Waverly Township Wastewater Treatment Plant Upgrade
Milnes Engineering Role:
Development of pilot study, design, permitting, construction management
Waverly Township, Lackawanna County, PA
Waverly Township undertook this project, assisted by a $1 million grant from the PA DCED H2O PA Program, in August, 2011 to upgrade its wastewater treatment facility to enhance its ability to provide nitrification in cold weather. The facility, constructed originally in 1986, consists of two aerated facultative lagoons in series, followed by disinfection and discharge to a small stream nearby. Due to the lengthy detention times in the lagoons, water temperatures near freezing are common in winter, making consistent conversion of ammonia difficult. Research led Milnes to the Amphidrome Cold-Nite process, a biologically active filter developed by Severn Trent Services and used successfully throughout the New England states. Waverly Township entered into an agreement with the manufacturer’s representative, F R Mahony & Associates of Rockland, Mass., to conduct a one-year pilot study to assess its nitrification performance, specifically on lagoon effluent. The test concluded that although the demonstration unit was not stressed to its design loading limit due to the mildness of the 2011-2012 winter, the filter will reliably nitrify wastewater treatment plant effluent from aerated facultative lagoons having water temperatures in the mid-30s F.
Milnes Engineering developed a full-scale design based on ammonia-nitrogen effluent limits of 4 mg/l summer/12 mg/l winter, which was permitted by PA DEP in April, 2013. The system consists of three reactors in parallel, constructed in concrete tanks below grade. The tanks are insulated above so that naturally-occurring heat from the surrounding earth is retained and helps to maintain temperature in the reactors near 50F for healthy biological activity. The reactor processes are exothermic which also works to maintain the internal temperature. Above the reactor tanks a small masonry building houses aeration blowers, controls and chemical feed equipment. The original facility’s hydraulic profile made it possible to insert the reactors between the second lagoon and the chlorine contact tank with forward flow entirely by gravity.
Construction contracts totaling $1678000 were awarded to Quandel Construction Group and Everon Electrical Contractors in June, 2013. Construction was completed and the equipment placed in operation in May, 2014. The Amphidrome upgrade is expected to produce fractional effluent ammonia-nitrogen at the 360000 gallons per day permitted flow rate.