This manual is part of a series of guides devised by the Oxfam Public Health Engineering Team to help provide a reliable water supply for populations affected by conflict or natural disaster. The e...
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The manual for the UV PURA UVSS Ultraviolet Water Disinfection System.
Halogen DisinfectionDescripción completa
The arsenic poisoning due to contaminated groundwater in West Bengal, India, and all of Bangladesh has been thought to be limited to the Ganges Delta despite early survey reports of arsenic contamination in groundwater in the Union Territory of Chand
Human activities are considered to be contamination. Every persons wants clean water for drinking, bathing and other domestic uses, but not everybody appreciates the fact that our own actions are often the worst enemy in achieving that goal. Ground w
Groundwater model is regarded as the best tool to conceptualise the hydro geological situation in the groundwater basin and to predict the potential environment and socioeconomic impacts of…Full description
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Kolhapur city is one of the major cities in Maharashtra and well source of water bodies available in the western region of Maharashtra. But still facing the water scarcity in summer days due to the polluted water is unfit to use. Kolhapur district an
Water and WasteWater Treatment, commissioning
Water and Sewer Design
water supplyFull description
Water and Slurry HammerDescription complète
Grounding issues in instrumentation
Ground ImprovementFull description
Aramco
AramcoDescripción completa
Disinfection & Grou Gr ound nd Wat ater er Tan ank k
Disinfection of Drinki Dri nking ng Wate Waterr
Chlorination
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DISINFECTION Disinfection is accomplished both by filtering out harmful microbes and also by adding disinfectant chemicals in the last step in purifying drinking water.
Water is disinfected to kill any pathogens which pass through the filters. Possible pathogens include viruses, bacteria, including Escherichia coli, Campylobacter and Shigella, and protozoans, including G. lamblia and other cryptosporidia. In most developed countries, public water supplies are required to maintain a residual disinfecting agent throughout the distribution system, in which water may remain for days before reaching the consumer. Following the introduction of any chemical disinfecting agent, the water is usually held in temporary storage - often called a contact tank or clear well to allow the disinfecting action to complete.
One drawback is that chlorine from any source reacts with natural organic compounds in the water to form potentially harmful chemical by-products trihalomethanes (THMs) and haloacetic acids (HAAs), both of which are carcinogenic in large quantities and regulated by the United States Environmental Protection Agency (EPA). The formation of THMs and haloacetic acids may be minimized by effective removal of as many organics from the water as possible prior to chlorine addition. Although chlorine is effective in killing bacteria, it has limited effectiveness against protozoans that form cysts in water (Giardia lamblia and Cryptosporidium, both of which are pathogenic).
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Example:
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If flow rate =120000 m3/d
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and chlorine dose = 1. ppm,
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Total wt of CL2 for one day = Q x dose
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= 120000 x 1. / 1000 = 120kg
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Total wt of CL2 for six months = 120x 6x30 / 1000 = 21.6 ton
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Chlorine dioxide
Is another faster-acting disinfectant. It is, however, relatively rarely used, because in some circumstances it may create excessive amounts of chlorite, which is a by-product regulated to low allowable levels in the United States. Chlorine dioxide is made in water and added/used in water to avoid gas handling problems; chlorine dioxide gas accumulations may spontaneously detonate.
Ultraviolet and other Methods
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UV radiation (light) is very effective at inactivating cysts, as long as the water has a low level of colour so the UV can pass through without being absorbed. The main disadvantage to the use of UV radiation is that, like ozone treatment, it leaves no residual disinfectant in the water. Because neither ozone nor UV radiation leaves a residual disinfectant in the water, it is sometimes necessary to add a residual disinfectant after they are used. This is often done through the addition of chloramines, discussed above as a primary disinfectant. When used in this manner, chloramines provide an effective residual disinfectant with very little of the negative aspects of chlorination.
