Phosphorus

About: Phosphorus is a research topic. Over the lifetime, 53120 publications have been published within this topic receiving 939731 citations. The topic is also known as: element 15 & P.

In situ stabilization of soil lead using phosphorus.

Abstract: In situ stabilization of Pb-contaminated soils can be accomplished by adding phosphorus. The standard remediation procedure of soil removal and replacement currently used in residential areas is costly and disruptive. This study was carried out to evaluate the influence of P and other soil amendments on five metal-contaminated soils and mine wastes. Seven treatments were used: unamended control; 2,500 mg of P/kg as triple superphosphate (TSP), phosphate rock (PR), acetic acid followed by TSP, and phosphoric acid (PA); and 5,000 mg of P/kg as TSP or PR. A significant reduction in bioavailable Pb, as determined by the physiologically based extraction test (PBET), compared with the control upon addition of P was observed in all materials tested. Increasing the amount of P added from 2,500 to 5,000 mg/kg also resulted in a significantly greater reduction in bioavailable Pb. Phosphate rock was equally or more effective than TSP or PA in reducing bioavailable Pb in four out of five soils tested. Preacidification produced significantly lower bioavailable Pb compared with the same amount of P from TSP or PR in only one material. Reductions in Pb bioavailability as measured by PBET were evident 3 d after treatment, and it may indicate that the reactions between soil Pb and P occurred in situ or during the PBET. No further reductions were noted over 365 d. X-ray diffraction data suggested the formation of pyromorphite-like minerals induced by P additions. This study suggests that P addition reduced bioavailable Pb by PBET and has potential for in situ remediation of Pb-contaminated soils.

Modelling of activated sludge systems

Abstract: Evolution of Activated Sludge Modelling - Energetics of Microbial Processes - Reactor Kinetics of Microbial Processes - Traditional Approach to Activated Sludge Modelling - New Concepts in Activated Sludge Modelling - Biological Oxidation of Nitrogen - Biological Nitrogen Removal Biological Excess Phosphorus Removal - Experimental Assessment of Biological Treatability

Controlled versus Conventional Drainage Effects on Water Quality

Abstract: Fertilized cropland is a potential nonpoint source of nitrogen and phosphorus, which can contribute to the nutrient enrichment of surface water ecosystems. Research has shown that agricultural drainage water may contain fertilizer nutrients and pesticides. Nitrogen and phosphorus are present in drainage outflow primarily because of the addition of fertilizer, which results from the change in land use following drainage improvements instead of from the mere installation of drainage. Yet, public concern for the environment has led to a general criticism of agricultural drainage for degrading water quality. Controlled drainage has been recognized in some states as a best management practice to reduce the transport and delivery of nitrogen and phosphorus to sensitive surface waters. This article summarizes and compares water quality impact associated with conventional and controlled drainage practices. Nitrogen and phosphorus reductions of 30% to 50%, resulting from controlled drainage are reported in several...