Compound Polyphosphates For Improving The Stability Of The Pipe Network Water Quality Applied Research

Drinking water was transported by the water supply pipe network unit to the end user process, the stability of the pipe network of water quality decline, deterioration of water quality and other phenomena occur. In this paper, Minhang District, urban water supply pipe network pipe DN10015years of age without lining coated cast iron pipes and20years of age DN100painted cement mortar lined cast iron pipe for the study. In improving the water supply pipe network stability and protection against the inner wall of the erosion effects and the role of the main research areas when hexametaphosphate and complex calcium and magnesium ions in water and sodium hexametaphosphate and zinc sulfate complex.Experimental evaluation of water quality indicators stability of water supply pipe selection color, turbidity, pH and other water quality indicators; indicators evaluate the chemical stability of water supply pipe using index IL, Ryznar stability index IR, Larsen ratio LR, erosion Index AI; evaluate water supply pipe biological stability index of total bacteria HPC.The reactor used for research pipeline variation of corrosion inhibitor formulations under different conditions of water quality in the water pipe network of chemical stability and biological stability, the results are as follows:Index IL, Ryznar stability index IR, Larsen ratio LR, erosion index AI four indicators show Minhang District water supply pipe network peripheral faucet water bodies showing corrosive piping would cause erosion. Was on the pipe wall after corrosive water erosion substances into the water, bringing risks to water quality and safety.Hexametaphosphate as a separate add-release agents slowed erosion of piping water to curb the rate of substance on the wall to release water. Experimental results show that the inhibition effect of sodium hexametaphosphate water with increasing inhibitor concentration increased, but the higher the concentration, the more enhanced the effect was not significant, affected marginal effect. Experimental results were significant in hexametaphosphate5mg/L (as P).After adding sodium hexametaphosphate and zinc complex inhibitor, sodium hexametaphosphate due role in making the pipe water stability enhanced corrosion weakened. When added to7.407mg/L sodium hexametaphosphate/(NaPO3)6and1.0mg/L Zn2+(ZnSO4) experiment works best. From the comparison chart, the inhibition effect is inferior to add sodium hexametaphosphate as release agent.After adding sodium hexametaphosphate, chemical stability of water has been greatly improved, stabilized after the water quality indicators, stop adding corrosion inhibitors, various water quality indicators does not exceed the water, indicating that inhibitors play a role. With prolonged to10days, the total iron content of the effluent water is higher than the total iron content, inhibition effect has decreased, that Ming added inhibitor to be stable after10days of water quality can be guaranteed.by adding front and rear walls of the inhibitor on the count of the number of microorganisms, found that the addition of phosphorus in water caused no significant effect on the number of microorganisms wall, corrosion inhibitor added after roughly at the same level, no water added phosphorus brought explosive growth of microorganisms.