The Research On The Application Of Modified Powder Activated Carbon In The Treatment Of Micro-pollutant Source Water

It's about seventy years ago for the powder activated carbon (PAC) used to treat drinking water and wastewater firstly. It's a kind of ideal sorbent because of the extended surface area, high adsorption amount and rate, and specific surface reactivity. The powder activated carbon was particularly to treat the water changing much with season variety and the unexpected water pollution.The author used the source water of Luan River and the Fen He Reservoir to carry out experiments as following: firstly, the water purification experiment for modified PAC, confirming the best adding point and the best adding dosage of modified PAC; the effect on the water purification of coagulant and the water purification between the modified PAC and the original PAC. Secondly, confirming the application condition of PAC. Thirdly, the experiment of water purification of modified PAC in combination with ozone. Fourthly, the experiment of making use of PAC to treat the water polluted with high concentration organic matter. Fifthly, the study of using PAC to adsorpt the aniline, the poisonous Cr⁶⁺, heavy metal ion Hg²⁺ dissolved in experimental source water.According to the experiments' results the main conclusions were as follows: For the water of Luan River, firstly, the best dosage is 15mg/L of the PAC modified with H₂O₂ when added to the mixing tank and the removal rate of COD_Mn and UV₂₅₄ were 43.23%, 55% for filtered water respectively that increased by 6% and 8% compared with water purification of using original PAC. Secondly, the best dosage was 10mg/L of coagulant when the modified PAC's being 15mg/L (modified with H₂O₂). Thirdly, the better adding point is the first oxidative jar according to the water purification between the PAC(modified with NH₃·H₂O) when added to the first oxidative jar and the mixing tank. Fourthly, when the PAC modified with NH₃·H₂O was added to the first oxidative jar the removal rate of COD_Mn and UV₂₅₄ were increased by 5% and 9% respectively compared with using original PAC. Fifthly, when the coagulant's dosage was 10mg/L the water purification for reduction-modified PAC was best. Sixth, the PAC should be used in order to lighten the load of subsequent treatment process when the COD_Mn and UV₂₅₄ of source water are above 4mg/L or 0.055. Eighth, when oxidative-modified PAC was used together with ozone the removal rate of COD_Mn and UV₂₅₄ increased by 5% and 8% respectively when compared with oxidative-modified PAC only used. Ninthly, as reductive-modified PAC was used together with ozone the removal rate of COD_Mn and UV₂₅₄ increased by 5% and 8% respectively compared with reductive-modified PAC only used.For the water of Fen He Reservoir, firstly, when the PAC was added the removal rate of COD_Mn and UV₂₅₄ were 56% and 33% which were above 12% and 10% respectively for the condition that the PAC wasn't added. Secondly, for the removal effect of aniline, when the dosage of PAC was 50mg/L,the removal rate of aniline were 73%,70%,82%,73%,82.39%,30% and 31% respectively that were related to the each concentration of aniline dissolved in experimental source water. Thirdly, the pH's value of experimental source water play an important role for the removal effect of Cr⁶⁺, according to the experiments' results, the best value of pH was 3. Fourthly, as the concentration of Hg²⁺ was 0.05μg/L, the dosage of PAC was 40mg/L, the removal rate of Hg²⁺ was just about 33.82%.PAC pre-treatment technology proved to be an economical, convenient and efficient technology for micro-pollutant water source, and it can be used with other pre-treatment technologies, it can not only improve the effect of water purification but also lighten the pollution of membrane and extend the flush periods.