Health risks from pathogens in sewage: Implications for Australian sludge management guidelines
Literature concerning pathogen densities in untreated wastewater sludge was reviewed to aid an assessment of the health risks associated with the use of municipal sludge. No information on pathogen densities in Australian sludges was found so risks were assessed using pathogen densities in other countries and infection rates in Western Australia. Based on information from other countries it was estimated that an individual handling sludge and ingesting 0.1 g of sludge would have a greater than 1% chance of becoming infected with Giardia, less than 25% chance of contracting a helminth infection, approximately 1% chance of becoming infected with an enteric virus and less than 1% chance of contracting a Salmonella infection. However a qualitative risk assessment based on reported infection rates in Western Australia suggested that enteric viruses in wastewater sludge pose the most risk followed by Salmonella and Giardia. These risk assessments and a limited amount of epidemiological evidence suggest that digested wastewater sludge is not suitable for unrestricted marketing to the public. Guidelines in the US and UK follow this philosophy. Two issues of concern for Australian sludge guidelines are the use of indicator organisms to predict pathogen densities and the possibility of Salmonella regrowth in composted wastewater sludge.
|Publication Type:||Journal Article|
|Murdoch Affiliation:||School of Environmental Science|
|Publisher:||Australian Water Association|
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