Water Treatment Works Integrated Application Of Comprehensive Water-saving Model

Urban water supply plant is an important national infrastructure, it will also consume a large amount of water in the production process, commonly known as self-water. Most of water consumption in China's water treatment works waste more,with great water-saving potential. First, this paper investigated the self-water consumption of China's urban water supply plants in different regions;summarized the low of self-water consumption and current situation of water saving. Second, this article studied the operation law of the water plant which had wastewater recycling systems and complemented the comprehensive water-saving model. Third, this article made a application research of the comprehensive water-saving model in the water plant which had wastewater recycling systems and validated the model's accuracy, sensitivity and guidance . This study will have a great significance of reducing water consumption, energy efficiency, lowering production costs for water supply plant.Based on the collected water consumption survey from the 47 water supply plants in the eastern region, the paper analyzed the following elements : 1) consumption characteristics of the type of process units, water consumption characteristics and it's impact factors of urban water plants water in different areas; 2) the structure of flocculation and sedimentation tank in water supply plant and its impact on the state of row masons, on the water plant self-water consumption rate and on the solid rate of sludge water ; 3) the effect of filter structure and backwashing to the backwashing loss and results; 4) the rate and characteristic of wastewater reuse in water supply plant.The results showed that the sludge water of the flocculation tank was pretty small and water consumption rate reached the lowest point. Apart from the phenomenon that the temperature and turbidity were significantly low in north-east region as long as large dosage of flocculants , the water consumption of the flocculation tank usually lower than 0.5 percent. The sludge water of the settling tank was ranked in the middle level, and its water consumption rate was uasually in the range of 0.6 percent to 3 percent. The water used for backwashing the filter reached the uper most of the water consumption which usually higher than 2.5 percent . Water consumption of the advection sedimentation tank is between 1 percent and 3 percent, and water consumption rate of the inclined tube sedimentation tank was between 0.5 percent and 2 percent . The water consumption of the sedimentation tank which adopted the mechanical method to expel sludge was lower than the sedimentation tank which adopted the gravity method to expel sludge. Water consumption of V model filter was lower than the double valve filter. If the double valve filter was transferred to air-water backwash filter , the water consumption rate could drop 1 percent. The location of wate treatment plant which constructed water reuse system was out of balance , those region which developed faster could have more such plants, and most of those plants directly consume the reused water. Compared the different regions , we could find that the average of water consumption rate was higher in north-east region, which could reach 6 percent. However, water consumption rate of the ShengZheng region was comparetively lower, which reached nearly 3 percent. Based on the investigation and analysis of water consumption of urban water supply plant, a in-depth study is made on the optimization strategy of the major consumption unit of urban water supply plant,making a further improvement on the original water-saving model of urban water supply plant,and add on the contents of the evaluation for the reuse system.Three basic modules of improved water-saving model of urban water supply plant follows.(1) Comprehensive evaluation of water status. The module mainly includes sludge water, calculation of backwash water consumption rate,calculation of reuse rate of water,and the analysis,evaluation and water-saving potential of processing unit water consumption rate.(2) Optimization and water-saving of the processing unit.The module includes optimization of cycle,lasting and sludge method of mud sludge unit,optimization of cycle,lasting and anti-flushing method of filter backwash,and optimization of the reuse operating parameter and the selection for reuse method of reuse unit.(3) The evaluation of efficiency indicators after transformation, including changes of waste water produced by water plant before and after transformation,evaluation of environmental benefits and economic benefits, as well as for urban water supply plant with reuse unit, by calculating the cost of saving water and consumption of running, to evaluate the economic benefits of recycling unit.We did composit research by adopting water saving model in S, L and M water treatment plant in ShengZheng region. The results showed that city water supply plant could reach the taget of reduction self-used water by revising the parameters of the techonology units and controlling the main water consumption units. Because of the construction scale and water reuse system difered significantly, the economic benefits varied comparatively . The research showed that the economic benefits of the M plant reached the highest level. The amount of water used for expelling sludge was 4704.1 thousand m3 per-year, which caused the 4191.2 thousand yuan per-year of reduction. The technology of water reuse play a important role in L plant, which could retrieve the self-used water and save 1264.3 thousand yuan per-year for the plant. Besides the costs of the water could reduce 0.025 yuan/m3. The results indicated that region which have long distance of water supplying system and high costs of water production could construct the water resuse system. The plant could save self-use water and have a excellent economic effects by adopting this technology.