Wastewater Treatment Plant Site Remediation

Background

The Site is approximately 32-acres in size and was first developed in 1964 from farmland, when the Town built the WWTF. Expansions to the WWTF were completed in the early 1970s, and the treatment plant continued to operate until 1986, when a sewer connector was constructed to connect the Town sewer system to the Greater Lawrence Sanitary District (GLSD). Subsequently, WWTF structures were demolished by the Town in 2017 and 2019. The Town retains ownership of the Site property, and currently allows the Salem Animal Rescue League (SARL) to operate an animal shelter in the northern portion of the Site.

During excavation of the sewer connector line at the Site in 1986, impacted soil and groundwater were encountered. Following discovery of the impacted soils, numerous investigations were completed to assess the nature and extent of the apparent release. The contamination was mapped and a remedial action plan was developed. The goal of the plan is to clean up the site such that it can be redeveloped with limited activity.

Remediation Activity - Electrical Resistance Heating

How it Works - Electrical Resistance Heating (ERH)

2022 Town Meeting approved $6.75 million for the soil and ground water remediation of the site. 161 steel sheet pile electrodes will be installed in the contaminated area. Sheet pile electrodes are large sheets of steel that are driven into the ground. The depth of the electrode depends on their location within the treatment area and depth of the contaminant. Power will be connected to the electrodes and the soil will be heated to a maximum temperature of 104oF. A vapor control system using vacuum pumps will be constructed and the vaporized ground water will be captured and passed through a condenser followed by carbon filter.