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Rural water supply
Published in Sandy Cairncross, Richard Feachem, Environmental Health Engineering in the Tropics, 2018
Sandy Cairncross, Richard Feachem
If it is important for water supply technology to be chosen so that it can be made to work under the existing construction conditions, it is even more important that it should continue to work under the prevailing maintenance conditions. A water treatment plant, for example, generally requires a level of attention and skill in operation quite unattainable in a small community. Since there is little point in installing water treatment facilities if they will not be reliably operated, it is almost always preferable to find a source of good-quality water and protect it from pollution, rather than to take water from a doubtful source and treat it. Pumps, too, of any kind, frequently break down or fall into disuse in rural areas. Motorised pumps, especially, should only be installed where adequate arrangements have been made to pay for their running costs (see Chapter 4).
Conclusion: Future Trends and Scope
Published in Sirshendu De, Anirban Roy, Hemodialysis Membranes, 2017
It is clear that reprocessing of hemodialyzers is an important operation. But, in the Indian or, for that matter, any developing country’s context, it is very difficult to afford such reprocessing machines at each and every dialysis center. A typical hemodialysis machine itself costs as high as $9000, a reverse osmosis water treatment plant costs $1500, and other paraphernalia too cost $1500. Importantly, it is well reported that for dialysis therapies, around 58% of the total cost per dialysis session can be attributed to the cost of the dialyzer alone.24 This is because, although the infrastructure for dialysis sessions is provided and subsidized by the government, it is the patient’s responsibility to bring a dialyzer for treatment. In India, all dialyzers are imported and it becomes cumbersome and at times frustrating for patients to get hold of a new dialyzer; hence, crude methods are adopted for cleaning used ones and reusing them again. As such, for developing countries, the problem lies not in the paraphernalia, but in the economics of manufacturing a dialyzer.
Regulation of swimming pools *
Published in Jamie Bartram, Rachel Baum, Peter A. Coclanis, David M. Gute, David Kay, Stéphanie McFadyen, Katherine Pond, William Robertson, Michael J. Rouse, Routledge Handbook of Water and Health, 2015
The concerns associated with the operation of pools are numerous, for example the production of disinfectant by-products, and water contamination issues, but also energy and water use. Large bather loads have the potential to exacerbate these if they are not managed effectively. In addition, different pool types present specific challenges with regard to safety issues. For example, hotels and clubs may have intermittent use which may place a burden on the water treatment plant; in addition, they may be managed by non-technically trained staff. Likewise school pools may be subject to similar issues. Outdoor pools may be especially easy to access and therefore may require particular attention towards security features. Cruise ships may utilise marine water which may present special challenges with regard to treatment. Hydrotherapy pools also require specific considerations in terms of controls and monitoring due to their nature – small size, warm water, easy access. Home pools face particular issues as they are easily accessed by children, posing a particular drowning risk, and are often maintained by owners who have little or no knowledge of the potential risks. Further details on how these specialised pools should be operated can be found in the Pool Water Treatment Advisory Group guidelines (PWTAG, 2009).
Marked regional variations in the prevalence of inflammatory bowel disease in a limited geographical region are not associated with compounds in the drinking water
Published in Scandinavian Journal of Gastroenterology, 2019
Fredrik Segerman, Spencer Clarkson, Klas Sjöberg
The prevalence rates were stated as number of patients per 100,000 inhabitants. The prevalence rates of CD and UC, respectively, in different municipalities were compared with an un-paired two-tailed t-test. Incidence rates were calculated as number of cases per 100,000 person-years under exposure and were reported as mean values and range. Due to skewed distribution of the measured chemical compounds, the median values were used to calculate representative data on mineral content in the water for each water treatment plant. A water representative for each municipality was calculated using weighted mean values based on every water treatment plant and its coverage ratio, respectively. The coverage ratios of different water treatment plants were reported as median percentage with associated quartiles and interquartile range (IQR). The putative differences in minerals between the municipalities were estimated with Kruskall-Wallis rank sum test. Statistical analyses were conducted in SPSS (IBM. SPSS Statistics for Mac. Version 23.0. Armonk, NY: IBM; 2015).
Membrane biofouling by chlorine resistant Bacillus spp.: effect of feedwater chlorination on bacteria and membrane biofouling
Published in Biofouling, 2018
Gopal Bhojani, Sweta Binod Kumar, Nirmal Kumar Saha, Soumya Haldar
Isolated bacteria with different morphologies were incubated in nutrient broth for 4 h with shaking. Subsequently, 25 μl of broth containing fresh bacterial culture were used to inoculate 2.5 ml of nutrient broth and in the next step, the same was exposed to sodium hypochlorite (purchased from Finar India Ltd., Ahmedabad, Gujarat, India) solution (0.5 ppm) for 0, 5, 10, 15, 20, 25 and 30 min for initial screening of chlorine resistant strains. After exposing to sodium hypochlorite solution for the specific time period, the broth was immediately dechlorinated using 1 ppm sodium metabisulphite (purchased from Finar India Ltd) solution. Samples of bacteria from the dechlorinated solution were then plated on nutrient agar and kept in an incubator at 37°C overnight. All experiments were conducted in triplicate. Free chlorine concentration and completeness of the dechlorination step were ensured colorimetrically using a MColortest (chlorine test kit) purchased from Merck Life Science Pvt Ltd., Bangalore, Karnataka, India. The chlorine test kit can measure chlorine in a free or combined state in the range 0.1 to 2.0 ppm with a colour scale graduation of 0.1, 0.2, 0.3, 0.4, 0.6, 0.8, 1.0, 1.5 and 2.0. The bacteria which appeared on the nutrient plate were chlorine resistant; these were then isolated and preserved at –80°C until further analysis. For all the experiments other than the initial bacteria screening step, 25 μl of fresh bacterial culture were further inoculated in 2.5 ml of sterile chlorine free tap water. Tap water was chosen to nearly match the pretreated water quality (before chlorination) in the water treatment plant. Chlorination of water containing bacterial sample was carried out for 15 and 30 min only. Sodium hypochlorite solution, 0.5 ppm free chlorine, was used for chlorination.