This study reports the feasibility of using municipal wastewater biosolids as an alternative carbon source for biological phosphorus removal.The biosolids were treated by a lowtemperature,thermal alkaline hydrolysis p...This study reports the feasibility of using municipal wastewater biosolids as an alternative carbon source for biological phosphorus removal.The biosolids were treated by a lowtemperature,thermal alkaline hydrolysis process patented by Lystek International Inc.(Cambridge,ON,Canada)to produce short-chain volatile fatty acids and other readily biodegradable organics.Two sequencing batch reactors(SBRs)were operated with synthetic volatile fatty acids(Syn VFA)and readily biodegradable organics produced from the alkaline hydrolysis of municipal wastewater biosolids(Lystek)as the carbon source,respectively.Municipal wastewaters with different strengths and COD:N:P ratios were tested in the study.The reactors’performances were compared with respect to nitrogen and phosphorus removal.It was observed that phosphorus removal efficiencies were between 98%–99%and 90%–97%and nitrogen removal efficiencies were 78%–81%,and 67%for the Syn VFA and Lystek,respectively.However,the kinetics for phosphorus release and uptake during the anaerobic and aerobic stages with Lystek were observed to be significantly lower than Syn VFA due to the presence of higher order VFAs(C4 and above)and other fermentable organics in the Lystek.展开更多
This study investigated the acute nickel toxicity on nitrification of low ammonia synthetic wastewater at 10, 23, and 35°C. The nickel inhibition half-velocity constants(K_(I,Ni)) for ammonia oxidizing bacteria(A...This study investigated the acute nickel toxicity on nitrification of low ammonia synthetic wastewater at 10, 23, and 35°C. The nickel inhibition half-velocity constants(K_(I,Ni)) for ammonia oxidizing bacteria(AOB) and nitrite oxidizing bacteria(NOB) based on Ni/MLSS ratio at 10, 23, and 35°C were 5.4 and 5.6 mg Ni/g MLSS, 4.6 and 3.5 mg Ni/g MLSS, and 9.1 and 2.7 mg Ni/g MLSS, respectively. In addition, chronic toxicity of nickel to nitrification of low ammonia synthetic wastewater was investigated at 10°C in two sequencing batch reactors(SBRs). Long-term SBRs operation and short-term batch tests were comparable with respect to the extent of inhibition and corresponding Ni/MLSS ratio. The μ_(max), b, and K_o of AOB were 0.16 day^(-1), 0.098 day^(-1) and 2.08 mg O_2/L after long-term acclimatization to nickel of 1 mg/L at 10°C, high dissolved oxygen(DO)(7 mg/L) and long solids retention time(SRT) of 63–70 days. Acute nickel toxicity of nitrifying bacteria was completely reversible.展开更多
基金financial support from the Natural Sciences and Engineering Research Council of Canada
文摘This study reports the feasibility of using municipal wastewater biosolids as an alternative carbon source for biological phosphorus removal.The biosolids were treated by a lowtemperature,thermal alkaline hydrolysis process patented by Lystek International Inc.(Cambridge,ON,Canada)to produce short-chain volatile fatty acids and other readily biodegradable organics.Two sequencing batch reactors(SBRs)were operated with synthetic volatile fatty acids(Syn VFA)and readily biodegradable organics produced from the alkaline hydrolysis of municipal wastewater biosolids(Lystek)as the carbon source,respectively.Municipal wastewaters with different strengths and COD:N:P ratios were tested in the study.The reactors’performances were compared with respect to nitrogen and phosphorus removal.It was observed that phosphorus removal efficiencies were between 98%–99%and 90%–97%and nitrogen removal efficiencies were 78%–81%,and 67%for the Syn VFA and Lystek,respectively.However,the kinetics for phosphorus release and uptake during the anaerobic and aerobic stages with Lystek were observed to be significantly lower than Syn VFA due to the presence of higher order VFAs(C4 and above)and other fermentable organics in the Lystek.
基金supported by the Natural Sciences and Engineering Research Council of Canada(No.CRDPJ 458990-13)
文摘This study investigated the acute nickel toxicity on nitrification of low ammonia synthetic wastewater at 10, 23, and 35°C. The nickel inhibition half-velocity constants(K_(I,Ni)) for ammonia oxidizing bacteria(AOB) and nitrite oxidizing bacteria(NOB) based on Ni/MLSS ratio at 10, 23, and 35°C were 5.4 and 5.6 mg Ni/g MLSS, 4.6 and 3.5 mg Ni/g MLSS, and 9.1 and 2.7 mg Ni/g MLSS, respectively. In addition, chronic toxicity of nickel to nitrification of low ammonia synthetic wastewater was investigated at 10°C in two sequencing batch reactors(SBRs). Long-term SBRs operation and short-term batch tests were comparable with respect to the extent of inhibition and corresponding Ni/MLSS ratio. The μ_(max), b, and K_o of AOB were 0.16 day^(-1), 0.098 day^(-1) and 2.08 mg O_2/L after long-term acclimatization to nickel of 1 mg/L at 10°C, high dissolved oxygen(DO)(7 mg/L) and long solids retention time(SRT) of 63–70 days. Acute nickel toxicity of nitrifying bacteria was completely reversible.
