The Challenge:
The Three Rivers Wastewater Treatment Plant had noted deficiencies in odor control, solids handling, organic capacity, and septage handling. These deficiencies were noted as areas of noncompliance by the Michigan Department of Environmental Quality (MDEQ) and had generated complaints from neighbors concerned about odor problems. Three Rivers needed to make improvements to its 2.75-MDG municipal treatment plant to bring the plant into compliance with NPDES permit limits.
The Solution:
Following the recommendations outlined in a State Revolving Fund project plan prepared by ARCADIS FPS, odor control facilities and corrective measures were designed. A solids handling system was installed with the conversion of existing digesters to an autothermal thermophilic aerobic digestion (ATAD) system followed by dewatering and further volume reduction through a thermal dryer; additional organic (secondary treatment) capacity was added; and a new septage receiving station was constructed on site. The City realized a cost savings in operating the plant by coupling the ATAD and thermal dryer system operations. The systems reduce sludge volume, increase operational, sludge processing and disposal flexibility, and produce three forms of Class A (per EPA Part 503) beneficial use biosolids. The facility is able to produce liquid Class A, 15 percent to 25 percent cake Class A, and 90 percent dried Class A biosolids. This second-generation ATAD system is the first municipally owned and operated system in the U.S. The thermal dryer is the first municipally permitted system in Michigan. In addition to planning and design, ARCADIS FPS provided bidding and construction engineering services for the project, along with construction monitoring services. Improvements at the Three Rivers Wastewater Treatment Plant were completed in 2002.
The innovative combination of solids handling processes earned the Three Rivers Wastewater Treatment Plan Improvements project an Honor Award from the Michigan ACEC. This project received the highest award in the Water/Wastewater category statewide.
