Overview
Residuals sold, used, and distributed, for land application in Massachusetts are subject to an Approval of Suitability (AOS), which classifies residuals for different uses based on chemical quality and treatment to reduce pathogens. Sludge and septage regulated according to 310 CMR 32.00 are referred to as “residuals” and are subject to an Approval of Suitability.
Residuals Include:
- treated biosolids produced from sanitary wastewater sludge,
- drinking water treatment facility sludge,
- industrial facility sludge, and
- short paper fiber sludge.
PFAS in Wastewater and Sludge
- Public PFAS portal with residuals data
- PFAS in Wastewater and Sludge (includes PFAS in wastewater and sludge projects since 2020)
- PFAS in Wastewater and Sludge Stakeholder Group
- How to submit residuals PFAS data in eDEP
For more information about MassDEP’s regulation of residuals, contact the Residuals Program at massdep.residuals@mass.gov.
Frequently Asked Questions about Residuals
What is the difference between sludge, residuals, and biosolids?
Sludge is the solid material in wastewater, either from wastewater treatment plants or on-site septic tanks. Biosolids is sanitary sludge that has been treated to ensure that it can be applied to land as a fertilizer or soil amendment. Residuals is a general term for both sludge and biosolids.
How are biosolids and residuals created?
First, water is removed from the sludge (called "dewatering") with centrifuges, vacuums, drying beds or presses. Then the material is stabilized using one or more treatment methods in order to reduce pathogens and odors and make the biosolids available for use as fertilizer or soil amendments.
Does the EPA regulate biosolids and residuals?
EPA only regulates the beneficial reuse of biosolids through land application (but not non-sanitary residuals). EPA's "Regulations for the Use and Disposal of Sludge" (40 CFR Part 503) set pathogen removal and metals standards for biosolids. In some areas, MassDEP's standards are stricter than EPA's, and state regulations and permits also address areas not covered by EPA.
How can I learn more information about land application of biosolids and residuals in Massachusetts?
MassDEP regulations for the Land Application of Sludge and Septage (310 CMR 32.00) require that treated sludge meet the following conditions:
- Sampling and Analysis Plan: documents how samples of biosolids or residuals will be collected, analyzed, and reported to MassDEP. The plan should describe sample preparation, preservation, and conveyance to certified laboratories.
Sampling and Analysis Plan approvals do not expire. However, MassDEP must be notified of any change in materials or processes that may affect the sampling locations or the number of samples required. - Approval of Suitability: classification of biosolids for different uses, based upon the chemical quality and the degree to which it has been treated to reduce pathogens in the sludge.
- Land Application Certification: management standards for the spreading and incorporation of biosolids or residuals on a specific parcel of land. Land Application Certificates must be updated each year.
In addition, biosolids and residuals must meet regulated treatment requirements. The type of treatment dictate whether biosolids are categorized as Type I, Type II, or Type III. Available uses for each Type are outlined below:
- Type I biosolids and residuals may be used as commercial fertilizers and soil conditioners.
- Type II biosolids and residuals require additional MassDEP permitting in order to be applied to land. Their use is restricted to a specific parcel of land.
- Type III biosolids and residuals is restricted and any application must be recorded on the deed to the parcel of land on which it is applied.
Regulations Pertaining to Residuals and Biosolids
Wastewater Treatment Plants That Produce Biosolids in Massachusetts
The following facilities produce biosolids, which may be available to users directly or through retail outlets. For more information, contact the facility directly.
Dartmouth Water Pollution Control Division
759 Russells Mills Road
Dartmouth, MA 02748
508-999-0740
Greater Lawrence Sanitary District
240 Charles Street
North Andover, MA 01845
Email
Hoosac Water Quality District
667 Simonds Road
Williamstown, MA 01267
413-458-5016
Ipswich WWTP
20 Fowlers Lane
Ipswich, MA 01938
978-356-6635
Massachusetts Water Resources Authority
190 Tafts Avenue
Winthrop, MA 02153
Southbridge WWTP
P.O. Box 1020
83 Dresser Hill Road
Southbridge, MA 01550
508-764-4927
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.
Stakeholder Meetings
Find more information about past and upcoming PFAS in Wastewater and Sludge Stakeholder meetings. Please send questions and comments to massdep.npdes@mass.gov.