A lab-scale intermittently aerated sequencing batch reactor（IASBR）was applied to treat anaerobically digested swine wastewater（ADSW）to explore the removal characteristics of veterinary antibiotics.The removal rate...A lab-scale intermittently aerated sequencing batch reactor（IASBR）was applied to treat anaerobically digested swine wastewater（ADSW）to explore the removal characteristics of veterinary antibiotics.The removal rates of 11 veterinary antibiotics in the reactor were investigated under different chemical organic demand（COD）volumetric loadings,solid retention times（SRT）and ratios of COD to total nitrogen（TN）or COD/TN.Both sludge sorption and biodegradation were found to be the major contributors to the removal of veterinary antibiotics.Mass balance analysis revealed that greater than 60%of antibiotics in the influent were biodegraded in the IASBR,whereas averagely 24%were adsorbed by sludge under the condition that sludge sorption gradually reached its equilibrium.Results showed that the removal of antibiotics was greatly influenced by chemical oxygen demand（COD）volumetric loadings,which could achieve up to 85.1%±1.4%at 0.17±0.041 kg COD/m-3/day,while dropped to 75.9%±1.3%and 49.3%±12.1%when COD volumetric loading increased to 0.65±0.032 and1.07±0.073 kg COD/m-3/day,respectively.Tetracyclines,the dominant antibiotics in ADSW,were removed by 87.9%in total at the lowest COD loading,of which 30.4%were contributed by sludge sorption and 57.5%by biodegradation,respectively.In contrast,sulfonamides were removed about 96.2%,almost by biodegradation.Long SRT seemed to have little obvious impact on antibiotics removal,while a shorter SRT of 30–40 day could reduce the accumulated amount of antibiotics and the balanced antibiotics sorption capacity of sludge.Influent COD/TN ratio was found not a key impact factor for veterinary antibiotics removal in this work.展开更多
An intermittently aerated sequencing batch reactor （IASBR） and a traditional sequencing batch reactor （SBR） were parallelly constructed to treat digested piggery wastewater, which was in high NH4＋ -N concentratio...An intermittently aerated sequencing batch reactor （IASBR） and a traditional sequencing batch reactor （SBR） were parallelly constructed to treat digested piggery wastewater, which was in high NH4＋ -N concentration but in a low COD/TN ratio. Their pollutant removal perfonnance was compared under COD/TN ratios of 1.6-3.4 d and hydraulic retention times of 5 3 d. The results showed that the IASBR removed TN, NH4＋-N and TOC more efficiently than the SBR. The average removal rates of TN, NH4＋-N and TOC were 83.1%, 96.5%, and 89.0%, respectively, in the IASBR, significantly higher than the corresponding values of 74.8%, 82.0%, and 86.2%. in the SBR. Mass balance of organic carbon revealed that the higher TN removal in the IASBR might be attributed to its efficient utilization of the organic carbon for denitrification, since that 48.7%- 52.2% of COD was used for denitrification in the IASBR, higher than the corresponding proportion of 43.1%-47.4% in the SBR. A prc-anoxic process in the IASBR would enhance the ammonium oxidation while restrict the nitrite oxidation. Anoxic duration of 40-80 min should be beneficial for achieving stable nitritation.展开更多
文摘A lab-scale intermittently aerated sequencing batch reactor（IASBR）was applied to treat anaerobically digested swine wastewater（ADSW）to explore the removal characteristics of veterinary antibiotics.The removal rates of 11 veterinary antibiotics in the reactor were investigated under different chemical organic demand（COD）volumetric loadings,solid retention times（SRT）and ratios of COD to total nitrogen（TN）or COD/TN.Both sludge sorption and biodegradation were found to be the major contributors to the removal of veterinary antibiotics.Mass balance analysis revealed that greater than 60%of antibiotics in the influent were biodegraded in the IASBR,whereas averagely 24%were adsorbed by sludge under the condition that sludge sorption gradually reached its equilibrium.Results showed that the removal of antibiotics was greatly influenced by chemical oxygen demand（COD）volumetric loadings,which could achieve up to 85.1%±1.4%at 0.17±0.041 kg COD/m-3/day,while dropped to 75.9%±1.3%and 49.3%±12.1%when COD volumetric loading increased to 0.65±0.032 and1.07±0.073 kg COD/m-3/day,respectively.Tetracyclines,the dominant antibiotics in ADSW,were removed by 87.9%in total at the lowest COD loading,of which 30.4%were contributed by sludge sorption and 57.5%by biodegradation,respectively.In contrast,sulfonamides were removed about 96.2%,almost by biodegradation.Long SRT seemed to have little obvious impact on antibiotics removal,while a shorter SRT of 30–40 day could reduce the accumulated amount of antibiotics and the balanced antibiotics sorption capacity of sludge.Influent COD/TN ratio was found not a key impact factor for veterinary antibiotics removal in this work.
文摘An intermittently aerated sequencing batch reactor （IASBR） and a traditional sequencing batch reactor （SBR） were parallelly constructed to treat digested piggery wastewater, which was in high NH4＋ -N concentration but in a low COD/TN ratio. Their pollutant removal perfonnance was compared under COD/TN ratios of 1.6-3.4 d and hydraulic retention times of 5 3 d. The results showed that the IASBR removed TN, NH4＋-N and TOC more efficiently than the SBR. The average removal rates of TN, NH4＋-N and TOC were 83.1%, 96.5%, and 89.0%, respectively, in the IASBR, significantly higher than the corresponding values of 74.8%, 82.0%, and 86.2%. in the SBR. Mass balance of organic carbon revealed that the higher TN removal in the IASBR might be attributed to its efficient utilization of the organic carbon for denitrification, since that 48.7%- 52.2% of COD was used for denitrification in the IASBR, higher than the corresponding proportion of 43.1%-47.4% in the SBR. A prc-anoxic process in the IASBR would enhance the ammonium oxidation while restrict the nitrite oxidation. Anoxic duration of 40-80 min should be beneficial for achieving stable nitritation.
