Officials review secondary treatment at Sand Island, EPA rules and health data

City officials and council members discussed secondary wastewater treatment, regulatory requirements and scientific monitoring for the Sand Island Treatment Plant during the Committee on Executive Management meeting May 28.

Roger Babcock, director of the Department of Environmental Services (ENV), explained the federal framework that sets minimum wastewater treatment standards under the Clean Water Act and described why secondary treatment is prescribed to remove suspended solids and biochemical oxygen demand (BOD). "Secondary treatment requires 85% removal" of BOD compared with lower removal at primary treatment, Babcock said, adding that requirements can vary by discharge location and sensitivity.

Council members and ENV staff reviewed the current status of Sand Island: the plant historically operated under primary treatment for much of its capacity, and a phased upgrade to secondary treatment is…