Sludge is the solid material in sanitary wastewater, either from wastewater treatment plants or on-site septic tanks. Biosolids are sludge that has been treated to ensure that it can be safely applied to land as a fertilizer or soil amendment (these are called beneficial reuses). Residuals is a general term for both sludge and biosolids.
Residuals & Biosolids FAQs
- Residuals & Biosolids: Frequently Asked Questions
Frequently-asked questions addressing differences between sludge, residuals, and biosolids, regulatory mechanisms and more.
Residuals & Biosolids Policies & Guidance
- Blending Policy - Guidance Document 87-1: Utilization of Blended Sludge Compost
Policy on the utilization of blended sludge compost (compost mixed with sand, peat, or other materials).
- Composting Operations Within Zones of Contribution (Zone II) and Interim Well Head Protection Areas (Interim Zone II)
Preventing drinking-water contamination from stored sludge and septage.
- Horticultural Use Policy
Clarifying the allowable use of wastewater-treatment sludge in horticultural operations.
- Hydrogeologic Evaluations - Guidelines
Hydrogeological evaluations for proposed landfill sites define the geology of the site, groundwater flow paths and rates, design characteristics of the landfill liner, and the location of all proposed groundwater protection and monitoring systems.
- Large Privately Owned Treatment Works - Minimum Contractual Requirements for Reuse or Disposal of Residuals
Requirements for large publicly-owned treatment works seeking to contract out sludge reuse or disposal.
- Multi-Site/Single Ownership
Allowing a single application for land application of sludge or septage to cover multiple sites under the same ownership.
- Residuals Landfill Plan Submittal List
Plan approval application submittal requirements.
- Sludge Analysis Guidelines
Parameters of a sampling and analysis plan for wastewater treatment sludge and septage.
- Sludge Compost Facilities - Minimum Technical Information Needs for Submittal of Plans and Specifications
Technical information required for plans and specifications for sludge compost facilities.
- Sludge Disposal - Redundancy Requirements
Requirements for back-up facilities for wastewater treatment plants that may not be able to dispose of sludge throughout their design life (20 years).
- Sludge Landfills - Closure/Post Closure Requirements
Procedures and certifications required for closing a residuals landfill.
- Sludge Landfills - Design & Operation
Parameters for the environmentally safe design and operation of sludge landfills.
- Labeling Requirement and Additional Information Regarding Biosolids Containing Molybdenum
Due to the potential for molybdenum toxicity in ruminant animals, biosolids containing this element must carry a warning label. November 2016.
Other Sources of Information about Residuals
- US EPA Biosolids Home
Guidance and resources from EPA on biosolids management.
- US EPA Municipal Technologies: Use and Disposal of Biosolids (Sewage Sludge)
Federal rules and standards, technical reports, and guidance from EPA on biosolids management.
- Massachusetts Water Pollution Control Association Listing of Treatment Plants
Massachusetts Water Pollution Control Association listing of wastewater treatment facilities in the state.
- Massachusetts Water Resources Authority Bay State Fertilizer Program
The Massachusetts Water Resources Authority's sludge-recycling program converts sludge from wastewater treatment into fertilizer pellets for commercial sale.
- National Academy of Sciences Report on Biosolids Land Application
Report from the National Academy of Sciences identifying how current risk-assessment practices and knowledge regarding chemicals and pathogens in biosolids can be used to update and strengthen the scientific basis and credibility of EPA's biosolids regulations.
- North East Biosolids and Residuals Association
NEBRA promotes environmentally-sound and publicly-supported recycling of biosolids and other residuals in New England and eastern Canada.
- USDA Agricultural Research Service Agricultural Uses of Municipal, Animal, and Industrial Byproducts
Report on potential agricultural uses for municipal, industrial, and animal byproducts.