Saturday, April 28, 2012
In a second of what appears to become a running series on busting some preconceived notions about greywater, the first posting focused on dispelling the myth that pirating of greywater from wastewater flows would somehow or another cause concerns about the flows within sewers and increasing the "loading" of the wastewater quality to the point of making the wastewater treatment ineffective. Another concern discussed on the Rainbow Water Coalition was the issue of "dangerous" bacteria and viruses in greywater here, here and here.
One of the papers that will be presented at the 12th World Wide Workshop for Young Environmental Scientists WWW-YES-2012 Urban waters: resource or risks? held in Arucil, France during late May, 2012 is titled:
Assessment of waterborne pathogenic bacteria in greywater and irrigation soils by researchers Maya BENAMI, Moshe HERZBERG, Ezra ORLOFSKY, Amit GROSS and Osnat GILLOR in the Department of Environmental Hydrology and Microbiology at the J. Blaustein Institutes for Ben-Gurion University of the Negev
Reusing greywater (GW) for irrigation is recognized as a sustainable solution to water conservation in arid lands. One of the major impediments for reuse of GW is the presence of pathogenic microorganisms. The presence and abundance of nine pathogens and indicators was investigated in three GW treatment systems and their respective irrigated soils. The GW and soils were monitored bi-monthly over the course of a year using culture dependent and independent methods. The presence of the pathogens and indicators was analyzed and compared in GW versus freshwater (FW) irrigated soils. The results showed that comparable types of pathogens and fecal indicator bacteria including Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Salmonella enterica, Pseudomonas aeruginosa, Enterococcus faecalis, Shigella spp., and Vibrio cholerae were found in the treated GW and their corresponding irrigated soils, while Campylobacter jejuni was found in none of the analyzed samples. Although the FW and GW irrigated soils contained a similar array of bacterial pathogens and indicators, we cannot establish their source. Spatial and temporal scales were found to have no impact on the diversity or abundance of pathogens and indicators in the treated GW or irrigated soils. With our experimental set-up our results suggest that GW irrigation has minor effect on the pathogen and indicator diversity and abundance in irrigated soils.
Read some of the other excellent 16 papers on urban waters prepared by the next generation of water professionals!
Posted by Todd Jarvis at 11:40 AM