Study On The Treatment Effect Of Hydrotalcite/ultrafiltration Combined Process On Micro-polluted Groundwater

In this test,taking the slightly polluted groundwater quality in the mining area as the reference,the simulated water sample is obtained by the water distribution,using the water c/ultrafiltration combination process,and the treatment effect is tested.The main research contents include:turbidity,ammonia nitrogen,UV_254,TOC,Mn²⁺,Cl^-and Cr⁶⁺concentration,to discuss the treatment effect of PVDF ultrafiltration membrane on the simulated water sample,the influence of aeration on PVDF ultrafiltration membrane water treatment effect,the influence of changing operating conditions on the water treatment effect of the combined process,and the optimized operation conditions of the response surface method.We found that the ultrafiltration membrane had a good removal effect on turbidity,and the removal rate always remained above 96%.The ultrafiltration membrane has the ability to remove organic matter in water,and the average removal rate of UV₂₅₄and TOC is 22.7%and34.3%,but the removal effect of small molecules and soluble substances such as ammonia nitrogen and Mn²⁺,Cl^-and Cr6⁺in water is poor.Aeration improved the removal rate of ammonia nitrogen,UV₂₅₄,TOC and Mn²⁺,while the average removal rate of ammonia nitrogen,UV₂₅₄,TOC and Mn²⁺increased by 10.0%,9.1%,8.0%and 10.4%,respectively,while the removal rate of Cl^-and Cr⁶⁺increased less.In the single factor test,the addition of adsorbent plays a good adsorption effect on ammonia nitrogen,UV₂₅₄,TOC,Cl^-and Cr⁶⁺.With the addition of adsorbent,the maximum removal rate of ammonia nitrogen,UV₂₅₄,TOC,Cl^-and Cr⁶⁺can reach 61.3%,86.4%,75.3%,65.1%and 96.8%,however,the addition of water talc on the removal effect of Mn²⁺is limited.With the increase of running time,the removal rate of ammonia nitrogen,UV₂₅₄,TOC,Cl^-and Cr⁶⁺were all increased first and then decreased.The change of aeration has little effect on the removal effect of ammonia nitrogen,Cl^-and Cr⁶⁺,while the increase of aeration improves on the removal of UV₂₅₄and TOC.The increase of backwash water helps to alleviate membrane pollution.With the increase of backwash water,the combined process improves the removal efficiency of ammonia nitrogen and TOC,and the removal effect of UV₂₅₄is always good.The removal efficiency of Mn²⁺,Cl^-and Cr⁶⁺increases first and then decreases with the increase of backwash water.The results of the operation conditions of ammonia nitrogen and TOC removal by Box-Behnken Design model show that when the adsorption dose is 283.09 mg/L,the running time is 49.61min,and the reverse washing water is 112.43L/h,the removal rate of ammonia nitrogen can reach 73.77%,387.10mg/L,36.80min,and 145.71 L/h,and the removal rate of ammonia nitrogen can reach 76.55%.According to the test,it is known that the hydrotalc/ultrafiltration combination process has a good removal effect on turbidity,ammonia nitrogen,UV₂₅₄,TOC,Cl^-and Cr⁶⁺,and the ultrafiltration out water can meet the requirements of domestic drinking standards for these indicators.The removal of Mn²⁺was slightly worse.The test device of this combined process is simple,simple operation,small area,which can play a good role in purifying the slightly polluted groundwater,and is suitable for promoting the groundwater purification process in rural areas.