Water disinfection sewage

Sodium hypochlorite is employed as a disinfectant and deodorant in dairies, creameries, water supplies, sewage disposal, and households. It is also used as bleach in laundries. As a bleaching agent, it is very useful for cotton, linen, jute, rayon, paper pulp, and oranges. 

In the United States and Canada even biologically pretreated municipal waste waters (secondary sewage effluents) are usually UV disinfected by passing through huge irradiation channels before they are drained into the surface water and released into natural cycles. It has been shown that UV irradiation is a power-... 

L. K. Wang and M. H. S. Wang, General theories of chemical disinfection and sterilization of sludge. Part I, Water and Sewage Works 125(7), 30-32 (1978). 

Use Pigments, reagent, etching aluminum, disinfectant, textiles (dyeing and calico printing), flocculant in water and sewage purification, soil conditioner, polymerization catalyst, metal pickling, chelated iron products, intermediate. 

Use Active ingredient in dry bleaches, dishwashing compounds, scouring powders, detergent-sanitizers, swimming pool disinfectants, water and sewage treatment, replacement for calcium hypochlorite. 

Waterborne pathogens were responsible for tens of thousands of deaths during the first 150 years of U.S. history, with more than 50,000 deaths from typhoid fever as late as 1900-1904 Worldwide, cholera outbreaks were eventually traced to contaminated water. Disinfection of water in the early 1900s with chlorine compounds and then with elemental chlorine nearly eliminated waterborne diseases such as cholera, typhoid, dysentery, and hepatitis in U.S. cities. Together with improvements in sewage treatment, this ranks among the most important contributions made by science and engineering to the improvement of human health.0... 

Disinfection. Water and sewage sludge can be disinfected by adding hydrated lime to raise the pH to above 11 for 1 to 2 days (see sections 28.1.7 and 28.4.4). 

The quality of drinking water is very important to human welfare. The pollution of water by sewage has been linked to the spread of diseases such as cholera and typhoid fever. Elimination of these diseases in developed countries has been a direct result of purification of such water, principally by disinfection using chlorine. 

Chlorine gas is used to disinfect drinking water and sewage, and in the production of organic chemicals such as pesticides and vinyl chloride, the building block of plastics called polyvinyl chlorides (PVGs, Section 14.5). Chlorine gas is commonly among the top chemicals produced each year in the United States. Almost all chlorine gas is made by electrolysis of aqueous sodium chloride. The other product of sodium chloride electrolysis, sodium hydroxide, is equally valuable because it is the most commonly used base in industrial processes. The reaction in electrolysis of aqueous NaCl is... 

Hypochlorite can be produced by the reaction of chlorine gas with sodium hydroxide solution. On-site generation of hypochlorite avoids storage and transport difficulties associated with chlorine gas, and is convenient for many applications, including sewage treatment, sterilisation of water, disinfection, biological growth prevention and enhanced oxidation of, for example, cyanide wastes. The electrochemical generation of hypochlorite has been the subject of several reviews (see [84]). 

Calcium hypochlorite is a dry chlorine donor produced by the introduction of chlorine in aqueous suspensions of calcium oxide at 20° C. The product is suitable for use in applications where the disinfecting and oxidizing power of chlorine are needed e.g. in the beverage and food industry, and in hospitals for hard surface cleaning, for water treatment including waste water and sewage effluent, in pulp and paper mills, in taimeries. 

There are two reasons why the concentration of quaternaries is beheved to remain at a low level in sewage treatment systems. First, quaternaries appear to bind anionic compounds and thus are effectively removed from wastewater by producing stable, lower toxicity compounds (205). Anionic compounds are present in sewer systems at significantly higher concentrations than are cations (202). Second, the nature of how most quaternaries are used ensures that their concentrations in wastewater treatment systems are always relatively low but steady. Consumer products such as fabric softeners, hair conditioners, and disinfectants contain only a small amount of quaternary compounds. This material is then diluted with large volumes of water during use. 

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