Challenge: The occurrence of per- and polyfluoroalkyl substances (PFAS) in water supply wells in New Jersey is widespread. In response, the State was among the first in the country to establish maximum contaminant levels (MCLs) for PFAS, requiring the construction of new wellhead treatment facilities or replacement with alternative non-contaminated sources. New Jersey American Water (NJAW) operates hundreds of wells in New Jersey. Recognizing the potentially significant costs that would be passed to their customers, NJAW requested INTERA’s assistance to better understand PFAS contamination in their wells and develop cost-effective mitigation measures.

Solution: INTERA and our subcontractor BESST utilized USGS-developed dynamic flow and chemistry profiling technology to identify, under normal operating conditions, the discrete zones contributing flow to a well and each zone’s water quality. The detailed flow and chemistry profiles were evaluated along with aquifer characteristics and well construction details to determine the feasibility of re-engineering existing wells to block discrete zones of poor water quality. INTERA performed water quality sampling for PFAS in strict accordance with State guidance and special protocols to minimize the potential for cross contamination. 

Results: Since 2019, INTERA and BESST have completed dynamic flow and chemistry profiles for twelve NJAW wells. The results have been used to make decisions regarding capital investments in well abandonment and replacement, new treatment facilities, and well modifications to improve water quality. To the extent that raw-water quality is improved, investments in treatment infrastructure may be downsized, deferred, or reduced entirely. For existing treatment, on-going operating costs for chemical use and residuals management may be reduced.