Farm fields and forests receiving biosolids applications are carefully selected and managed to ensure the protection of water resources. Biosolids contain organic and inorganic nitrogen and can be applied to dramatically accelerate plant growth. However, the addition of too much nitrogen, whether from biosolids, animal manures or from commercial fertilizers, can leach into groundwater or run off into waterways.
In Virginia, each application of biosolids must meet the specific nutrient needs of the soil and the proposed crop, as documented by a Nutrient Management Plan approved by the Virginia Department of Conservation and Recreation, Division of Stormwater Management. This reduces the potential for excess nitrogen levels in the soil that could leach into ground water or move in runoff.
Biosolids nitrogen is released slowly as soil microbes convert organic nitrogen into plant available inorganic nitrogen. This process, along with adherence to buffers, helps protect the Chesapeake Bay from nutrient runoff. In contrast, buffers are not required for chemical fertilizers, which are highly soluble and can easily run off into receiving waters.