The Pilot Scale Research Of The Coupled Carbon Dioxide And Lime To Modify The Water Stability

The Zhujiang river downstream water quality presents low chemical stability, itgenerates serious pipe corrosion and increases energy consumption of delivery andwater turbidity，even causes red water phenomenon. It effects dissolved oxygen andresidual chlorine, and creates biological instability, thereby, it brings about thepropagation of pathogenic bacteria.Therefore, it is significant to improve the waterchemical stability.The paper mainly concerns on the pilot scale research of the process coupledwith carbon dioxide and lime to perfect the water stability. The specific studies are asfollows:(1) The research on the influence by different carbon dioxide and lime towater stability.(2)The pilot scale research of the confirming the dosing way of carbondioxide.(3) The pilot scale research of the confirming the dosing sequence of carbondioxide and lime.(4) The pilot scale research of the confirming the dosing point ofcarbon dioxide and lime.(5)The taste analysis of the process coupled with carbondioxide and lime.(6)The technico-economical comparison between the processcoupled with carbon dioxide and lime and the rest remineralization process.Different carbon dioxide and lime dosing exert a tremendous influence. Thechange rule of judge indexes is similar to pH value、alkinity、calcium hardnesswith the dosing quantity, the above three indexes are the main influence factors onthe water quality stablility at a certain extent. When the dosing of carbon dioxide andlime is46mg/L、47mg/L respectively, the various index of the product waterpresents at a better level, and the influence to coagulation and sediment is quite low.The effluent of adopting the injector and contactor to dose carbon dioxide is oflittle difference on the utilization rate of carbon dioxide,The injector reaches21.9%-31%，while the contactor is18.77%-29%.As the dosing of carbon dioxide and lime is same, the water stability of effluentis more or less the same while changing the dosing sequence, the little dissimilarylies in their use ratio. If possible, it is suggested that shortening the dosing timeinterval is beneficial to utilize both of the stuff,and can improve the utilization rate.The dosing point of the carbon dioxide and lime is of great influence tocoagulation and precipitate. The performance of the coagulation and precipitate isgood when the dosing point of lime is before the coagulation. When the lime additiveis the same as coagulation, the turbidity and the aluminum concentration of the effluent presents quite bad.The taste analysis on the effluent of the the coupled with carbon dioxide andlime shows of little negative influece when the alkinity and the pH value reaches80mg/L and8.2-8.5respectivly.As one of the remineralization process, the process coupled with carbon dioxideand lime performs well in controlling the corrosion of pipes and improving the waterstability while comparing the process coupled with carbon dioxide and limestone.With the development of research and the growth of the economic, both of theprocesses are of wide prospect.