Anke J. Brouwer-Hanzens

Bio: Anke J. Brouwer-Hanzens is an academic researcher from University of New South Wales. The author has contributed to research in topics: Infiltration (hydrology) & Soil water. The author has an hindex of 3, co-authored 3 publications receiving 246 citations.

Transport of MS2 Phage, Escherichia coli, Clostridium perfringens, Cryptosporidium parvum and Giardia intestinalis in a Gravel and a Sandy Soil •

Abstract: To define protection zones around groundwater abstraction wells and safe setback distances for artificial recharge systems in watertreatment, quantitative information is needed about the removal of microorganisms during soil passage. Column experiments were conducted using natural soil and water from an infiltration site with fine sandy soil and a river bank infiltration site with gravel soil. The removal of phages, bacteria, bacterial spores, and protozoan (oo)-cysts was determined at two velocities and compared with field data from the same sites. The microbial elimination rate (MER) in both soils was generally >2 log, but MER in the gravel soil was higher than that in the fine sandy soil. This was attributed to enhanced attachment, related to higher metal-hydroxides content. From the high sticking efficiencies (>1) and the low influence of flow rate on MER it was deduced that straining played a significant role in the removal of Escherichia coli and Cryptosporidium parvum oocysts in the gravel soil. Lower removal of oocysts than the 4-5 times smaller E. coli and spores in the fine sand indicates that the contribution of straining is variable and needs further attention in transport models. Thus, simple extrapolation of grain size and particle size to the extent of microbial transport underground is inappropriate. Finally, the low MER of indigenous E. coli and Clostridium perfringens observed in the soil columns as well as under field conditions and the second breakthrough peak found for Cryptosporidium and spores in the fine sandy soil upon a change in the feedwater pH indicate a significant role of detachment and retardation to microbial transport and the difficulty of extrapolation of quantitative column test results to field conditions.

Transport of MS2 phage, Escherichia coli, Clostridium perfringens, Cryptosporidium parvum and Giardia intestinalis in a gravel and a sandy soil : additions and corrections

Abstract: To define protection zones around groundwater abstraction wells and safe setback distances for artificial recharge systems in water treatment, quantitative information is needed about the removal of micro-organisms during soil passage. Column experiments were conducted using natural soil and water from an infiltration site with fine sandy soil and a river bank infiltration site with gravel soil. The removal of phages, bacteria, bacterial spores, and protozoan (oo)cysts was determined at two velocities and compared with field data from the same sites. The microbial elimination rate (MER) in both soils was generally >2 log, but MER in the gravel soil was higher than that in the fine sandy soil. This was attributed to enhanced attachment, related to higher metal-hydroxides content. From the high sticking efficiencies and the low influence of flow rate on MER it was deduced that straining played a significant role in the removal of Escherichia coli and Cryptosporidium parvum oocysts in the gravel soil. Lower removal of oocysts than the 4-5 times smaller E. coli and spores in the fine sand indicates that the contribution of straining is variable and needs further attention in transport models. Thus, simple extrapolation of grain size and particle size to the extent of microbial transport underground is inappropriate. Finally, the low MER of indigenous E. coli and Clostridium perfringens observed in the soil columns as well as under field conditions and the second breakthrough peak found for Cryptosporidium and spores in the fine sandy soil upon a change in the feedwater pH indicate a significant role of detachment and retardation to microbial transport and the difficulty of extrapolation of quantitative column test results to field conditions.

Transport and Fate of Microbial Pathogens in Agricultural Settings

Abstract: An understanding of the transport and survival of microbial pathogens (pathogens hereafter) in agricultural settings is needed to assess the risk of pathogen contamination to water and food resources, and to develop control strategies and treatment options. However, many knowledge gaps still remain in predicting the fate and transport of pathogens in runoff water, and then through the shallow vadose zone and groundwater. A number of transport pathways, processes, factors, and mathematical models often are needed to describe pathogen fate in agricultural settings. The level of complexity is dramatically enhanced by soil heterogeneity, as well as by temporal variability in temperature, water inputs, and pathogen sources. There is substantial variability in pathogen migration pathways, leading to changes in the dominant processes that control pathogen transport over different spatial and temporal scales. For example, intense rainfall events can generate runoff and preferential flow that can rapidly transport...