Successful Removal of Manganese and Other Trace Constituents from Surface Water of Highly Variable Quality Using Intermittent Operation of Rapid Clarification

摘要

A complex treatment system was designed and built for an industrial facility to processraw stormwater prior to discharge to the environment, which required meeting a series oflimits from a stringent NPDES permit. After extensive pilot studies, a treatment trainconsisting of pre-oxidation, rapid clarification, sand filtration, bag filters and granularactivated carbon was selected. A major challenge for this system was its intermittentoperation, as it was dictated by weather conditions. Rapid clarification performedsuccessfully as a robust pretreatment to neutralize turbidity peaks during strong storms,which in turn allowed optimal operation of the downstream units. Meeting the manganeselimit of 0.05 mg/L represented the most challenging part of the project, but wassuccessfully achieved with a systematic approach to operation and monitoring. Carefulconsideration was given to the operation of the system under continuous startup andshutdowns corresponding to operation before, after and in between rain events.