| Drinking water is an indispensable resource in People’s daily life.The quality of water quality is directly related to human health.In recent years,water shortage,pollution and other problems continue to appear,and people’s requirements for drinking water quality and safety are getting higher and higher,so it is particularly important to ensure the safety of drinking water.In this paper,the hygienic status of drinking water in Yinzhou District of Ningbo city was tested and analyzed,and the key control points in drinking water production were analyzed with Hazard Analysis and Critical Control Point(HACCP)system.The main results were as follows:(1)According to GB5749-2006 and GB/T5750-2006,water samples were collected and tested for 7 types of drinking water in this area from January 2019 to December 2020,including urban centralized water supply,small water plant,secondary water supply,secondary control water,rural water supply,water inspection for building completion and water supply for self-built facilities;thirty-eight related indexes(including sensory and physical indexes,metals,inorganic nonmetals,organic compounds,disinfection by-products,disinfectants,microorganisms,etc.)were detected in 1168 samples.Among them,the qualified rate of samples tested in 2019 was 89.88%,and the qualified rate of test items was 98.60%.In 2020,the qualified rate of tested samples was 95.16%,and the qualified rate of tested items was 99.01%.The water sample test results in 2020 were better than those in 2019.(2)In 2019,the pass rate of sensory traits odor and taste was 97.92% and turbidity was the lowest,and the pass rate of manganese metal was relatively low.Among the microbiological indexes,escherichia coli had the lowest qualified rate.In the detection results in 2020,the qualified rate of sensory traits turbidity was 95.36%,odor and taste was the lowest,and the qualified rate of microbial indicators escherichia coli was the lowest.The pass rate in 2020 was all higher than that in 2019.(3)In the test results of 2019,the qualified rate of water inspection after the completion of the building is 100%,and the qualified rate of the remaining water sources is lower than 100%.From high to low,urban centralized water supply was 93.05%,small water plants was 92.11%,rural water supply was 89.96%,secondary water supply was85.71%,water supply of self-built facilities was 82.14% and secondary control water was81.40%,wihch is the lowest.In 2020,the qualified rate of all kinds of water sources increased significantly.The qualified rate of small water plants,secondary water supply and secondary control water reached 100%.The qualified rate of remaining water sources from high to low were rural water supply which was 95.12%,urban centralized water supply,which was 94.59% and self-built water supply,which was 86.11%.(4)Carry out quality control of drinking water according to HACCP system.After confirming the process of water supply system,hazard analysis was carried out by risk occurrence scoring standard,and risk assessment analysis was carried out for the hazard points with scores of 20≤X < 25.Combined with the critical control point decision tree,the critical control points were determined as raw water,adding alum,adding lime,adding chlorine,flocculation and precipitation,and water transportation.Aiming at the above key control points,the HACCP system of drinking water production combined with the actual water supply plant is proposed. |
PDF Full Text Request