Animal Waste, Water Quality and Human Health

Transport of livestock-derived pathogens within catchments 237influent, and that the HRP, ASP and MP components of the system caused a 2.92log 10 EC reduction in the influent from the FP. Log 10 rates of EC attenuation for thetreatment of sewage range from 1.50 for a FP (Reinoso, Torres et al. 2008) to 2.57(dry conditions) and 3.64 (wet conditions, when influent concentrations werealmost 10 × higher) for a large lagoon (Kay 2005). Attenuation of pathogensrecorded in the FP ranged from 0.34 (coliphages) to 1.12 log 10 (helminth eggs).Overall, the median microbial attenuation within ponds is 1.12 log 10 (Figure 2).Figure 6.2 Summary pathogen/FIO attenuation data for the six BMPs for which datasets havebeen compiled.Vegetative treatment areas (VTAs) for treating feedlot runoff (see: Table 6.2,Section B). VTAs are areas cropped with grass or forage through which influent,either directly from a feedlot or via a vegetative infiltration basin (VIB; seeconstructed wetlands, below), passes as a surface flow. Attenuation occurs as aresult of filtration, sedimentation, soil infiltration and associated die-off.Gharabaghi, Rudra et al. (2006) report almost all particles >40 µm beingcaptured within the first few metres of flow, whereas smaller particles generallyremain in suspension and Schmitt, Dosskey et al. (1999) note the importance ofinfiltration (in relation to pesticides). Based largely on a review of >40 studies inthe USA by Koelsch, Lorimor et al. (2006), FC attenuations of between 0.16