Operation Parameters Optimization Of Rapid Filter Under The Condition Of Influent With Low-turbidity

With the rapid process of China’s industrialization and urbanization and rapid development of China’s economy and society, our drinking water has been polluted to varied degrees, and there are serious risks of drinking water security. To solve these problems, the state promulgated the 《Standards for Drinking Water Quality》(GB5749-2006) in2006, and all indicators was implied on July1,2012. The new water quality standards require controlling finished water turbidity below1NTU, this puts forward higher requirements to design and operation of the filter. If basing on the existing filter type at the same time, and meeting the requirements of finished water turbidity, operation parameters of filters need to be different from the past experience. based on the above situations, and combined with the water quality during the test water sources of the Y plant in any City, this paper explores operating characteristics and optimizing the operation parameters of rapid filter at the low flowing turbidity, so as to come with production optimal adjustment of filter operation with a reference value of operating parameters.Firstly, in the case of the turbidity1~2NTU after the water sink,by controlling the turbidity (≤0.8NTU) of the filtered water number or the particles of the filtered water (≤60个/ml) or head loss reached1.5m, the filter type and filter speed were optimized. Through studying a filter containing examine changes in the amount of mud before and after filtration, dual-media filter effects come to be better than homogeneous quartz sand. By comparing the treating turbidity to effluent turbidity of the different filter depth, the treating UV254content to effluent UV254content of the different filter depth, the pending ammonia content to effluent t ammonia content of different filter depth and the head loss of different filter depth varing with filter running time, drawn the optimμm range of filter filtration rate of both filter media are8m/h～9m/h.Secondly, due to the high precision and high sensitivity of the particle counting instrμment, it is used in combination with the turbidity to optimize the filter operating parameters. Through changes of the filtered water turbidity and particle count analysis and correlation in the filter running stable, it was obtained that the particle counting and turbidity has some relevance. However, throughout the period of the filter operation, changes of particle counting can be more timely and more sensitive than turbidity to an indication of filter effluent quality situation. By analyzing changes of the nμmber of particles of the beginning of treatment and the filtered water, combined with the analysis of the filtered water turbidity, it was obtained that the optimal filtration rate of both homogeneous quartz sand and dual-media filter are8m/h, the running cycle of both filter media is36h, backwash: air blast10.85L/m2/s, time3min, flush intensity2.6 L/m2/s, time11min; optimal filtration rate of dual-media is8m/h, running cycle is36h, backwash: air impact strength of25m3/h,time3min; flush intensity6m3/h, time11min.Finally, analyzing the filtration rate effected on the filter head loss and the relationship between the filter head loss and filtered water turbidity. It was obtained that the filtration rate was the great influence to the head loss by analyzing, the greater of filtration rate and the more quickly the head loss growth rate increases. According to the actual changes of the head loss and the filtered water turbidity following the running time,and establishing the mathematical relationship between the head loss and the filtered water turbidity in the filtration velocity V=8m/h, finally it was verified that the best filtration rate of the uniform media filter and dual media filter was8m/h. If controlling the filtered water turbidity under0.5NTU, when the pressure cycle will reach1.5m, the water quality cycle also will content0.5NTU, in which the filter will be in the best operating conditions. This also provides a reference and ideas for determining the pool backwash head loss of the rapid filter.