Part 1. What are Biosolids?

Biosolids are a natural, safe, and endlessly renewable resource that improves our environment, lowers costs to consumers, and strengthens our farming communities. Biosolids begin as waste—your poop to be exact. Scientists developed a wastewater treatment process that turns what you flush into vital nutrients for plants and soil. This is a safe, inexpensive way to keep your utility bill low, improve our environment, and provide farmers with better 1

Because biosolids are loaded with nitrogen, phosphorus, and many other key nutrients needed to grow plants, the most popular use is as compost or natural fertilizer to improve soil for farms and home gardens. Farmers and gardeners are the biggest users of biosolids—they used more than half of the biosolids produced by wastewater plants in 2019 according to the EPA. Parks and golf courses are other large users of biosolids. 1

Rich in nutrients, biosolids actually improve the health of the soil and allow for the slow release of key compounds like nitrogen and phosphorous; key nutrients needed to grow healthy plants. Farmers also benefit from biosolids, which are much more economical than traditional chemical fertilizers which can be very expensive. 1

Part 2. Are Biosolids Safe?

Before biosolids can be used for land application, they must meet strict regulations and quality standards that are governed by the Environmental Protection Agency and the Indiana Department of Environmental Management (IDEM). These agencies monitor the use of biosolids, set standards for biosolids production and use, and determine reporting requirements. The federal standards were first enacted over three decades ago in 1993, founded on public health and environmental science. These are the US EPA “Part 503” regulations and they are regularly reviewed and updated every two years. Part 503 identifies approved treatment processes to remove pathogens (microscopic organisms that can cause disease in humans) and make solids less odorous. Additionally, these treatment methods make the resulting biosolids less attractive to “vectors,” like flies. By the time the required treatment and testing procedures are complete, biosolids leave the wastewater treatment facility as a safe and environmentally friendly alternative to traditional commercial fertilizers. 2

Just like traditional fertilizers, biosolids are required to be applied to land at the appropriate agronomic rate. This means that the plants are getting the right amount of nutrients at the right time and in the right place. Not only is this optimal for farmers, but it’s what’s best for the environment too. Many farmers will work with their local extension agent to determine the agronomic rate for their specific area, soil, and crop. 3

Indiana has its own requirements for biosolids application in addition to Part 503. The Indiana Department of Environmental Management (IDEM) oversees the management of biosolids within the state and has specific regulations and permitting requirements that must be followed by facilities and entities involved in the production, handling, and land application of biosolids. In addition to ensuring the safe production and use of biosolids, the IDEM regulations keep our roadways clean during the transport of biosolids from the wastewater treatment plant to the fields. These state-specific regulations work in conjunction with the EPA regulations to ensure the safe use of biosolids in Indiana. 4

Utilities across the country have been safely making biosolids for decades and long-term scientific studies have consistently demonstrated that biosolids recycling is safe and beneficial when performed in accordance with federal and State regulations. 5

Federal and state regulations, industry and farming best management practices and nature provide multiple layers of protection for our streams, groundwater, and wells. Because biosolids improve soil structure and water-holding capacity, multiple studies have shown that biosolids actually help to reduce runoff into our streams and leaching into groundwater. Biosolids contain nitrogen and can be applied to crops as a fertilizer. However, the addition of too much nitrogen, whether from biosolids or from a commercial fertilizer, can be detrimental to plant growth or can degrade groundwater or surface water. As such, sites receiving biosolids applications are carefully selected and managed to ensure the protection of water resources. 5

Food grown using biosolids is safe to eat, and it’s safe to play on parks and golf courses where biosolids are used to improve the health of the turf. Biosolids have been used safely for decades. Biosolids are regularly monitored to ensure they comply with federal and state regulations. Hundreds of academic and scientific studies have shown that biosolids are a safe and responsible alternative to chemical or animal fertilizers. 1

Part 3. What are the benefits of using biosolids? What is land application and why is it important?

Applying biosolids to farmland has been shown to increase the soils’ ability to store carbon, which keeps it out of the atmosphere, helping to reduce greenhouse gas emissions. The use of biosolids also reduces the need for chemical fertilizers, which contribute significant amounts of greenhouse gas emissions when they are manufactured and used. Land application of biosolids also can have economic and waste management benefits (e.g., conservation of landfill space; reduced demand on non-renewable resources like phosphorus; and a reduced demand for synthetic fertilizers). 3

Using biosolids for land application is a win-win for sustainability. Not only do biosolids supply necessary nutrients to build healthy soils, but it diverts biosolids from being disposed of in landfills. Farmers also benefit from biosolids, which are much more economical than traditional chemical fertilizers which can be very expensive. 1

Land application is the application of biosolids to land to improve the soil and fertilize crops or other vegetation grown in the soil. Nearly half of the biosolids production in the US is currently being used beneficially to improve soils. 6

Part 4. How does Columbus use biosolids?

Columbus City Utilities processes nearly 1,200 tons of biosolids per year, and approximately half of this is utilized as a fertilizer and land applied, diverting it from the landfill.

Following requirements and best practices for biosolids, land applications in Columbus are limited to specific times of the year. These limitations ensure that plants receive and can use the nutrients from the biosolids. However, this also means that Columbus has to store biosolids during the times when it can’t be land applied. Columbus City Utilities, farmers, and other storage providers use biosolids-specific storage facilities and methods, which are designed to protect local water sources and environmental habitats.

Yes! Land application of biosolids is a common practice in Indiana due to the many environmental and agricultural benefits. 7 There are over 10,000 land application sites in Indiana. 8


  1. Water Environment Federation. (2021). Biosolids Communication Toolkit. Water Environment Federation. Available online at
  2. United States Environmental Protection Agency (US EPA). (2024). Biosolids Laws and Regulations. Available online at
  3. US EPA. (2023). Basic Information about Biosolids. Available online at
  4. Indiana Department of Environmental Management (IDEM). (2024). Land Application. State of Indiana. Available online at
  5. Mid-Atlantic Biosolids Association. (2022). Fact Sheets & Helpful Information Sheets. Available online at
  6. US EPA. Office of Wastewater Management, & United States. Environmental Protection Agency. Office of Wastewater Management. Municipal Technology Branch. (1994). A plain English guide to the EPA part 503 biosolids rule. US Environmental Protection Agency, Office of Wastewater Management. Available online at
  7. Beecher, Ned.; Juliana Beecher; Janine Burke-Wells; Maile Lono-Batura; Nora Goldstein; Greg Kester; and Bill Toffey. 2022. National Biosolids Data Project: Biosolids management in the U. S. Available online at
  8. (2024). IDEM Land Application Users. State of Indiana. Available online at
  9. (2024). IDEM Land Application Permits and Notifications. State of Indiana. Available online at