Your search found 4 records
1 Nelson, K. L.. 2005. Small and decentralized systems for wastewater treatment and reuse. In Committee on US-Iranian Workshop on Water Conservation and Recycling. Water conservation, reuse, and recycling: Proceedings of an Iranian-American Workshop. Washington, DC, USA: National Academic Press. pp.54-66.
(Location: IWMI-HQ Call no: 333.91 G000 COM Record No: H037704)
2 Silverman, A. I.; Akrong, M. O.; Amoah, Philip; Drechsel, Pay; Nelson, K. L.. 2013. Quantification of human norovirus GII, human adenovirus, and fecal indicator organisms in wastewater used for irrigation in Accra, Ghana. Journal of Water and Health, 11(3):473-488.
Wastewater irrigation ; Wastewater treatment ; Health hazards ; Pathogenic viruses ; Feaces ; Microorganisms ; WHO / Ghana / Accra
(Location: IWMI HQ Call no: e-copy only Record No: H046528)
(0.54 MB)
Quantitative microbial risk assessment (QMRA) is frequently used to estimate health risks associated with wastewater irrigation and requires pathogen concentration estimates as inputs. However, human pathogens, such as viruses, are rarely quantified in water samples, and simple relationships between fecal indicator bacteria and pathogen concentrations are used instead. To provide data that can be used to refine QMRA models of wastewater-fed agriculture in Accra, stream, drain, and waste stabilization pond waters used for irrigation were sampled and analyzed for concentrations of fecal indicator microorganisms (human-specific Bacteroidales, E. coli, Enterococci, thermotolerant coliform, and somatic and F+ coliphages) and two human viruses (adenovirus and norovirus genogroup II). E. coli concentrations in all samples exceeded limits suggested by the World Health Organization, and human-specific Bacteroidales was found in all but one sample, suggesting human fecal contamination. Human viruses were detected in 16 out of 20 samples, were quantified in 12, and contained 2–3 orders of magnitude more norovirus than predicted by norovirus to E. coli concentration ratios assumed in recent publications employing indicator-based QMRA. As wastewater irrigation can be beneficial for farmers and municipalities, these results should not discourage water reuse in agriculture, but provide motivation and targets for wastewater treatment before use on farms.
3 Kumpel, E.; Woelfle-Erskine, C.; Ray, I.; Nelson, K. L.. 2017. Measuring household consumption and waste in unmetered, intermittent piped water systems. Water Resources Research, 53(1):302-315. [doi: https://doi.org/10.1002/2016WR019702]
Water use ; Household consumption ; Measurement ; Water availability ; Water supply ; Water distribution systems ; Water storage ; Storage containers ; Water tanks ; Pipes ; Water loss ; Metering ; Water users ; Socioeconomic environment ; Urban areas / India / Hubli-Dharwad
(Location: IWMI HQ Call no: e-copy only Record No: H048047)
(1.35 MB)
Measurements of household water consumption are extremely difficult in intermittent water supply (IWS) regimes in low- and middle-income countries, where water is delivered for short durations, taps are shared, metering is limited, and household storage infrastructure varies widely. Nonetheless, consumption estimates are necessary for utilities to improve water delivery. We estimated household water use in Hubli-Dharwad, India, with a mixed-methods approach combining (limited) metered data, storage container inventories, and structured observations. We developed a typology of household water access according to infrastructure conditions based on the presence of an overhead storage tank and a shared tap. For households with overhead tanks, container measurements and metered data produced statistically similar consumption volumes; for households without overhead tanks, stored volumes underestimated consumption because of significant water use directly from the tap during delivery periods. Households that shared taps consumed much less water than those that did not. We used our water use calculations to estimate waste at the household level and in the distribution system. Very few households used 135 L/person/d, the Government of India design standard for urban systems. Most wasted little water even when unmetered, however, unaccounted-for water in the neighborhood distribution systems was around 50%. Thus, conservation efforts should target loss reduction in the network rather than at households.
4 Thebo, A. L.; Drechsel, Pay; Lambin, E. F.; Nelson, K. L.. 2017. A global, spatially-explicit assessment of irrigated croplands influenced by urban wastewater flows. Environmental Research Letters, 12(7):1-13. [doi: https://doi.org/1748-9326/12/7/074008]
Irrigated land ; Farmland ; Urban wastes ; Wastewater treatment ; Water reuse ; Water quality ; GIS ; Sanitation ; Surface water ; Irrigated farming ; Downstream ; Catchment areas ; Public health ; Case studies
(Location: IWMI HQ Call no: e-copy only Record No: H048203)
http://iopscience.iop.org/article/10.1088/1748-9326/aa75d1/pdf
https://vlibrary.iwmi.org/pdf/H048203.pdf
https://vlibrary.iwmi.org/pdf/H048203.pdf
(1.43 MB)
When urban areas expand without concomitant increases in wastewater treatment capacity, vast quantities of wastewater are released to surface waters with little or no treatment. Downstream of many urban areas are large areas of irrigated croplands reliant on these same surface water sources. Case studies document the widespread use of untreated wastewater in irrigated agriculture, but due to the practical and political challenges of conducting a true census of this practice, its global extent is not well known except where reuse has been planned. This study used GIS-based modeling methods to develop the first spatially-explicit estimate of the global extent of irrigated croplands influenced by urban wastewater flows, including indirect wastewater use. These croplands were further classified by their likelihood of using poor quality water based on the spatial proximity of croplands to urban areas, urban wastewater return flow ratios, and proportion of wastewater treated. This study found that 65% (35.9 Mha) of downstream irrigated croplands were located in catchments with high levels of dependence on urban wastewater flows. These same catchments were home to 1.37 billion urban residents. Of these croplands, 29.3 Mha were located in countries with low levels of wastewater treatment and home to 885 million urban residents. These figures provide insight into the key role that water reuse plays in meeting the water and food needs of people around the world, and the need to invest in wastewater treatment to protect public health.
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