PCBs, Playgrounds, and Parks: Lessons Learned from MMSD's Collection System Legacy Pollutant Problem

In June 2007, as part of routine sewer cleaning, legacy polychlorinated biphenyls were unknowingly disturbed, resulting in contaminated biosolids at Milwaukee Metropolitan Sewerage District's (MMSD) treatment facilities. MMSD heat dries biosolids, producing Milorganite®, which is typically sold both to retail and professional markets. Heat dried biosolids that did not meet Milorganite® specifications (non-spec biosolids) and unknowingly contaminated with PCB's, had been given to local parks and schools, who had applied the product to playgrounds and parks. This paper will present how MMSD managed the issue and present lesson learned.