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Proposed Project Team and Experience <br /> Wastewater Treatment Facility Improvements, Litchfield, MN (2011) <br /> Contact: Bruce Miller,City Administrator,320-693-7201 <br /> The City of Litchfield worked closely with Bolton&Menk on facility <br /> planning, engineering,project financing and construction phases of their <br /> wastewater treatment facility improvements project. Expansion of the <br /> City's major industry coincided with implementation of more stringent <br /> ter. <br /> effluent limits and deteriorating infrastructure.A detailed review of the <br /> existing trickling filter/activated sludge facility served as a basis for <br /> maximizing all unit processes and selection of improvements with the <br /> lowest impact on both community and industrial user rates,while it <br /> provided the greatest possible increase in treatment capacity. <br /> The facility's overall treatment capacity was more than doubled with <br /> the addition of intermediate clarifiers,trickling filter upgrades, aeration equipment, replacement <br /> of the media filtration and chlorine disinfection system, and expansion of the biosolids process. <br /> Biosolids improvements not only provide additional liquid storage,but also modify the current <br /> two-digester system to allow parallel or series operation.A floating gas holding cover,mixers and <br /> a heat exchanger on Digester No. 2 provide additional digestion capacity and allow the City to <br /> utilize the methane gas. Other facility improvements include upgrades to the supervisory, control <br /> and data acquisition (SCADA) system, conversion of an existing building to garage space, and <br /> miscellaneous piping modifications. <br /> Litchfield is a relatively small community of approximately 6,700 residents. However,the average <br /> design load for this facility is 15,800 lb CBOD5/day, or the equivalent of nearly 100,000 residents. <br /> nWastewater Treatment Facility, Buffalo, MN (20081 <br /> Contact: Merton Auger, City Administrator, 763-682-1181 <br /> Bolton&Menk,Inc.was retained by <br /> the City of Buffalo to prepare a Wastewater System <br /> Evaluation.The primary focus of the evaluation was <br /> the expansion of the facility to meet the needs of a f C <br /> growing population and a new biosolids treatment and <br /> handling process. The City faced increasing difficulty <br /> in the hauling and land application of the biosolids due <br /> to development pressures adjacent to the application <br /> sites and public intolerance of land application in these <br /> areas.The City required a process that produced a Class <br /> A biosolids,was highly energy efficient,and resulted in <br /> a smaller volume of solids to haul and dispose of. <br /> The proposed process to meet these requirements was a belt dryer and an incinerator. Biosolids <br /> produced by the facility are first dewatered with belt presses. Biosolids "wet"cake is then <br /> transferred to the belt dryer,where they are dried to approximately 95%dry, resulting in Class <br /> A biosolids.The biosolids are then burned in a traveling grate incinerator to recover heat energy, <br /> which is recycled to heat and dries the biosolids.This heat recovery system reduces the natural gas <br /> demands for drying by approximately 90%. <br /> Wastewater Treatment Facility Improvements I City of Elk River, Minnesota 6 <br />