What Are Biosolids?

In its simplest definition, biosolids can be described as solid organic matter derived from the wastewater treatment process and used as fertilizer. Biosolids are nutrient-rich organic materials that hold a lot of benefits when used correctly. It contains essential plant nutrients as well as beneficial organic matter. 

The terms biosolids and sludge are often used interchangeably, but these two concepts are not exactly the same. Sewerage sludge is a term used to describe the solids that have been separated from municipal wastewater during treatment. On the other hand, biosolids describe sewerage sludge that has been treated and meets requirements for EPA pollutants and pathogens. 

What Are Biosolids Used For?

There are various types of application for biosolids. Biosolids may be used to help promote growth in agricultural crops. In addition, biosolids may be used to fertilize parks and gardens, as well as be used to reclaim mining sites. There are rules and regulations for the use of biosolids. For example, when biosolids are used to promote the growth of crops, the use of biosolids is restricted to the number of nutrients required by the plants. 

The use of biosolids as land fertilizer is not a new concept. In fact, biosolids have been used as a fertilizer for centuries by cultures around the world. Germany and the Netherlands are on a list of European countries that utilize most of their biosolids on agricultural land. 

The Benefits of Using Biosolids

There are several benefits associated with the use of biosolids on agricultural lands, such as:

Organic matter

Biosolids possess increased organic matter which is transferred into the soil. The increased organic matter is evident in an indirect manner. There are more leaves and plant roots. This means that plants can better photosynthesize and draw nutrients from the soil through their roots. Thus, the plants grow bigger and fuller. 

Nutrient supply

Another key benefit is the nutrients that are added to the soil, such as:

  • Nitrogen (N)
  • Phosphorus (P)
  • Potassium (K)

Better soil structure

Biosolids will eventually decompose in the soil. This process creates a substance that acts as glue. The glue then binds soil particles together. When the soil is glued together, you are left with soil that is stable and has good physical properties.

Higher yields

Biosolids contain trace minerals that directly influence the yield of a crop. Biosolids create significantly higher yields. The health of the soil is affected by trace minerals. And, the healthier the soil, the better the harvest.

A lot of soil does not contain the required trace minerals to allow plants to grow optimally. Biosolids are the only type of fertilizer that contains such a wide range of the necessary trace minerals that plants need. There is currently no other fertilizer on the market that contains the same amount of trace minerals, such as biosolids.

To create a fertilizer that would equal the number of trace minerals found in biosolids, it would require several different composts to be mixed together. This can be quite costly, and many farmers aren’t able to financially justify such a purchase.