The Habitat for Humanity repurposed a former convent into 10 safe, affordable condominium-style homes. A large project for this Chapter on its own, it also included the challenge of environmental restoration resulting from former underground petroleum storage tanks. SAK began working with Habitat for Humanity when reinforcement of the building's foundation revealed unexpected environmental conditions beneath the building.
SAK worked closely with Habitat for Humanity to promptly address conditions cost effectively while maintaining the project's building schedule. "Our No. 1 objective was to ensure a safe living environment to future residence" says Stephen Sakakeeny, Principal. To accomplish this task, SAK undertook an expedited site assessment. The soil, groundwater, soil gas, and indoor air were extensively tested to assess risk prior to building occupancy. Building materials were noted to be off-gassing during the build-out based on the indoor air results which necessitated re-evaluation of the data after removal of non-petroleum compounds. Habitat volunteers excavated a soil vapor recovery trench and installed the piping for passive venting in the lower basement of the building based on SAK’s design and under SAK observation. The passive venting system is now operational. SAK together with Habitat worked tirelessly to identify and evaluate potential funding sources until a Brownfields loan was secured though MassDevelopment.
SAK directed the excavation and off-site disposal of petroleum contaminated soil and conducted additional assessment to define the nature and extent of petroleum contamination which was detected to extend beneath the building. During initial monitoring, light non-aqueous phase liquid (LNAPL) was detected. SAK conducted an LNAPL assessment and transmissivity study, the results of which indicated that the LNAPL was stable and not recoverable; two positive factors toward site closure. Additional rounds of groundwater sampling confirmed that contaminant levels did not exceed regulatory thresholds. Additional rounds of indoor air sampling confirmed that the oil release was not impacting indoor air. Soil gas sampling confirmed that passive venting would be sufficient for long-term mitigation of potential indoor air impacts. SAK conducted a cumulative risk characterization (Method 3), the results of which indicated that a condition of no significant risk (NSR) to human health was present at the site.