High-concentration nitrite-containing wastewater that presents extreme toxicity to human health and organisms is difficult to be treated using traditional biological process.In this study,a novel microwave-enhanced ch...High-concentration nitrite-containing wastewater that presents extreme toxicity to human health and organisms is difficult to be treated using traditional biological process.In this study,a novel microwave-enhanced chemical reduction process(MECRP)using sulfarninic acid(SA)was proposed as a new manner to treat such type of wastewater.Based on lab-scale experiments,it was shown that 75%-80%nitrite(NO2-)could be removed within time as short as 4 min under 50 W microwave irradiation in pH range 5-10 when molar ratio of SA to nitrite(SA/NO2-)was 0.8.Pilot-scale investigations demonstrated that MECRP was able to achieve nitrite and chemical oxygen demand(COD)removal with efficiency up to 80%and 20%,respectively under operating conditions of SA concentration 80 kg/m3,SA/NO2-ratio 0.8,microwave power 3.4 kW,and stirring time 3 min.Five-day biological oxygen demand(BODs)/COD value of treated effluent after MECRP was increased from 0.05 to 0.36(by 620%),which clearly suggested a considerable improvement of biodegradability for subsequent biological treatment.This study provided a demonstration of using microwave irradiation to enhance reaction between SA and nitrite in a short time,in which nitrite in wastewater was completely converted into nitrogen gas without leaving any sludge and secondary pollutants.展开更多
基金supported by the National Natural Science Foundation of China(No.50678045)
文摘High-concentration nitrite-containing wastewater that presents extreme toxicity to human health and organisms is difficult to be treated using traditional biological process.In this study,a novel microwave-enhanced chemical reduction process(MECRP)using sulfarninic acid(SA)was proposed as a new manner to treat such type of wastewater.Based on lab-scale experiments,it was shown that 75%-80%nitrite(NO2-)could be removed within time as short as 4 min under 50 W microwave irradiation in pH range 5-10 when molar ratio of SA to nitrite(SA/NO2-)was 0.8.Pilot-scale investigations demonstrated that MECRP was able to achieve nitrite and chemical oxygen demand(COD)removal with efficiency up to 80%and 20%,respectively under operating conditions of SA concentration 80 kg/m3,SA/NO2-ratio 0.8,microwave power 3.4 kW,and stirring time 3 min.Five-day biological oxygen demand(BODs)/COD value of treated effluent after MECRP was increased from 0.05 to 0.36(by 620%),which clearly suggested a considerable improvement of biodegradability for subsequent biological treatment.This study provided a demonstration of using microwave irradiation to enhance reaction between SA and nitrite in a short time,in which nitrite in wastewater was completely converted into nitrogen gas without leaving any sludge and secondary pollutants.
