National Pollutant Release Inventory Reporting Guidance on Biosolids


The purpose of this document is to provide clear guidance for the reporting requirements of biosolids for wastewater treatment facilities (including municipal, institutional, and industrial).

Background Information

When insoluble materials are extracted from wastewater, the collected residue may contain organic materials, nutrients, pathogens, metals, and organic chemicals. These residual materials removed from the facility's wastewater treatment processes are referred to as "biosolids".

A number of the National Pollutant Release Inventory (NPRI) substances reside in biosolids. Guidance to date has been that the biosolids are not a product and therefore the NPRI substances in the biosolids should be reported to the NPRI as a transfer for disposal. However, some facilities have suggested that some reporting changes should be made to better reflect the industry's varied approach to biosolids, including:

  • Biosolids should be reported as transfers for recycling, rather than as transfers for disposal, or
  • Biosolids should be partitioned in such manner that it would allow reporting the nutrients in the biosolids as recycling and metals as disposal, or
  • Biosolids should be exempt from the reporting all together

Environment Canada (EC) has reviewed and evaluated the options of reporting changes for biosolids based on these suggestions.


EC continues to hold the opinion that biosolids (and the NPRIsubstances in the biosolids) are a by-product of wastewater treatment process (i.e. a waste) and not an intentionally produced product. As a result, the wastewater treatment facilities must continue reporting the NPRI substances in biosolids.

It is recognized that biosolids are transferred off-site for composting, recycling, or disposal. Their ultimate destination, in decreasing order of frequency of use, is: land treatment (i.e. land application or land farming), incineration, or landfill.

Under the existing NPRI definition, land application or land farming, incineration or landfill of biosolids are considered as the activities to be reported under "disposal". If biosolids are transferred off-site for recycling where they are treated or processed to be manufactured into compost or other products, they should be reported under the "recycling" activities within the descriptive category of "other - other recovery, reuse and recycling activities not described above".

The following table summarizes the reporting requirements for the NPRIsubstances in biosolids:

Summary Of The Reporting Requirements for the NPRISubstances in Biosolids

Reporting Requirements for the NPRI Substances in Biosolids
Biosolids Management ActivitiesReporting Modes
Recycling 1Transfers for recycling in the method classified as "other"
LandfillingOff-site disposal in the method classified as "landfill"
IncinerationOff-site treatment prior to final disposal in the method classified as "incineration or thermal treatment"
Land ApplicationOff-site disposal in the method classified as "land treatment"

1 Facilities that compost biosolids:

Facilities that compost biosolids and other materials can produce a number of different grades of compost. Compost that meets the CCME guidelines for category A compost (Guidelines for Compost Quality (CCME PN 1340 - 2005), is considered a product for the purposes of the NPRI. Other categories of compost from biosolids should be reported as transfers for recycling.

Note that all NPRI substances in a particular stream are to be reported in a consistent manner. If biosolids are sent to a landfill, then the quantity of NPRI substances sent to landfill need to be reported under this category even if it meets CCME category A compost. If the material is sent for recycling into compost then all NPRI substances in the stream need to be reported under recycling.


Composting - Refers to a natural biological process, carried out under controlled aerobic conditions, which converts organic material into a stable humus-like product called compost. Composting has the potential to manage all of the organic material in the waste stream which can not be otherwise recycled.

Recycling - Includes any activity that prevents a material or a component of the material from becoming a material destined for disposal.

Disposal - Means the final disposal of a substance to landfill, land application or underground injection, either on the facility site or at an off-site location. Disposal also includes treatment at an off-site location prior to final disposal.


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