Study On The Effect Of Sulfate On The Treatment Of High Ammonia Organic Wastewater

On April 2,2015,“Water pollution control action plan”?commonly known as“ten articles of water”?issued by the State Council has clearly pointed out that the emission of pollutants should be controlled.Therefore,it is necessary and imperative to take action on the treatment of industrial wastewater.In China,the annual emission of high sulfate ammonia organic wastewater discharged from the synthetic industries could be accounted for 1/5 of the total industrial wastewater.The high ammonia could easily cause eutrophication of water body if it was not effectively treated.Besides,due to lack of the relevant knowledges and experiences of the treatment of high sulfate ammonia organic wastewater,the phenomenon of sulfur poisoning of sludge was often occurred in the chemical wastewater treatment plant.Moreover,it would inevitably lead to waste of resources and the second pollution.To solve those problems,the effect of sulfate on the treatment of high ammonia organic was studied by our research.The study was divided into two parts.In the first part,the artifical water distribution and the Sequencing Batch Reactor?SBR?were used to study the limited value of sulfate endured by the sludge,the performance of sludge and the removal efficiencies of pollutants by gradually increasing the sulfate(SO₄^2-)concentration of influent.In the second part,the operation of the chemical industrial wastewater plant was studied according to the lab-scale results and experience.The main conclusions are followed:?1?The SBR was adopted to treat the sulfate and high ammonia organic wastewater and the COD_cr removal efficiency,ammonia removal efficiency and total nitrogen efficiency could achieve 90%,92%and 85%respectively under the following conditions:the COD_cr concentration of influent 1000mg/L with sodium acetate?CH₃COONa?as the carbon resources,the ammonia concentration of influent200mg/L,aerobic running 24 hours,anaerobic running 12hours.The activated sludge could endure the sulfate concentration of 6500mg/L and the sludge system would crash and was unable to restore activity if the sulfate concenetration was above8000mg/L.?2?With the increase of sulfate concentration and the effect of sulfute reduction products,the activity of sludge declined.The main biological phase of sludge changed from metazoan to protozoa,and finally the planktonic animals.Besides,the main sludge mocrostructure were bacillus and coccis.?3?By the method of analyzing the depletion of COD_cr and NO₃^-reduction in anaerobic tank,it was inferred that sulfate reduction and autotrophic denitrification desulfurization gradually strengthened and the heterotrophic denitrification weakened with the improvement of sulfate concentration and coordination of ecological laws of microorganism.The total nitrogen removal efficiency reached above 80%under the action of both two parts.?4?According to the laboratory static tests and actual pretreatment processes operating,the pre-processing scheme was worked out:The average of sulfate reaching 53.5%with the dosage of lime,PAC and PAM were 6g/L,12mg/L and4mg/L respectively under normal running periods.It ensured that the sulfate concentration of raw wastewater was less than 5000mg/L before entering the biological system.?5?Through four months'operation of the A/O system,the average COD_cr,ammonia and total nitrogen removal efficiencies reached 94.6%,92.1%and 85.1%respectively without any exteral carbon sources under the conditions as followed:the sulfate concentration of influent 2000?5000mg/L,the ammonia nitrogen and total nitrogen concentrations less than 300mg/L.Based on the above research,the quality of effluent of the high ammonia organic wastewater treatment plant could meet the direct emission standard of Discharge standard of water pollutants for ammonia industrial?GB13458-2013?and,ultimately,concluded with the successful acceptance.