Importance of evaluating phosphate levels in tubewells in high arsenic areas of Asia

Significant levels of naturally occurring phosphates in groundwater in some arsenic affected regions can potentially reduce removal efficiencies of some critical iron-based arsenic treatment systems that currently are among the most simple and low-cost treatment approaches. From March-December 2007, the Massachusetts Institute of Technology (MIT), the Centre for Affordable Water and Sanitation Technology (CAWST) and LEDARS, a Bangladeshi NGO, conducted pilot testing in Bangladesh of the Kanchan Arsenic Filter. Because of the varying phosphate levels in groundwater in different districts in Bangladesh, the project also included an analysis of phosphate data from arsenic studies conducted by other organizations in high arsenic areas in Vietnam, Cambodia, West Bengal and Inner Mongolia and compared them to results from Bangladesh and Nepal.The results from the analysis indicated that the ratio of iron to phosphates in the groundwater might be a good indicator for the effectiveness of iron-based arsenic removal systems in high arsenic areas

Kanchan arsenic filter: evaluation and applicability to Cambodia

Arsenic contamination of drinking water in rural Cambodia has driven the search for mitigation options. The Kanchan Arsenic Filter for household water treatment is being evaluated for its applicability as one potential solution to this crisis. In 2008, ten Kanchan filters, in 5 configurations, were tested over a 30 week period. Each filter treated 40 L/day. The ground water had arsenic and phosphate concentrations averaging 637 μg/L and 5.09 mg/L respectively, representing challenging source water. Arsenic removal averaged 9597% for all configurations. After the first week of start up, all but 1 in 224 samples achieved the Cambodian standard of 50 μg/L. Arsenic removal was not significantly affected by the flow rate or the cleaning of the filter. There was no apparent depletion of arsenic adsorption capacity over the 30 weeks (8400 L filtered). Iron and turbidity removals were also very high, improving the user acceptability of this technology

Cryptosporidium contamination of water in Africa: the impact on mortality rates for children with HIV/AIDS

There are currently an estimated 2 million children with HIV/AIDS worldwide, 90% of whom are in subSaharan Africa. Currently approximately 500,000 to 700,000 children acquire HIV infection per year and approximately 300,000 children died of AIDS in 2007. Children living with HIV/AIDS are at particular risk of chronic diarrhea from Cryptosporidium (Cryptosporidiosis) and if infected they are far more likely to suffer major complications or death. Cryptosporidiosis has been found to be a significant predictor of childhood death in subSaharan Africa. Studies in subSaharan Africa have shown a high prevalence of, cryptosporidiosis in children aged 636 months, particularly among children who are malnourished or HIV positive and during rainy seasons. For example, heavy rains from November 2005 to February 2006 in Botswana led to a dramatic increase in admissions and visits to hospitals and health centers of infants leading to the death of 22% of inpatient infants. Adequate sanitation and water treatment are critical for minimizing Cryptosporidium exposure for children living with HIV/AIDS

Effectiveness of different household water treatment approaches for people living with HIV/AIDS in Africa

Adults and children living with HIV/AIDS are more susceptible to microbiological contamination of water. The 2008 WHO guidelines for people with HIV state that the “lack of … safe water and safe management of human waste exposes people with HIV to increased risk of transmission of waterborne and other enteric pathogens.” A number of different household water treatment (HWT) approaches can potentially be used depending on local availability in a particular area. Some examples of effective HWT are biosand filters, ceramic filters, SODIS, combined flocculationchlorination and chlorination. For water sources with high turbidity (seasonally or year round) the effectiveness of the HWT approach under high turbidity conditions should be considered as part of selecting the appropriate HWT approach. Biosand filters, ceramic filters, flocculationchlorination, and SODIS are effective at removing or inactivating Cryptosporidium and pathogenic bacteria commonly associated with persistent diarrhea depending on the turbidity of the water source. Combining chlorination with a preceding turbidity and Cryptosporidium oocyst removal step potentially provides optimal HWT for people living with HIV/AIDS