In 2004, 124 people lived in Pingree Grove, Illinois, just west of Chicago. By 2020, more than 9,000 call Pingree Grove home. That's a 477% annual population growth rate over 16 years. That kind of growth placed significantly more demand on the Village's Wastewater Treatment Plant (WWTP). To keep up with the growth, Village officials voted to expand the WWTP. Fehr Graham, which serves as Village Engineer, designed the plant's improvements to accommodate today's population and future growth.
Our team suggested doubling the wastewater treatment capacity from 1 to 2 million gallons per day while also ensuring the cost of wastewater treatment would not be substantially higher for residents. Fehr Graham included plans to add mechanical primary treatment units to reduce secondary treatment costs and help increase the treatment capacity without adding aerated tanks. The mechanical primary treatment units use one tenth of the area of conventional primary clarifiers, which is a huge advantage to a rapidly growing community.
To ensure the mechanical primary treatment units would be effective, Fehr Graham conducted pilot testing at the WWTP as part of the preliminary design. The secondary treatment system will be financed by adding anaerobic and anoxic tanks for biological nutrient removal to further clean the water. Construction began in spring 2021 and should be completed in 2024.