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• What are Biosolids?
• How are Biosolids genarated and processed?
• How are Biosolids used?
• Can anyone apply Biosolids to land?
• Are Biosolids safe?
• What about metals?
• What about bacteria and viruses?
• What about ground and surface water?
• Do Biosolids smell?
• Are there regulations for the land application of Biosolids?
WHAT ARE BIOSOLIDS?
Biosolids are the nutrient-rich solid organic matter recovered from the treatment of domestic wastewater in a wastewater treatment facility. Biosolids are a beneficial resource, containing essential plant nutrients and organic matter and are recycled as a fertilizer and soil amendment on agricultural land. When treated and processed, these wastewater residuals can be recycled and applied as fertilizer to improve and maintain productive agricultural soils and enhance plant growth.
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HOW ARE BIOSOLIDS GENERATED AND PROCESSED?
Biosolids are generated when solids generated during the treatment of domestic wastewater are treated further to meet specific regulatory requirements for beneficial use. The regulation of biosolids quality actually begins before the wastewater reaches the treatment plant. In many larger wastewater treatment systems, including Hamilton's, pre-treatment regulations require that industrial facilities pre-treat their wastewater to remove many hazardous contaminants before it is sent to a wastewater treatment plant. Wastewater treatment facilities monitor incoming effluent streams to ensure their treatability, recyclability of biosolids and compatibility with the treatment plant process. For more information see Hamilton's Sewer Use By-Law #04-150 or call 905-542-2424 extension 5190.
Once the sewage reaches the wastewater treatment plant, the sewage goes through physical, chemical and biological processes that clean the wastewater and remove the solids. Solids are then treated to eliminate objectionable odors. Pathogen reduction also occurs in the treatment processes to remove disease-causing organisms, such as bacteria, viruses and parasites. By properly treating sewage sludge, the international scientific community recognizes the resulting material as biosolids which can be land applied as a valuable fertilizer and soil amendment, instead of taking up space in a landfill or other disposal facility.
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HOW ARE BIOSOLIDS USED?
After treatment and processing, biosolids can be recycled and applied as fertilizer or soil conditioner to improve and maintain productive soils and stimulate plant growth. The controlled land application of biosolids completes a natural cycle in the environment.
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CAN ANYONE APPLY BIOSOLIDS TO LAND?
Anyone who wants to use biosolids for land application must comply with all relevant federal and provincial regulations. Approval (i.e.: Certificate of Approval) is required and enforced by the Ministry of Environment (MOE). Only a licensed contractor operating with an approved Certificate of Approval is allowed to land apply biosolids in Ontario.
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ARE BIOSOLIDS SAFE?
Decades of Canadian and International research have demonstrated that biosolids can be safely used on agricultural land for improved crop production. The Ontario Ministry of the Environment has reviewed current practices, public health concerns and regulatory standards, and has concluded that "the MOE has approved the land application of sewage biosolids for more than 25 years with no documented adverse impacts on agricultural production, or human and animal health where Ministry Guidelines were followed". Environment Canada stated, "There is little evidence to incriminate treated biosolids in disease outbreaks when treatment and application are performed in a careful and controlled manner”.
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WHAT ABOUT METALS?
Ontario’s guidelines do not permit the application of biosolids with metal concentrations over specific regulated limits. These are conservatively set to prevent toxicity or health impacts in plants, animals and humans. The concentrations of regulated metals in the Woodward Treatment Plant biosolids are well below Ontario’s guidelines. Soils are also tested for metals prior to biosolids land application to ensure that the soils receiving biosolids are within the MOE’s Guideline limits.
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WHAT ABOUT BACTERIA AND VIRUSES?
There have been no reported illnesses caused by land application of biosolids in Canada. The Woodward Treatment Plant’s biosolids have gone through an anaerobic treatment process which stabilizes them and destroys many of the disease-causing organisms. Mandatory waiting periods between biosoilds land application and harvesting of specific crops or pasturing of domesticated animals provides for the safety of crops, animals and humans.
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WHAT ABOUT GROUND AND SURFACE WATER?
Guidelines in Ontario control how, where, how much and how often biosolids can be spread to ensure that ground and surface water is not contaminated. Biosolids are applied at a rate that allows the crops to use most of the nutrients as they become available. This keeps the nutrients from ending up in ground and surface waters. Metals in biosolids are generally in a form that is hard to dissolve in water and tend not to move out of the area to which they were supplied.
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DO BIOSOLIDS SMELL?
Biosolids may have their own distinctive odor depending on the type of treatment and processing at the wastewater treatment plant. Some biosolids may have a slight musty, ammonia odor. Others have a stronger odor that may be offensive to some people. Compounds that contain sulfur and ammonia, which are both plant nutrients, cause most odors. As a way of managing odors at the field, biosolids are incorporated into the soil within a few hours of application.
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ARE THERE REGULATIONS FOR THE LAND APPLICATION OF BIOSOLIDS?
Yes. Ontario has regulations governing biosolids land application in the Environmental Protection Act (EPA) and the Nutrient Management Act (NMA). In addition, the Canadian Food Inspection Agency (CFIA) has standards in the Fertilizer Act governing the sale of biosolids as a fertilizer or soil conditioner. Biosolids that are to be land applied must meet these strict regulations and quality standards. These regulations contain strict numerical limits for metals and pathogens in biosolids, processing requirements, maximum application rates to land, management practices and analysis requirements, record keeping and reporting requirements for all land applied biosolids In addition, the MOE and the Ontario Ministry of Agriculture and Food (OMAF) have several research studies underway to determine if more stringent regulations are required in the future. Biosolids are one of the most studied materials that have ever been regulated by the MOE and previous Ontario research indicates that the land application of sewage biosolids when applied according to guidelines is an environmentally safe and sustainable practice.
The contents of this information is presented in good faith and are intended as general guidance on matters pertaining to biosolids. All information provided is believed to be accurate and reliable
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