DECENTRALIZED TREATMENT: Moving toward Sustainability

Jim Kreissl USEPA ORD, retired WHAT IS “SUSTAINABILITY”?

• Most accept the Brundtland Commission’s definition: “…development that meets the needs of the present without comprimising the ability of future generations to meet their own needs.” Another definition is “meeting the needs of humans and nature for the long term” DEPICTION OF SUSTAINABLE DEVELOPMENT DECISION-MAKING

Social Equity

Environment Economy TYPICAL ONCE-THROUGH URBAN WATER MANAGEMENT SYSTEM

Precipitation Water supply

Urban area

Water returned directly (storm sewers) and indirectly (sanitary sewers) to surface waters often several drainage basins downriver from water supply source HOW DOES SUSTAINABILITY APPLY TO WATER QUANTITY ISSUES?

• The urban (once-through) approach with conventional centralized technology has proven to worsen soil drying by lowering ground water tables due to infiltration into leaky, deeply-buried (typically 25 ft or more) sewers, while reducing sewer capacity to carry (eg, Boston and Long Island) HOW BAD ARE THESE LOSSES?

• In the Boston area, 60% of the sewer capacity is used for carrying “clear water’ from infiltration • USEPA’s own standards for acceptance of newly constructed sewers could result in clear water using 40% of pipe capacity when the sewer is below the water table WHAT ARE THE IMPACTS ?

• Residential, agricultural, industrial, and community wells needs to be extended deeper to retain capacity, increasing costs and energy required to operate. • Cities are asking huge rate-hikes to upgrade existing leaky sewers that mostly carry infiltrated water and to expand treatment facilities that are treating mostly “clear” water. ANY OTHER WATER QUANTITY ISSUES? • Lots!! Starting with stream flow issues… Because storm-sewer based development quickly misdirects that would normally infiltrate the soil directly to ground water, resulting in local stream overflows during these wet periods and abnormally low flows during dry ones • The overall effects include depleted aquifers and reduced evapotranspiration which can cause heating and drying of the land FATE vs DEVELOPMENT HOW DOES THIS RELATE TO WATER QUALITY? • The biggest source of surface water contamination in the US is storm runoff from agricultural fields and urban areas • Excessive, first-flush, runoff leads to flashy streams that erode stream banks and become polluted with sediment, pathogens, and nutrients • Ground water quality degrades faster without dilution from percolation of precipitation that forests, prairies, and other pervious areas provide TYPICAL RURAL WATER MANAGEMENT

Water from private/public wells Precipitation

Rural community or single dwelling

Indoor usage returned to Most precipitation and outdoor local ground water after soil treatment usage returned to local ground water TRADITIONAL SEPTIC SYSTEMS HOW ABOUT NUTRIENTS FROM ONSITE SYSTEMS?

• Modeling data imply onsites can make a major nutrient contribution to nearby surface waters based on their presence in the area • TMDLs must be performed on local watersheds to show the relative amount of total pollutant contributions that are from septic systems. • Onsite systems located in riparian zones (especially in karst, fine soils, and steep slopes) can contribute significant levels of nitrogen to receiving waters, so that more complex onsite designs are needed in those areas.

PHOSPHORUS

• Phosphorus is generally removed from the effluent as it passes through the soil after infiltration • Since P-removal is dependent on soil surface area and reactivity, it generally reduces with time • Uniform dosing/resting high in the soil profile maximizes the capability to remove P from the effluent. • If reuse for is planned, P-removal would be counterproductive ONSITE SYSTEM MAJOR CONTAMINANTS • The primary contaminants from poorly-sited or poorly-performing onsite systems are pathogens, which is the #1 stream contaminant that comes from human wastes and runoff • In most cases, wastewater nitrogen travels to ground water and then to nearby surface waters fed by those aquifers (controlled by soil characteristics, hydrogeology, and technology) • Phosphorus is generally removed by local soils • EDCs and other unregulated chemicals are likely better removed in the soil than by treatment plants WHAT IS THE DECENTRALIZED APPROACH? • It is a holistic, cost-efficient method of solving water quality and quantity problems. • It requires an effective and sustainable management program. • It targets the biggest problem areas and minimizes infrastructure investment. • It employs simple technologies and maximizes soil dispersal and reuse opportunities. TYPICAL CHARACTERISTICS

• CENTRALIZED – Conventional gravity sewers – Single treatment facility – Discharge to surface water • DECENTRALIZED – Onsite or alternative collection system – Multiple treatment facilities – Discharge to ground water or reuse A VISUAL DESCRIPTION

Centralized Decentralized approach DECENTRALIZED/DISTRIBUTED PLANNING/DESIGN STRATEGY • Use the most passive technologies that can meet performance requirements • Reuse and aquifer recharge preferred over conventional receiving water discharge • Minimize inter-basin transfer of water • Management program is appropriate to technologies chosen • Maximize use of viable existing systems WHY IS THIS A GOOD THING?

• Existing Communities . Can solve wastewater and other water-related problems. . Minimal initial investment, “satisfy the need”.

• Developers . Allows more lots and greater open space. . Open and common areas can serve as soil dispersal and/or reuse facility locations and social amenities. . Increased developer profits and resident aesthetics. SO HOW CAN SUSTAINABILITY APPLY TO ONSITE AND DECENTRALIZED SYSTEMS?

• Local area and watershed management decisions need to be based on sustainable life-cycle costs and energy requirements of system components, as well as on community protection, vision, and aesthetics • Distributed wastewater management must be made an integral part of the land-use planning processes, local ordinance upgrades, and state regulations in order to approach sustainability • Onsite/decentralized systems can minimize energy demands required to maintain performance, promote reuse of wastewater and stormwater, and can be aesthetically pleasing and compatible with any community vision SO HOW CAN ONSITE AND DECENTRALIZED SYSTEMS IMPROVE SUSTAINABILITY?

• Compared to conventional sewer systems these technologies minimize the energy required to fabricate, transport, and construct through use of lightweight/recycled components, minimal transport costs/energy, and low-energy, less- time-consuming construction techniques • Decentralized wastewater and stormwater management approaches minimize impacts on local hydrology and enhance local community aesthetics, health, and economy while assuring needed quantity and quality of water resources to support long-term community goals CONVENTIONAL SEWERS THE CONVENTIONAL SEWER SOLUTION

Collection Pipe System – Deep (8 to 25 feet) pipes, with frequent (every 200-300 feet) , and lift stations to maintain gravity flow at minimum velocity (75 to 85% of total facilities cost) Treatment System – A single large treatment facility, usually some form of , with additional processes as necessary to meet discharge standards Discharge - Usually, direct surface water discharge; in some cases soil discharge is required, but in all cases extracted waters from several upstream basins are transferred to one downstream location COMPARISONS

• CENTRALIZED • DECENTRALIZED • Old and taught • New and not taught • High capital cost • Lower capital costs • Transfers water away • Keeps water close from source • Short, less-disruptive • Long, disruptive construction construction • Basic operations skills • Skilled operator need required WHICH DECENTRALIZEDTECHNOLOGIES ARE MOST OFTEN USED? Septic Systems – Most passive and effective system where local conditions permit. Better Pretreatment – Fixed-film and filter alternatives are more robust, perform more reliably, and need less O/M than activated sludge types. For special locations, membranes replace settling and attain reuse quality Better Soil Dispersal – The larger the system capacity, the greater the need for pressurized or drip distribution and resting to maximize soil contact time and treatment potential. Low-Cost Collection – Minimizes capital and O/M costs, infiltration/inflow, and construction duration and community disruption. LOW-COST COLLECTION SYSTEMS • Alternative collection systems (ACS) almost always have significantly lower capital costs • ACS reduces infiltration and inflow (I/I) owing to shallow burial, fewer and tighter joints, and lack of manholes • Require less community disruption and construction period duration LOW-COST COLLECTION SYSTEMS Effluent Sewers (STEG and STEP)

Composed of: interceptor tanks (& pumps for STEP) Shallow, small dia. mains w. fewer pipe joints Effluent Sewer and cleanouts (STEG) LOW-COST COLLECTION SYSTEMS System

Composed of: Grinder Pump small-diameter pressurized collection system Grinder/pump with controls Like vacuum, Grinder Pump System To Treatment leaves no residuals on lot LOW-COST COLLECTION SYSTEMS Vacuum Sewers Vacuum System is composed of: holding tanks with vacuum valves Small diameter collection pipes  Central vacuum collection Vacuum System station/no electric connection on lot

SINGLE-PASS MEDIA FILTERS

Inspection Service Riser

Inlet Outlet Pipe to Dispersal System Watertight Tank VEGETATED SUBMERGED BED AKA: SUBSURFACE FLOW WETLAND FLEXIBILITY TO MEET PERFORMANCE DEMANDS SOIL DISTRIBUTION

• Better distribution and shallow placement allows the entire soil infiltration area to be used: – provides better oxygen diffusion for aerobic treatment by microbes – increases the contact time between the wastewater and soil, and – enhances nitrogen removal PRESSURE DISTRIBUTION Drip Dispersal

Filtration Unit

Treatment Tank House

Well Pump Tank

Drip Tubing (2 Feet On Center) Shed

Property Line MANAGEMENT PROGRAM

• Distributed/decentralized solutions require a responsible management program • Most surveys show that homeowners are willing to pay about $30 to $40 per month for efficient wastewater services (most do) • The challenge is to develop an effective and sustainable WATER management program at the least cost to the community MORE BASIC MANAGEMENT PRINCIPLES

• The management entity does not need to perform every functional element of their management program. They can contract with trained and certified service providers to perform field work, or require citizens to enter into contracts with those service providers, overseen by the management program • Keep the community involved on review boards and advisory councils to reinforce their program ownership • Make compliance rules as friendly as possible, with transparent enforcement and monetary incentives • Involve the regulators in the process to avoid misinterpretations and build trust. WHAT ARE SOME TOWNS DOING?

• Converting sludge digesters to co-digestion energy generators by accepting local industrial/commercial organic wastes and producing reusable methane gas • Reusing stormwater and treated wastewater for irrigation of golf courses and municipal parks and flushing • Limiting impervious surfaces and storm sewers and maximizing reuse opportunities in new developments with cisterns and gardens • Using “just in time” infrastructure investments • Preserving the most ecologically valuable lands that sequester carbon and promote ecological processes • Providing economic incentives to reward homeowners and others for incorporating green concepts WHERE ARE DECENTRALIZED APPROACHES BEING USED? • There are scores of such distributed management and decentralized technology solutions employing decentralized technologies across the US • The following examples are categorized by the types of problems being addressed by them, but many more exist than these. PROTECTION /RESTORATION OF SURFACE WATERS

• Panarama, Iowa • Otter Tail Lake, Minnesota • Keuka Lake, New York • Georgetown Divide PUD, California • Stinson Beach, California • Charlotte County, Florida • Nags Head, North Carolina QUALITY PROTECTION

• Block Island, Rhode Island • Westbrook, Connecticut • Tisbury, Massachusetts • La Pine, Oregon • Willard, New Mexico MULTIPLE PROBLEMS

• Paradise, California – surface/ground water quality • Sea Ranch, California – surface water quality and hydraulic failures of septics • Pena Blanca, New Mexico – ground water quality and hydraulic failures of septics • Cuyler, New York – surface water quality and hydraulic failures of septics THANKS FOR YOUR ATTENTION

Any Questions?