Analysis Of Water Quality Characteristics Of Qingdao And Feed Water Advanced Treatment Process Design

According to the analysis of Qingdao’s urban water supply from 2015-2021,the structure of Qingdao’s water supply sources has changed significantly,with an average exploitation rate of 40.3%of the city’s water resources.Local water sources fluctuate greatly under the influence of drought and other factors,and guest water gradually becomes Qingdao’s main water supply source,accounting for more than 60%of the city’s total water consumption.The total amount of water resources is small and the difficulty of development and utilization is the basic water situation in Qingdao at this stage.It is the development plan of Qingdao’s water supply in the future to carry out deep treatment and expansion of existing water plants,improve the guaranteed capacity of urban water supply,and improve water quality and standard.By analyzing the raw water quality of the Jihongtan Reservoir（currently the only reservoir for diverting yellow and river passenger water in Qingdao）,using p H,turbidity,ammonia nitrogen,total nitrogen,COD_Mn,UV₂₅₄,algae,fluoride and sulfate as indicators,it is concluded that the overall state of Jihongtan Reservoir is mildly eutrophic,and the raw water pollutant indicator of total nitrogen has exceeded the surface water environment III water quality standard;in autumn and winter,there is often The water contains a certain amount of fluoride ions and sulfate,and the average value is close to the limit of the national standard;the content of organic matter is high,mainly humus.According to the analysis of the characteristics of the original water quality of the Jihongtan Reservoir and the depth treatment target of the water plant,a water plant in Qingdao used ozone-bio-activated carbon and ultrafiltration membrane treatment combined process for the depth treatment and expansion project after process selection.The main contents of the project include:1 new pre-ozone contact tank with a design scale of 360,000 m³/d,and 1 new integrated pool with a design scale of 360,000 m³/d for deep treatment,including intermediate lifting pump room,post-ozone contact tank,activated carbon filter tank and backwashing machine room.Newly built 1 ozone workshop reuse pool,1 new 180,000m³/d ultrafiltration membrane treatment workshop,including intermediate lifting pump room,post-ozone contact pool,activated carbon filter and backwashing machine room and other facilities.Analysis of the operation effect of the water plant:after the activated carbon filter,the average turbidity can be steadily reduced to below 0.1NTU;most of the COD_Mn is removed in the deep treatment stage.The ozone activated carbon process increased the turbidity removal rate,average COD_Mn removal rate,and average UV₂₅₄ removal rate by2.1%,16.3%,and 20.4%,respectively,compared with the conventional treatment process;ultrafiltration increased the turbidity removal rate,average COD_Mn removal rate,and average UV₂₅₄ removal rate by only 0.6%,5.3%,and 2.7%,respectively,compared with carbon filtration.Through the three-dimensional fluorescence spectroscopy,combined with the fluorescence area integration method can be seen that the urban conventional water treatment process on the removal of organic matter in raw water,the application of ozone-activated carbon depth treatment,the factory water humic acid reduced significantly,humic acid substances fluorescence area standard volume removal rate of76.7%,compared with the conventional treatment process to improve the removal effect of 32.5%.Ozone-activated carbon depth treatment is sufficient to meet the current factory water quality standards and improve the water purification capacity of the water plant,but the ultrafiltration membrane treatment on the overall water quality improvement effect is weak.