Study On Process Optimization Of Surface Waterworks For Micro-polluted Water

In the conventional treatment process of the water purification plant,organic pollution of the source water is the main cause of the decline in process operation quality and water quality problems.Chengbei Reservoir,which is an important drinking water source in Gaomi City,Shandong Province,has upstream water sources such as Xiashan Reservoir water and Yellow River water.There are different levels of organic matter pollution in the water quality.The two types of source water are alternately or mixed into the Chengbei Reservoir,and the water quality fluctuations and instability are significant,which increases the difficulty of water quality treatment.It is difficult for conventional process water plants to ensure that the water quality meets the standards,and process optimization and upgrades are needed.Relying on the Sunvim water plant in Gaomi City,Shandong Province,and taking the source water of Chengbei Reservoir as the research object,this article conducts research on the removal of organic matter in micro-polluted water.Through the combination of laboratory tests and production site model tests,the existing conventional processes are strengthened,and The feasibility of technological upgrading was explored through biological pretreatment experiments.The test verified and evaluated the effects of different unit processes and their combinations,and optimized the process parameters.The conclusions of the study are as follows:?1?Enhanced coagulation can effectively improve the removal effect of organic matter in raw water by conventional treatment processes.In this experiment,PAC flocculant and PAM coagulant were added,combined with potassium permanganate pre-oxidation and powder activated carbon adsorption to achieve the effect of enhanced coagulation.Through PAC dosing experiment and PAM coagulant dosing experiment,the optimal dosing amounts of PAC and PAM were determined to be 70 mg/L and 0.05 mg/L,respectively;The removal rates of turbidity,chromaticity,COD_Mn and UV₂₅₄ reached 87.38%,47.83%,53.12%and 18.26%under the conditions of 0.6 mg/L and 15 mg/L of potassium permanganate and powdered activated carbon,respectively.?2?The test results show that the biological aerated filter?BAF?has a significant effect on pretreatment of micro-polluted water.With Using the filter media with a thickness of 1500mm,the daily average removal rates of turbidity,color,COD_Mn,UV₂₅₄,algae and ammonia nitrogen reached 60.81%,48.11%,20.83%,7.13%,51.28%and 31.13%respectively;With the"BAF-powder activated carbon"combined process being used in the raw water treatment test,The removal rates of turbidity,color,COD_Mn and UV₂₅₄ reached 97.00%,89.72%,55.45%,and35.59%,respectively,which was 9.62%,41.89%,2.33%,and 17.33%higher than the"potassium permanganate-powder activated carbon"process,respectively.?3?The volcanic rock media was used in the BAF experiment.It was found that the COD_Mnn removal efficiency of the 1500mm media is significantly higher than that of the 800mm media.In order to ensure the treatment effect,The COD load of influent should be limited to 5 kg/?m³·d?or less,and the hydraulic load should be limited to 8 m³/?m²·h?or less.When the temperature is below 10?,the removal rate of COD_Mn decreases obviously;The dissolved oxygen concentration of the raw water was higher than 6mg/L,and no effect of stopping the aeration on the removal effect of COD_Mn has been found.?4?The test shows that the granular activated carbon?GAC?-quartz sand dual media filter has a significantly better effect than the ordinary sand filtration.The daily average removal rates of turbidity,chromaticity,COD_Mn,UV₂₅₄ and ammonia nitrogen by GAC-sand filtration?GSF?reached 75.32%,57.88%,27.27%,25.01%and 28.54%,which were 5.50%,10.13%,14.63%,14.03%and 8.03%higher than that of ordinary sand filter,respectively.The biodegradation offsets the decline in the removal rate of organic matter caused by the decrease of the adsorbed iodine value to some extent.Changes in pH and dissolved oxygen can be used as a reference for biodegradation.?5?The test shows that the backwash cycle of the GAC-sand dual media filter is longer than that of the single-layer sand filter.The current backwash cycle was determined to be 48h by measuring the head loss of the filter layer and the turbidity of the filtered water;The water washing intensity was determined to be 12L/?s·m²?by testing the backwashing intensity and the expansion rate of the filter layer;With the removal rate of organic matter by activated carbon analyzed,and combined with the requirements of GB5749-2006"Sanitary Standards for Drinking Water",the COD_Mn limit value of the GSF influent was identified to be 4mg/L;comprehensively considering the operating life of activated carbon,cost and filter structure,the Feasibility of transforming the single-layer filter into GSF was discussed.?6?The test shows that BAF as a pretreatment process can significantly improve the removal effect of organic matter.When the raw water pollution is serious,the BAF-powder activated carbon combined process can be used.At the same time,the GAC-sand dual media filter can be used for enhanced filtration to increase the removal rate of COD_Mn.All of above provides ideas for the optimization and reconstruction of Sunvim water plant.Potassium permanganate can be used in combination with powdered activated carbon;the water plant should still plan for the construction of advanced treatment facilities to ensure that the water quality meets the national standard requirements.