Wastewater Treatment Plant Improvements

The City of Monticello operates a 1.1 MGD WWTP with a peak capacity of 2.4 MGD. The facility discharges to Lake Freeman and has stringent NPDES limits, and has used ferrous chloride for phosphorus removal for over 30 years. The new improvements include a new headworks facility with a multi-rake fine screen for peak flows up to 30 MGD to screen all influent flows, including CSO’s that bypass the downstream treatment processes. A four-pump raw sewage pump station conveys the screened flow to a new vortex grit removal system.

Wessler prepared the Preliminary Engineering Report (PER) evaluating several options to meet the LTCP requirements and the projected 20-year growth of the City, ultimately selecting the AquaPASS® system for its full BNR capabilities to meet current phosphorus limits and anticipated future total nitrogen limits. The new biological process includes a flow-through AquaPASS® system by Aqua-Aerobics Systems.