Dispelling Biosolids Human Waste Fertilizer Dangers

In Canada and the United States, biosolids recycling is seen as an environmentally sound and affordable method for managing wastewater. When done according to stringent regulations, biosolids can help communities protect the environment by providing a safe source of organic fertilizers.

In Ontario, sewage sludge is required by law to be pre-treated in accordance with provincial regulations to remove toxic elements prior to discharge into the sewer system. The province is engaging in continuous efforts to inform the public about the benefits of biosolids dispelling human waste fertilizer dangers.

What are Biosolids?

Wastewater treatment plants employ physical, chemical, and biological means to purify sludge from households and industries before being reintroduced into the waterways. This process results in organic residuals called biosolids. Biosolids are further treated to remove pathogens and harmful micro-organisms as well as minimize foul odour. Treatment methods include heat systems, digestion, lime stabilization, pasteurization and composting. Biosolids are rich in nutrients and can be recycled into natural fertilizers to enhance agricultural farm lands. It must abide by the regulatory limits for contaminants, pathogens and odour to be considered safe for farmlands as a non-agricultural source material (NASM).

How Safe Are Biosolids?

Although biosolids have been applied to farmlands for centuries, there has still been a lot of public concern regarding the presence of various organisms and compounds that may cause harm once it enters the food chain.

Most pathogens are eradicated via the use of digestion, high-temperature and stabilization processes. It should also be noted that after biosolids are applied to agricultural lands, the harsh soil conditions kill these organisms so that they no longer cause any risk. According to a National Research Council Study initiated by the United States Environmental Protection Agency (EPA) in 1996, crops that were fertilized with biosolids, as long as treatment and land application follow the US regulatory standards, are safe for human consumption. In 2000, another study was conducted by the Water Science and Technology Board of the National Research Council/National Academy of Sciences (NAS) to review the science and methodology standards for biosolids. It confirmed that biosolids present a negligible risk to consumers.

Pharmaceuticals like antibiotics, antimicrobial triclosan and triclocarban, flame retardants, plasticizers, and natural and synthetic hormones have been reportedly present in wastewater. However, some of these chemicals are naturally removed through the treatment process and whatever remains have concentrations that are not significant enough to pose any threat.

According to Water Environment Association of Ontario (WEAO), “North American and European researchers have reported that polybrominated diphenyl ethers (PBDEs, flame retardants), some classes of antibiotics, some anti-inflammatory, lipid regulating, anti-epileptic, and anti-depressant pharmaceuticals, the antimicrobial compounds triclosan and triclocarban, bisphenol A and other plasticizers, and musk fragrances are present in biosolids at parts-per-billion (ppb) to parts-per-million (ppm) concentrations. Perfluorinated compounds and the naturally occurring hormone estrone are found at ppb concentrations. Surfactants, including the nonylphenol class, are found at ppm to parts-per-thousand concentrations.” To put things in perspective, imagine planting soybeans at a rate of 200,000 seeds per acre, 1 ppm is equal to to 1 seed in 5 acres. 1 ppb is equivalent to 1 seed in 5,000 acres. The Province of Ontario is approximately 230 million acres.

In terms of trace metals in biosolids, the Canadian Food Inspection Agency (CFIA) has standards in place to ensure that metals in fertilizers are based on the maximum acceptable cumulative metal addition to soil and the application rates over a 45-year period. In most provinces, the application rate depends on the agronomic and fertilization practices, as well the type of soil.

The Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA), together with the Ministry of Environment and Climate Change (MOE), oversees Ontario’s biosolids land application program. It has set regulations under the Ontario Water Resources Act, the Environmental Protection Act, and the Nutrient Management Act to ensure that biosolids do not adversely affect food quality, human health and the environment.

The MOE inspects about 200 sites a year. Municipalities also check areas that are under their local programs to guarantee that service providers are strictly complying with regulations. The Canadian Food Inspection Agency (CFIA) regulates the sale and import of biosolids intended for use as a fertilizer or supplement and issues a Letter of No Objection (LONO) for sale of products that meet its standards and requirements under the Fertilizers Act and Regulations.

OMFRA maintains that there are no documented cases of negative effects from biosolids that have been applied to agricultural land. In addition, there are no recorded cases of employees involved in the wastewater treatment process or the land application of biosolids that have experienced any health issues thereby further dispelling human waste fertilizer dangers.

If you are a municipality in Ontario and in need of a biosolids management solution, please feel free to contact us at 1 (877) 479-1388.

Water Environment Association of Ontario (WEAO)

Dispelling Biosolids Human Waste Fertilizer Dangers
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