Prior to 2007, Concord, Massachusetts wastewater treatment plant operated under a NPDES permit that allowed a seasonal phosphorus limit of 0.7 mg/L. But with the issuance of a new five-year permit with a phosphorus limit of 0.2 mg/L and the probability that future limits could reach as low as 0.05 mg/L, Concord needed a treatment solution that would be reliable and cost-effective today and over the long term.
Choosing Effluent Flexibility, Operating Reliability and a Small Footprint
When compared to dissolved air flotation (DAF), media filtration and sand ballasted technologies, Concord’s consulting engineers recommended the CoMag® System for its:
- Ability to provide effluent TP values from 0.2 mg/L to ≤ 0.05 mg/L simply by adjusting the flocculent dose
- Reliability of operation — conventional flocculation and coagulation coupled with high rate clarification and no filters to clog or backwash
- Capital cost savings given its small clarifiers and footprint