AGRONOMIC EFFECTS OF LAND APPLICATION OF WATER-TREATMENT SLUDGES

Economic, regulatory, and legal constraints on alternative disposal methods are raising interest in land application of water treatment sludges. Understanding the agronomic and environmental issues is essential before a land-based disposal program is implemented. Water treatment sludges may favorably modify the pH and water-holding capacity of soils but generally have little fertilizer value. Supplemental phosphorus (P) fertilizer will usually be needed to offset the strong P-binding capacity of these sludges. Heavy metal concentrations can be limited in sludges primarily by controlling the purity of the coagulant chemicals.