Nutrient transfer by runoff from sewage sludge amended soil under simulated rainfall

Abstract

Abstract. Wastewater sludges are used in agriculture as soil amendment and fertilizer, with regard to their organic matter and nutrient content. However, availability of nitrogen and phosphorus from sludge-amended soils and their transfer in runoff may lead to eutrophication of downstream surface water. The aim of this study is to establish and compare the effect of two different sludges on these transfers: an anaerobically digested and thermically stabilised sludge (Seine-Aval treatment plant, sludge no. 1), and a limed sludge (Saint-Quentin treatment plant, sludge no. 2). Experiments were performed on 12 sloping micro-plots (1 m × 1 m) submitted to sludge spreading and controlled rainfall simulation. Runoff water was sampled and analysed for concentrations in nitrogen species and phosphorus. Results show that spreading of sludge no. 1 increased both ammonium nitrogen (mean of 1.1 mg L −1 N-NH 4 vs. 0.2 mg L −1 N-NH 4 for control micro-plots) and particulate phosphorus concentrations (mean of 2 mg L −1 P vs. 1.1 mg L −1 P for control micro-plots) in runoff water. On the other hand, sludge no. 2 did not induce any significant effect on nutrient concentrations in runoff. These results are related to chemical composition and physical treatment of sludges. This study underlines the existence of a short-term risk of nutrient mobilisation by runoff after sludge spreading on soil, and the need to check precisely the impact of this practice on water quality.

Nitrogen and Phosphorus Loss Potential from Biosolids-Amended Soils and Biotic Response in the Receiving Water

“…While biosolids application was comparable in the current study and the aforementioned, the TN and TP concentrations in runoff were relatively high by comparison to anaerobically digested or alkaline‐stabilized biosolids in similar studies (e.g., Elliott et al, 2005; Quilbé et al, 2005; White et al, 2010). However, TP concentrations were comparable to those in runoff from anaerobically digested or lime‐stabilized biosolids studied by Penn and Sims (2002), and from biosolids produced by biological nutrient removal processes (Elliott et al, 2005; Penn and Sims, 2002).…”

“…Mobilization of nutrients in anaerobically digested biosolids was not surprising. As in the current study, Quilbé et al (2005) and Penn and Sims (2002) found an increase in TP in runoff from anaerobically digested biosolids. This was true regardless of whether the treatment process used Fe to immobilize P (Penn and Sims, 2002).…”

“…Runoff from all soils generally had high N:P, with this ratio increasing over successive rainfall events in biosolidsamended soils. Previous experiments considering P and N in runoff from biosolids-amended soil included a diversity of sources and biosolids production methods (Penn and Sims, 2002;Quilbé et al, 2005;White et al, 2010). As might be expected, this diversity in composition and production method yields conflicting results.…”

“…In addition, it is apparent that the methods of production and stabilization can affect nutrient mobilization. Quilbé et al (2005) applied two different municipal biosolids to an agricultural soil. Anaerobically digested biosolids resulted in substantial increase in total P (TP) (~90%) in runoff, whereas lime-stabilized biosolids did not.…”

Riparian Grazing Impacts on Streambank Erosion and Phosphorus Loss Via Surface Runoff1

“…In order to simulate rainfall, a portable 1.27-cm 30W single-nozzle (Tossell et al, 1987) was placed 1.7 m above the soil surface ( Figure 3). It was suspended from two iron stakes connected by a PVC (polyvinyl chloride) pipe (Tossell et al, 1987;Nolan et al, 1997;Quilbe et al, 2005). A nozzle pressure of 48.3 kPa was produced with a gasoline-powered pump to produce a mean rainfall intensity of 7 cm ⁄ 30 min on a 0.5-m 2 plot.…”