Approximately 40% of biosolids (sewage sludge) produced in the U.S. are incinerated or landfilled rather than land applied due to concern over non-point source P (phosphorus) runoff. The objective of this study wa...Approximately 40% of biosolids (sewage sludge) produced in the U.S. are incinerated or landfilled rather than land applied due to concern over non-point source P (phosphorus) runoff. The objective of this study was to determine the impact of chemical amendments on WEP (water-extractable phosphorus) in applied treatments and DRP (dissolved reactive phosphorus) in runoff from biosolids-amended soils. Rainfall simulations were conducted in 2006 on field plots fertilized with biosolids that had been treated with alum [(A12804)3" 14H20], ferric chloride (FeC13) or an alum-based WTR (water treatment residual) at a rate of 20% (wt/wt) to reduce DRP in runoff. In 2007, rainfall simulations were conducted using WTR/biosolid blends of 15% and 30% (wt/wt) that were allowed to incubate for three weeks prior to application. Cumulative DRP runoff load observed for the 20% WTR treatment was not significantly different from other chemical treatments and resulted in a 45% reduction in DRP runoff as compared to the untreated biosolids application. Cumulative DRP runoff load in 2007 for the 15% and 30% WTR treatments resulted in significantly lower DRP loads compared to untreated biosolids and led to DRP runoff load reductions of 78% and 85% (compared to the untreated biosolids application), respectively.展开更多
文摘Approximately 40% of biosolids (sewage sludge) produced in the U.S. are incinerated or landfilled rather than land applied due to concern over non-point source P (phosphorus) runoff. The objective of this study was to determine the impact of chemical amendments on WEP (water-extractable phosphorus) in applied treatments and DRP (dissolved reactive phosphorus) in runoff from biosolids-amended soils. Rainfall simulations were conducted in 2006 on field plots fertilized with biosolids that had been treated with alum [(A12804)3" 14H20], ferric chloride (FeC13) or an alum-based WTR (water treatment residual) at a rate of 20% (wt/wt) to reduce DRP in runoff. In 2007, rainfall simulations were conducted using WTR/biosolid blends of 15% and 30% (wt/wt) that were allowed to incubate for three weeks prior to application. Cumulative DRP runoff load observed for the 20% WTR treatment was not significantly different from other chemical treatments and resulted in a 45% reduction in DRP runoff as compared to the untreated biosolids application. Cumulative DRP runoff load in 2007 for the 15% and 30% WTR treatments resulted in significantly lower DRP loads compared to untreated biosolids and led to DRP runoff load reductions of 78% and 85% (compared to the untreated biosolids application), respectively.