Study Of Water-Air Pulse Flushing In Dringking Water Distribution Systems In Daqing

More and more people enjoy the convenient of tap water, along with the persist increasing of country economy. Dwellers have gradually changed their attention to drinking water from hydraulic pressure and quantity to quality. The newest drinking water standard requests that the quality of water at consumers'faucet must fulfill it,too. Though multi-advanced techniques in drinking water was used to satisfy the standard, the second pollution which was caused by corrosion of flow pipe, sedimentation of mineral in water and growth ring inside the pipelines lead to water quality deterioration again. The second pollution would threat consumers'health also. Pipeline flushing was one of the effective methods to resolve the water secondary pollution problem.In this investigation, we compared the actuality of the overseas and domestic pipeline flushing techniques. After analyzing the advantages and disadvantages of flushing technique, based on the characteristic of pipelines in Daqing city, water-air pulse flushing was adopted to clean the pipelines. Define the diameter more than 400mm as big caliber pipelines, the ones less than 400mm as the uptown pipelines and study them respectively.To make sure the optimal outlets of the drain diameter, small-scale flushing set was designed with three twenty meters long pipelines (DN 500, 600and 700mm) simulation. Small-scale experiments were done to find out the optimal outlets diameter, and then revised them according to actual pipelines flushing datum. Project experiments were done to make sure the optimal operational parameters, including the optimal length, outlets diameter, air pressure and hydraulic pressure. Measure the pipelines thickness before and after flushing with ultrasonic instrument so as to evalution cleaning effects.The flushing air pressure and hydraulic pressure were fixed in the uptown pipelines. So the main tasks were selection of reasonable flushing scheme and the optimal position of air inlets and drain outlets.Water-air pulse flushing could effectively clean out deposits inner drinking water distribution systems, alleviate secondary pollution of tap water, improve water quality, decrease the resistance of water supplying, and reduce the consuming of energy source. The analysis of economical and societal benefit proved that compared with the traditional water flushing, water-air pulse flushing could save a great deal of water resource.