Client: South Sangamon Water Commission

Location: Chatham and New Berlin, Illinois

Donohue designed a new water supply system for the South Sangamon Water Commission in Central Illinois. The system includes a new well field, new treatment facilities, and a raw water main system between the two. The facilities are designed to provide 1.9 mgd of water on an average day, with a firm capacity of 3.3 mgd.

Alternatives considered during the evaluation phase included microfiltration, diatomaceous earth filtration, pre-packaged proprietary treatment units, and conventional filtration with coagulation, flocculation, and sedimentation. The evaluation revealed that the most cost-effective solution was micro-filtration. The treatment train also includes ion-exchange to soften the water and aeration to oxidize and remove iron prior to micro-filtration. The facilities can produce 1.9 mgd in a single shift, minimizing annual production costs.

Donohue’s services included obtaining all required permits, including the permit establishing the Water Commission as a recognized public water supplier. Sustainability features at the facilities include porous pavements, bioswales and bio-retention facilities to reduce suspended solids in the Sangamon River.