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Agronomic Rate - The annual whole biosolids application rate (dry weight basis) designed to provide the amount of nitrogen needed by the crop and to minimize the amount of nitrogen in the biosolids that passes below the root zone of the crop.

Biosolids - Nutrient-rich organic material produced from the stabilization of sewage sludge and residential septage that meet specific criteria and are suitable for land application.

Metals - Inorganic substances commonly found in sewage sludge. The regulations include limitations on arsenic, cadmium, copper, lead, mercury, molybdenum, nickel, selenium and zinc.

PCBs - (polychlorinated biphenyl) Organic compounds that have various industrial applications.

Pathogens - Disease-causing organisms, such as certain bacteria, viruses and parasites.

Permit - One of three biosolids general permits developed to implement the new sewage sludge regulations.

Residential Septage - A liquid or solid material removed from a septic tank, cesspool, portable toilet, or similar device that receives only domestic sewage. This excludes grease-trap pumpings and commercial or industrial waste.

Sewage Sludge - a solid, semisolid or liquid residue generated during the treatment of wastewater in a treatment works.

Soil pH level - The acidity of soil. Soils with a pH between six and nine are considered acceptable. Under six would constitute too much acid, whereas above nine would mean too little acid.

Soil Tilth - Cultivated land; the state of aggregation of a soil especially in relation to its suitability for crop growth.

Vector Attraction - The characteristic of sewage sludge that attracts rodents, flies, mosquitoes, or other organisms capable of transporting infectious agents.