San Jose Water Pollution Control Plant Mercury Study — City of San Jose
The San Jose/Santa Clara Water Pollution Control Plant (SJ/SC WPCP or “Plant”) conducted a multi-year study of mercury fate and transport from October 2004 to May 2007. This was one of the largest focused studies of mercury behavior in a wastewater treatment plant. The study was focused on examining the efficiency and main mechanisms of mercury removal in various plant processes and whether net production of more toxic forms of mercury (e.g., methylmercury) occurs in any process within the plant. The study showed that the plant is highly efficient at removing mercury that enters as raw sewage. Concentrations are reduced nearly 99%, 97%, and 50% for total mercury, methylmercury, and dissolved mercury, respectively. There was no evidence of net production of methylmercury, i.e., the Plant does not add to the toxicity or bioavailability of the mercury flowing through it.