Study On Treatment Of Wastewater Containing NH₄⁺-N And Cu²⁺ In Copper Mining Area

In the copper mining area,A large amount of heavy metal Waste-water was produced during the copper mining process.At same time the large amount of ammonia-nitrogen wastewater was generated in the residents'lives and farmers'fertilization process around the mining area.These two types waste-water are mixed leachate into the underground around the mining area to form the copper mining sewage which contain Cu²⁺,NH₄⁺-N.Aiming at this kind of sewage,it is treated by combining the adsorption method and the biological aerated filter method which contain low concentration Cu²⁺,NH₄⁺-N.Preparation copper slag-based ceramsite with copper smelting waste slag which produce from the smelting process.Using the prepared porous ceramsite to remove Cu²⁺of the sewage,After adsorption the liquid enters the BAF process to further remove NH₄⁺-N in the sewage.Research on the optimized preparation conditions of copper slag-based ceramsite.and explored the adsorption and removal rule of Cu²⁺with modified copper slag-based ceramsite.Under different operation,the removal of BAF on NH₄⁺-N after adsorption and decopperization was studied.The results shows:?1?Under the conditions of copper slag:sodium bicarbonate:pore forming agent?mass ratio?=10:1:1,calcining temperature being 1050°C,holding time 30 minutes,a ceramsite was prepared with optimized performances which meet the requirements of the national standard.The performance index which contain mud content=0.161%,hydrochloric acid solubility=0.195%,bulk density=0.561 g/ml,compressive strength130²00 N,porosity=53.61%.?2?The optimal conditions for the removal of Cu²⁺from sewage by modified copper slag based ceramsite are:the initial concentration is 50mg/L,the initial pH is 5,the adsorption temperature is 35?,the adsorption is 1 g.Under these conditions,the adsorption reaches equilibrium at 90 min,and the adsorption capacity is 0.936 mg/g,the adsorption process of Cu²⁺with modified porous ceramsite satisfies the pseudo second order kinetic equation,Langmuir isotherm adsorption model.The adsorption of modified ceramsite is monolayer adsorption.?3?When the initial concentration of Cu²⁺,NH₄⁺-N is 20mg/L,100mg/L,respectively.Under the optimize condition the removal rate of Cu²⁺can reach 85%after270 min adsorption by modified ceramsite.It can meet the requirements of discharge standard,the concentration of NH₄⁺-N in the adsorbed solution is 95.27mg/L,which needs further treatment by BAF process.?4?For BAF process composite hanging film method was adopted,under the condition that the ration of sewage inflow and activated sludge is 4:1 and the aeration rate is 1.2 L/min.BAF membrane hanging was successful.Acco rding to the single factor test,the optimal process parameters of BAF are HRT=6 h,C/N ratio is 4:1,pH of influent water is 8,Under this condition,BAF c an remove NH₄⁺-N and TN in simulated sewage,the removal rates are 96%a nd 65%respectively,and the NH₄⁺-N in the effluent water meets the discharge standard.