An analysis of water purification treatment process in water treatment plant

   The study of water purification treatment process in waterworks is the key to saving water resources and improving the quality of tap water. At present, the water consumption in urban construction is increasing, but the water purification treatment in the tap water plant is still dominated by the traditional treatment method, coupled with the untimely updating of the water purification treatment facilities, which affects the quality of water purification treatment, and the trend of deterioration of the water environment can not be improved. In this development context, it is necessary to increase the attention to the water purification treatment process in the tap water plant, based on the current water purification treatment process in the tap water plant, continuous innovation and optimization, and the integration of new treatment technologies, in order to improve the quality of tap water purification treatment, enhance the capacity of tap water purification treatment, and improve the current situation of pollution of clean water sources.

First, the significance of tap water purification treatment process      

     As an important base of urban water supply, waterworks can effectively remove various impurities in the source water, convert it into healthy water to ensure that residents use water in a timely manner, rest assured that the enhancement of its water purification and treatment capacity is directly related to the daily water safety of urban residents. At present, the water pollution problem is very serious, water treatment plant water purification pressure multiplied. Especially in the construction of urbanization, industrial production waste water discharge, domestic waste disposal and other insufficient science, these have exacerbated water pollution. Expanding the scope of water pollution requires further optimization of water purification and treatment processes to better improve the water pollution situation. Coupled with the improvement of urban water quality requirements standards, so we must actively carry out water purification and treatment process innovation and upgrading, comprehensive treatment of water pollution at the same time, to further improve the quality of tap water to improve in. With the development of science and technology and the continuous exploration of water purification treatment technology, water treatment plants can increase the research efforts on water purification treatment process, further optimization of suspended solids and the treatment of various impurities, improve the degree of attention to the treatment of water pollution, and effectively improve the organic pollution of the water supply, and actively upgrade the traditional double-valve filter pool for the V-shaped pool, so as to improve the efficiency of the water treatment, to ensure the safety of water quality.

Second, the current situation of water pollution

    Water purification and treatment process research, must master the water quality pollution situation, and thus develop specific, targeted water purification and treatment program. Water quality pollution, including water pollution, tap water transmission process may occur in the secondary pollution, water purification and other pollution caused by improper treatment.
1. Water pollution      
Water pollution is the key to water quality problems. According to the survey of water pollution in recent years found that China's river pollution rate of 82%, there are obvious differences in the degree of pollution, and which has been 40% of the water source can not be used as drinking water. Statistics of urban waters, nearly 78% can not be treated as drinking water. Not only that, by industry, agriculture and other impacts, China's groundwater is also seriously polluted. Visible, water pollution control is urgent, must improve water purification treatment means. Effective treatment of industrial wastewater, to prevent automobile exhaust and pesticides and other water pollution, especially the benzene and phenol and other substances, to improve the situation of heavy metal water pollution, these are water purification and treatment of the problem to be solved.
2. Pollution in the transportation process     
 After scientific treatment of tap water through the water plant, through the water pipeline to thousands of households. If there is improper management or other problems in this process, the water will be polluted again. The most common secondary pollution is mainly concentrated in the pipeline network rust or breeding bacteria, as well as treatment is not in place to produce the dirt, etc., the existence of these factors alone has a limited impact on the tap water, but mixed with each other will breed a variety of toxic substances, and even carcinogenic. Therefore, the secondary pollution of tap water must be emphasized.
3. Improper water treatment process     
Water purification treatment is an important means of improving water quality, the proportion of contaminated water in our country is very large, it must be water purification treatment to improve the water source. The actual treatment, water purification treatment has certain limitations, the increasingly serious pollution makes water purification treatment more and more difficult. Although the water treatment is constantly improving, but the overall coagulation, precipitation, filtration, disinfection based on microbial contamination of water pollution, heavy metal contamination, etc., the conventional water treatment process has been unable to ensure that water purification and treatment of safety, on this basis, but also to further upgrade the water purification and treatment process, so as to achieve a more desirable water purification and treatment results.

Third, the water purification treatment process in the water plant
1. Pre-oxidation treatment     
 Pre-oxidation treatment is one of the common treatment methods in water purification treatment in water treatment plant. Pre-oxidation treatment is an upgrade of the traditional water purification treatment, first of all, through the oxidant will destroy the surface of the inorganic particles in the water, after breaking the protection of organic matter, inorganic particles are affected by the stability of fluctuations, and finally get effective treatment. In the pre-oxidation treatment, the earliest oxidizing agent is chlorine, but in practical application, chlorination by-products will be produced, so there are limitations in application. Potassium permanganate was then introduced and put into the polluted water source. Experimental research found that potassium permanganate can effectively deal with organic pollutants in contaminated water to remove by-products of chlorination, help coagulation effect is very good, but also has the role of deodorization, etc., can improve the purification and treatment of water, reduce the content of polycyclic aromatic hydrocarbons, etc.”. As a strong oxidizer type, potassium permanganate pre-oxidation treatment: especially for low-temperature, low-turbidity water sources, in addition to the pollution effect is significant. The use of potassium permanganate as a means of pre-oxidation treatment, can to a large extent, the humus caused by the odor and color changes in the elimination, and restore manganese, overall water purification treatment effect is stronger than chlorinating agents.

2. Activated carbon adsorption method      
Activated carbon adsorption function is inseparable from its own activated carbon fiber, the main material is activated carbon, which belongs to the hollow medium, can effectively adsorb organic pollutants in the water, but also has the effect of removing the chromaticity, to improve the turbidity of the water, to a certain extent, to reduce the sewage discharge and the water pollution, and to effectively improve the water treatment of water purification plant social and economic benefits. Activated carbon adsorption method has been applied in many countries, which can purify the water source and improve the water quality. If the organic matter in the water source has the same pore size as that of the activated carbon, it can stimulate the adsorption capacity of the activated carbon and enhance the removal rate of organic matter.      
Commonly used types of activated carbon mainly include granular activated carbon (GAC), powder activated carbon (PAC), biological activated carbon (BAC). Among them, granular activated carbon has outstanding stability in water purification treatment, can effectively adsorb organic matter in water, has wide adsorption area and high organic matter removal rate, and is widely used. However, in practical application, the need to consume more infrastructure costs, can not adapt to sudden pollution, there is a risk of nitrite and so on. Bio-activated carbon adsorption method has a long treatment cycle, high treatment efficiency, can improve water quality to a large extent, but in the actual treatment, it is easy to block, activated carbon microporous treatment is not in place and other phenomena.

3. Membrane filtration     
 Membrane filtration water purification treatment, mainly based on the theory of differential pressure, the organic matter in the water for physical separation. Membrane filtration application can effectively remove carcinogenic substances in the water. In recent years, the membrane filtration method is becoming more and more common, water purification and treatment of broad prospects. According to the relevant research summary found that the normal operation of the membrane filtration method, even if the water quality changes during this period, still does not affect the effect of its water purification and treatment, also able to remove all the impurities in the source water. Membrane filtration, including ultrafiltration, microfiltration, bacteria in the water source and colloid treatment is ideal. However, membrane filtration in the treatment of organic matter is not very ideal, the effect of salt treatment in general.      

Membrane filtration water purification treatment does not require excessive costs, very suitable for small-scale water purification treatment projects, ideal treatment effect, reasonable treatment costs. For the unit volume is relatively small, but also can be automatically controlled by the water source, the use of nanofiltration to remove the mutant substances, change the water color, total organic carbon removal rate of 90%, can be assimilated into organic carbon removal rate of 80%. Nanofiltration also has the efficacy of de-bacteria, changing the conventional chemical disinfection method, using physical disinfection. Nanofiltration treatment before the need to acidify the water, add anti-scaling agents, which can prevent the occurrence of ionic precipitation, improve the membrane filtration treatment of particle contamination, but also to improve the removal of organic matter and the treatment of pathogenic bacteria. Need to pay attention to this period, control the membrane filtration pressure, the requirements need to be controlled at 0.8 ~ 1.0MPa.       
Membrane filtration method of the overall operation is more cumbersome, although it can effectively remove organic matter and pathogenic bacteria, but the same will affect the anion and cation in the water source, so that the long-term drinking of tap water will threaten human health. In this case, adjust the pore size of the reverse osmosis membrane, which must be <2nm, so that organic matter and microorganisms can be effectively removed, but also be able to purify the water, transformed into semiconductor ultrapure water for industrial production. Reverse osmosis membrane water purification treatment method, although the treatment effect is better, but the actual application of technical expertise and water purification treatment there is a “mixed” phenomenon. Pure water can only be used in industrial production, not conducive to drinking. Moreover, the treatment method, will encounter the phenomenon of blocking the filter membrane, resulting in the source water to be re-contaminated, so in practical application, but also need to combine the actual situation, to take a series of measures to improve the filtration treatment of insufficient, such as adjusting the filter membrane microporous spacing, increase the quartz sand filters, which improves the effect of water purification treatment of the water treatment plant.

4. Ozone oxidation      
Ozone oxidation water purification treatment, is currently more commonly used water treatment methods. Ozone oxidation water purification treatment principle: ozone in the water will be gradually converted to hydroxyl radicals, which indirectly oxidize decomposition of mainly ammonia, organic matter and a large number of microorganisms, the beginning of the reaction has a very fast speed, which makes the selectivity is relatively small. All kinds of acid and alkali environment can ensure that the organic matter in the water quickly oxidized into a large number of inorganic substances, especially the iron, manganese, sulfur and other reduction reaction substances, but also lead to humus such as the color of the water body. In addition, high oxidation potential is the main feature of ozone, in the microbial cell membrane has a strong diffusivity, and microbial cells in the presence of organisms for oxidation, but also damage to the chain structure of the organisms, resulting in cell death, which can inhibit the growth of bacteria and algae, effectively improve the quality of tap water for a variety of more tenacious microorganisms also have a better inhibition of the vitality of microorganisms. Combined with the above ozone oxidation treatment, on the basis of chlorine disinfectant converted to ozone can also achieve better results, will not consume too much reagent usage, shorter action time, and the formation of various hazardous substances will also be reduced, thereby improving the quality of water purification treatment of tap water.      

In summary, the water purification treatment process is related to the water quality of the water plant and the residents of the living water safety. With the diversified development of water purification treatment process, membrane filtration, pre-oxidation treatment, activated carbon adsorption and other commonly used water purification treatment methods are applied to tap water purification treatment, which can help to improve the pollution of water sources and improve the quality of tap water. In the scientific application of water purification treatment process, but also to do a good job of management, improve water purification treatment and water protection awareness, recognizing the importance of water resources, thus protecting the safety of water sources, reduce water pollution, and effectively deal with water impurities.