Biosolids are the nutrient-rich, organic by-product of the wastewater treatment process which can be recycled and used to enhance soil conditions.
Long-term scientific studies have repeatedly demonstrated that biosolids recycling is safe. Monitoring of biosolids, soils, water resources and plants continue to show benefits from recycling. These studies formed the basis for federal and state biosolids regulations. The application of organic matter from biosolids can improve the physical, chemical and biological properties of soil. Organic matter can reduce soil erosion, increase water-holding capacity, provide nutrients for plant growth, and provide food and energy for beneficial soil microorganisms. Land applying biosolids is a great method of recycling, and it provides an excellent nutrient source for crops. Land application not only provides the landowner with a product that is excellent for the soil, but is also saves valuable landfill space. Biosolids provide the soil with nitrogen, phosphorus, potassium, trace minerals, and other nutrients vital to the production of crops. In addition, there are strict guidelines that we must adhere to for Class B Biosolids, including setbacks from wells, streams, public buildings, and more.
As part of the Federal 503 Monitoring rules all biosolids that are to be land applied must first be tested for Heavy Metals. Almost everything in our world has some extremely small amount of metals in it. Even toothpaste has metals in it, but the big question is, “How much?” The Federal EPA, through very exhaustive research and testing, has determined the maximum allowable amount of certain metals that are allowed in biosolids. Before biosolids are received at our facilities, every source is tested and verified to assure that the material is well within these limits.
The Federal EPA 503 rules require that all biosolids must meet certain treatment levels to assure the public that the material is safe for land application. The method that is used to measure this is called Pathogen Reduction. This is used to determine how much treatment the biosolids have had and how many disease-causing organisms could be present in the biosolids. We use a verification method called Fecal Coliform. Disease-causing organism are everywhere in our world, even on our hands, which is why normal washing practices are encouraged for everyone. The question we must ask as it relates to biosolids is, “At what level are the disease-causing organisms low enough to not cause a potential threat to humans?” Prior to receiving biosolids at our facilities, all biosolids must be well below the maximum allowable limit to assure complete compliance with all State and Federal regulations.
Ted & Terry Merrell are the co-owners of Merrell Bros. Inc. They live in Kokomo, Indiana, and before the first biosolids center was ever constructed away from the base of operations, they installed a biosolids center very close to both owners’ personal residences. This was intentionally done so that the owners would be able to make sure that the biosolids center concept did not cause or disrupt the lives of area residents and or neighbors. Because of that concern, great care is taken to make sure that odors are not an issue. The Federal EPA also addresses this issue as it relates to what they call Vector Attraction Reduction. What this term means is the ability of some outside source such as a wild animal, rodent, or domestic pet to be able to walk out onto a field and step into the biosolids and then transfer it back to a human or child. The Federal government has listed several methods to use to satisfy this requirement. Two of the methods we utilize are approved by the EPA. These two methods are called incorporation and direct injection. Both of these methods cover the biosolids with soil so that it cannot be seen or smelled. Covering the biosolids with soil reduces the potential for odor and vector attraction.
The use of biosolids is regulated by the federal and state governments. It has a long history of safe use as an alternative fertilizer. No more biosolids based nutrients can be applied to a field than the crop being grown can take up. This limitation practically eliminates the potential for groundwater contamination. Conversely, there is no regulatory limit to the amount of commercial fertilizer that can be applied to a field, making the potential for groundwater contamination from commercial fertilizer is greater than from the proper use of biosolids. Under certain economic conditions, such as when the price of crop being grown is high, and commercial fertilizer cost are low, farmers may choose to apply excess fertilizer to assure maximum crop yields. The nutrients in the excess fertilizer can easily contaminate the groundwater on and downstream of the field. In addition, recycling biosolids to grow crops reduces the use of valuable landfill space which would have been to dispose of this waste product.
Land applying biosolids completes the nutrient recycling circle. The nutrient circle begins with the farmer harvesting a crop. Using corn as an example, the corn is either processed into food for humans or fed to animals which will become food to sustain human life. Some of the nutrients in food eaten by humans pass through our bodies into sewer systems of municipalities across the country. The sewer lines empty into waste water treatment plants, where the waste water is thoroughly cleaned, then released into streams. The solids which are removed in the waste water cleaning process contain valuable nutrients. If recycled as biosolids, these nutrients are used to fertilize the next crop. And as long as there is human life, the supply of biosolids is never-ending. The Environmentally friendly part of this recycling program is that it is a complete 100% recycling method that does not release any greenhouse gases or carbons and can perpetually go on forever without any byproduct.