The Research On Water Chemical Stabilization In Jinan Water Supply System

The study was from "National water pollution and management major projects"-the research and comprehensive demonstration of drinking water safety in the Yellow River downstream. In this paper the evaluation index system of water chemical stability was determined According to the situation of Ji’nan city water supply system; the water chemical stability of supply system in Jinan was investigated; The Influence on the iron release of the different water quality was researched; The control methods of the water chemical stability of the water supply system were studied. Main research contents and results of this paper were summarized as follows:(1)Because of the Ji’nan city water supply pipe is mainly formed by metal pipe and cement pipe, so the CCPP, AI, Larson three water stable indexes were used to evaluate water stablization in this paper, but LSI and the RSI were commonly used to evaluation water stablization in the domestic, so LSI and RSI are also incorporated into.(2) On the basis of surveying of water stablization of water supply system in the ji nan, it was found that the raw water, treated water, tap water were corrosive and aggressive in the most time of a year.52.7%of the raw water with severe corrosion;27.8%of the raw water with moderate corrosion;19.4%of the raw water with slight corrosion.64%of the treated water with severe corrosion;30.5%of the treated water with moderate corrosion;5.5%of the treated water with slight corrosion.58.9%of the tap water with severe corrosion;20.3%of the tap water with moderate corrosion;20.83%of the tap water with slight corrosion.(3) To comprehensive of the CCPPP,LSI and RSI, the corrosion of the raw water, treated water, tap water at a low level in the summer and in the spring; The risk of iron release in distribution by the anion to penetrate turbcles in corroded iron pipes was exist. (4) Iron release shows positive correlations with the concentration of chloride and sulfates, and negative correlations with pH,alkalinity. The concentration of chloride and sulfates had very little change between the raw water and treated water, So it is impractical to control iron release by to reduce the concentration of chloride and sulfates.(5) On the basis of surveying of water stablization of water supply system in the ji nan, it was found that the raw water, treated water, tap water has little change,so to improve the chemical stability of treated water is the key which can improve the water chemical stability of the water supply system.As to the effect of different type water mixing methods, the water can be close to stabilization when the rate of the treated Quehua water:the treated Dongyuan water≤1:3.(6) As to the effect of various pH control methods, NaOH> Ca(OH)2> Na2CO3> NaHCO3. To comprehensive and analysis of the test results, Economic and the existing water treatment processes, the water can be close to stabilization when dose lime5-8mg/L.