Water Management Services
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Water Management Services
Water Plant Projects
Water Treatment Plant Attentions and Modifications
Hendersonville Utility District (HUD)
Water Management Services LLC, provided planning, design, and construction inspection services for the new Hendersonville Utility District (HUD) water treatment plant. When deciding to expand the capacity of the treatment facilities, HUD was faced with the fact that traditional treatment techniques may not be adequate for compliance with ever evolving water regulations. Because of this, HUD chose to construct a new treatment facility that will meet the needs of the water system and provide the ability to meet future regulatory requirements.
The design of the HUD water treatment plant utilizes advanced treatment technologies to provide for the purification of drinking water. These processes include dissolved air flotation, membrane filtration, granular activated carbon contactors, UV disinfection, and onsite generation of sodium hypochlorite.
These dissolved air flotation units allow for loading rates of 12 gpm/ft2, which is much greater than that of a traditional settling basin. The units promote the removal of organics by floating the sludge, which is removed by a scraper mechanism. This process requires approximately 30% less coagulant and provide for effective removal of organic material, such as algae, that create problems for membrane filters.
A Pall membrane system will be used for the filtration. The membranes provide for the removal of all material greater than 1 micron. This provides for a 3-log removal credit for cryptosporidium, and a constant effluent water quality.
After filtration, water will enter the granular activated carbon contactors. These contactors provide for the adsorption of dissolved organic precursors and humic acids that react with chlorine to form disinfection by-products. This process also eliminates taste and odor problems that are common with surface water.
To eliminate the concerns of storing gas chlorine the facility will generate a 0.8% bleach solution from salt. The process uses salt and electricity to generate a low concentration bleach solution to obtain free chlorine residual in the finished water.
Upon completion of the capital improvement project, HUD will have a water treatment plant which enables continued compliance with existing regulations and the flexibility to adapt to future regulatory changes.
Water Treatment Plant Additions and Modifications
Columbia Power & Water Systems (CPWS)
Water Management Services LLC, under contract with Columbia Power & Water Systems (CPWS), provided planning, design, and construction inspection services for the additions and modifications to the CPWS water treatment facility. The CPWS water treatment plant is a typical surface water treatment plant utilizing flash mixers, settling tanks, rapid sand filtration, and gas chlorine for disinfection, with a rated capacity of 20 MGD.
As water regulations continue to evolve, CPWS found that traditional treatment techniques were not adequate for compliance with the Stage 2 Disinfection By-Products (Stage 2 DBPR) and the Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR). In addition to compliance with these impending regulatory changes, CPWS also wished to evaluate the benefit of replacing gas chlorination with onsite sodium hypochlorite generation.
Water Management Services personnel conducted a nine month treatability study to evaluate the formation potential for Disinfection By-Products (DBP) and to evaluate various treatment techniques for the removal of DBP precursors. Additionally the treatability study evaluated the treatment techniques for removal/inactivation of cryptosporidium and onsite sodium hypochlorite generation. The results of the treatability study provided the basis of design for the additions and modifications to the CPWS water treatment plant.
Water Management Services petitioned the Division of Water, on behalf of CPWS, for an extension of the Stage 2 DBPR regulatory deadline. Water Management Services extensively researched the requirements for such an extension and thoroughly documented the request. Subsequently, CPWS received a two-year extension for compliance with the Stage 2 DBPR. This was the first extension ever granted by the Division of Water for a federal drinking water regulation. The extension has allowed the water system to maintain compliance with DBP regulations while the capital improvement project is completed.
Upon completion of the capital improvement project, CPWS will have the necessary facilities to ensure continued compliance with existing regulations and the flexibility to adapt to future regulatory changes.
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