Problem: When the wastewater treatment plant in Madison, Indiana, received a new phosphorus limit of 1.0 ppm, the staff assessed the processes and found that biological removal alone would not suffice.
Solution: The team decided to add a chemical-feed. Since frequent rains increased flow but diluted the influent phosphorus entering the plant, plant leaders ruled out flow-based feeds and instead chose a ChemScan mini oP Analyzer from In-Situ for its large, blockage-resistant sample tubing, internal self-cleaning and low cost of ownership. It measures effluent phosphorus in 15-minute increments and dictates the chemical feed accordingly.
Result: The analyzer enables staff to confirm compliance in real time. With its low-maintenance operation, the small staff can deploy labor efficiently. The process uses polyaluminum chloride to precipitate phosphorus, which ends up in the biosolids. Precise chemical control helps minimizing sludge production. 800-446-7488; www.in-situ.com
