| The situation of domestic water resource is not optimistic under every circumstance.A large part of drinking water sources are in micro-pollution,and even worse.Micro-polluted source water refers to the physical and chemical indicator and microbiological indicator of water that do not meet the requirements for drinking water source water in the Surface Water Environment Quality Standard(GB 3838—2002).Therefore,micro-polluted source water contains not only organic micro-polluted source water,but also some heavy metal or conventional indicator such as sulfate,nitrate,etc.The traditional water purification process cannot purify the micro-polluted source water,so new technology which can improve the quality of drinking water and will be feasible in technology and economy should be founded.Ultrafiltration and activated carbon have become advanced technology for drinking water,and the existing process is to build it separately.This paperdesigned a particle-activated carbon-ultrafiltration integrated water purification column to achieve the combined construction.The purpose of this paper is mainly to study the ability to treat micro-polluted source water after the construction of the combined.There were three main types of water quality:micro-polluted water containing sulfate and nitrate,micro-polluted water containing hexavalent chromium,and micro-polluted water containing ammonia nitrogen and COD.The energy consumption comparison between split construction and combined construction was discussed,and the practical application value of the GAC-UF integrated water purification column was analyzed.In this paper,the dynamic analysis of the static adsorption of granular activated carbon,the separate ultrafiltration and the separate activated carbon,and the dynamic experiment of the integrated water column were compared and analyzed.The static experiment mainly analyzed the effect of activated carbon on the adsorption of pollutants from five aspects: adsorption time,temperature,activated carbon dosage,p H value and concentration.The dynamic experiment mainly analyzed the ability of the integrated water column to purify the micro-polluted source water from the comparison of raw water p H value,flow rate,activated carbon thickness,pollutant concentration,and ultrafiltration,granular activated carbon,and integrated water purification column.The main conclusions showed follows:(1)Static experiment showed that granular activated carbon had agreater removal effect on nitrate nitrogen,sulfate and hexavalent chromium.For sulphate,a good effect was obtained at a p H of 8;for hexavalent chromium and nitrate nitrogen,good results could be obtained at acidic p H of 5.5,and the nitrate nitrogen removal rate at p H 8 was only next to p H 5.5.And the removal rate of the three substances increased with the increase of the amount of activated carbon,the adsorption time and the influent concentration.The removal rate of nitrate nitrogen and sulfate increased with temperature,and hexavalent chromium reversed.(2)Dynamic experiments show that the integrated water column had a certain degree of removal of micro-polluted water containing nitrate and sulfate.When the concentration of nitrate nitrogen and sulfate influent did not exceed 1.25 times that of the drinking water standard,the water quality after the integrated water column could reach the drinking water quality standard.Under the experimental conditions of this paper,the removal rate of nitrate nitrogen could reach 23.01%,and the removal rate of sulfate could reach 29.86%.(3)Dynamic experiment showed that the integrated water column had a certain removal effect on hexavalent chromium micro-polluted source water.When the concentration of hexavalent chromium in raw water did not exceed0.1 mg?L-1(ie,twice the drinking water standard)and the p H was 5.5,the concentration of hexavalent chromium in the effluent of the integrated water column was lower than that of drinking water.The limit of hexavalent chromium in water quality was 0.05mg?L-1.(4)Dynamic experiments showed that after the integrated water column has treated micro-polluted source water containing COD and ammonia nitrogen for a period of time,the granular activated carbon in the integrated water column will be transformed into biological activated carbon and the integrated water column will be used to treat ammonia nitrogen.The integrated water purification column after the membrane was formed can reach the drinking water standard(ie,less than 0.5mg?L-1)after the raw water with influent ammonia nitrogen concentration not exceeding 1.5mg?L-1 was treated.And also had a stable removal rate of nitrite nitrogen.(5)Through the experimental comparison of micro-polluted source water treated by single ultrafiltration,separate granular activated carbon and integrated water column,it could be concluded that the combined effect of ultrafiltration and granular activated carbon was greater than the effect of the two alone,and had a synergistic effect.(6)From the perspective of the removal rate of each pollutant,under the experimental conditions,this integrated water column was suitable for the treatment of sulfate,nitrate,hexavalent chromium,ammonia nitrogen concentration was less than 312.5mg?L-1,12.5mg?L-1,0.1mg?L-1,1.25mg?L-1micro-polluted water.(7)The energy consumption and cost of constructing activated carbon and ultrafiltration membranes were both smaller than those of separate construction. |
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