Scope of Service

Treating Wastewater

Four to Nine Million Gallons a Day in Normal Conditions

The work done by a wastewater treatment plant is measured in MGD (millions of gallons per day) units.

On normal days, users of the DeKalb Sanitary District generate between 4.0 and 8.0 Million Gallons of wastewater. The chart that follows shows the average daily flow of wastewater to the plant for the year 2011 by month in millions of gallons.

Much More in Heavy Rainfall Conditions

Although the District is constantly improving the collection system to try to prevent excess flows during heavy rainfall events, undiscovered connections between the storm sewers or house tiling systems and the sanitary sewers still exist. That means that during rain events, water floods the collection system raising the plant flow to astonishing levels of 30, 40 or 50 Million Gallons of wastewater a day for brief periods of time, challenging the plant and its operators.

Serving a Variety of Users

Residential

Residential users include about 40,000 residents in and around the City of DeKalb.

Commercial and Retail

The District also serves the service and commercial businesses in its Facilities Planning Area. These include restaurants, retail stores, health care providers, recreational and entertainment enterprises.

Industrial

The industrial sector includes local industries that are considered "Significant Industrial Users" under the Environmental Protection Agency's National Pollutant Discharge Elimination program. The discharges of these and other industrial users are regulated to protect the population and the environment. Testing is done to assure that the regulated industrial users are following the stipulations of their discharge permits.

University

The District treats the wastewater generated by Northern Illinois University. The more than 24,000 students attending NIU in DeKalb account for a significant proportion of the total wastewater volume that the plant at 303 Hollister Avenue treats and discharges to the Kishwaukee River.

The operation of the treatment plant is complicated by the University's large population, which is more than half that of the City of DeKalb itself. The flow coming to the plant from the University varies with the class schedule. The volume of wastewater the plant must handle jumps dramatically when the students return to campus and falls dramatically when they leave.

The treatment plant's design depends on biological organisms to remove organic substances from the wastewater. These living communities of organisms adjust to their environment. The quick upswing or downswing upsets the organisms, demanding great expertise on the part of plant operators to keep the biological treatment system in balance.