Water, treatment municipal supplies

Ozone has been used eontinuously for nearly 90 years in municipal water treatment and the disinfeetion of water supplies. This praetiee began in Franee, then extended to Germany, Holland, Switzerland, and other European countries, and in reeent years to Canada. Ozone is a strong oxidizing substance with baetericidal properties similar to those of ehlorine. In test conditions it was shown that the destruetion of baeteria was between 600 and 3,000 times more rapid by ozone than by ehlorine. Further, the baeterieidal aetion of ozone is relatively unaffeeted by ehanges in pH while ehlorine effieaey is strongly dependent on the pH of the water. 

A good example of the use of microelectrophoresis experiments is supplied by the study of ferric floes, which are widely used in municipal water treatment plants. The zeta potentials shown below were derived from the measured floe electromobilities using the Smoluchowski equa-... 

Ground water is the source of water supplied by municipal treatment plants to more than 2 million Canadians (7). In addition, there are more than 500,000 drilled wells in Canada that mainly serve rural populations not served by municipal supplies (8). Ground water has several advantages over surface waters, for example, constant temperature, consistent quality, relatively dependable constant supply, and... 

There is a scarcity of Canadian data on ground water quality. In 1979, a survey was undertaken by the Department of National Health and Welfare. Water samples were taken at 30 water treatment plants in 29 municipalities serving 5.5 million consumers, including all major population centers (11). Only three of these were ground water sources where minimal or no treatment was practiced. The total organic carbon content of these ground waters was less than half of that found in water supplies taken from rivers and lakes, and the trihalomethane content was also significantly low. 

Beginning in about 1990, the first microfiltration/ultrafiltration plants were installed to treat municipal surface water supplies [14,15], The driver was implementation of an EPA surface water treatment rule requiring all utilities in the United... 

Concerns about groundwater contamination and municipal water supply quality have driven much of the growth of various water treatment schemes involving nanofiltration as a stand-alone process or in combination with RO and/or UF in a broad range of water treatment systems delivering precise purity levels and attractive process economics. Other established applications include corn syrup concentration, recycling of water-soluble polymers, effluent treatment for the food and beverage industry, metal... 

Multimedia pressure filters can be used as stand alone treatment, when the feed sources is relatively clean water, such as a potable municipal supply, or in series with clarification, for river and other surface waters. 

Otto Ozonators. Before 1930, Otto ozonators, built and put into use in numerous municipal water treatment plants, were of the flat electrode type with two dielectrics, assembled as in arrangement A, Figure 1, and supplied with 500-cycle current. 

In order to lower the iron concentration in groundwater prior to pumping raw water to the municipal water treatment plant, air is injected into the groundwater source. The injected air oxides the iron in the groundwater. This process involves the periodical injection of air into groundwater via a series of wells that surrounds a production well. This application was implemented in a groundwater supply system in Pembroke, MA. 

The oxidation of halides results in the formation of highly soluble and potentially toxic species, including perchlorate, iodate and bromate. The presence of these chemicals in drinking water supplies has become an important issue for municipal water supplies, as well as for the bottled water industry. These species are not only present in many source waters, but also can be formed or introduced during water treatment. 

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