A Lakeside Community Tackles a WWTF Upgrade

Blodgett Landing, a community of about 145 homes on the shores of Lake Sunapee in Newbury, New Hampshire, operates a 50,000-gpd wastewater treatment facility (WWTF) that is unable to meet current groundwater discharge standards with the existing Imhoff tank and sand filters/rapid infiltration basins (RIBs). A pilot project was begun in 2001 to reduce nitrate loadings to the groundwater. Effluent from the first bank of sand filters was recycled back to the sludge zone of the Imhoff tank to promote denitrification. Subsequently, a synthetic liner was installed in the primary bank of sand filters/RIB to convert them to sand filters. Effluent from the sand filters was captured and recycled back to the lower portion of the Imhoff tank to promote denitrification and therefore reduce nitrate concentrations discharged to the groundwater.Although successful in reducing effluent nitrate concentrations, seasonal limitations of the system require an upgrade of the wastewater treatment system to meet the year-round needs of the community. An engineering study determined that a new package plant was the most cost-effective means of upgrading the WWTF. An evaluation of current package plant technology found that there were a number of systems that could fit Blodgett Landing's geographical, technical, and financial needs.