The Oconomowoc Wastewater Treatment Facility in Oconomowoc, Wisconsin, demonstrates how online phosphorus monitoring supports long-term compliance. Treating an average of 2.4 mgd, the utility must maintain a total phosphorus effluent limit of 0.95 mg/L. To meet this requirement efficiently, Oconomowoc WWTF installed YSI’s Alyza IQ PO4 analyzer to continuously monitor orthophosphate and automate ferric chloride dosing for phosphorus removal.
Since its installation in 2020, the analyzer has measured orthophosphate every 15 minutes at the plant effluent, downstream of chemical addition in the aeration basins. These real-time readings directly control two ferric dosing pumps, targeting a 0.52 mg/L orthophosphate residual. This automated feedback loop has delivered consistent, low-level phosphorus control for five years. Daily laboratory TP results closely align with the analyzer’s measurements, confirming long-term accuracy and reliability. Oconomowoc has remained in compliance with its effluent limit since installation, with only one brief exceedance attributed to a toxic waste event.
The Alyza IQ PO4 is available in single- or dual-channel configurations and is designed to minimize maintenance while maximizing accuracy and reliability. It features automatic cleaning and calibration, no-spill reagent containers, and uses just 5 µL of reagent per measurement — allowing reagent changes every six months. An automated temperature control system within a double-insulated cabinet ensures stable performance in varying conditions. The analyzer measures orthophosphate with a 0.02 mg/L resolution and is engineered for rugged wastewater environments.
Oconomowoc’s success with the Alyza IQ demonstrates how advanced instrumentation and automated control simplifies compliance and optimizes performance. By pairing smart analyzers with chemical dosing control, the utility achieved predictable chemical costs, consistent effluent quality, and progress toward long-term nutrient management goals.
YSI, a Xylem brand, offers solutions for monitoring water quality and quantity with sensor technologies.
937-767-7241 | info@ysi.com | ysi.com
