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Biosolids Application

What Are Biosolids?

“Biosolids”, treated and stabilized municipal wastewater treatment product, are a valuable fertilizer resource.

As required by USEPA, since 1988 the District has provided biosolids to area farmers.  Biosolids contain nutrients such as nitrogen, phosphorus, and potassium; micronutrients from metals such as copper and zinc; and valuable humus that commercial fertilizers cannot provide. Beneficial soil conditioning is also provided, as organic matter deposited in soil increases water holding capacity and cation exchange capacity.


How is the District’s Land Application Program Regulated?

The US EPA and Illinois EPA regulate the program and issue the District a permit containing application limits, and monitoring and annual reporting requirements.  The District’s program includes voluntary additional ground water testing (lysimeter) and plant tissue analyses.  These allow the District to verify application rates and to detect any potential negative environmental impacts that may occur.

Prior to application, biosolids are stabilized to reduce pathogens using anaerobic digestion.  Biosolids are then stored in lagoons for at least three years to allow for optimum concentration and stabilization. Biosolids are routinely analyzed for nutrient content, metal content, and organic and synthetic pollutants.

The District retains a Certified Professional Agronomist to identify candidate farm fields and provide recommendations regarding biosolids application.  The agronomist samples the soil of each candidate field and provides a corresponding report, along with biosolids nutrient content, to the farmer, landowner and District.  Application rates are calculated based on the agronomic demand of the particular crop grown.


What Method Does the District Use to Safely Apply Biosolids?

Biosolids are injected beneath the soil surface with specially-designed equipment.  When properly applied, biosolids will not be on the surface of the farm field.  It will appear as though the field has been plowed.  Because biosolids are stabilized and then applied with this method, odors are virtually eliminated.

Biosolids are hauled to each field in enclosed tank trucks and immediately applied.  Care is taken to minimize local truck traffic.  The District employs specialized, private contractors to conduct the hauling and application of biosolids. The District routinely and frequently inspects their operation.

The application season typically begins in late July, after the earliest crops are harvested, and continues into November.  Timing of applications coincides with the type of crop grown; wheat is harvested in summer, and soybeans and corn in fall.


The District is committed to the responsible implementation of the Biosolids Land Application Program.  If you have any questions or concerns, you are encouraged to contact the District Engineering Department at 708-754-0525 x14.  Treatment plant tours are welcome.

700 West End Avenue, Chicago Heights, IL 60411

Phone: 708-754-0525


Fax: 708-754-3940