Shanghai is an international megacity with a highly concentrated population and economy. Drinking water safety is directly related to the health of the people, as well as to the sustainable development and harmony and stability of Shanghai's social economy. The water supply pipe network is an important part of the urban water supply system and the last link and weak link in ensuring water quality safety. This technical invention is an important achievement achieved in ensuring and regulating the water quality of water supply pipe networks with the support of the national major project for water pollution control and control "Safe Distribution and Demonstration Technology of Drinking Water"(2009ZX07421 -005) and related projects of Shanghai City Science and Technology Commission, Shanghai Urban Investment Corporation and Shanghai City Water Supply Enterprises.
Maintaining a certain concentration of residual chlorine in the water of the pipe network is the most effective technology to ensure the biosafety of the water quality of the pipe network. Due to the lack of in-depth research on the regeneration of microorganisms in the pipe network under the water quality of the pipe network and the environmental conditions of the pipe wall, the established attenuation model cannot scientifically guide the regulation or safety guarantee of microorganisms in the water in the pipe network; The developed control software lacks intuitive and rapid evaluation or early warning functions for managers, and cannot quickly and intuitively display the control effect. These are key and common technical problems that have been troubling water departments and water affairs or public health supervision departments.
This project provides a statistical model based on the real-time ArcGis geographical information system, using the residual chlorine values and microbial indicators of online monitoring points of the pipe network, and using the pipe network water quality information platform to visualize the residual chlorine in the effluent of the water plant and the secondary pressurized pumping station of the pipe network. Real-time joint debugging and control technology. This technology can avoid considering various complex factors that affect the attenuation of residual chlorine in the pipe network, thereby avoiding the shortcomings of poor applicability and low accuracy of models caused by the complexity of previous models and the lack of microbial indicators at relevant monitoring points.
The core technology of this project is first to establish a statistical model between the residual chlorine value of the online monitoring point of the water supply pipe network and the total number of bacteria at that point. According to this model, the minimum residual chlorine value that should be maintained to ensure that the total number of bacteria at that point meets the standard can be calculated; Secondly, a calculation model for the residual chlorine value of the discharged water from the water plant and the effluent from the secondary pressurized pumping station is established under the conditions of ensuring that the residual chlorine at the most unfavorable points of the pipe network is qualified. Using this model, the disinfectant can be added at multiple points in the water supply pipe network, reducing the output of the water plant. The amount of dosing achieves even distribution of residual chlorine in the pipe network and reduces the risk of disinfection by-products; The third is to apply ArcGIS real-time display technology to the water quality regulation of urban pipe networks for the first time, allowing managers to quickly identify areas with insufficient residual chlorine in the pipe network and promptly observe the residual chlorine regulation effect in the pipe network.
This project technology has been applied to the digital water quality informatization platform in the central Urban area Shanghai City Water Supply Dispatch Monitoring Center and the drinking water hygiene supervision and early warning system of the Shanghai City Health Supervision Institute. Since the application of this technology, the residual chlorine in the factory water of Shanghai City has dropped from an average of 1.97 mg/L before 2010 to 1.2 mg/L in 2014. At the same time, the content of chloroform, a disinfection by-product, has dropped from 5.9-10.1μg/L to 2.5-4.6μg/L, and the water quality has been significantly improved.
The core technology of this project has been published in Water Research, the top journal in the international water treatment field, and has been authorized by invention patents. It has played an important role in the daily operation and maintenance of water quality in the central Urban area of Shanghai City and has made great contributions to improving the water quality of drinking water in Shanghai City; It plays the role of "eyes" and "brain" in ensuring water supply security for major events such as the World Expo; this project technology will help improve Shanghai City water safety emergency risk response capabilities and the digital management level of smart cities. In addition to being mainly used in the urban water supply industry, this patent can also be used in online monitoring, evaluation and emergency regulation of public health supervision and other fields where online real-time display of changes in online monitoring points is required. This project has obtained 2 invention patents and 3 software copyrights; it has published 2 monographs translated works and published 16 Chinese and English articles.