Centre Ave New Rochelle, NY

Just blocks away from the New Rochelle train station, this property offers luxurious amenities for the 530+ apartments. The two 28-story towers replace an electroplating/metal finishing business that was in operation between 1971 and 2018. Due the impacts of this type of work, the property entered into a Brownfield Cleanup Agreement mid-2019 for a conditional Track 1 clean-up.

SESI’s geotechnical and environmental services worked efficiently as the property was undergoing remediation and Support of Excavation (SOE) work. This synergy also helped in developing the groundwater remedy. Borehole geophysics and a geotechnical investigation were used to identify the fractures and water/contaminant bearing zones within the rock strata.

The groundwater (GW) remediation involved the treatment of dense non-aqueous phase liquid (DNAPL) in fractured gneiss bedrock in addition to a mix of contaminants (per- and polyfluoroalkyl substances [PFAS], petroleum hydrocarbons, metals and 1,4 dioxane) within limited space. SESI conducted the injection remediation while the building foundations were being constructed. The historic discharges included chlorinated solvents (1,1,1 Trichloroethane), petroleum hydrocarbons, PFAS, 1,4 dioxane, and metals, which all resulted in GW levels that exceeded the NYS GW standards by several orders of magnitude in certain cases. The property consisted of a 100x200 foot lot, and the treatment area was limited to 100x100 foot with a shallow bedrock at 10-15 foot below existing grade.

SESI evaluated several different remedial options and determined in situ chemical oxidation (ISCO) followed by the injection of a permeable reactive barrier (PRB) to be the most effective and economical for treating the site contamination. The approach involved applying PersulfOx® as ISCO to reduce the high concentration of organic contaminant mass at the bedrock source zone, followed by injection of PlumeStop® as a PRB to treat PFAS and prevent residual contaminant migration beyond the site boundary.

The applied remedy reduced groundwater contaminant concentrations by more than 95 percent and substantially reduced the mass flux at the property boundary. The successful remedial effort earned the site a Certificate of Completion (COC) through New York State's Brownfield Cleanup Program, facilitating the new development in this commercially valuable area.

Engineering controls to mitigate the potential for vapor intrusion were also prescribed for the building.

SESI is proud to be part of the cleanup efforts across New York State. In 2022 SESI Consulting Engineers was responsible for 14% of all COCs in the New York State Brownfield Cleanup Program.