Better technology, improved water quality focus for South Beloit Wastewater Treatment Plant


Design: January 2017 to December 2017
Construction: June 2018 to Present



IEPA Water Pollution Control Loan

» Planned improvements.
» Assisted with funding.
» Prepared preliminary final design.
» Completed construction administration and observation.

The City of South Beloit's Wastewater Treatment Plant was at a critical point where significant improvements were needed to comply with the Illinois Environmental Protection Agency (IEPA) regulations. The facility needed to increase its capacity for expected population growth, comply with nutrient removal requirements and increase its wet-weather treatment capability.

Our team worked with the City to improve the Wastewater Treatment Plant with new preliminary, secondary, tertiary, disinfection and solids treatment facilities. The improvements allow the facility to produce a higher quality effluent compliant with IEPA nutrient removal requirements, improved Class A solids residual quality for agricultural uses, a 33% increase in treatment capacity and a 15% reduction in electrical energy consumption. The design included new preliminary treatment units with dual-stage screening and stacked tray grit removal between the stages. The units remove rags, plastic, sand, oil, fat, grease and paper products in preliminary treatments.

Starting in June 2018, Plant 1 was converted into an Enhanced Biological Phosphorous Removal treatment process with Integrated Fixed Film Activated Sludge (IFAS) technology. The rectangular aeration tanks were divided into anoxic-, aerobic- and IFAS-containing zones with an anaerobic reactor and two secondary clarifiers built adjacent to the modified aeration basin structures. Secondary effluent travels to a flocculation basin, passes through a set of tertiary media disc filters and goes through an ultra-violet radiation system for disinfection before discharging to the Rock River.

The package plants (Plants 2 and 3) will be converted to digesters and will be operated like a sequencing batch reactor, alternating between fill, react and settle modes to remove excess nitrogen and reduce oxygen consumption from the sludge and recycle side streams. This sludge processing will be enhanced by sludge dewatering and stabilization equipment that will produce Class A biosolids. Sludge storage and maintenance buildings will also be built to support the operation of these facilities. 

The community is expected to have full use of the improvements in November 2020.