Runoff Phosphorus Losses from Surface‐Applied Biosolids

Abstract

Runoff losses of dissolved and particulate phosphorus (P) may occur when rainfall interacts with manures and biosolids spread on the soil surface. This study compared P levels in runoff losses from soils amended with several P sources, including 10 different biosolids and dairy manure (untreated and treated with Fe or Al salts). Simulated rainfall (71 mm h(-1)) was applied until 30 min of runoff was collected from soil boxes (100 x 20 x 5 cm) to which the P sources were surfaced applied. Materials were applied to achieve a common plant available nitrogen (PAN) rate of 134 kg PAN ha(-1), resulting in total P loading rates from 122 (dairy manure) to 555 (Syracuse N-Viro biosolids) kg P ha(-1). Two biosolids produced via biological phosphorus removal (BPR) wastewater treatment resulted in the highest total dissolved phosphorus (13-21.5 mg TDP L(-1)) and total phosphorus (18-27.5 mg TP L(-1)) concentrations in runoff, followed by untreated dairy manure that had statistically (p = 0.05) higher TDP (8.5 mg L(-1)) and TP (10.9 mg L(-1)) than seven of the eight other biosolids. The TDP and TP in runoff from six biosolids did not differ significantly from unamended control (0.03 mg TDP L(-1); 0.95 mg TP L(-1)). Highest runoff TDP was associated with P sources low in Al and Fe. Amending dairy manure with Al and Fe salts at 1:1 metal-to-P molar ratio reduced runoff TP to control levels. Runoff TDP and TP were not positively correlated to TP application rate unless modified by a weighting factor reflecting the relative solubility of the P source. This suggests site assessment indices should account for the differential solubility of the applied P source to accurately predict the risk of P loss from the wide variety of biosolids materials routinely land applied.

Field‐Scale Evaluation of Biosolids‐Derived Organomineral Fertilizers Applied to Winter Wheat in England

“…In those soils care must be exercised not to apply OMF if there was an inherent risk of P transfer to water courses such as in eroded soil, in runoff or through drainage, and within hydrologically connected areas. This observation is consistent with studies dealing with land application of biosolids (e.g., Pote et al, 1996;Haygarth et al, 1999;Elliott et al, 2005). Despite this, dissolved reactive phosphorus (DRP) concentrations in runoff are dependent on techniques used for P removal during the wastewater treatment process (Sibbesen and Sharpley, 1997).…”

Phosphorus Release Characteristics from Biosolids-Derived Organomineral Fertilizers

“…Siddique et al (2000) indicated that the relatively faster rate of P saturation and P leaching in monocalcium-treated soil compared with sludge-treated soil reflect how P sources influence the velocity of adsorption-desorption reactions. With respect to residual effect of P in fertilizers and sewage sludge, research (e.g., Kamprath 1967;Kelling et al 1977;Morgan 1997) showed that following soil application, phosphorus can be utilized by crops in subsequent seasons, e.g., up 8 to 10 years post-application, that is, in the absence of exports or losses of that phosphorus by mechanisms such as transport in overland flow (e.g., McDowell and Sharpley 2002;Elliot et al 2005) or leaching (e.g., Siddique et al 2000;Elliot et al 2002b). Table 4 shows the availability of P in the soil relative to total P applied as fertilizer based on Equation (1).…”

Effect of Methodology in Estimating and Interpreting Water‐Extractable Phosphorus in Animal Manures

“…However, Haggard et al (2005) observed strong relationships between manure WEP and runoff P from poultry litter for extractions ratios ranging from 10:1 to 200:1. Other studies have also observed strong relationships between manure WEP and runoff for lesser extraction ratios (Vadas et al, 2004b; 20:1 to 40:1 for poultry manure) or greater extraction ratios (Elliott et al, 2005;200:1 for biosolids). Therefore, it is not clear that one specific extraction ratio ultimately gives the best assessment of potential P loss in runoff from surface-applied manures, especially considering that rainfall and runoff hydrology can have just as an important impact on P loss in runoff as manure WEP Vadas et al, 2004aVadas et al, , 2005.…”