If all of the above-listed conditions cannot be satisfied, Level B protection, using pressure- demand SCBAs or supplied air, is required. APRs with chemical cartridges/canisters must not be used for protection in environments containing constituents that can reasonably be expected to be near, at, and/or above the limitation of the Protection Factor (PF) for the respirator. The maximum working environment is determined by multiplying the PF for the type of respirator by the TLV for the chemical substance under consideration (Maximum Use Concentration [MUC] = PF x TLV). A list of PFs is shown in Table L-1.

TABLE L-1

RESPIRATORY PROTECTION EQUIPMENT PROTECTION FACTORS

Protection Type of Air-Purifying Respirator Factor

Half-Face APR 10

Full-Face APR 50

Powered APR, Half Mask 50

Powered APR, Full Face 1,000

Airline or Supplied-Air Respirator, Pressure-Demand, or Other Positive 1,000 Pressure, Full Face

Pressure-Demand or Other Positive-Pressure SCBA 10,000

5. Pressure-demand SCBA, or pressure-demand supplied-air full-face masks with attached escape bottles, must be used when entering areas containing oxygen-deficient atmospheres, unknown atmospheres, or atmospheres considered to be at or above IDLH

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levels. Personnel (with appropriate SCBA apparatus) will not enter IDLH environments without emergency justification by and approval of a site safety manager or responsible project manager. An emergency is constituted by and defined as an already existing life- threatening situation.

6. The length of time that an APR canister or cartridge is effective in removing hazardous material from ambient air will depend on the type and concentration of hazardous material in the air, the temperature and humidity of the working atmosphere, and the level of effort required for a worker to accomplish assigned tasks. The higher the breathing rate, temperature, or humidity, the more frequently canisters or cartridges will need to be replaced. These maximum operating periods vary according to manufacturer, so it will be necessary to monitor the total use of cartridges and canisters during all work requiring a respirator. Cartridge and canister manufacturers have tables or calculation methodologies available for users to determine required change-out schedules. Note that APRs (except for a few chest-mounted gas masks) are not appropriate for use with H2S gas.

A written respiratory protection program is a legal requirement for the use of respiratory protection equipment. Requirements for a minimal acceptable program can be found at 29 CFR 1910.134(b). Programs would include the use of engineering controls wherever possible.

7. Employees with beards should not work in areas where tight-fitting face piece respirators may be necessary. To assure a proper face seal, employees must be fit tested on the respirator they will wear. Fit testing should recur at least annually.

8. For employees who wear glasses, respirator eyeglass inserts should be provided if full-face masks are used.

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M. SPECIAL CONDITIONS

Certain types of work may present unusual problems at sites with special conditions. Examples include:

1. Sites containing construction and demolition (C&D) debris, especially those with crushed C&D waste and high-moisture environments. These have the potential to generate concentrations of H2S (greater than 1,000 ppm) which are above the IDLH value of 100 ppm. Employees involved in operations where H2S concentrations in the landfill gas system are above 100 ppm should be required to wear personal H2S monitors at all times while working at the landfill.

Extreme care and positive-pressure supplied air or SCBA should be available for cutting or opening any gas or leachate and condensate lines at such landfills. Cheek-cartridge APRs are not appropriate protection from H2S, CH4, or CO2, since (1) none are approved for hydrogen sulfide, and (2) APRs cannot protect against simple asphyxiants.

2. An ensemble of personal protection that works against infectious waste (not useful for immersion) would include a Tyvek suit, appropriate gloves and boots, and a NIOSH- approved respirator with a P-100 high-efficiency particulate filter (HEPA, P-100) incorporated into the mask canister or cartridge. Personnel should avoid or minimize contact with any waste, and should be cautioned about possible contact with sharp objects such as needles. The HEPA filter may be combined with an OV/AG cartridge or canister.

3. For protection against gas vapors while drilling or working around an open well casing, consider using a four-gas meter for continuous monitoring and supplied air SCBA. Saranex or Tyvek suits may also be required, along with appropriate gloves and boots. Adequate measures must be taken to prevent heat stress.

4. For protection from exposure to airborne asbestos fibers, the minimum requirement includes a respirator with a P-100 (HEPA) filter and a Tyvek suit. The suit may be coated or uncoated. Special regulations exist for asbestos (for complete requirements, see Asbestos Standard, 29 CFR 1910.1001).

5. Additional protection may be required if significant levels of vinyl chloride or benzene (or other more toxic chemicals) are found during characterization. Action levels for vinyl chloride and benzene are listed in the NIOSH guide. The maximum threshold limit value for benzene or vinyl chloride to which workers may be exposed over an 8-hour period is 1 ppm. The maximum concentration of vinyl chloride to which workers may be exposed in any given period is 5 ppm. If higher levels of vinyl chloride are found, respiratory protection levels may need to be adjusted to Level B (SCBA or supplied air), if engineering controls cannot reduce those levels. Because vinyl chloride and benzene are both regulated carcinogens, exposure should be limited whenever possible (wherever possible, exposure of vinyl chloride and benzene should be held to zero). Uncontrollable concentrations must be minimized through the use of appropriate respiratory protection.

6. Special compliance requirements apply for personnel whose work potentially exposures them to vinyl chloride, benzene, and asbestos concentrations above action levels. Regulations concerning vinyl chloride are found in the Vinyl Chloride Standard in 29 CFR

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1910.1017; benzene is regulated through the Benzene Standard in 29 CFR 1910.1028. Compliance requirements may vary with each compound and by state, but will likely include: a. Mandatory training. b. Medical recordkeeping. c. Exposure monitoring and recordkeeping. d. Certifications. e. Specific protective equipment requirements.

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SECTION II: LANDFILL GAS MONITORING, SAMPLING, AND ANALYSIS

A. INTRODUCTION

The purpose of this section is to provide information on the current array of accepted procedures and instruments used for field monitoring, field sampling, and laboratory analysis of landfill gas generated at municipal solid waste (MSW) landfills. This document is based on a consensus of practices employed by researchers, scientists, engineers, and regulatory agencies at various waste sites nationwide.

The monitoring and sampling techniques presented in this section focus on commonly used portable devices and instruments. Stationary instruments generally are not considered here; however, several types of apparatuses are available. Stationary instruments and continuous monitors are beginning to grow in importance as improvements are made in equipment durability, detection technology, data storage, and data transfer rates. Additional procedures on landfill gas monitoring can be found in the SWANA publication, “Landfill Gas Operations & Maintenance – Manual of Practice (1997).”

Monitoring and sampling of landfill gas components can be conducted at vertical and horizontal gas collection devices, within landfill gas collection system piping, at the landfill surface, within buildings and structures, in soils adjacent to the landfill, and in air quality studies. A number of state regulations and the Federal NSPS regulations require the determination of emissions from a landfill’s cap.

Landfill gas is composed of two major gases: methane, and carbon dioxide with smaller amounts of nitrogen, oxygen, and other trace components making up the balance of the constituents. Once gas extraction commences, levels of nitrogen and oxygen tend to increase. Because these gases generally are present in large quantities, they are measured in terms of the percent volume occupied in the air. Other volatile organic gases present in landfill gas, and are usually detected at levels of less than 1 percent or in trace concentrations, typically at the part-per-million or part-per-billion level (note that 1 percent by volume equals 10,000 ppm). The equipment used to monitor and sample trace gases requires more sensitivity and more sophistication than the equipment used to measure the four major gases. Table A-1 summarizes the sampling parameters discussed in this section and lists the corresponding field monitoring or sampling equipment associated with each parameter.

The remainder of this section is organized as follows:

 Field monitoring procedures and equipment are discussed as they pertain to measurement of the principal and trace gas components of landfill gas.

 Additional information is provided for measurement of landfill gas-related variables, such as gas pressure, gas flow, and water levels.

 Field sampling procedures are presented for the collection and transportation of representative gas samples for subsequent instrument quantification at a laboratory.

 General procedures and techniques for landfill gas sample analysis are described, with an emphasis on the measurement of trace gases (VOCs). References for this section are presented at the end.

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How an investigation is planned and implemented, the type of data required, field conditions, etc. can all have an effect on the type of monitoring and sampling instruments, the sampling collection equipment, and the approach for laboratory analysis implemented. Careful planning should be accomplished prior to conducting fieldwork.

Landfill gas investigations may be designed according to the geology of the site, the type and age of the waste, any existing gas control measures, the potential for off-site gas migration (for explosion, surface emissions, and/or odor concerns), and environmental regulation compliance. The following provide some examples of why an investigation may be necessary:

 To evaluate the potential for landfill gas migration, either in buildings or confined spaces, on- or off-site.

 To protect workers in areas where landfill gas may collect by determining whether breathable and non-explosive atmospheres are present.

 To test the effectiveness of landfill gas protection or recovery systems.

 To identify the quality and/or quantity of landfill gas component gases, particularly methane, for potential use as an energy source.

 To identify the trace volatile component present in landfill gas that can be associated with corrosion or odors (e.g., hydrogen sulfide), human health effects (e.g., vinyl chloride, benzene, etc.), or other problematic conditions.

 To determine success in meeting state or federal air quality standards associated with emissions from MSW landfills. Including New Source Performance Standards (NSPS).

 To record and evaluate parameters related to landfill gas collection or migration, such as: water table depth, condensate formation, leachate generation history, gas velocity or flow, and gas pressure in a controlled system or within a landfill.

TABLE A-1

LANDFILL GAS FIELD INVESTIGATION EQUIPMENT

Type of Parameter Device Measurement

Landfill Gas Methane (CH4) Infrared Detector Constituent Sampling Catalytic Oxidation Detector Thermal Conductivity Meter Flame Ionization Detector

Carbon Dioxide (CO2) Infrared Detector Colorimetric Detector Tube

Oxygen (O2) Electrochemical Cell

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TABLE A-1

LANDFILL GAS FIELD INVESTIGATION EQUIPMENT

Type of Parameter Device Measurement

Hydrogen Sulfide (H2S) Electrochemical Cell Colorimetric Detector Tube Volatile Organic Sampling Bags Compounds (VOCs) Evacuated Canisters Adsorbent Traps (pump/aspirator) Colorimetric Detector Tube Photo Ionization Detector Gas well, flare stack, Temperature Liquid Filled Thermometers surface point, ground Bimetallic Thermometers surface Thermocouples RTDs and Thermistors Infrared Devices Landfill gas Flow, and Gas Pressure Magnehelic Gauge Pressure Sampling Digital Manometer U-Tube Manometer Gas Flow Pitot Tube Orifice Plate Thermal Anemometer Mass Flowmeter Venturi tube flowmeter Surface Emissions Surface Emissions Flame Ionization Detector (USEPA Monitoring Method 21) Landfill Liquids Field Fluid Levels Leachate, Water Level Indicator Measurement Condensate Oil/Water Interface Detector Bubbler tube

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B. FIELD MONITORING

1. General

Landfill gas investigations generally include monitoring for methane, carbon dioxide, and oxygen. With the use of portable field instruments, field monitoring can establish concentrations of these gases quickly and accurately. Similarly, field instruments can be used to determine values for other gas-related parameters. With the promulgation of the NSPS regulation, nitrogen is an acceptable parameter to use to balance and tune a wellfield; therefore, nitrogen is also a gas, which may be monitored in the field. Practical and accurate monitoring of nitrogen in the field is not readily available through portable instruments; however, stationary units such as a gas chromatograph (GC) can be used to accomplish this monitoring. Nitrogen can also be collected in canisters and bags and sent to a laboratory for GC analysis. Landfill gas-specific portable field monitoring instruments calculate an approximate value for percent nitrogen called Balance Gas, which is assumed to be percent nitrogen, by subtracting the percentages of methane, carbon dioxide and oxygen from 100.

Field monitoring instruments generally require the gas sample to be drawn into a detector chamber under a steady flow condition, usually by a battery operated pump. Care should be taken when using such instruments for sampling from small void spaces. If a sample is drawn too rapidly, the concentration detected on the instrument may appear lower than the value actual through dilution. A steady and accurate reading will be obtained when the aspiration rate is less than or equal to the rate of replenishment. The battery-operated pump typically cannot operate if the vacuum exceeds 100 inches of vacuum. The amount of vacuum present at the monitoring point needs to be considered in selecting the proper instrument or procedure for sampling. Portable instruments that are used in the detection of flammable or other gases operate using various thermal chemical principles; each principle of measurement and associated instrument has related advantages and disadvantages, as discussed below. A moisture trap should always be used on the sampling line to avoid damage to the monitor’s sensors.

2. Liquid Levels

Liquid levels (e.g., water, leachate, landfill gas condensate) can be measured within wells or holding tanks with an electronic battery powered water level measuring device available from several suppliers. These devices have short probes attached to 100 to 300 feet of insulated wire, usually marked at tenth of 1 foot or metric intervals. Upon contact with water, an electronic circuit is completed, and a light or an alarm (or both) is activated, and the depth reading can be made and recorded. Typically, these liquid level indicators are light-weight and easy to use. When verifying a liquid level within a well casing, false readings may occur if the probe comes in contact with condensation on the interior pipe walls. This often occurs if the well casing has shifted and becomes misaligned. Installation of a protective cover (like a bottle with the bottom cut out) can reduce this problem. Also, an additional weight can be added the probe to facilitate measuring the depths of deeper installations.

3. Gas Pressure

Gas pressure (and vacuum) measurements can be collected at points along the gas collection system piping, and at other monitoring points such as off-site wells and probes. For gas probes,

II-4 pressure readings are obtained to determine whether subsurface soils (or waste materials) are under pressure or vacuum conditions relative to atmospheric conditions.

Gas pressures associated with landfill gas systems can be measured readily with a Magnehelic pressure gauge, an electronic pressure gauge or a U-tube manometer. Electronic pressure transducers are incorporated into landfill gas specific monitoring instruments.

Digital Manometer/Pressure Indicator--

A battery-powered, hand-held digital pressure indicator is available for measurement of positive, negative, or differential pressure. The instrument uses an internal pressure transducer to measure the pressure at the inlet port, and uses a digital readout that displays the measurement up to two decimal places. This type of device is accurate to within 2 percent of the full scale. The digital indicator is available in ranges from zero to 200 inches of water column, and zero to 150 psi. This type of device is included in dedicated landfill gas monitoring instruments.

Advantages

 No leveling of the instrument is required.  High accuracy.  Small, hand-held instrument.  No potential of toxic fluid loss.  One unit is appropriate for all pressure ranges encountered.  Able to measure pressure in inches of water column or inches of mercury.

Disadvantages

 Requires power source (battery).  LCD readout can be problematic in extreme cold.  Sensitive to water vapor, which is common with landfill gas.

Magnehelic--

A Magnehelic (trade name) pressure gauge is a small, hand-held device, which senses changes in gas pressure through the use of an internal diaphragm. When connected to a port of a monitoring well, subsurface gas pressures are indicated in inches of water with a pointer on the face of the Magnehelic gauge. This gauge is capable of reading both positive, negative, and differential pressure conditions in landfill gas collection system piping, gas monitoring wells, or probes. Separate Magnehelic gauges are available to accommodate varying ranges of gas pressure (e.g., zero to 0.25 inches of water, zero to 5 inches, and zero to 100 inches).

Advantages

 Highly responsive (accuracy within 2 percent of full scale).  Resistant to shock and vibration.  No liquids involved.  Small and portable.

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Disadvantages

 Separate gauges needed to accommodate a wide range of pressures.  Each port measures only positive or negative.  Gauges must be held vertical for accurate measurement.  Sensitive to water vapor, which is common with landfill gas.

U-Tube Manometers--

A U-tube manometer is used to measure positive, negative, or differential pressures in a monitoring well or landfill gas collection system piping in inches of water or mercury (as the displaced fluid). A U-shaped tube is filled about half-way with fluid (to the zero point) with both ends open to the atmosphere, and the fluid at the same height in both tubes. Application of a positive or negative pressure (when connected to a monitoring well or probe) at one end of the tube will result in a change in the fluid level; the total difference in fluid level represents the pressure. Manometers can be made of glass, of rigid, shatterproof tubing mounted on durable backings, or of flexible plastic tubing which can be rolled for transport.

Advantages

 High accuracy.  No batteries or power source needed.  One port measures both positive and negative pressures.  Provides direct measurement of pressure.  Device is capable of measurements over the full range of pressures expected.

Disadvantages

 Potential to lose fluid (e.g., water or mercury) during transport.  Must be held vertical and secured when in use.  Must have a scale that covers needed range.

4. Temperature

Temperature is measured for many applications on the landfill. Some examples of temperature measurement for landfill applications include landfill gas temperature during well head monitoring, ambient temperature during sample collection, flare stack temperatures and blower bearing temperatures during blower/flare station monitoring, soil and refuse temperature during well drilling, and flowing gas temperature during flow rate monitoring.

Temperature is easily measured with a variety of equipment, some of which is specifically designed for particular applications. Common temperature measuring devices include liquid filled thermometers, bimetallic thermometers, thermocouples, resistance temperature devices (RTD’s), thermistors, and infra-red devices.

Liquid-Filled Thermometers--

Common liquid-filled thermometers indicate temperature by the expansion of a liquid, typically mercury or an organic liquid, in a sealed tube.

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Advantages

 Inexpensive.  Does not require electric power.  Does not pose and explosion hazard.  Stable and accurate even after repeated cycling.

Disadvantages

 Cannot be used for point source measurement.  Liquid may be an environmental hazard (mercury).  Do not generate data that is easily recorded.  Generally used to measure a relatively narrow range of temperatures.  Fragile.

Dial-Type Bimetal Thermometers--

Bimetallic thermometers indicate temperature using the different rate of expansion between metals. Two metals are bonded together in a strip that is attached to an indicating needle. When the metals expand or contract at different rates due to temperature changes, the needle moves to indicate the temperature on a dial scale.

Advantages

 Inexpensive.  Does not require electric power.  Does not pose and explosion hazard.  More durable than liquid filled thermometers.

Disadvantages

 Cannot be used for point source measurement.  Do not generate data that is easily recorded.  Generally used to measure a relatively narrow range of temperatures.  Not as accurate as other devices and accuracy may degrade with repeated cycling.

Thermocouples--

A thermocouple is made of two strips of different metals joined at one end. Changes in temperature at the joined end of the thermocouple induce changes in the electromotive force that can be measured electronically and converted to a digital temperature readout. Thermocouples may be fixed in place or portable.

Advantages

 Inexpensive.

 Can measure temperature at a point location.

 Produces data that can be electronically recorded or logged.

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 Accurate.

 Can measure a wide range of temperatures (typically, -270 to 2,300°C or -457 to 4,172°F).

Disadvantages

 Requires use of an electronic “reader” to display the temperature.  Electronic equipment may pose an explosion hazard.  Resistance temperature devices (RTD’s) and thermistors.

RTD’s and thermistors use the fact that the electrical resistance of a conductive material changes with changes in temperature. RTD’s use a metal as the conductive material, and thermistors use a ceramic semiconductor. The resistance is measured electronically and converted to a digital temperature readout. The advantages and disadvantages of resistance devices are similar to those of thermocouples, although these devices are generally more expensive. RTD’s are more stable than thermocouples, but have a more restrictive temperature range (-250 to 850°C, or -418 to 1,562°F). Thermistors are very accurate, but have an even more restrictive range (-40 to 150°C or -40 to 302°F).

Infrared Devices--

Infrared devices measure the amount of radiation emitted by a surface. All surfaces emit infrared radiation depending on the temperature of the surface. The efficiency at which a particular surface emits infrared radiation varies with different surfaces and is quantified by a property termed emissivity. Infrared radiation can be measured with small handheld devices that can measure a point source temperature, such as a blower bearing or flare surface, without contacting the surface. On a larger scale, infrared imaging devices can measure temperature over large areas such as a landfill surface. Infrared imaging is a specialized application has been used on landfills in the study of subsurface fires.

Advantages

 Non-contact measurement of temperature.  Can measure temperature at a point location.  Produces data that can be electronically recorded or logged.  Accurate.  Can measure a wide range of temperatures.

Disadvantages

 Thermal imaging requires the use of specialized equipment.

 Emissivity of surfaces varies and the IR device must be suitable for the particular surface being measured.

5. Gas Flow

Gas flow measurements are required for the proper operation of landfill gas collection systems and for gas sampling. There are several techniques for measuring flow; accordingly, the

II-8 equipment can be stationary (as with installed orifice plates, venturi meters, mass flow samplers, turbine-type air velocity meters, etc.) or portable, as in case of pitot tubes or hot-wire anemometers.

Many factors should be considered when selecting a flow meter technology. From a flow meter perspective, landfill gas is a dirty wet gas of varying composition. Specific design conditions (e.g., multiple flare systems, beneficial use and flare systems operating in parallel, etc.) often require a large flow rate turndown ratio. All of these factors should be considered when selecting a flow meter technology.

Laminar flow is a primary factor in the performance of virtually all flow meter technologies. To promote laminar flow, the use of flow conditioners, or a minimum straight pipe length of 10 pipe diameters upstream and 4 pipe diameters downstream of the flow measuring device, is recommended and is generally acceptable.

For best results, it is important to properly specify expected operating conditions at the flow device when purchasing or calibrating the meter. Depending on the technology used, the parameters of primary importance may include pipe ID, temperature, pressure, flow range and gas composition.

A few common devices are discussed below:

Pitot Tube--

Total pressure (P+) minus static pressure (Ps) in a header line equals the velocity pressure. The pitot tube is a stainless steel, L-shaped probe attached by tubing to a meter which measures the differential of P+ and Ps.

Essentially, a pitot tube consists of an impact tube (which receives total pressure input) fastened concentrically inside a second tube of slightly larger diameter which receives static pressure input from radial sensing holes around the tip. The air space between inner and outer tubes permits transfer of pressure from the sensing holes to the static pressure connection at the opposite end of the pitot, and then, through connecting tubing, to the low or negative pressure side of a manometer. When the total pressure tube is connected to the high pressure side of the manometer, the velocity pressure is indicated directly.

Gas flow is determined from the velocity present reading and associated charts related to gas velocities within pipes of known diameters. To use the pitot tube, a sampling port hole of appropriate diameter must be drilled into the gas collection system piping.

Advantages

 Portable, few parts.  Sturdy, not easily damaged or corroded.  With correct operation, accuracy is within 2 percent.  Inexpensive.

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Disadvantages

 Dirtied easily by condensate and particulates. Cleaning required after each use.

 Accurate in straight ducts only. Elbows or other obstructions in the line will cause turbulence; should have at least 10 pipe diameters upstream and 4 pipe diameters downstream of the measuring port.

 Need to take traverse readings (sectional and cross-sectional) and average these results. Accurate measurements are dependent on tube placement within the pipe and care should be taken to ensure proper placement of the tube is achieved during traverse measurements.

Orifice Plates--

Orifice plates are widely used in fluid and gas-flow systems for flow measurement and as flow limiters. As defined, they are relatively small, thin, metal plates inserted cross-sectionally into the gas header line between two bolted flanges. The plate has a reduced diameter (in relation to the header pipe) which relates by formula to the diameter of the pipe and the differential pressures taken at the adjacent measuring points across the orifice. The two ports may be located within the flange bodies or may be built into the header. To calculate gas flow at the orifice, a pressure measurement is taken at each port to determine the pressure differential; other variables in the gas equation are either known or estimated. Orifice plates are often used to measure landfill gas flows at the well head assembly of the gas extraction device. Often orifice plates installed at the gas extraction well head assembly are used to trend wellfield data and are not used as absolute flow measurement devices.

Advantages

 Relatively inexpensive, readily available.  Provides accurate readings.  Readily installed.  Permanent fixture, repetitive readings can be taken.

Disadvantages

 Orifice plates can block gas condensate drainage, which may also cause freezing in winter conditions.

 In-line installation creates greater system head loss.

 Must have proper flow/orifice plate ratio for differential pressure readings to be accurate.

Thermal Anemometers and Mass Flow Meters--

As with the pitot tube, a port hole must be made in the gas collection system piping for insertion of the anemometer. These devices have a temperature probe heated to a standard temperature which responds to the cooling effect of the gas as it passes over the probe.

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The temperature differential is translated into air velocity units (feet per minute) on an LED screen or to a deflecting vane meter, depending on the model. While accurate for the purpose of some investigations, hot-wire anemometers, like pitot tubes, need to be used in a program where traverse readings are taken and averaged to obtain readings of greater accuracy.

Advantages

 Quick to set up.  Portable and lightweight.  New models measure other temperature directly.  Easy to read.

Disadvantages

 Traverse readings should be taken.  Turbulence may affect readings.  Not particularly sturdy.  Expensive to repair and calibrate.

Mass flow meters used for fixed installations (such as flare stations) provide reliable accurate flow readings if the correct operating conditions are specified. The following is recommended:

 Landfill Gas Composition: Specify the expected typical concentration of the primary components in landfill gas (typically, methane, carbon dioxide, and nitrogen). If available, use the site-specific average extraction composition.

 Landfill Gas Flow Range: Use design/expected minimum and maximum flow rates with a reasonable safety factor.

 Landfill Gas Temperature Range: If site-specific data are available, use the minimum minus 20°F and the maximum plus 20°F over the prior. Typical standard temperatures in the United States are corrected to 60°F or 68°F.

 Landfill Gas Pressure Range: Use design/expected conditions at minimum and maximum flow rates or site-specific data with a reasonable safety factor. The typical standard pressure in the United States is corrected to 14.7 pounds per square inch absolute (psia).

6. Methane

Methane content is the most significant parameter for landfill gas investigations. Oxygen and gas pressure readings are parameters that are recorded primarily as supportive information for the methane content readings. The measurement of methane content can be accomplished either by using a portable meter in the field or by collecting samples in the field and analyzing them for methane concentrations in the laboratory. Field sample collection and laboratory analysis are discussed later in this section.

Methane content measured in the field is generally expressed as percent methane by volume in air (typical for landfill gas collection system operation). Alternatively, methane concentration may be expressed as a percent of the lower explosive limit (LEL) of methane in air (typical for

II-11 probe, or combustible gas monitoring). Methane is combustible in concentrations ranging between 5 and 15 percent in air; thus, 100 percent of the LEL equals 5 percent methane in air. For lower concentrations of methane, often the percent LEL is reported, since monitoring often is mandated based on concentrations at or below the LEL. Additionally, NSPS and various state regulations require that surface emissions from a sanitary landfill be measured in ppm of methane.

Catalytic oxidation detectors are commonly used to measure the percent LEL of methane or other flammable gases. These types of detectors are useful in measuring relatively low concentrations of flammable gas in air. However, they will respond to any flammable gas, and therefore must be calibrated for the specific gas under investigation. For example, a detector calibrated for methane in air will indicate a positive reading for combustible gas if hydrogen gas (in air) is passed through the detector (when no other flammable gas is present).

The accuracy of readings also may be affected within oxygen-deficient atmospheres. Readings are suspect unless sufficient oxygen is available to assure complete oxidation of the gas. Some LEL scale-only instruments may not respond at all to flammable gas at such low oxygen levels. Thus, a “zero” reading could be misinterpreted as meaning that methane is not present. To overcome this problem, field meters are usually equipped with a second detector that measures the methane gas concentration in a different manner.

The thermal conductivity detector measures the total concentration of all flammable gases in the sample by comparing its thermal conductivity against an internal electronic standard representing normal air. These detectors can measure the full zero to 100 percent range of gas concentrations. Thermal conductivity detectors measure a physical property, and therefore are not affected by variations in oxygen levels. They can be affected, however, by mixtures of methane and carbon dioxide. Such mixtures can cause inaccuracies in the instruments because each gas affects the thermal conductivity of the cell in a different manner. Manufacturers have recognized this problem, and will calibrate their instruments using mixtures of the two gases in air. Therefore, it is essential that this type of instrument be properly calibrated in relation to the appropriate gas mixture.

A third type of detector is the flame ionization detector. This instrument can detect the majority of organic materials drawn through a hydrogen flame. The portable versions of this detector are sensitive, and operate typically in the 1 to 10,000 parts per million (ppm) by volume range. Generally, these instruments are used for detecting low concentrations of flammable gas present at soil surfaces and in soil gas, and in buildings/structures and confined spaces.

Combustible Gas Indicators--

Commonly used for methane detection in the field, combustible gas indicators are battery- powered, hand-held meters which have both catalytic oxidation and thermal conductivity devices (for LEL and volume gas measurements, respectively) that share a common display. Operators should avoid assuming that one display is simply a more sensitive scale than the other. In some models, however, the two detectors are linked in such a way that if the gas concentration is above the LEL value, the LEL reading goes off the scale when the instrument is switched to the LEL gauge. This feature averts ambiguous readings caused by low oxygen levels.

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These combustible gas indicators can be “poisoned” by various gases, such as hydrogen sulfide and organic lead compounds. Because the detector can fail, recalibration and detection replacement should be performed regularly. In addition, some manufacturers supply “poison resistant” detectors that require less frequent replacement.

Advantages

 Small, portable, and self-contained for field use.  Internal battery.  Simple to operate.

Disadvantages

 Thermal conductivity instruments can be damaged by other gases, requiring calibration or parts replacement.

 Low oxygen content can give inaccurate zero percent LEL readings.

 Non-selective; limited to combustible fraction of gas.

 Chlorinated vapors may cause a catalytic reaction, indicating a flammable condition which does not actually exist, thereby requiring frequent calibration of the instrument.

Infrared Gas Analyzer--

Infrared equipment can be used to measure specific gases and gas mixtures. Typically, this equipment consists of an infrared source and an infrared detector. As an infrared beam is projected through a gas sample, the amount of light absorbed at various wave lengths correlates to the concentration of methane and carbon dioxide present. Such meters are capable of measuring methane and carbon dioxide over a range of 0.5 ppm to 100 ppm. Percent methane and LEL readings are shown on a digital readout; readings can be stored, and some optional equipment is available to take readings at multiple locations over time, unattended. The wavelength of the analyzer must be selected to reduce interference or false positive readings.

Portable meters have been developed and are popular for field monitoring. Infrared analyzers are also available for detection of gases in large void spaces, such as buildings, under floors, manholes and other confined spaces. IR detectors are reliable, stable, and generally unaffected by weather. Calibration of the field units should be performed daily. Most units have a computer memory which stores multiple calibration gasses and concentrations, as well as readings and monitoring location identifiers. Portable IR units have become the standard for field analysis of methane at landfills.

Advantages

 Infrared sensor will not be poisoned by typical landfill gas. Since some volatile gasses will affect the IR reading, it is recommended that the use of carbon absorption pre- filters be used in certain applications.

 High accuracy.

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 Low oxygen levels will not affect LEL readings.

 Self-calibrating.

 Can store field data for subsequent downloading.

 Can be set to select the most appropriate range to measure gas levels (zero to 10 percent, and zero to 100 percent).

Disadvantages

 Greater power requirements (reduced battery life) when compared to combustible gas indicators.

 Interference can result in fault positive detections.

 Expensive.

7. Carbon Dioxide

Portable meters are available for measuring carbon dioxide concentrations using infrared technology; the operative ranges are zero to 5 percent, and zero to 100 percent. These instruments may be coupled with an oxygen and combustible gas meter to give an analysis of the three major component gases.

Carbon dioxide, a major component of landfill gas, can be detected using colorimetric detector tubes (as in the Draeger-type tube) or portable electronic meters with built-in pumps. In the case of colorimetric detector tubes, a sample is drawn over a specially formulated chemical and produces a color change. Detector tubes can be used only once and are subject to interference by other gases and chemical vapors. Using this colorimetric method, the range of detection with these tubes is commonly between 0.15 to 60 percent by volume.

8. Oxygen

Oxygen content often is measured in conjunction with landfill gas investigations, either in the raw gas, gas extraction wells, monitoring probes, or in confined spaces. Monthly oxygen monitoring from individual well heads is a compliance requirement of the NSPS. The presence of oxygen in landfill gas extraction wells can be an indicator of over extraction. Oxygen in header lines can be an indicator of a pipe separation or leak. Reduced oxygen levels in monitoring probes may be an indicator of increased potential for gas migration. Oxygen meters are available in various forms, and are sometimes built into the housing of landfill gas monitors or combustible gas indicators. Generally, oxygen meters employ an electrochemical cell as the sensor. Oxygen meters may incorporate an alarm, an LED indicator, or a combination of the two. Alarm levels are adjustable over a limited range.

Electrochemical Cell Detectors--

Oxygen from a sample is drawn into the instrument by an internal pump and is passed over the electrochemical cell where an electrochemical reaction occurs. The rate of the reaction is proportional to the concentration of oxygen in the sample. The percent of oxygen by volume in

II-14 air is displayed on the face of the meter. Various models measure ranges from zero to 25 percent and zero to 100 percent oxygen in air.

Advantages

 Typically included as part of another meter.  Easy to use.  Portable; operates on batteries.  Accurate readings.

Disadvantages

 Loss of sensitivity due to moisture.  Corrosion and chemical poisoning are problems.  Electrochemical cell has limited shelf life.  Instrument requires frequent calibration.

9. Hydrogen Sulfide

Note: Please review Section I (Health and Safety) for an explanation of the life- threatening hazards associated with hydrogen sulfide.

The measurement of hydrogen sulfide in landfill gas can be accomplished either directly with a portable gas meter in the field or through sampling and subsequent laboratory analysis. Hydrogen sulfide may be present at low levels in landfill gas, usually less than 1 percent by volume in air.

Electrochemical Cell Indicators--

Portable hydrogen sulfide meters are available which use an electrochemical cell consisting of two precious metal electrodes with an acid electrolyte. A current is generated by the electrochemical reaction of hydrogen sulfide gas, which diffuses into the reaction chamber. The current produced is directly proportional to the hydrogen sulfide concentration, and the reading is displayed on the screen. Various hydrogen sulfide meters are available, with operating ranges commonly from 1 to 2,000 ppm. Some meters are available with a lower detection limit (0.003 ppm) and an operation range of 0.001 ppm to 50 ppm. Some meters equipped with oxygen and combustible gas sensors and alarms are also available.

Advantages

 Easy to use.  Portable.  Often exists as part of combustible gas meter.

Disadvantages

 Most hydrogen sulfide gas meters do not have operational ranges less than 1 ppm.

 Other gases may interfere with accurate hydrogen sulfide readings (i.e., produce positive concentrations). Frequent calibration checks are required.

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Colorimetric Detector Tubes--

As in the detection of carbon dioxide, colorimetric detector tubes are made for the detection of hydrogen sulfide gas. These chemical detection tubes contain a specific chemical that reacts with hydrogen sulfide to produce a color change. The aspirator hand pump is used to obtain a prescribed sample volume of gas.

Advantages

 Portable  Easy to use.  Relatively inexpensive.

Disadvantages

 Limited accuracy.  Interference from other gases may occur.  Single use only.  Susceptible to operator error.

10.

Carbon monoxide (CO) is an off-gas resulting from incomplete combustion. CO, therefore, can be a good indicator of subsurface oxidations (fires). CO levels approaching 1,000 ppm may be an indicator of a subsurface fire. CO can also be present in landfill gas originating from certain types of wastes, such as ash and similar wastes.

CO can be measured in the field using portable instrumentation or colorimetric detector tubes, or samples can be collected for laboratory analysis by a gas chromatograph.

Electrochemical Cell Detectors--

Portable instruments have been developed which pass a gas sample by an electrochemical sensor to detect the presence of CO. The gas diffuses into the sensor and through the membrane to the working electrode. When the gas reaches the working electrode, a chemical reaction occurs. This reaction creates an electronic signal which is used to determine the concentration of CO in the gas sample.

Advantages

 Easy to use.  Portable.  Often exists as part of a combustible gas meter.

Disadvantages

 Loss of sensitivity due to moisture.  Corrosion and chemical poisoning.  Electrochemical cell has limited shelf life.  Instrument requires frequent calibration.  Detection range may be limited (typically, 0 to 500 ppm).

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Chemical Tube Detectors--

Chemical detection tubes are available in a variety of detection ranges from several manufacturers for the measurement of carbon monoxide. Detection tubes for CO have the same advantages and disadvantages as tubes for measurement of other gaseous constituents. Chemical interference is of particular concern when using detector tubes to measure CO. The use of an activated carbon pre-filter to absorb potentially interfering hydrocarbons may be required, depending on the manufacturer of the detection tube. Detection tubes with an integral pretreatment layer to minimize most hydrocarbon interference are available.

Advantages

 Portable.  Easy to use.  Relatively inexpensive.

Disadvantages

 Limited accuracy.  Interference from other gases may occur.  Single use only.  Highly susceptible to operator error.

11. Siloxane

Siloxanes, which are found in landfill gas, have become a concern because of the potential to damage landfill gas-fired power equipment. Siloxanes are organosilicon compounds with the empirical formula R2SiO, where R is an organic group. Some examples are dimethylsiloxane ([SiO(CH3)2]n) and diphenylsiloxane ([SiO(C6H5)2]n ). Silicones are a variety of siloxanes.

Because of their desirable properties, siloxanes are found in a wide array of products, such as consumer products (cosmetics, deodorants, water repellant coatings, soaps) and industrial products (lubricants, sealants and solid or semi-solid plastic-like materials). They are not only becoming more popular in many applications, but are proposed as replacements for other products (for example, to replace perchloroethylene in dry cleaning). Since they are not currently considered environmentally detrimental, the trend for their increased use is likely to continue. This could also mean an increase in siloxane concentrations in landfill gas.

The combustion byproducts of siloxane include silicone dioxide, or silica, which is a solid mineral. When landfill gas burns, the formed silica would tend to coat surfaces such as turbine blades, heat exchangers, valves, and piping. As the coating thickens, it can obstruct flow, impede heat transfer, or unbalance rotating equipment. This is a concern to equipment manufacturers, who may not want warrant the performance of equipment because of potential risks.

Testing for siloxanes may need to be done prior to equipment section in order to characterize the types and concentrations of siloxane. This information would help to select generation equipment and as well as to design treatment facilities. Testing would also need to be done to determine the effectiveness of treatment.

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While each test method uses GC/MS, there is not yet a consensus for techniques and standards between laboratories, nor a consensus between manufactures for analytical methods. The same is true for sampling methods. Some testing is selective for certain compounds or groups of compounds and others evaluate total silica. Operators need to work closely with equipment manufacturers to determine acceptable sampling and test methods.

There are three sampling methods available: methanol impinger, evacuated canister, and Tedlar bags. Each method has advantages and disadvantages, but the most popular methods are methanol impinger and canister.

Methanol impinger uses a series of chilled impingers containing methanol. Sometimes another liquid adsorbent is used, such as mineral oil. This method is somewhat time-consuming and may not capture 100 percent of siloxane, but it does provide a composite sample and low detection limits, and is a widely accepted technique.

The canister method uses evacuated Summa canisters, which usually take a short-term sample. There are concerns that siloxane may be adsorbed onto the canister walls, and that it is a less widely used technique. However, it may provide more accurate results and lower detection limits.

12. Other Trace Gases

Identification and monitoring of trace gases, commonly termed volatile organic compounds (VOCs), or Non-Methane Organic Compounds (NMOC), generally require collection of a gas sample and subsequent analysis in a laboratory. Several methods are available for both sampling and analyzing the organic compounds. Tedlar bags or Summa canisters are typically used for sample collection. Analytical methods include GC/MS.

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C. FIELD SAMPLING

1. General

This section discusses field sampling of two types: (1) grab samples, and (2) measuring gas emissions continuously over the entire landfill surface. A grab sample indicates the types of gases and their concentration in the emissions, but measures only at one point and at that moment. Landfill gas emission varies spatially, over short times, and with the age of each portion of the landfill. Gases flow mainly through isolated and erratically spaced preferential flow paths in the landfill and cap, so gas emissions vary greatly across the surface. In addition, gases are diluted by atmospheric air when they reach the surface. Several methods can account for spatial variation and gas dilution.

2. Grab Samples – Delivery Devices

Three basic delivery systems are available for use in transporting landfill gas from its source (landfill probe, well, or extraction system header) to a sample container: hand aspirator, electric hand-held personal pump, and portable vacuum pumps.

Hand Aspirator--

This device is inexpensive and practical for obtaining small gas volumes. Typically, hand aspirators are used with portable combustible gas indicators or for delivery of a small gas volume to a colorimetric detector tube or a sample bag. Drawbacks of aspirators include lack of flow control, contamination from outside air sources, obtaining samples from environments with substantial vacuum, and small sample volumes.

Personal Pumps--

Several manufacturers supply portable, hand-held pumps for gas sample collection. These personal pumps can be clipped to the operator’s belt, and have optional flow regulators and timers which allow the operator to perform other tasks while the pump is sampling. Typically, these pumps are sturdy and can operate for several hours on rechargeable batteries. These pumps are suitable for bag sampling, as well as for combustible gas meters and colorimetric detector tubes, and charcoal adsorption tubes.

Vacuum Pumps--

Other vacuum pumps are available for field sampling with a greater vacuum is required to obtain a sample. Typically, electric vacuum pumps can be employed to operate either from a permanent power source or from a 12-volt DC battery.

The advantages of vacuum pumps include large sample flow rates, sturdy construction, and a low potential for air contamination. These pumps can be used to deliver landfill gas to canister- type samplers so as to provide a pressurized sample for subsequent laboratory analysis.

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3. Grab Samples – Sample Containers

Adsorbent Traps--

These devices are generally glass or stainless steel tubes filled with a collection medium (such as Tenax, activated charcoal, or silica gel), which serves as an adsorbent for constituents found in landfill gas. The gas stream to be sampled is passed through the tube and the adsorbents at a recorded flow rate and volume. The purpose of this sampling technique is to selectively adsorb and concentrate specific classes of trace compounds onto the media for later desorption and analysis in the laboratory. Generally, each tube is equipped with pressure/vacuum type seals at each end. The inlet end of the tube is connected directly to the gas stream, while the outlet is connected to either a vacuum pump or pressure regulator for sampling from sources under either a negative or positive pressure. Desorption at the laboratory is performed through extraction by use of liquid, solvents, or through applying a heat source to the tube.

Advantages

 Easy to transport compared to whole air samples on sampling bags.  Adsorbents can be selected based on the specific VOCs to be sampled.  Most trace landfill gas components can be quantitatively adsorbed.  Concentration of the target analyses in the field with proper sampling train.

Disadvantages

 Adsorbents have limited adsorbative capacity and may become saturated.

 Sample delivery system capable of providing precise flows is required.

 Adsorbent capacity may be affected by the temperature and pressure of the system.

 Proper laboratory handling is required to desorb gases, introducing additional sources of potential error.

 Compounds with a low molecular weight may not be trapped effectively.

 Multiple analyses cannot be performed on a single tube.

 Sampler should be present during sample collection.

Canisters--

These sample containers can be made of stainless steel, glass, or aluminum and can be used for both quantitative and qualitative analysis of gas samples. Due to their sturdy construction and ability to hold a large volume of gas in a compressed state, repeated gas analyses can be performed. Sizes for canisters range from small “bombs” (250, 500, and 1,000 cc) to 6-liter canisters. Aluminum bombs may be adequate for principal landfill gas components (methane, carbon dioxide, oxygen, nitrogen, hydrogen, and carbon monoxide). However, canisters constructed of stainless steel are preferable due to their relatively inert nature. The inside of these canisters usually is treated with the patented SUMMA polishing process. This treatment coats the inside of the canister with a chrome-nickel oxide. Additionally, glass or Teflon lined canisters are available.

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The size of the canister used is dependent on whether pre-concentration of the sample is needed (in a case of low concentrations, as in ambient air samples), the length of sample time (grab versus integrated over time) and the actual sample volume desired. Samples are obtained generally by utilizing a pump and flow regulator or rotameter. Gas samples can be pressurized within the canister to obtain actual sample volumes that are greater than the size of the canister. Alternatively, a vacuum may be applied to the canister prior to sample collection, so that samples may be obtained directly without the use of a pump.

Advantages

 Pressurized canisters can be leak tested to check integrity of sample train.  Multiple analyses can be performed from a canister.  Operator need not be present during the sampling run.  Sample volumes do not need to be measured and recorded.  When sampling using the canister vacuum, no power source is required.  Durable and easy to transport.  Canisters can be reused with proper cleaning.

Disadvantages

 Large canisters may be inconvenient to transport if large numbers of samples can only be reached by foot.

 Each component of the sample train must be cleaned prior to additional sampling.

 Air leaks in system elements upstream of the canister are a potential source of error.

 Power source is needed for positive pressure sampling.

 Shipping is an expensive and time consuming process.

 Shipping combustible gas must conform to strict DOT regulations.

Sampling Bags--

Sampling bags generally are manufactured from one of several layered synthetic materials such as Teflon, rubber, Tedlar, or mylar, or a combination of layered materials such as polyester, vinyl, and aluminum. Bag sizes generally vary from less than 1 liter up to 180 liters. Bags are equipped with one or two sample inlet/outlet valves, for connection to the sampling train or for extraction of the sample for laboratory analysis.

Samples can be collected by one of two methods. In one method, a pump is placed between the bag and the sample source to obtain a grab or time integrated sample. Otherwise, the bag is attached to the inlet inside of a tightly sealed container or drum and the vacuum pump is connected to the outlet port. The vacuum formed inside the drum allows the bag to fill to obtain a grab sample.

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Advantages

 Capable of obtaining large sample volumes.

 Purging of container is not required.

 When a sample is collected in a vacuum container, decontamination of the pump and components is not necessary.

 Multiple analyses may be performed from a single sample.

Disadvantages

 Sample storage within bags is a limitation; some compounds may pass through bag sidewalls. Analysis should be conducted within 24 hours.

 Bags have potential to leak or puncture.

 They are bulky when filled and awkward for transport.

 Translucent bags may allow photo-degradation of certain landfill gas components prior to analysis.

 Water vapor and landfill gas may condense inside the bag.

 Polyester, vinyl, aluminum, and rubber bags are reactive to certain landfill gas components.

 Shipping is an expensive and time consuming process.

Photo Ionization Detector--

Photo Ionization equipment works by ionizing a stream of gas and measuring the electrical signal given of by ionizing organic compounds. An ultraviolet lamp is the source of the ionization. These lamps are manufactured in different voltages to ionize different ranges of compounds. Lamps can be changed to isolate specific ranges of compounds. PIDs do not detect methane; however, methane and extremely high concentrations of compounds have a response factor reducing effect.

Advantages

 Can detect quantity of total organic gasses other than methane.

 Useful in determining if there are extraordinary high amounts of organic vapors in the landfill gas stream.

Disadvantages

 Expensive.

 Moisture-sensitive.

II-22  Must have an ionization potential chart of the compounds suspected in the gas stream in order to choose the correct lamp.

4. Sampling Gas Emissions of the Entire Landfill

The landfill could be completely covered by a gas barrier such as an impermeable tent and the emissions measured directly. The areas involved and the need for continuous monitoring, however, make a total cover unfeasible. Statistically valid sampling across an uncovered surface can accomplish the same end. Several methods are available:

Hoods (Flux Chambers)--

Hoods, so-called flux chambers, covering 1 to 2 m2 area at random locations across the landfill surface can measure the emissions. The hoods have small openings to the atmosphere to prevent pressure buildup inside and to minimize atmospheric dilution. The number of hoods is determined by the accuracy required and by the spatial variation of the emissions. The amount of air withdrawn from a hood for flushing the lines and analysis should be known so that the change of concentration, due to atmospheric air dilution into the chamber, gives a rough estimate of the amount of landfill gas entrapped by the hood since it was last sampled and evacuated. The number of hoods depends on the accuracy required and the spatial variation of the emissions. At a typical landfill, probably two to three dozen hoods would be required. When the coefficient of variation, the standard deviation of the measurements divided by the average of the measurements, is less than 0.3, the average is probably sufficiently accurate to satisfy regulatory demands.

Advantages

 Inexpensive. The major expense is the analytical equipment which is also required by other sampling methods.

Disadvantages

 Hood locations must be changed periodically because the hood may change the flow characteristics of the cap.

 Requires a power source in the field.

 Gives only a rough estimate of emission rates.

Micrometeorological Monitoring (Eddy Correlation)--

The gas concentration gradient upward from the landfill surface measures the amounts and types of gases emitted. Masts three meters tall containing gas sampling ports, sonic anemometers, cap anemometers, net radiometers, thermometers, and wind vanes measure the gas concentration gradient and wind data (to correct for atmospheric dilution). The mast samples an area of a few hundred square meters. The mast is moved between measurements to another random location across the landfill. A coefficient of variation of the measurements of <0.3 indicates the average probably accurately reflects the landfill’s emissions.

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Advantages

 Masts measure an area of several hundred m2, so relatively few locations are needed.

 Equipment costs of the physical measurements are moderate. The major initial and operating costs are for chemical gas analysis, as is true of any sampling method.

 Measurement does not affect gas emissions.

 Conducive to continuous monitoring.

 Equipment is relatively field-hardy.

 Suitable for the low emission rates of landfill gas.

 Yields emission rates directly.

Disadvantages

 Data analysis is complex, but help is available.  Requires a power source in the field.  Equipment is cumbersome.

Fourier Transform Infrared (FTIR)--

Infrared (IR) light absorption can measure the concentrations of many gases in air. FTIR is a variation that attempts to overcome the interferences of water and carbon dioxide, which also absorb IR, in the air. An FTIR device can measure the gas concentrations between a source and detector as far as 100 m apart.

Advantages

 FTIR is portable.  FTIR measures a large area.

Disadvantages

 Expensive.  Equipment was not field-hardy, but should be improving.  Yields only a rough estimate of the amount of gas emissions.

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D. SAMPLE ANALYSIS

1. General

Analysis for the major and trace components in landfill gas can be conducted either in the field or in the laboratory, depending on the accuracy and time frame desired for analysis. Several manufacturers now supply portable gas chromatographs (GC), which can be used readily in the field for “real time” analysis. Alternatively, GC and GC/MS (mass spectrometer) systems can be mounted on a more permanent basis in trailers or vans where continued field analysis is desired. The advantages of GC and GC/MS instruments for analysis of landfill gas samples include reliability, accuracy, repeatability, quality assurance documentation, quality control, defendability, low detection limit, and automation of analysis and data storage. A brief discussion of GC and GC/MS detection systems is given below.

2. GC Multi-Detector Systems

The gas chromatograph utilizes a separation technology to identify and quantify specific gases present in the sample when compared to known standards. A GC equipped with a fused silica capillary column is frequently used for the separation of landfill gas trace compounds.

GC technology greatly includes the introduction or injection of a gas sample into the instrument port via a valve. The sample is transported by a carrier gas (e.g., helium) through a column specific to the separation required for identification/quantification of the target analyte(s). Separation of the analytes is achieved by repeated sorption and desorption as the sample progresses through the column. Effectiveness of the separation depends on the temperature of the column, the flow rate of the carrier gas and the physical or chemical interaction between the sample mixture and the column. On leaving the column, the gas is passed through a detector, and the response is recorded electronically or on a chart recorder.

The GC is used in conjunction with the detector appropriate for the specificity and sensitivity of the analysis performed. The following is a summary of the detectors frequently used with the GC for landfill gas analyses.

Non-Specific Detectors-- a. Electron capture detector (ECD) - A highly sensitive and selective detector. This method is capable of determining subpicogram quantities of halogenated compounds. This system is able to capture electronegative atoms from the chromatographic column and record their peaks at a linear response up to 4 orders of magnitude above baseline. b. Electrolytic conductivity detector (EICD) - This system has been found useful in assessing the quality of landfill gas allowing detection of halogenated, sulfonated, and nitrogen- containing compounds. Without a GC separation, this system can be used to determine the total levels of the three above-mentioned families. c. Photoionization detector (PID) - The PID is most utilized for analyzing aromatic species of organic and some inorganic gases in the picogram to microgram range. This system utilizes an ionization process which occurs as a result of adsorption of a photon by a molecule. The PID is a non-destructive method, so it may be used in series with other detectors so that simultaneous and selective analyses of two separate analyte groups may be tested.

II-25 d. Lead acetate detectors - This method can be used either with a GC, or the gas sample can be directly injected into the detector. This system is used for determining the presence of sulfur-containing compounds through pyrolizing the sample, which results in the conversion of sulfur-containing compounds to hydrogen sulfide. This system can be used for continuous monitoring in the field. e. Flame photometric detector (GC/FPD) - This system is used for the detection of sulfur compounds in landfill gas in the ppm and ppb range, and does not require preconcentration. This method may be used to determine individually specified sulfur components or total sulfur concentration.

Advantages

 Less expensive than GC/MS.  Less sample volume is required for analysis.  Is more sensitive than GC/MS (ECD may be 1,000 times more sensitive).

Disadvantages

 Multiple detectors must be calibrated.  Compound identification may not be definite.  Data interpretation similar to GC/MS.  Potential interference from co-eluting compound(s).  Cannot identify unknown compound outside range of calibration or without standards.  Does not differentiate targeted compounds from interfering compounds.

The type of standard (i.e., standard gas mixture) with which sample gases are compared during chromatography is important for determining the accuracy of results. Standards are available from a number of commercial sources, either as single components or as a mixture within an inert gas. Standards that are suitable both in terms of component and concentration should be used. Calibration standards are injected both before and after sample analysis as a quality check of the accuracy and reproducibility of the resulting data.

3. GC/MS Systems

The detector systems are used with GC/MS instruments for identification and quantification of trace compounds in landfill gas. Generally, GC/MS is listed for analysis of gas compounds present at ppm or ppb levels.

The MS/SCAN detector system is used to identify qualitatively all compounds present in a sample. This system provides positive identification (not quantification) of compounds detected when compared against an initial compound library.

The MS/SIM (Select Ion Mode) detector system is used to identify and quantify a target list of compounds. Compound quantification is accurate and detection limits for trace compounds in landfill gas can approach 1 ppb.

II-26

Advantages

 Conclusive compound identification.  Less operator interpretation is necessary than for multi-detector GC.  Little interference from co-eluting peaks.

Disadvantages

 Greater cost than multi-detector GC systems.  Greater sample volume is required than for a multi-detector GC.

II-27 E. APPLICABLE REFERENCES AND ANALYTICAL METHODS

A listing of references and technical documents applicable to the sampling and analysis of landfill gas is given below. While this listing is not exhaustive, it provides guidance to the reader to plan and conduct sampling programs, to determine proper analytical methods.

1. Pollack, A.J.; Holdren, M.W., McClenny, W.A. “Multi-Absorbent Preconcentration and Gas Chromatographic Analysis of Air Toxics with an Automated Collection/Analytical System,” JAWMA, 41:1217 (1991).

2. McClenny, W.A.; Pleil, J.D., Evans, G.F. “Canister-Based Method For Monitoring Toxic VOCs in Ambient Air,” JAWMA, 41:1308 (1991).

3. Holdren, M.W.; Smith, D.L. “Stability of Volatile Organic Compounds While Stored in SUMMA - Polished Stainless Steel Canisters,” Final Report, EPA Contract 68-02-4127, WA-13, 1987.

4. Hsu, J.P.; Miller, G; Moran, V. “Analytical Method for Determination of Trace Organics in Gas Samples Collected By Canister,” J. Chrom. Sc. 29:83 (1991).

5. Winberry, W.T., Jr.; Murphy, N.T.; Riggan, R.M. “Method TO-14,” in Compendium of Methods for the Determination of Toxic Organic Compounds In Ambient Air, EPA-600/4-89- 017, June 1988.

6. Pau, J.C.; Knoll, J.E., Midgett, M.R. “A Tedlar Bag Sampling System for Toxic Organic Compounds in Source Emission Sampling and Analysis,” JAWMA, 41:1095 (1991).

7. Kerfoot, H.B.; et al. “Analytical Performance of Four Portable Gas Chromatographs Under Field Conditions,” JAWMA, 40:1106 (1990).

8. Barbola, M.J.; Shen, T.T. “Planning Air Monitoring for LDLs at Waste Sites,” in Measurement of Toxic and Related Air Pollutants, Proceedings of 1988 EPA/APCA Symposium.

9. Test Methods for Evaluating Solid Waste, U.S. Environmental Protection Agency, SW-846, November 1986.

10. Test Methods for Evaluating Solid Waste, Physical/Chemical Methods: Update Package, U.S. Environmental Protection Agency, A389-148076, 1989.

11. S. Ausma; G. C. Edwards; C. H. Fitzgerald-Hubble; L. Halfpenny-Mitchell. “Volatile hydrocarbon emissions from a diesel fuel-contaminated soil bioremediation facility,” JAWMA 52:769, 2002.

Additional Listings

II-28

SECTION III: MATERIALS AND EQUIPMENT

A. INTRODUCTION

This section will present an overview of the materials and equipment that are available to manage landfill gas at a sanitary landfill. The handling of landfill gas comes about for two reasons. One is the control of gas for environmental/regulatory reasons. This can include control of subsurface migration, odors, and surface emissions, or a combination of these factors. The second reason involves the collection and use of landfill gas as an energy source. Many systems may also need to meet both environmental/regulatory and energy-use needs simultaneously.

Generally, landfill gas control systems must meet existing regulatory agency requirements at both Federal and local jurisdictions. Regulating agencies that influence the design and operation of landfill gas management systems (LFGMS) may include: Federal and State EPA Offices, State Air Quality Management Boards, local Department of Health, and any other state or Federal regulating agency. Because of the extended operation of process equipment and control technology, LFGMS must also be adaptable to future regulatory requirements.

Materials and equipment used to handle landfill gas will be subjected to certain conditions that should be considered during system design. Materials that come into contact with gas should be corrosion-resistant because of the high moisture content of the gas and certain acids that may be present. Another consideration resulting from the moisture content of the gas is the need to remove condensate that accumulates at various points in the system. Special design features should be included to minimize the chance of fire or explosion due to the flammability of some gas-air mixtures. While pressure differentials in gas collection systems are relatively low (under 1 psig), certain types of processing require high pressure (up to 500 psig). The temperature of the gas varies greatly depending on the landfill and climate, but is usually well within the capabilities of commonly available construction materials (65F to 120F).

Other chemical constituents may also be present in landfill gas that can cause maintenance and deterioration problems with gas handling equipment. Siolxanes, H2S, moisture, and particulates are examples of these chemicals. The design of landfill gas handling systems should consider the potential maintenance and emission issues from these chemicals, and incorporate specific previsions to gas handling equipment to remove or operate under the influence of these compounds.

Additional design factors resulting from construction of a system in and on a landfill will also affect the materials and equipment selected. Among these are:

 Exposure to waste or leachate.  Differential settlement.  Site maintenance and closure.  Proximity to heavy equipment work or travel areas.

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B. GAS CONTROL FOR MIGRATION

Production of landfill gas creates a positive pressure within the landfill; this pressure acts as a driving force (convection), causing landfill gas migration into surrounding soils and through surface soils. In addition, a concentration gradient causes diffusive flow of landfill gas away from the landfill (i.e., landfill gas flows from areas of high concentration into areas of lower concentration). Most of the landfill gas will vent to the atmosphere through the surface of the fill; however, under certain soil conditions and landfill configurations, the driving forces described can result in off-site subsurface migration of landfill gas.

Landfill gas migration can create a hazard, since the methane present in the gas is combustible. Methane is a colorless, odorless gas that is potentially explosive at concentrations between 5 and 15 percent by volume in air (the explosive limits for methane), and in the presence of oxygen a source of ignition. At higher concentrations, methane is flammable. Federal and State regulations will generally consider subsurface landfill gas migration controlled when the concentration of methane at the landfill boundary is maintained below 5 percent by volume (the LEL). However, Federal and State regulations will generally require a nondetectable concentration of methane within structures that are typically occupied (25% V/V – 25% LEL).

In addition to the traditional extraction well/header/blower type systems that are used to control migration (materials and equipment discussed below), alternative methods for controlling landfill gas migration are: (1) interceptor trenches; (2) barrier walls; (3) combination interceptor/barrier trenches; (4) perimeter vacuum extraction systems; and (5) perimeter pressure air injection systems. Variations of these can also be applied to building protection systems for buildings that are located on or near waste fill areas. Passive methods of building protection include: (1) sub-slab geomembranes, and (2) lateral vent systems. Active methods include: (1) sub-slab extraction or air injection systems; and (2) crawl space ventilation systems.

The first three alternatives for controlling off-site migration are considered passive control measures; accordingly, their operation and maintenance requirements are usually minimal. The perimeter extraction and air injection systems utilize wells, piping, and blowers, and therefore require routine operational care and maintenance. Normally, extraction systems require a flare or comparable device to burn the gases, whereas air injection systems require no flare. All types of systems require monitoring to verify their effectiveness. The final technology selection must consider the capital investment, maintenance costs, and environmental regulations and compliance issues.

The lateral movement of landfill gas can be controlled by either barrier or ventilation systems (see Figure 1, attached). Gas movement can be controlled by barriers constructed of relatively impermeable materials. Ventilation control systems intercept gas that is moving laterally and provide a low resistance path to the surface. Common locations for gas control systems are shown in Figure 2.

1. Barrier System

Barrier systems are constructed outside of the landfill area and extend to a low permeability bottom seal or natural barrier (e.g., bedrock or groundwater). Impervious liner materials used to control gas flow include geomembranes or to a lesser extent natural clays. Selection of geomembrane materials should be based on the performance required. Table B-1 lists important properties that should be exhibited by the geomembrane. In the past, materials which

III-2 have been used for control of landfill gas include polyvinyl chloride (PVC), chlorinated polyethylene (CPE), and Hypalon. Over the last 10 years, high-density polyethylene (HDPE) has been the material of choice. HDPE materials used are typically 20 to 60 mils thick.

TABLE B-1

DESIRABLE PROPERTIES OF MEMBRANE MATERIALS

Property Purpose

Relatively low permeability To isolate the area to be protected from landfill gases High resistance to puncture and tearing To ensure the integrity of the membrane in order to effectively isolate the area from gas flow Ease of seaming, patching To ensure the continuity of the barrier Durability To provide long-term protection from the continued generation of landfill gas Good elongation characteristics To withstand, without rupturing, a significant elongation Flexibility To preclude stiffening when ambient temperatures are relatively low Reasonable cost To ensure cost-effective design Inert Nature To resist chemical and microbiological attack

Natural soil barriers may serve as efficient barriers to gas migration, provided that the soil is properly graded and is maintained in a nearly saturated condition. The soil selected must have a high enough fines content to achieve the necessary level of low permeability. Generally, this will mean soils predominantly of a clayey nature, and may include soils classified as ML, CL, MN, or CH according to the Unified Soil Classification System (ASTM D-2487). Dry soils (even dry clays) are ineffective barriers, as they include voids through which gas can migrate.

Slurry walls are non-structural barriers constructed primarily to intercept and impede the flow of fluids underground. The two basic types of slurry walls are soil bentonite (SB) and cement bentonite (CB). Depending on the nature of the project, either method may have technical or economic advantages over the other. Slurry walls have been installed at several landfills to control landfill gas migration.

In both SB and CB construction, a 2- to 4-foot wide trench is excavated using a backhoe or other specialized equipment. The trench is prevented from collapse by keeping it full of bentonite slurry during excavation. Bentonite is a type of commercially available clay which swells to 10 to 13 times its dry volume upon complete hydration. In the case of SB walls, the trench is subsequently backfilled with a mixture of soil (normally spoils from the trench) and bentonite slurry (Figure 3). With the CB method, cement (or cement and additives) is added to

III-3 the bentonite slurry and allowed to set and subsequently harden. Both methods produce a barrier with low permeability to gases or liquids.

Permeability values for liquids through slurry walls range from 1 x 10-5 to 1 x 10-8 cm/sec for SB and CB walls. For this reason, and because they are usually less costly, SB walls are more commonly used.

Generally, SB walls cost less than CB walls to construct, particularly if the material excavated from the trench is suitable for use as backfill. However, SB walls usually require a larger work area in order to store and mix excavated soils with bentonite slurry. In general, minimum work areas on the order of 50 feet wide are required for SB wall construction.

The use of CB walls may be advantageous at sites where work space is limited and the excavated materials are unsuitable as backfill material (e.g., building rubble or trash). However, they are more costly to construct because the materials used (cement and cement set-up retarders) have to be imported to the site. The disposal of excavated soils is an added cost. However, no backfill mixing operation is required with CB walls as with SB walls.

Grouting techniques have been used in the engineering field primarily to increase the stability of coarse-grained soils by filling in the pore spaces; to provide underpinning or increased bearing capacity to foundations; and to seal cracks and joints in concrete materials and underground structures. When applied, grouts set as rigid materials with relatively low porosities. Grout curtains also have been used to control the outflow of liquid pollutants at disposal sites.

2. Vent Systems

Vent systems to control landfill gas migration include trenches, gravel filled vent wells, and combinations thereof. Venting may be accomplished through either passive or induced exhaust systems. Passive systems provide a mechanism of venting landfill gas due to the natural pressures of the generation of landfill gas within the sanitary landfill. To control emissions the collected landfill gas should be vented through a flare which is operated and designed per 40 CFR 60.18.

Regulatory agencies are moving away from passive systems and requiring active systems to deal with controlling the landfill gas. However, New Source Performance Standards (NSPS) do allow the installation of a passive collection system if the passive collection system is installed in disposal areas with liners on the bottom and all sides in all areas in which gas is to be collected and routed to control system that complies with 40 CFR 60.756 (b)(2)(iii). 40 CFR 60.752 (b)(2)(ii(B).

Passive vent systems rely on highly permeable material placed in the path of gas flow, creating an engineered “path of least resistance.” Porous material can be placed in a trench between the landfill and the area to be protected. Perforated pipe can be laid within the porous material to function as a collector manifold, directing the gas to a point of controlled release through frequent vertical riser pipes. The primary requirement of the porous material is that it be highly permeable to gas flow. Gravel is a relatively low cost material that can be effective provided that it does not contain a large percentage of fine materials, and is not subject to breakdown due to the acidic nature of condensate.

III-4

An induced exhaust (active extraction) system consists of a series of gravel filled wells and/or trenches. Both wells and trenches utilize pipe (perforated or overlapping with annular spacings through which landfill gas is collected. A typical well is shown in Figure 4. These wells can be located outside of the actual landfill limits (see Figure 5) or can be installed within the landfill (see Figure 6). A typical trench and internal trench layout is included in Figure 7.

The location of the system, whether in or out of the landfill, is a key design decision and is dependent on a variety of factors, including:

 Site geology.  Limits of waste fill.  Site topography.  Property boundaries.  Level and extent of migration.  Owner and operator requirements.  Permit and permitting agency requirements.

All other things being equal, it is best to install gas systems in the landfill, to control gas at its point of generation. This is true for two reasons. First, refuse is more porous than soil so removal efficiency per unit of energy is superior. Second, there is less likelihood of mixing air and landfill gas in explosive concentrations when operating an in-refuse gas collection system.

In an induced exhaust system, laterals connect well and/or trenches with a main landfill gas header system. The gas withdrawn at each well or trench is collected in a pipe network known as the gas collection header. A motor/blower unit draws the gas to a central point where the gas is either discharged to the atmosphere, or burned in a flare or energy recovery system to control odors and VOC emissions.

The piping materials used in trenches, wells, or for gas collection headers should be compatible with the landfill environment. Typically, the pipe used in the landfill gas systems is polyvinyl chloride (PVC), high-density polyethylene (HDPE), or fiberglass-reinforced plastic (FRP). Pipe materials are discussed in more detail in the section below. Some systems have used polymer- coated, corrugated steel pipes for site-specific reasons.

Motor/blowers and flares used for induced exhaust systems will be discussed in more detail in the following section on landfill gas recovery. Every gas control system should also include a series of monitoring probes placed between the control system components and the area to be protected. These probes are used to assure that the installed system is effectively controlling the migration of the landfill gas. Probes are often constructed from PVC or HDPE materials; and drilled to specific depths to match existing geology of surrounding strata.

3. Air Injection

In addition to barrier and ventilation control systems, air injection systems can provide gas control by injecting air into natural soils adjacent to a landfill to (1) provide a positive pressure zone overcoming gas migration into surrounding native soils; and (2) dilute gas concentrations with air to non-hazardous levels. The components of air injection systems (wells, pipes, blowers, etc.) are generally the same as induced exhaust systems described above. The proper operation of this system is critical to mitigate the potential of inducing a subsurface fire.

III-5 C. GAS CONTROL FOR ODORS AND SURFACE EMISSIONS

The typical system used for odor control and surface emissions control is an active gas control system. This system requires the operation of gas moving equipment to induce a vacuum into the sanitary landfill for the extraction of landfill gas. Typical extraction system equipment components include vertical or horizontal extraction wells or trenches, lateral and header piping, and bower flare stations. The materials and equipment used for these is the same as is used in landfill gas recovery systems as discussed below.

The use of landfill cover systems also contribute to effective control of odors and surface emissions. The cover system is most effective when it creates an impermeable barrier between the waste and the atmosphere, limiting landfill gas and odors from escaping the landfill surface and limiting air from intruding the landfill waste and landfill gas collection well or trench. For landfills that are being capped, there are several final cover systems options, and they usually either utilize clay, geomembrane, or a geosynthetic clay liner (GCL) as its impermeable barrier. The federal Subtitle D regulations, 40 CFR 258 require that “the final cover system must be designed and constructed to have a permeability less than or equal to the permeability of any bottom liner system or natural subsoils present, or a permeability no greater than 1 x 10-5 cm/sec, whichever is less.” This requirement is mainly to minimize rain/water infiltration into the landfill and to control odors, but it also helps increase the effectiveness of gas control systems installed in landfills.

III-6 D. GAS RECOVERY

Typical gas recovery systems in use today (see Figures 8 and 9) employ landfill gas trenches and/or extraction wells. They typically consist of perforated or overlapping pipe casing placed in the refuse, backfilled with permeable material (such as gravel), and sealed with impermeable material to prevent the inflow of air. Suction is applied to each extraction trench and well to withdraw the gas and transport it to a processing area by means of a pipe network referred to as a gas collection header. A motor/blower unit or compressor is usually the source of the applied suction. The landfill gas is typically combusted in a specially designed flare to insure efficient combustion. The gas extracted from the landfill with a motor/blower or compressor usually undergoes some sort of dehydration or moisture knock-out (see Figure 10).

Landfill gas can be used directly “as is” or upgraded to a higher heating value. Medium-Btu gas can be used or sold for industrial boilers-burners, cogeneration (heat and electricity), electrical generation, on-site space heating and/or hot water heating, lighting, and recreational uses. Landfill gas can be upgraded to pipeline standard (high-Btu) gas for injection into nearby utility company pipelines. Processed landfill gas can also be used to fuel conventional vehicles with converted carburetion systems.

Raw landfill gas can be used for space heating or hot water heating. The only processing required may be simple water and particulate removal depending on the make-up of the landfill gas. There is no need for an elaborate and expensive processing technology. Furthermore, since such uses do not require large volumes of gas, they are suited to the many smaller landfills across the country.

Pipeline quality gas (upgraded to about 1,000 Btu) can be used for any application for which natural gas is used. Consequently, most large landfills pursue this application of landfill gas. In addition to moisture and particulate removal, processing includes CO2 and trace compound removal.

No matter what the application, the recovery system contains a gas collection system, which includes the following components.

1. Pipe and Associated Materials

Typically, polyvinyl chloride (PVC), high-density polyethylene (HDPE), and/or fiberglass- reinforced plastic (FRP) pipe is used for landfill gas collection systems.

PVC is produced by refining petroleum into naphtha, then to ethylene. Ethylene and chlorine are then combined to form vinyl chloride which is reacted with a catalyst to form PVC. The PVC resin (or powder) is then mixed with a variety of additives to form the desired specific formulation of PVC required. The additives can include pigments, lubricants, stabilizers, and modifiers. The amounts and types of these additives have a significant effect on the final PVC product. For example CPVC pipe (chlorinated PVC) exhibits better temperature resistance than regular PVC.

PVC formulations used for piping purposes contain no plasticizers and little of the other ingredients mentioned. These are known as rigid PVC’s and are differentiated from the plasticized, or flexible PVC’s, such as those used to make upholstery or luggage.

III-7 Standards for PVC pipe are given in ASTM D 1784. This identifies PVC with six different cell classes, which group the pipe by various physical characteristics. Most of the time in landfill gas collection work, the designer must decide between Schedule 40 and Schedule 80. Schedule 40 is a thinner walled pipe than Schedule 80 and cannot be threaded. Schedule 80 PVC pipe may be threaded and is used for more severe applications at higher working pressures.

PVC’s in general can be joined by adhesive heat, or mechanical methods. Rigid PVC pipe is usually joined by adhesives. There are specific types of adhesives recommended for use with both Schedule 40 and 80 pipe, and one must be careful to use the appropriate type.

PVC pipe has excellent resistance at room temperature to salts, alcohol, gasoline, ammonium hydroxide, and sulfuric, nitric, acetic, and hydrochloric acid, but may be damaged by ketones, aromatics, and some chlorinated hydrocarbons. PVC becomes excessively brittle below 40°F, and the maximum temperature ranges from 150 to 220°F depending on the type of PVC. PVC pipe will not support combustion.

Polyethylene (PE) pipe is made from high-density polyethylene (HDPE). HDPE is a thermoplastic material polymerized from ethylene at controlled temperatures and low pressures. Ethylene is a member of the olefin group that also includes propylene and butylene. This helps to account for HDPE’s waxy feel.

HDPE’s are generally divided into two density ranges: 0.941 to 0.959 gms/cc, and 0.960 to 0.963 gms/cc. Polymers having densities lower than 0.960 gms/cc are manufactured by polymerizing ethylene in the presence of an alpha olefin comonomer such as butane-1 or hexane-1. The comonomer’s presence is included in order to control the crystalline structure, and therefore the chemical and physical properties of the HDPE. The types of HDPE pipe used in the landfill gas industry fall into the lower density category mentioned above. This lower density results in an improvement in impact resistance, environmental stress crack resistance, and flexibility. ASTM D 1248 classifies PE’s into four types, depending on the density of the natural resins.

HDPE pipe is classified according to ASTM D 2513, which employs a four-digit material designation code. This specification defines the polyethylene pipe types most familiar to those in the landfill gas industry (e.g., PE 3408). Because of the wide variety of polyethylene pipe materials used today, an additional ASTM standard (D 3350) was developed to augment ASTM D 2513.

HDPE pipe must be joined by heat methods. Pipe segments and fittings are fused to one another at temperatures in the 400ºF range. Different thicknesses and types of pipe require different temperatures. There is no known suitable chemical adhesive for polyethylene.

Fiberglass-reinforced plastic (FRP) piping typically is noted for its thermal and dimensional stability, chemical resistance, strength, durability, and good electrical properties. Epoxies reinforced with fiberglass have very high strengths and resistance to heat. Chemical resistance of the epoxy resin is excellent in nonoxidizing and weak acids, but not good against strong acids. Alkaline resistance is excellent in weak solutions. The glass reinforcement is many times stronger at room temperature than plastics, does not lose strength with increasing temperature, and reinforces the resin effectively up to 300°F. It is intended for long, straight runs rather than for systems containing many fittings. The glass reinforcement is located near the outside wall, protected from the contents by a thick wall of resin and protected on the

III-8 outside by a thin wall of resin. Chemical resistance may be affected by any exposed glass. Epoxy resin has a higher strength at elevated temperatures than polyester resins, but is not as resistant to attack by some fluids.

Polyester resins reinforced with fiberglass have good strength and chemical resistance, except to alkalies. Some special materials in this class, based on bisphenol, are more alkali resistant. The recommended service temperature range is 0 to 220°F. The pipe is rated as self- extinguishing.

When selecting the material to use, a number of factors should be considered. Ultimately, the service life of a pipe material will depend on the intrinsic durability of the material and the conditions under which it is exposed during service.

Some of the specific factors that must be considered when selecting a pipe material are discussed below.

Chemical Resistance--

Extensive research has been done on the chemical resistance of plastic pipe materials and numerous charts are available that give the relative resistance of a material to a specific chemical. Not as clearly understood, however, is the resistance of plastic materials to the mixtures of chemicals that may present themselves to a pipe in actual service conditions in the landfill environment. Research done by the U.S. Environmental Protection Agency (EPA) on plastic materials used for linings has shown a wide variety of changes in physical properties can occur after exposure simulating service conditions. Among these are large weight gains (swelling) and loss of strength.

Strength--

Pipe strength is dependent on the type of material the pipe is made from, the wall thickness of the pipe, and its installation. In most landfill gas collection systems, the collector pipes are not buried very deeply (typically less than 10 feet). Some collection trenches in deep canyon landfills can have as much as 200 feet to 400 feet of refuse above them. Materials utilized in these circumstances must be able to withstand the overburden. Many successful uses of polymer or asphalt coated corrugated steel pipe has been used in these circumstances. For typically shallow landfills, however, since the collector pipes are operating under a vacuum, one must consider both the vacuum in the pipe, which is tending to pull it in from the inside, as well as the dead load on top of the pipe, which is tending to crush it from the outside. Additionally, any live loadings (such as at a road crossing) must be considered.

Rigid and flexible pipe deals with strength in the service environment in two very different ways. With rigid pipe, the strength of the pipe itself is the predominant source of support against crushing. Flexible pipe relies on the backfill around it to act as a system (pipe and soil) to resist crushing.

Strength considerations for both HDPE and PVC pipe have been extensively researched and are well documented in manufacturer’s literature. Published strength characteristics are specified at certain temperatures. Actual service temperatures are very important and must be considered in designing the pipe system so that changes in strength characteristics due to elevated temperatures are accounted for in the material selected.

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Stress Cracking--

There are four types of stress cracking that can occur in plastics under certain conditions. They are:

 Environmental.  Solvent.  Thermal.  Oxidative.

All plastics are subject to solvent, thermal, or oxidative stress cracking when improperly applied or installed. Of the four categories above, environmental stress cracking is the only one that is restricted to Type IV density HDPEs. Most all of the PE 3406’s and 3408’s have excellent resistance to environmental stress cracking, because they are produced from high molecular weight copolymers.

Thermal Expansion and Contraction--

All materials change dimensions as a result of temperature changes. A temperature increase results in an increase in size, a temperature decrease results in a decrease in size. HDPE and PVC differ greatly in their respective changes in size as temperature changes. PVC expands 0.00003 inches per inch of length per degree F of temperature change. HDPE pipe is three times that at 0.00009 inches/inch/degree F. In a buried environment, where the temperature fluctuations should be minimal and the pipe is supported on all sides by soil, thermal expansion is of less concern. However, in systems where the collector pipes are above ground, thermal expansion and contraction must be accounted for in the design.

Weather Resistance--

Changes in the physical properties of plastic pipe can be caused by various kinds of exposure to the outdoor environment. Weather effects can be minimized or eliminated by the proper storage and installation of the pipe. Materials not protected from ultraviolet radiation with the addition of carbon black (e.g., PVC) should be protected both during storage and in service to prevent degradation from UV radiation. Certain UV resistant coatings can be applied to the pipe.

Header In – Line Isolation Valves--

Isolation valves are typically installed to accommodate isolation of various portions of the landfill gas collection system. Isolation of sections is often required due to system maintenance, system expansion, or removal of sections due to landfill operations. Isolation valves should be constructed of corrosion resistive materials such as PVC, HDPE, or certain coated metals. The location of the isolation valve should also be at high points of the landfill gas collection system. This will prevent the accumulation of condensate if the valve was in the closed position. A buried valve installation will require valve stem extensions, which will enable the technician to operate the valve above ground. The installation of an isolation valve may require an increase in maintenance costs. Failure of the valves may be due to damage valve liner, damaged valve stem extension, or leakage due to faulty tightening of fasteners. However, the proper placement and installation of isolation valves will provide an enhancement of the operation of the landfill gas collection system.

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2. Blowers and Compressors

A blower or compressor is used to create a vacuum to withdraw the landfill gas from the landfill gas collection trenches and wells and transport it to the processing location. Many types of blowers and compressors have been used for landfill gas recovery. The amount of gas, the vacuum required for collection, and the pressure required for processing or end use of the gas are key factors in selection of an appropriate blower or compressor. The selection of the properly sized blower or compressor may be influenced by the expected operating and maintenance costs of the equipment. As an illustration, the installation of a variable speed controller enables the blower equipment to speed up or slow down which may decrease the expected electrical operating costs. The variable speed controller reacts to a set point, which may be either a pressure or flow signal from a particular sensor.

When ordering a blower or compressor, consideration must be given to the material of construction due to the corrosive nature of the gas. Most manufacturers offer units constructed from a variety of materials and optional protective coatings. Landfill gas control and recovery systems have used blowers and compressors from many different manufacturers including Aerovent, Allis Chalmers, Gardner-Denver, Hauck, Hoffman, Paxton, Roots, Ingersol Rand, Cooper Bessemer, etc.

The amount of free water and particulates within the process stream should be minimized. There are three types of blowers in use in landfill gas systems. A brief description of each type of machine as well as the advantages and disadvantages of each are as follows:

Centrifugal Blowers (Single and Multi-Stage)--

Centrifugal units are classified as “constant pressure (or vacuum), variable volume (flow)” machines. In other words, variable flow rates may be achieved across the entire performance curve. Flow variation is achieved by use of a butterfly valve attached to the inlet of the unit. Advantages and disadvantages are:

Advantages (Single Stage)

 Easy to operate.  Simple.  Low cost.

Disadvantages (Single Stage)

 Low head pressure.  Should be protected against surge.

Advantages (Multi-Stage)

 Higher head pressures possible.

Disadvantages (Multi-Stage)

 Must be protected against surge.

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Positive Displacement Lobe Type Blowers--

Positive displacement or rotary lobe units are the opposite of centrifugal units. They are classified as “constant volume, variable pressure” machines. Volume may only be varied by a speed change of the rotating lobe via a variable frequency controller or sheave adjustment ratio change. Advantages and disadvantages are:

Advantages

 Higher discharge pressure.  Fixed flow rate.

Disadvantages

 Noisy.  Fixed flow rate.  More subject to damage from landfill gas than centrifugal blowers.

3. Flares and Flame Arresters

Open Flame Flares--

Open flame flares, also known as “candle” or “utility” flares, have been widely used on landfills for years. Utility flares offer an economical method of disposing of the landfill gas.

However, sophisticated pipe flares (operating at higher flow rates and tip velocities) require flame stabilizers to prevent the flame from extinguishing itself. Also in these units, windshields allow the flame to establish itself and resist high wind conditions, and automatic energy-saving pilots sense the landfill gas flame and automatically relight the flare, if necessary. Flame verification typically employs thermocouple and Ultra-Violet detection technology. The operation of open flame flares may require local air permits and must meet the requirements of 40 CFR 60.18, which outlines the operation of an open flare. It is recommended that permitting of flare equipment be coordinated with a consultant, which is familiar with local and federal environmental regulations. NSPS/EG control requirements can be met by an open flare designed and operated within the limits of 40 CFR 60.18.

Enclosed Flares--

Enclosed flares (also known as ground flares) differ from open flame flares in that both landfill gas and the air flows are controlled. While landfill gas is “pushed” through the flame arrester and burner tips by a blower, the flare stack “pulls” or drafts the air through air dampers and around the burner tips.

Enclosed flares are used in landfill gas applications for one of two reasons (to hide the flame and control the emissions). Enclosed flares designed solely to hide the flame are often referred to as “invisible flares.” These flares are normally characterized by a short stack height of 20 to 30 feet. Residence times are typically about 0.3 seconds.

At full landfill flow rates, the flame inside an invisible flare is often close to the top of the flare. In many cases, invisible flares are designed to enclose the “flame envelope,” but allow “tails” of

III-12 flame to burn above the top of the flare. As landfill gas is primarily methane and carbon dioxide, the flame tails are clear and might only be seen at night. Emissions from invisible flares are very dependent upon the landfill gas flow and methane concentration.

Enclosed flares used to minimize NOx, CO, and hydrocarbon emissions, while at the same time maximizing the destruction of trace compounds such as vinyl chloride and aromatic compounds, are known as emission control enclosed flares. These requirements are often contradictory, requiring design compromises to maximize the flare performance. For example, high operating temperatures reduce CO and hydrocarbon emissions, but also increase the NOx levels. The enclosed flare should be designed not only to meet today’s emission regulations, but should also be able to operate at more stringent conditions if needed by future regulations.

Emission control enclosed flares are characterized by a 35 to 50 feet overall height. The additional height is a key design requirement for emission reduction as the flare height provides the draft and mixing energy for the landfill gas and combustion air.

Enclosed flares utilized for demonstrating NSPS/EG compliance must comply and be tested in accordance with regulatory requirements.

In order to prevent a flashback of combusting gases from the flare through the process station and collection system, a flame arrester is inserted in the inlet line to the flare. Typically, the material of construction for flame arresters is stainless steel, aluminum, or other metal alloys.

Flame arresters installed in the horizontal position should have a means of drainage. Flame arrester elements should also be designed so that they are removable for easy cleaning.

A flame arrester should be installed immediately upstream of all flares and an automatic shutdown valve installed in cases where free gas can be vented in an area which may be hazardous. The capital investment of enclosed flares also requires the installation of concrete pads, electrical infrastructure, and mechanical piping. As a result, it is important that the design consultant be familiar with environmental regulations and local civil design regulations.

4. Condensate Handling

Condensate traps must be designed to continuously drain condensate from landfill gas header and transmission lines under both negative and positive operating pressures, and still maintain a seal between the gas stream and the atmosphere. This is most easily accomplished with a U- tube constructed of the same material as the pipe transporting the gas, and properly designed to handle the anticipated condensate and vacuum in the system. Condensate drainage points are typically installed at low points in the landfill gas collection system. Liquids, which are collected in the low point of the U-traps may be gravity drained to a central collection tank via a force main. Force mains may be buried in the common ditch with the buried header system. The U-traps are typically the point of highest maintenance due to the potential buildup of sediment and liquids in the low points of the system. The design of the U-trap must be designed to prevent the carryover of water into the landfill gas collection system.

The condensate knockout system achieves liquid removal by decreasing the velocity of the landfill gas, which allows the liquid droplets contained in the gas stream to drop out and drain to the condensate collection device.

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What can be done with collected condensate depends on the regulations governing the site. Currently, the three most common options are:

 Return to the landfill. This can only be done in synthetically lined Subtitle D landfill cells.

 Pipe directly into the sewer line for treatment at a wastewater treatment plant.

 Collect and hold in storage tanks on site for periodic removal, treatment, and disposal at a wastewater treatment plant.

The equipment and material used in items b and c above will include pipe, pumps, sumps, and storage tanks. As with gas-carrying system components, all condensate handling components should be corrosion resistant. PVC and PE are the most common types of piping material used for condensate handling. It is recommended that piping used to transport out of solid waste fill be double walled to contain leaks. Many sites are also using double walled tanks for storage of condensate. Landfill owners/operators and engineers should check with the local regulatory bodies to ascertain specific requirements on this.

5. Water Knockout Scrubbers

Water scrubbers or knockout vessels are often used on control and recovery systems to remove liquids (primarily water) in order to keep the gas from causing corrosion or line freeze-ups.

Water entrainment should not normally exceed one gallon/million cubic foot landfill gas carryover. Consequently, water knockout scrubbers are recommended upstream of blowers, compressors, and pumps. The typical water droplets should not exceed 25 microns in size. Scrubbers should be drained using a negative pressure water trap.

6. Liquid Removal Pumps

If condensate cannot be drained via gravity it will be necessary to install a system of pumps to assist in the removal of the liquids. The selection of the proper pumping system must address issues such as; capital investment, and hydraulic calculations of force main. Pumping systems may be either electrical or pneumatic.

Electrical Pumps--

Electrical pumps are typically submersible and constructed of corrosion resistant materials. The operation of the pump is controlled by a liquid level control mechanism. Also, a high liquid level float is also employed to notify the operator of the improper operation of the pump. Pumps must be installed at low point locations in vessels, which allow sufficient holding capacity of liquids. The installation of electrical pumps may be limited due to available electrical supply at the facility. Pump selection should be verified with an electrical engineer to verify sufficient electrical service. These pumps require extensive maintenance due to the mechanical equipment and the sediments, which are entrained in the liquid, may damage the pump impellers.

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Pneumatic Pumps--

Pneumatic pumps are constructed of corrosion resistant materials. The operation of the pump is controlled by air driven piston, which pushes the liquid out of the pump and into the force main. Pumps are installed at low-point locations in vessels, which allow sufficient holding capacity of liquids. The installation of these pumps requires sufficient air pressure of approximately 60 to 80 psi. As a result, an air supply line has to be installed to each pump location. This pump system is typically less maintenance than the electrical submersible pump alternative. These pumps typically will supply sufficient pumping capacity for the effective removal of condensate. However, the pneumatic pumps system will have a lower pumping rate when compared to the electrical pumping systems.

7. Electrical Equipment and Fixtures for Processing Stations

Processing station electrical equipment and fixtures should typically be classified as Class 1, Division 2, Group D of the National Electric Code. A distance of 10 feet from gas handling equipment should normally be adequate to make the area non-classified. Guidelines for classification should be API, recommended practice 500B, or NFPA 70C. Some local codes may be more restrictive than the aforementioned, and should be examined prior to design. Generally, NEMA 7 explosion proof enclosures should be used in areas near the flare and blowers and NEMA 4 enclosures used in other areas.

Electrical installations should be in accordance with API RP 540 and National Electrical Code or local codes where applicable.

Any areas with gas handling or processing equipment should have a fence with a minimum of 8 feet in height with barbed wire on top.

8. Landfill Gas to Energy Supplemental Information

Wells--

Well Bore and Pipe

There are currently no special or alternative materials used in the design or construction of a landfill gas extraction well that is used for supplying landfill gas to a beneficial use project, as opposed to a control/flaring use. There are differences possible in terms of well spacing, depth or details such as perforated depth, but these are design issues.

Dewatering

In order to maximize landfill gas flow from wells for a beneficial use project, more aggressive dewatering of fluids in the well is often done. The equipment used to do this consists of a pump placed in the well, and the necessary piping needed to support the pump. Materials and equipment typically used in the industry may include:

Electric Pump

In the past, some landfills used electric operated down-well pumps. These are rarely used today due to concerns with having an electrically powered device operating in a potentially

III-15 explosive environment. When they are used, it is essential that the pump always remain submerged to prevent the possibility of explosion. Also, it is necessary to use all explosion- proof equipment in the electric supply chain to the pump.

Pneumatic Pump

Due to the concerns stated above, coupled with technical improvements in the pumps themselves, the most common, and preferred, type of pump is pneumatic. There are variety of manufacturers and styles available and the specific type and capacity should be determined by an expert with experience in designing and specifying these dewatering pumps.

Power/Air Supply Lines to Pumps

1. Electric: As mentioned above, if used, electric supply lines to down-well pumps should be of materials suitable for hazardous environments (including explosion-proof), all-weather, and able to withstand the harsh environment of a landfill gas well.

2. Air supply lines: All of the above applies with the exception of explosion-proof, since there is no possibility of a spark source.

Discharge Lines from Pump

With either electric of pneumatic pumps, the discharge line should be an HDPE or similar material that is compatible with leachate/condensate.

Well Head

In landfill gas collection systems that are not supplying landfill gas to a beneficial use project, there are still in use, well heads that are able to allow the measurement and adjustment, at the well head, of landfill gas flow from the well. However, in a beneficial use project, it is critical that individual well flow be able to be measured, and often the wells are adjusted based on flow (as opposed to well head vacuum, for example). There are a variety of well head assembly designs that allow for the measurement of flow. They range from assemblies pieced together from in the field from various sourced parts, to complete ready-to-install well heads from specialty manufacturers. In all cases, the materials and equipment used should be of types and styles that are compatible and resistant to the environment that they will be used: PVD, HDPE, stainless steel, etc.

Laterals/Headers--

Materials

The materials and equipment used for landfill gas beneficial use for the lateral and header portions of a system are the same as for landfill gas collection for control: HDPE and PVC being the most common.

Valving

Valve materials and equipment for beneficial use are the same as for control projects – butterfly valves made of corrosion resistant material.

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Blowers/Compressors--

Materials

The materials and equipment used for supplying the vacuum/pressure necessary for a beneficial use project are the same as for control projects. The main difference encountered in beneficial use projects is that higher discharge pressures are often needed for beneficial use, and, as a result, higher capacity/pressure compressors are used. There are several types of compressors available, including screw, sliding vane and others; the specific selection is an engineering design/specification issue. In any case, the materials must be corrosion resistant, and compatible with landfill gas.

Metering/Measurement--

The Metering and Measurement landfill gas is a feature of beneficial use projects that is usually not done with as much precision or sophistication in control projects. The equipment used includes:

 Gas Chromatograph to determine the Btu content of the gas.  Thermal mass flow meter to measure the volume rate of the gas.  Programmable Logic Controller (PLC) to accumulate the Btu energy metered.

Each of these is described briefly below specific manufacturers and models should be determined by professional experienced in the selection and design of this equipment.

Gas Chromatograph

 Chromatograph.  Controller.  Sample conditioning.

Gas Volume Measurement

Landfill as volume is usually measured by a thermal mass flow meter. The manufacturer and model should be determined by an expert in the field.

Programmable Logic Controller (PLC)

There are a variety of PLC manufacturers that make equipment suitable for use in the metering and measurement of landfill gas.

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FIGURES

GLOSSARY OF HEALTH AND SAFETY ACRONYMS

GLOSSARY OF HEALTH AND SAFETY ACRONYMS

ACFM - Actual cubic feet per minute

ACGIH - American Conference of Governmental Industrial Hygienists

ANSI - American National Standards Institute

API - American Petroleum Institute

APRs - Air-purifying respirators

BACT - Best Available Control Technology

C - Ceiling exposure limit

CAA - Clean Air Act

CERCLA - Comprehensive Environmental Response, Compensation, and Liability Act

CFM - Cubic feet per minute

CFR - Code of Federal Regulations

CGA - Combustible gas analyzer

CGCs - Compressed gas cylinders

CH4 - Methane

CO2 - Carbon dioxide

GFCI - Ground-fault current interrupter

DOT - Department of Transportation

EG - Emissions Guidelines

FID - Flame ionization detector

FM - Factory Mutual

GAC - Granular activated carbon

GC - Gas chromatograph

H2S - Hydrogen sulfide

HDPE - High-density polyethylene

HEPA - High-efficiency particulate filter

IDLH - Immediately Dangerous to Life and Health

LEL - Lower explosive limit

LFG - Landfill gas

LFGCCS - Landfill gas collection and control system

MSDS - Material Safety Data Sheet

MSW - Municipal solid waste landfill

MUC - Maximum Use Concentration

MUL - Maximum Use Limitation

N2 - Nitrogen

NEC - National Electric Code

NFPA - National Fire Protection Association

NIOSH - National Institute of Occupational Safety and Health

NMOC - Non-methane organic compounds

NREL - National Renewable Energy Lab

NSPS - New Source Performance Standards

O2 - Oxygen

OM&M - Operation, maintenance, and monitoring

OSHA - Occupational Safety and Health Act

OVA-FID - Organic vapor analyzer-flame ionization detector

OV/AG - Organic vapor/acid gas

PEL - Permissible Exposure Limit

PF - Protection factor

PID - Photo ionization detector

PLC - Program logic controller

PPM - Parts-per-million

PSIA - Pounds per square inch absolute

PSIG - Pounds per square inch gage

PVC - Polyvinyl chloride

RCRA - Resource Conservation and Recovery Act

REL - Recommended Exposure Limit

ROG - Reactive organic gases

SCBA - Self-contained breathing apparatus (pressure demand type)

SCFM - Standard cubic feet per minute

SO2 -

SWANA - Solid Waste Association of North America

TCD - Thermal conductivity detector

TLV - Threshold Limit Value

TLV-STEL - Threshold Limit Value/Short-Term Exposure Limit

TLV-TWA - Threshold Limit Value/Time-Weighted-Average

TNMHC - Total non-methane hydrocarbons

TOC - Total organic carbon

UEL - Upper explosive limit

USEPA - United States Environmental Protection Agency

UL - Underwriters Laboratories

VOC - Volatile

LIST OF HEALTH AND SAFETY INFORMATIONAL WEBSITES

LIST OF HEALTH AND SAFETY INFORMATIONAL WEBSITES

General Health and Safety Websites

National Safety Council: www.nsc.org

 Information on chemicals.  Training.  Fact Sheets.

Occupational Health and Safety Administration: www.osha.gov/

 Laws and regulations.  OSHA field office locations.  Publications/research.

Federal Code of Regulations: www.gpoaccess.gov/cfr

 Code of Federal Regulations.

National Fire Protection Association: www.nfpa.org/

 Fact Sheets.  Codes and standards.  Research and reports.

Centers for Disease and Control and Prevention – National Institute of Occupational Safety and Health: www.cdc.gov/niosh/homepage.html

 Chemical safety.  Respirator Fact Sheets.

American Society of Safety Engineers (ASSE): http://www.asse.org/

 Fact Sheets.  Consensus standards.  Publication on health and safety topics.

American Industrial Hygiene Association (AIHA): http://www.aiha.org/

 Information on chemical hazards.

 Consensus standards for safety and health.

 Publication on health and safety topics and links to other sites for numerous health and safety topics.

Accident Prevention Plan

Washington State of Labor and Statistics - Outlines requirements for an effective accident prevention plan: http://www.lni.wa.gov/wisha/rules/corerules/HTML/296-800-140.htm - WAC296-800-14005

Hazard Communication

OSHA - Assists in complying with requirements of standard as well as information on interpretations and compliance assistance: http://www.osha.gov/SLTC/hazardcommunications/

CAL/OSHA - Informative publication on compliance with the Hazard Communication Standard: http://www.dir.ca.gov/dosh/dosh_publications/hazcom.pdf - search='hazard%20communication'

Hearing Conservation (Noise)

National Hearing Conservation Association - Offers information on hearing conservation publications and research and related links: http://www.hearingconservation.org/

OSHA - Information on hearing conservation topic: http://www.osha.gov/SLTC/noisehearingconservation/

Respiratory Protection

OSHA - Information on the respiratory standard and use of equipment: http://www.osha.gov/SLTC/respiratoryprotection/

Chemical Hazards

NIOSH Pocket Guide - Gives physical and chemical properties and hazard information for numerous chemical compounds: http://www.cdc.gov/niosh/npg/

CHRIS - Manual on emergency response to chemical hazards from the U.S. Coast Guard: http://www.chrismanual.com/toc.htm

Air Monitoring

SKC - Distributor of various types of real-time air monitoring devices for vinyl chloride, H2S, organics, and dust; has helpful information on available equipment for various types of monitoring applications: http://www.skcinc.com/

Beginners’ Guide to http://www.ees.adelaide.edu.au/pharris/biogas/beginners.html

Safety http://www.ees.adelaide.edu.au/pharris/biogas/safety.html Biogas Safety Devices for Sale http://www.varec-biogas.com/services.asp

Biogas and Safety http://www.biogas.psu.edu/Safety.html REFERENCES REFERENCES

1. American Conference of Governmental Industrial Hygienists. Threshold Limit Values and Biological Exposure Indices for 1990-1991.

2. California Administrative Code, Title 8, General Industry Safety Orders, State of California Department of Industrial Relations.

3. California Administrative Code, Title 8, Section 5155 (General Industry Safety Order 5155), Airborne Contaminants. State of California Department of Industrial Relations. November 1986 (Reprint).

4. California Administrative Code, Title 8, General Industry Safety Orders, Article 108, Confined Spaces. March 1990 (Reprint).

5. California Administrative Code, Title 8, General Industry Safety Orders Section 5144, Respiratory Protective Equipment. September 1985 (Reprint).

6. CHRIS Hazardous Chemical Data, U.S. Department of Transportation, United States Coast Guard, November 1984. Commandant Instruction M.16465.12A, November 1984.

7. Code of Federal Regulations, Title 29, Labor, Part 1910, Occupational Safety and Health Standards, 1990.

8. Code of Federal Regulations, Title 29, Labor, Part 1926, Safety and Health Regulations for Construction, Occupational Safety and Health Administration, 1990.

9. Code of Federal Regulations, Title 29, Labor, Part 1910.95, Occupational Noise Exposure, Occupational Safety and Health Standards, Occupational Safety and Health Administration, 1990.

10. Code of Federal Regulations, Title 29, Labor, Subpart I-Personal Protective Equipment, Occupational Safety and Health Standards, Occupational Safety and Health Administration, 1990.

11. Code of Federal Regulations, Title 29, Labor, Part 1910.134, Respiratory Protection, Occupational Safety and Health Standards, Occupational Safety and Health Administration, 1990.

12. Code of Federal Regulations, Title 29, Labor, Part 1910.1000, Subpart Z - Toxic and Hazardous Substances, Occupational Safety and Health Standards, Occupational Safety and Health Administration, 1990.

13. Code of Federal Regulations, Title 29, Labor, Part 1910.1200, Hazard Communication, Occupational Safety and Health Standards, Occupational Safety and Health Administration, 1990.

14. National Fire Protection Association, Fire Protection Guide, 16th Edition, National Fire Protection Association, Batterymarch Park, Quincy, MA 02269, 1986. 15. U.S. Department of Health and Human Services, NIOSH Guide to Industrial Respiratory Protection, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication, No. 87-116, September 1987.

16. U.S. Department of Health and Human Services, NIOSH Pocket Guide to Chemical Hazards, DHHS (NIOSH) Publication No. 90-117, National Institute for Occupational Safety and Health, Cincinnati, OH, June 1990.