Sewage Sludge Disposal

Sewage sludge is solid, semisolid, or liquid residue generated during the treatment of domestic sewage in treatment works. Sewage sludge includes, but is not limited to, scum or solids removed in primary, secondary, or advanced wastewater treatment processes, or materials derived from sewage sludge. Sewage sludge does not include ash generated during the firing of sewage sludge in a sewage sludge incinerator or the grit and screenings generated during preliminary treatment of domestic sewage in treatment works.

Section 405 of the Clean Water Act sets the statutory framework for regulating sewage sludge. EPA promulgated 40 CFR Part 503 in the Federal Register on February 19, 1993, which regulates sewage sludge that is applied to a land, placed on a surface disposal site or fired in a sewage sludge incinerator. 40 CFR Part 503 sets pollutant limits, requirements for reducing pathogens and vector attractions, as well as procedures for best management practices, sampling and monitoring, recordkeeping, long term plan and annual biosolids reporting.

Iowa’s sewage sludge land application rules are in Chapter 67, 567 IAC 67 (455B). Compliance with both the federal and state rules are implemented by the National Pollutant Discharge Elimination System (NPDES) permit issued to a municipal wastewater treatment facility.

According to 40 CFR 503 and 567 IAC 67, sewage sludge pollutant monitoring, disposal, and best management practices must be summarized in the biosolids annual report and submitted to the federal government and state agency each year on or before February 19 if a POTW is a major facility. A major facility is defined by federal and state rules as a Class I sludge management facility, a facility with design flow (average wet weather or AWW flow) of 1 million gallons per day (MGD) or greater, or a facility serving 10,000 people or more.

EPA requires all major POTWs to submit the biosolids annual reports electronically on the NPDES eReporting Tool (NeT) via EPA’s Central Data Exchange (CDX). In addition to the EPA’s annual biosolids report, Iowa requires a submission of supplemental biosolids information. By February 19 or every year, both the federal biosolids report and Iowa supplemental biosolids forms are required to be submitted to Iowa DNR biosolids email, ia-biosolids-annual-report@dnr.iowa.gov. For more information on EPA's NeT Biosoilds reporting, please see EPA's NeT Support page.

Annual biosolids reports from major POTWs in Iowa can be downloaded from EPA’s ECHO database.

Iowa Biosolids Land Application Site Tracking (iBlast) is a GIS database that provides information for the site locations on which biosolids are applied by Iowa’s major POTWs. iBlast displays land application site information including location, field size and name, and total amount of biosolids applied per year.

EPA Links:

• EPA BMPs for Use or Disposal of Sewage Sludge, Part 1 – Land Application of Sewage Sludge Removed from Lagoons
• EPA Biosolids Website
• EPA Pathogen Equivalency Committee

Iowa DNR Links:

• Iowa Wastewater Lagoon Cleanup and Closure Guidance
• DNR Wastewater Engineering Biosolids Annual Report Email Address: ia-biosolids-annual-report@dnr.iowa.gov
• DNR Field Offices 
• DNR Solid Waste Permitting (Industrial Wastewater Residuals Disposal)

Other Information:

• Iowa Dept. of Agriculture and Land Stewardship, Commercial Fertilizer