In a nutshell and on paper, biosolids have nothing but positive impact for the environment. Instead of the waste going straight to the landfills or incinerators, it goes through a treatment process that is able to produce a by-product that can be utilized as an organic fertilizer. In turn, this organic fertilizer can boost the nutrient consistency of the soil and help in the growth of plants, flowers, and crops. Biosolids are often used in agricultural farms, ranches, forestlands, home gardens, and in reclaiming mines.
However, the wrong land application of biosolids could affect the soil, water, and air. The negative impacts on water can result from the application of biosolids at rates that exceed the nutritional requirements of the plant or the vegetation. The excess nutrient (primarily nitrogen compound) can leak from the soil and into the groundwater. Runoff from rainfall could also carry excess nutrients to surface water.
The possibility of nitrogen compounds leaching from the soil and into groundwater is less likely, though, because biosolids are a slow-release fertilizer. The use of chemical fertilizers on the amended soil would still most likely pose a more dangerous threat than the leakage of nitrogen compound. That being said, the release or the application of biosolids must be done at agronomic rates. This would decrease the chances of any potential leaches or negative impact to the environment.
Negative impacts on the soil, on the other hand, could result from the mismanagement of biosolids land application. The land application of biosolids is strictly regulated to ensure that there would be no accumulation of metals and other harmful contaminants. Record keeping and reporting requirements on both the federal and state level are imposed on treatment plants to prevent mismanagement.
As for the negative impact to the air, the primary concern is the odor from the production of biosolids. Threat to human life and the environment are not the greater nuisance when it comes to applying biosolids on land. Rather, it’s the odor that emanate from the application that residents and neighborhoods are most concerned about.
There are methods that could decrease the odor of the biosolids, chief among these is stabilization processes such as digestion. Biosolids that have been disinfected through the addition of lime may emit ammonia odor but they are localized and they dissipate almost immediately. The stabilization process effectively reduces the odors and results in an operation that is less offensive and harmful than applying manure to soil.