Hygienic quality of artificial greywater subjected to aerobic treatment: a comparison of three filter media at increasing organic loading rates

With a growing world population, the lack of reliable water sources is becoming an increasing problem. Reusing greywater could alleviate this problem. When reusing greywater for crop irrigation it is paramount to ensure the removal of pathogenic organisms. This study compared the pathogen removal efficiency of pine bark and activated charcoal filters with that of conventional sand filters at three organic loading rates. The removal efficiency of Escherichia coli O157:H7 decreased drastically when the organic loading rate increased fivefold in the charcoal and sand filters, but increased by 2 log(10) in the bark filters. The reduction in the virus model organism coliphage ΦX174 remained unchanged with increasing organic loading in the charcoal and sand filters, but increased by 2 log(10) in the bark filters. Thus, bark was demonstrated to be the most promising material for greywater treatment in terms of pathogen removal.