Health and safety aspects of the use of products from urine-diversion toilets
Abstract (Summary)The management of human excreta is a concern since the generated volumes are increasing as a result of extended sewage and advanced wastewater treatment systems that have to deal with the ever-increasing population. Human excreta contain nutrients such as nitrogen (N), phosphorus (P) and potassium (K). The application of faeces to land has been suggested as a way of using these nutrients as fertilisers. Unfortunately, human faeces also contain a high concentration of pathogens, which limit its potential use as fertiliser. This study investigated the level of contamination of selected pathogens in faeces with moisture content of 28.9% and how application of coal ash, wood ash, NaOH and pasteurization reduces pathogens. Dehydrated faeces were analysed for total coliform (TC), faecal coliform (FC), Faecal Streptococci (FS), Salmonella spp, Aspergillus spp and helminth eggs. The results show that the amount of colony forming units of FC, TC, FS, and Salmonella spp was higher than Aspergillus spp. The numbers of pathogens were reduced in all different treatments. The wood and coal ash treatment resulted in 2 log reduction of TC, FC and FS during an 8 d experimental period. No Salmonella and Aspergillus spp survived treatment with NaOH, wood ash, coal ash, pasteurization at 60oC for 30 min, 70oC for 20 min and 90oC for 5 min. Helminth eggs were found in high numbers in untreated dehydrated faeces. Only helminth eggs survived after pasteurisation at 70oC for 20 min and 90oC for 5 min.
School Location:South Africa
Source Type:Master's Thesis
Keywords:sewage sludge as fertilizer microbial contamination
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