Official State of Iowa Website Here is how you know

Sewage Sludge

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; and a material 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.

The terms “sludge,” “sewage sludge,” and “biosolids” are sometimes used interchangeably, but “biosolids” are primarily sewage sludge that has been stabilized to the disposal standards per 40 CFR 503 and 567 IAC 67 through sludge treatment processes so that they can be beneficially used in the environment.

Sewage Sludge Disposal Regulations

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. 
The State of Iowa’s sewage sludge land application rule is in 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.

Biosolids Annual Report

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 Feb 19 if the 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 (use AWW in Iowa) of 1 million gallons per day (MGD) or greater and serving 10,000 people or more.
Since 2016, EPA has developed the NPDES eReporting Tool (NeT) and has required all major POTWs to submit the biosolids annual reports electronically 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 Feb 19, 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.

EPA’s Biosolids Report Search

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

Iowa Biosolids Land Application Site Tracking Map (iBlast)

Iowa Biosolids Land Application Site Tracking (iBlast) is a GIS application that provides information for the site locations on which biosolids are applied by Iowa’s major POTWs. 

Iowa Biosolids Annual Reports Search

Biosolids annual reports from the previous years are stored in DNR’s Electronic Records Document Search.

Innovative Sewage Sludge Treatment Process

New and innovative sewage sludge pathogen reduction process that is not defined by Class A or Class B in 40 CFR 503 or Class I or Class II in 567 IAC Chapter 67 needs to be reviewed by the EPA Pathogen Equivalency Committee (PEC) to demonstrate the process robustness and effectiveness in reducing pathogen. Details on how to submit the PEC process review can be found from EPA’s Pathogen Equivalency Committee website.

Other Biosolids Resources

  1. EPA Lagoon Sludge Management, Part 1
  2. Iowa Wastewater Lagoon Cleanup and Closure Guidance
  3. EPA Biosolids Website
  4. Pathogen Equivalency Committee


DNR Wastewater Engineering Biosolids (ia-biosolids-annual-report@dnr.iowa.gov)

DNR Field Offices 

DNR Solid Waste (Theresa Stiner, theresa.stiner@dnr.iowa.gov, 515-721-7979)

EPA Biosolids Excellence Center (Seth Draper, Draper.Seth@epa.gov, 913-551-7080)

Iowa Dept. of Agriculture and Land Stewardship, Fertilizer Administrator
(Lloyd Krutzfeldt, Lloyd.krutzfeldt@iowaagriculture.gov, 515-975-7183)