Soppe A.I.A.,Aqua for All Foundation |
Heijman S.G.J.,Technical University of Delft |
Gensburger I.,Engineers Without Borders Australia |
Gensburger I.,Downer Ltd |
And 5 more authors.
Journal of Water and Health | Year: 2015
The need to improve the access to safe water is generally recognized for the benefit of public health in developing countries. This study's objective was to identify critical parameters which are essential for improving the performance of ceramic pot filters (CPFs) as a point-of-use water treatment system. Defining critical production parameters was also relevant to confirm that CPFs with highflow rates may have the same disinfection capacity as pots with normal flow rates. A pilot unit was built in Cambodia to produce CPFs under controlled and constant conditions. Pots were manufactured from a mixture of clay, laterite and rice husk in a small-scale, gas-fired, temperaturecontrolled kiln and tested for flow rate, removal efficiency of bacteria and material strength. Flow rate can be increased by increasing pore sizes and by increasing porosity. Pore sizes were increased by using larger rice husk particles and porosity was increased with larger proportions of rice husk in the clay mixture. The main conclusions: larger pore size decreases the removal efficiency of bacteria; higher porosity does not affect the removal efficiency of bacteria, but does influence the strength of pots; flow rates of CPFs can be raised to 10-20 L/hour without a significant decrease in bacterial removal efficiency. © IWA Publishing 2015.
PubMed | Technical University of Delft, Without A Box, Aqua for All Foundation, Waterlaboratorium Noord and 3 more.
Type: Journal Article | Journal: Journal of water and health | Year: 2015
The need to improve the access to safe water is generally recognized for the benefit of public health in developing countries. This studys objective was to identify critical parameters which are essential for improving the performance of ceramic pot filters (CPFs) as a point-of-use water treatment system. Defining critical production parameters was also relevant to confirm that CPFs with high-flow rates may have the same disinfection capacity as pots with normal flow rates. A pilot unit was built in Cambodia to produce CPFs under controlled and constant conditions. Pots were manufactured from a mixture of clay, laterite and rice husk in a small-scale, gas-fired, temperature-controlled kiln and tested for flow rate, removal efficiency of bacteria and material strength. Flow rate can be increased by increasing pore sizes and by increasing porosity. Pore sizes were increased by using larger rice husk particles and porosity was increased with larger proportions of rice husk in the clay mixture. The main conclusions: larger pore size decreases the removal efficiency of bacteria; higher porosity does not affect the removal efficiency of bacteria, but does influence the strength of pots; flow rates of CPFs can be raised to 10-20 L/hour without a significant decrease in bacterial removal efficiency.
Lawson M.,University of Manchester |
Polya D.A.,University of Manchester |
Boyce A.J.,Scottish Universities Environmental Research Center |
Bryant C.,NERC Radiocarbon Facility |
And 3 more authors.
Environmental Science and Technology | Year: 2013
Microbially mediated reductive processes involving the oxidation of labile organic carbon are widely considered to be critical to the release of arsenic into shallow groundwaters in South and Southeast Asia. In areas where there is significant pumping of groundwater for irrigation the involvement of surface-derived organic carbon drawn down from ponds into the underlying aquifers has been proposed but remains highly controversial. Here we present isotopic data from two sites with contrasting groundwater pumping histories that unequivocally demonstrate the ingress of surface pond-derived organic carbon into arsenic-containing groundwaters. We show that pond-derived organic carbon is transported to depths of up to 50 m even in an arsenic-contaminated aquifer in Cambodia thought to be minimally disturbed by groundwater pumping. In contrast, in the extensively exploited groundwaters of West Bengal, we show that pond-derived organic carbon is transported in shallow groundwater to greater depths, in excess of 100 m in the aquifer. Intensive pumping of groundwaters may potentially drive secular increases in the groundwater arsenic hazard in this region by increasing the contribution of bioavailable pond-derived dissolved organic carbon drawn into these aquifer systems and transporting it to greater depths than would operate under natural flow conditions. © 2013 American Chemical Society.
Robinson D.A.,Stanford University |
Robinson D.A.,University of the West Indies |
Lebron I.,Stanford University |
Lebron I.,University of the West Indies |
And 5 more authors.
Water Resources Research | Year: 2010
A fundamental, and often intriguing question, in hydrology is "where does the water go?" This becomes particularly difficult to observe when water arrives at the ground surface and infiltrates into soils. The development of rapid, campaign-style imaging methods that do not need to be left in situ are therefore of great interest in tracking subsurface hydrological redistribution. We present a novel geophysical imaging approach identifying spatiotemporal variation consistent with soil water redistribution in a tropical deltaic soil. The intention is to provide additional insight into spatiotemporal soil hydrological/biogeochemical processes. The bulk soil electrical conductivity response (ECa) is primarily controlled by the clay content and type, the ions retained in the soil solution (ECe), and the soil water content (θ). Clay content can be assumed to be temporally static, whereas θ and ECe are temporally dynamic. By imaging over time, we can attempt to tease apart these contributing factors. In nonsaline soils θ is the major contributor to temporal changes in ECa. By exploiting an intensive rainfall event (75 mm), with time series spatial ECa measurements, before and after the event, we were able to identify zones of water depletion and accumulation and to provide an indication of the time required for the soil to return to its prior state. In addition, locations with more clay and salts were identified through response surface-directed soil sampling. We found important spatiotemporal variation across the level 4 ha field site that from visual inspection appeared uniform.
Irvine K.N.,State University of New York at Buffalo |
Richey J.E.,University of Washington |
Holtgrieve G.W.,University of Washington |
Sarkkula J.,Finnish Environment Institute |
Sampson M.,Resource Development International Cambodia
International Journal of River Basin Management | Year: 2011
Continuous monitoring of turbidity, dissolved oxygen (DO), conductivity, temperature, andfluorescence was done at five locations on the Tonle Sap Lake and the Mekong-Bassac Rivers near Phnom Penh, Cambodia, between 2004 and 2010 using autonomous datasondes. Seasonal, daily, and spatial trends were clearly identified in the data and were related to the annual monsoon rainy season-dry season cycle, system metabolism, system hydraulics, and in some cases, localized phenomena such as waste discharges. The datasondes were particularly useful to track the oxygenation of anoxic black water areas in the flooded forest fringe of the Tonle Sap that occurred during the rainy season freshwater pulse. A strongly developed vertical variation of turbidity, DO, and conductivity in the flooded forest fringe may be related to a combination of factors, including dissolved material release from bed sediment and a floating organic-rich particulate layer near the bottom of the lake. Grab samples for total suspended solids (TSS) were collected at the Preak Leap (PL) site (Mekong River)in 2009 and 2010. An excellent relationship was established between daily mean turbidity and TSS concentration for the PLsite, with r2 1/4 0.95. Autoregressive, integrated, moving average models adequately forecast water level and water quality data one month ahead.© 2011 International Association for Hydro-Environment Engineering and Research.
Bennett H.B.,University of Washington |
Shantz A.,Resource Development International Cambodia |
Shin G.,University of Washington |
Sampson M.L.,Resource Development International Cambodia |
Meschke J.S.,University of Washington
Water Science and Technology | Year: 2010
An 8 month investigation into the quality of water from open and rope-pump shallow wells in rural Cambodia was conducted. Wells were analysed for indicators of the health (arsenic, fluoride, manganese, nitrate, total coliforms, E. coli, male-specific coliphage) and aesthetic (iron, chloride, conductivity, total dissolved solids, hardnesss, turbidity, pH) quality of the water, and referenced to the Cambodian Drinking Water Standard when available. The shallow aquifer was chemically less of a health risk than the deep aquifer; however, microbial contamination was considerable for both shallow well types with mean E. coli loads of 103 CFU/100mL and male-specific coliphage contamination of 102 PFU/eluate. Temporal variation in microbial contamination was significant (p < 0.05), with overall loads decreasing during the dry season. The aesthetic quality of the water was poor for all samples, but worsened during the dry season. No significant difference was observed in the quality of water from open and rope-pump wells, despite their classification as unimproved and improved respectively by the WHO/UNICEF Joint Monitoring Programme. Contaminants present in both well types may readily be removed by simple water treatment, suggesting that household treatment may be more beneficial to rural Cambodian households than shallow aquifer source improvements. © IWA Publishing 2010.
Guppy L.,University of Western Australia |
Shantz A.,Resource Development International Cambodia
Geographical Research | Year: 2011
Two studies of domestic water quality were undertaken in rural Cambodia. The first was a programme of quantitative groundwater quality testing and modelling. The second was a qualitative study of perceptions of groundwater quality. This research aimed to compare and contrast findings of these studies in two communes in rural Cambodia. The quantitative study found that in both communes, there is a high risk of encountering bore water with levels of chemical contamination that are detrimental to human health. The qualitative study found that messages from water users is mixed - 60% of bore water users thought their groundwater was of good quality, but 97% treated their water at the point of use before drinking. Results suggest that villages in rural Cambodia would benefit from a better community understanding of groundwater quality and safe water, and the development of more informed domestic water options. © 2011 The Authors. Geographical Research © 2011 Institute of Australian Geographers.
Matteson A.R.,North Carolina State University |
Graves A.K.,North Carolina State University |
Hall A.M.,Resource Development International Cambodia |
Kuy D.,Resource Development International Cambodia |
Polizzotto M.L.,North Carolina State University
Journal of Water Sanitation and Hygiene for Development | Year: 2016
Rural communities within low-income countries frequently rely on a range of drinking-water sources, and each water source varies in its potential for biological contamination. The extent and source of biological contamination in primary drinking sources within Kien Svay, Kandal, Cambodia, were determined by fecal indicator bacteria (FIB) measurements, 16S rDNA genetic markers for human and bovine fecal Bacteroides, presence of the bloom-forming Microcystis species, and the microcystin toxin mcyD gene marker. Thirteen wells, 11 rain barrels, 10 surface-water sites, and five sediment samples were examined during the dry and wet seasons. Surface water was commonly contaminated with FIB, with up to 1.02 × 105 Enterococcus sp., 6.13 × 104 E. coli, and 2.91 × 104 total coliforms per 100 mL of water. Human and bovine Bacteroides were detected in 100 and 90% of the surface water samples, respectively. Concentrations of FIB in rain-barrels varied by site, however 91% contained human Bacteroides. Microcystis cells were found in 90% of surface water sites, with many also containing microcystin gene mcyD, representing the first report of microcystin-producing cyanobacteria in surface waters of Cambodia. The study results show that many potential drinkingwater sources in Cambodia contain harmful bacterial and algal contaminants, and care should be taken when selecting and monitoring water options. © IWA Publishing 2016.