Passive approach to wastewater treatment yields fewer GHGs and lower costs

The municipality put in a pumping system to divert pre-treated effluent through strong geotextile bags. The bags sit for up to 28 days, passively filtering the effluent and creating drier and lighter nutrient-rich compost. The compost is then used to fertilize sod fields in the region. This process produces a high-quality dried sludge (Grade A). It also significantly reduces the concentration of suspended solids in the wastewater treatment process, an important measure of water quality. It has also reduced trucking costs for sludge transportation and disposal by $30,000 per year. 

Within the first year, the facility had surpassed the town’s projections by dewatering 150,000 more gallons of sludge than anticipated (450,000 gallons in total). With much less sludge to transport for disposal, the town was able to reduce its greenhouse gas (GHG) emissions by 25.8 tonnes of CO₂e annually (equivalent to transporting 150 truckloads). Only four dump trucks are now required to transport the remaining sludge for disposal each year. 
 

The geo bags have been a welcome addition to the Montague treatment system. They are easy to use and provide a more natural, sustainable way to dispose of excess solid by-products.”

—Matt Duffy, Operator, Montague Wastewater Treatment Plant, Town of Three Rivers