American Society of Agricultural and Biological Engineers (ASABE)
Doi
Abstract
ABSTRACT. Sediments often play an important role in the temporary storage and release of phosphorus (P) in streams, espe-cially streams receiving municipal wastewater treatment plant (WWTP) effluent. The objective of this study was to evaluate sediment−aqueous phase P equilibrium in four Ozark streams, and to determine the effect of alum (Al2(SO4)3) and calcium carbonate (CaCO3) on stream sediment−P interactions and content of exchangeable P. Stream physicochemical properties were significantly affected by the effluent discharge from the WWTPs; of particular interest to this study was that the increase in P concentrations varied greatly among streams. Phosphorus inputs from WWTP significantly increased sediment equilibrium P concentrations (sediment−EPC0) and readily exchangeable sediment−bound P, while decreasing the P buffering capacity of stream sediments. Sediment−EPC0 values were as great as 7 mg L−1 downstream from one WWTP, suggesting that sediments are a transient storage pool of P and may release P back into the stream system when P inputs from the WWTP are reduced. The addition of alum and CaCO3 significantly reduced the sediment−EPC0 and readily exchangeable P, while increasing the ability of sediments to buffer increasing P loads
