What must be controlled to prevent runoff from land-applied biosolids?

To effectively prevent runoff from land-applied biosolids, controlling heavy metals is essential. Heavy metals can pose significant environmental risks when they leach into water bodies. These metals, which often come from industrial processes, can accumulate in the soil and potentially contaminate groundwater or surface water if runoff occurs. By monitoring and regulating the levels of heavy metals in biosolids before they are applied to land, treatment facilities can minimize the risk of these toxic substances entering the water supply.

While nutrient flow, toxic contaminants, and temperature variations are also important aspects of biosolid management, heavy metals specifically require close attention due to their long-term environmental and health implications. Excessive nutrient runoff can lead to eutrophication but is typically managed through best practices in land application. Toxic contaminants, while also a concern, often relate to organic substances rather than the metals that can persist in the environment. Temperature variations mainly affect biological processes within the treatment systems rather than directly influencing runoff control. Therefore, focusing on heavy metals is crucial for safeguarding water quality when biosolids are applied to land.