ODOR CONTROL SYSTEM

What is an Odor? An odor is defined as a sensation resulting from the reception of a stimulus by the olfactory sensory system. Controlling odors is an important consideration for protecting the environment and our community amenity. Odors can be generated from a vast range of sources including sewage treatment processes and industrial effluents.

Odor Control Technologies Typical odor emission control applications are the removal of odor from sewage treatment plants & sewage wet waste. Odor related complaints from communities surrounding WWTPs have been increasing for many WWTPs. Here, several emission sources need odor control equipment, e.g. such as pump stations, wet wells, sludge dewatering, manholes, air valve chambers, and sludge trans-shipment operations from silo into trucks. Sewage odor consists of mainly hydrogen sulphide & H2S is dangerous to be released to the environment. Hydrogen sulphide, the gas, also contains organic sulphur components (mercaptans, hydrocarbons) and ammonia.

Odor control technologies can be grouped into three distinct categories:

1. Chemical Absorption (acid and caustic wet scrubbing)

2. Biological Oxidation (bio-filtration and bio-scrubbing / bio trinkling filtration)

3. Adsorption (activated carbon and other adsorptive medias)

4. The Combination of above systems are usually used for Biological Oxidation & Chemical Scrubbing

Chemical Absorption: Chemical scrubbers achieve odor removal by mass transfer absorption via contact of air stream with aqueous solution on random packing material in a scrubbing chamber.

The liquid is typically water, adjusted to the proper pH and CHEMICAL DOSING oxidation potential by chemicals. TANK CHEMICAL STORAGE TANK CHEMICAL Two parameters define the performance of any absorption SCRUBBER scrubbing system. These are the efficiency of gas/liquid CHEMICAL DOSING PUMPS CHEMICAL contact and the adequacy of a chemical within the aqueous SCRUBBER CHEMICAL CHEMICAL TANK CIRCULATION phase to promote reaction and absorption. Corodex Industries FILLING PUMPS FRESH WATER uses a special media which increases the efficiency of the TANK SOFTENER scrubber in smaller tower size. FEED PUMPS

Main features:

1. Scrubbing liquid make-up system AIR FAN 2. Scrubbing liquid re-circulation system 3. Scrubbing liquid discharge system SOFTENER 4. Scrubbing liquid system (chemical for adjusting the pH and ORP value ) 5. Ventilation system Odor Control System

Biological Oxidation Biological oxidation is a process by which the bacteria and other types of micro-organisms consume dissolved oxygen and organic substances in wastewater, using the energy released to convert organic carbon into carbon dioxide and cellular materials.

BIO SCRUBBER Biological oxidation is broken into two broad categories: 1. Bio-oxidation using inorganic media (bio-scrubbers or bio-trickling filters)

2. Bio-oxidation using organic media AIR FAN (traditionally referred to as biofilters)

Main features:

1. Scrubbing liquid make-up system 2. Scrubbing liquid re-circulation system

NUTRIENT DOSING 3. Scrubbing liquid discharge system PUMPS

4. Nutrient dosing system NUTRIENT TANK

5. pH controller system BIO CIRCULATION PUMPS 6. Ventilation system TSE MAKE UP PUMPS TSE TANK

Adsorption Adsorption is a process that uses activated carbon to adsorb odorous compound into activated carbon material. This is accomplished by passing the odorous air across a DEODORIZER bed of activated carbon, allowing the adsorptive process to occur and releasing the clean air to atmosphere. AIR FAN

Main features: DEMISTER

1. Prefiltration system (demister) 2. Ventilation system 3. Carbon media

Combined Technologies

When a situation arises, where an odor stream contains both high levels of H2S and significant level of organic sulfur compounds. In a combined systems consisting of 2 technologies become more pratical. For this particular instance, a first stage system such as a bio-scrubber or catalytic carbon system might be used for removing the CHEMICAL H2S. A second stage bio-filter system would then be SCRUBBER CLEAN AIR STACK OUTPUT ideal to treat the mercaptans and any remaining H2S, which at this point would be at a very low level. AIR FAN

CHEMICAL Another situation that often requires a combination DOSING PUMPS approach is that of odor control in sensitive areas. There are times when the odor source is quite close to facility fence line. Some odor control technologies BIO SCRUBBER have an odor unit level at their discharge that might not be acceptable if the neighbors are close to the fence line. For example, bio-filters have an effluent odor unit (OU) level between 200 and 400 OU. This level may

CHEMICAL represent a considerable reduction of odors prior to the STORAGE TANK bio-filter but may still be too high for the neighbors. In CHEMICAL TANK FILLING

this case, a solution would be to add a second stage OROROUS CHEMICAL AIR CIRCULATION activated carbon system to further reduce the OU level PUMPS

BIO SOFTENER FRESH to 100 or less. This odor control technique is known as CIRCULATION WATER TANK PUMPS polishing. SOFTENER FEED PUMPS FRESH WATER TANK SOFTENER Odor control technologies comparison chart

Odor Control Types of odor H2S Concentration Air ow range Eciency Technology treated ppm m3/h %

Adsorption VOCs, H2S, broad range of Peak Less than 250 500 - 15,000 Greater than 99% (Activated Carbon) compounds Average Less than 50

Bioscrubber VOCs, NH3, H2S Less than 1000 500 - 50,000* Greater than 99%

Chemical Scrubber Soluble odorous compounds Up-to 2000 Greater than 2000 99.9% including NH3 500 - 50,000* *Capacity can be supplied as per cilent requirments

Common Odor Scenarios and Potential Solutions

Odors can be produced at a number of points within the wastewater collection system as well as within wastewater treatment plant (WWTP) itself. These odors can be caused by a combination of inorganic and organic compounds. Three common odor scenarios have been examined as follows. 1. Collection System - Pumping Station 2. WWTP - Headworks 3. WWTP - Sludge Dewatering

Looking at each scenario, the typical odor conditions such as types of odorous compounds present, how they are generated and their relative intensity is described. Then the best technology or combination of technology is recommended to solve the problem.

1. Collection System – Pumping Station The collection system which brings wastewater to the central wastewater treatment facility can be a major source of odor generation. When the waste water reaches the pumping station, the water is agitated and the H2S is liberated frvom the liquid phase to vapor phase, resulting in odor. The average H2S concentration is assumed to be 10 ppm. Other odorous compounds may be present but in very low concentrations. Solution The predominance of H2S combined with the lack of significant organic odorous compounds allows this application to be effectively solved with a single stage technology. At lower end of H2S range (10 ppm or less), an engineered biofilter or catalytic carbon system would be a good choice. At higher H2S levels, the biofilter becomes less of an adequate solution but a bioscrubber might now become an acceptable alternative. The particulars of pump stations include the proximity to neighbors and limited foot print space. For these additional reasons, activated carbon technology is highly preferred. 2. WWTP – Headworks Waste water from the collection system is brought into the treatment plant at the headworks. Hydrogen sulfide is typically the most prevalent odorous compound at the end headworks and can be present in concentrations from 5 ppm up to 50 ppm and beyond. Reduced sulfur compounds are usually also present from 50 ppb and higher. Solution The combination of significat level of H2S and reduced sulfur compounds requires a combination system for most effective solution. Here we can make a two stage system, consisting of a first stage bio-scrubber for H2S removal, followed by either an engineered biofilter or an activated carbon system. 3. WTTP – Sludge Dewatering Solids processes present some of the most intense odor challenges of all wastewater operations. The average H2S concentration can be assumed to be 10 ppm. Solution This challenging odor application is best solved with a combination technology. In this case, the significant loadings of all major types of odorous compounds would argue in favor of a bio-scrubber first stage (assuming the H2S levels are 20 ppm or less) to treat both H2S and ammonia followed by a biofilter second stage to reduce organic odors as well as to polish any remaining H2S or NH3. If average H2S levels are below 20 ppm, a first stage biofilter followed by a carbon polisher is a good choice. Three decades of engineering excellence Corodex has been supplying top quality water and wastewater treatment solutions for over 30 years. We have supplied over 250 water treatment systems, over 500 wastewater treatment plants, and numerous odor control systems.

The type of odor control systems we have supplied include Adsorption, Biological Oxidation, and Chemical ab- sorption.Corodex has supplied more than 40 odor control systems for various applications to clients like Dubai Airport, Jebel Ali Airport zone, Palm Jumeirah Island, Dubai and Abu Dhabi Municipality,Qatar Airport and Oman.

Project Profile

Adsorption Odor Control System Client: Nakheel, Dubai Capacity: 2,520 m3/hr Client Need: Treatment of odor from Sewage Pumping Station

H2S level: Average 30 ppm CRIN.CAT3.003.1010

Wet Chemical-scrubber Odor Control System

Client: Sharjah Municipality, Dibba Al Hisin Capacity: 1,250 m3/hr Client Need: Treatment of odor from Main Lifting Station H2S level: Average 40 ppmv Peak 250 ppmv

Combine Bio-scrubber and Carbon Adsorption Odor Control System Client: Sharjah Municipality, Sharjah Capacity: 3,011 m3/hr Client Need: Treatment of odor from main pumping station H2S level: Average 40-80 ppmv Peak 250 ppmv