Sewage biosolids are a nutrient-rich residue classified as a non-agricultural source material that can be applied to farmland as a soil builder or fertilizer, to promote healthy soils and healthy plants. Biosolids are used similarly as animal manure to help build organic matter, nutrients, microbial activity and micronutrients to soil.
In Ontario, spreading sewage biosolids on farmland during the winter months is prohibited. The spreading must adhere to the Nutrient Management Regulations that state biosolids cannot be spread from December 1 to March 31 of any year. In addition, biosolids cannot be spread on snow-covered or frozen ground regardless of the dates stated.
The Ontario government has good reason for putting these rules in place, as the number one priority of the regulation is to enhance the natural environment and provide a sustainable future for agricultural operations. Here at Wessuc, we also believe that protecting the environment is a priority, and we work hard to ensure that we follow the regulation and use best management practices for determining suitable field conditions for spreading throughout the year.
Spreading biosolids on snow-covered or frozen ground can increase the risk of run-off of biosolids into sensitive areas. This happens because biosolids cannot penetrate the frozen ground, and instead of entering the soil, they can wash off the field into surface water such as; ditches, streams, or ponds.
Run-off of nutrients into ditches, streams, ponds and non-agricultural areas can create adverse effects on humans, wildlife, aquatic life and the natural ecosystems. The two most common nutrients that can negatively impact non-agricultural land is nitrogen and phosphorus. In particular, phosphorus can accelerate eutrophication in our lakes and streams, resulting in the pollution of water through excessive algae growth which depletes oxygen and sunlight.
Furthermore, spreading of biosolids or any other nutrient on snow-covered or frozen land also does not have a benefit to the farmer. The number one reason why manures and biosolids are used on farm fields is because they help to increase the health of the soil. By adding nutrients to the soil, we can help to build healthy soils to grow crops. But, spreading fertilizers, manures, or NASM in the winter results in a significant loss of the applied nutrients to the environment by run-off, evaporation and wind erosion. As a result, farmers would have to apply more nutrients to their farm field to account for the loss of nutrients in the winter, which can be expensive and time consuming. The best time to capture the most nutrients possible for the soil is directly before planting or while there is a standing crop in the field. For this reason, farmers apply the majority of their nutrients during the spring before planting or after the crop has been planted.
People don’t stop going to the bathroom in the winter months.
Although spreading sewage biosolids in the winter is prohibited, we still need ways of managing the biosolids through the winter months. The main ways that we deal with this problem is by creating large storage sites, or lagoons to hold the excess material until the land is suitable for spreading. Every municipality handles their sewage biosolid storages differently. Some materials are stored as a liquid in large storage tanks, some are stored in outdoor lagoons, and some are dewatered and stored as solid materials in storage facilities.
Spreading of other nutrient in Winter
Sewage biosolids are the most heavily restricted materials in the Nutrient Management Act. It is designed this way because sewage biosolids contain human body waste, which can contain E. coli, and other pathogens that animal manures do not contain.
This means that all nutrients (fertilizers, manures or NASM materials) are created equally. Spreading of some NASM materials is permitted during the winter months, provided that they follow other sets of rules within the regulation, or follow best management practices. One of the reasons why nutrients may be spread during the winter is because storages are full due to unforeseen circumstances.
The storage of biosolids, other NASM, and manures is a common practice in Ontario. All new agricultural operations that have livestock must have a plan to manage their nutrients in the winter months. There are also similar regulations for any municipality or city that manages sewage biosolids under the Ministry of Environment.
But, sometimes the weather can cause problems for farmers, which makes it hard to distribute manures or NASMs in the dry months and storages may not have the capacity to hold the amount of material produced.
Some NASM materials (not including sewage biosolids) and manures can be spread on farm land during the winter months. In most cases, this is a last resort for farmers who have run out of storage space on their farms due to weather or other unforeseen circumstances. These farms should always be following the Nutrient Management Act and Best Management Practices when dealing with these situations.
as per the Nutrient Management Act, O. Reg 267/03 2002
- Snow covered ground:
- when used in reference to soil, means that a layer of snow with an average minimum depth of five centimeters.
- Frozen ground:
- when used in reference to soil, means that a layer of soil with an average minimum depth of five centimeters, located within the top 15 centimeters of the soil, is consolidated by the presence of frozen moisture.
- Non- Agricultural Source Material
- Best Management Practices:
- A practical, affordable approach to conserving a farm’s soil and water resources without sacrificing productivity.