Residuals & Biosolids

Reuse of treated wastewater residuals & biosolids is an environmentally safe process.

The Wastewater Program regulates the beneficial reuse of biosolids in Massachusetts through land application. It also regulates construction and modification of residuals treatment facilities, residuals landfills, and residuals incinerators.

What is the Residuals & Biosolids program?

What does the Residuals Management Program do?

The Program regulates the beneficial reuse of biosolids in Massachusetts through land application. It also regulates construction and modification of residuals treatment facilities, residuals landfills, and residuals incinerators.

What is the difference between sludge, residuals, and biosolids?

Sludge is the solid material in sanitary wastewater, either from wastewater treatment plants or on-site septic tanks. Biosolids is 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. MassDEP's program that oversees wastewater treatment sludge and biosolids is called the Residuals Management Program.

How are biosolids 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 safe for beneficial uses such as fertilizer or soil amendments.

Is all sludge regulated by the Land Application Regulations?

No. Only wastewater treatment residuals that are intended for use as biosolids are subject to MassDEP's Land Application regulations. The incineration or landfilling of wastewater treatment sludge is governed by MassDEP policy and guidance documents.

Does the EPA regulate biosolids?

Yes. EPA also regulates the beneficial reuse of biosolids through land application. 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 do we know that biosolids are safe to use?

MassDEP regulations for the Land Application of Sludge and Septage (310 CMR 32.00) ensure that biosolids are safe to use.

Wastewater treatment plants that treat sludge for beneficial use as a biosolids must meet the following conditions:

  1. Sampling and Analysis Plan: documents how samples of biosolids 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.
  2. 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. Approval of Suitability is revisited every two years.
  3. Land Application Certification: management standards for the spreading and incorporation of biosolids on a specific parcel of land. Land Application Certificates must be updated each year.

In addition, biosolids must meet strict quality standards for their proposed use:

  • Type I biosolids meet very high quality standards and may be used as commercial fertilizers and soil conditioners.
  • Type II biosolids meet a lower standard for use than Type I and require additional MassDEP permitting in order to be applied to land. Their use is restricted to a specific parcel of land.
  • Type III biosolids have also been treated for pathogen reduction, but typically have more chemicals and metals than Type II biosolids. Use of Type III biosolids is restricted and any application must be recorded on the deed to the parcel of land on which it is applied.

Sludge from industrial wastewater treatment processes is regulated by MassDEP's Bureau of Waste Prevention. 

Additional Resources

Wastewater Treatment Plants that produce biosolids

The following facilities produce biosolids, which may be available to users directly or through retail outlets. For more information, contact the facility directly.

Billerica Public Works
70 Letchworth Ave.
Billerica, MA 01862
Dartmouth Water Pollution Control Division
759 Russells Mills Road
Dartmouth, MA 02748
Greater Lawrence Sanitary District
240 Charles Street
North Andover, MA 01845
Hoosac Water Quality District
667 Simonds Road
Williamstown, MA 01267
Ipswich WWTP
20 Fowlers Lane
Ipswich, MA 01938
Marlboro East WWTP
860 Boston Post Road
Marlboro, MA 01752
Massachusetts Water Resources Authority
Mansfield WWTP
6 Park Row
Mansfield, MA 02048
Nantucket WWTP
188 Madaket Road
Nantucket, MA 02554
Pepperell WWTP
47 Nashua Road, P.O. Box 319
Pepperell, MA 01463
Somerset WWTP
116 Walker Street
Somerset, MA 02725
Springfield WWTP
P.O. Box 995
Springfield, MA 01101
Southbridge WWTP
P.O. Box 1020
83 Dresser Hill Road
Southbridge, MA 01550

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