GOING OUTSIDE THE TREATMENT PLANT FOR NPDES COMPLIANCE: NON-POINT SOURCE PHOSPHORUS REDUCTION BY STREAM RESTORATION

An evaluation was performed to determine the feasibility of meeting an NPDES permit-required phosphorus load reduction for a POTW through a non-point source stream restoration project. The alternative phosphorus load reduction project includes filter strips and bank stabilization to reduce sediment and particulate phosphorus discharge into the stream, plus natural stream channel restoration to improve habitat. For this POTW with a relatively stringent total phosphorus reduction requirement, the evaluation concluded that a non-point source phosphorus reduction stream restoration project could be implemented at a significantly lower cost than in-plant treatment that would require effluent filtration for phosphorus removal. Additional benefit from the stream restoration project would include habitat improvement which would provide potential improvement in receiving stream biological water quality criteria that would not be possible with POTW treatment alone.