NaHCO_(3)投加量对废铁屑耦合厌氧氨氧化系统脱氮效能的影响

Influences of NaHCO3 dosage on nitrogen removal efficiency of the waste iron scraps-coupled anammox systems

考察了进水中NaHCO_(3)投加量对废铁屑耦合厌氧氨氧化系统脱氮效能的影响.结果表明,NaHCO_(3)投加量由250mg/L逐渐减少至125mg/L,常规厌氧氨氧化系统(R1)TN去除率下降至65%以下,污泥比活性下降约16%,而废铁屑(10g)耦合厌氧氨氧化系统(R2和R3)TN去除率提升至76.9%~82.2%,并且污泥比活性比R1高39.5%~51.4%;NaHCO_(3)投加量的减少同时造成R1中ΔNO_(3)^(-)-N/ΔNH_(4)^(+)-N比逐渐升高至0.34,而R2和R3中ΔNO_(3)^(-)-N/ΔNH4_(+)^(-)N比低至0.2~0.21.进水中无机碳源(IC)不足(而非pH值或碱度)是导致R1脱氮效能恶化的主要原因,废铁屑耦合厌氧氨氧化系统可以有效应对无机碳源不足产生的不利影响并提升系统的脱氮效能.此外,在无机碳源不足(IC/TN=0.04)的条件下,废铁屑与厌氧氨氧化直接耦合系统(R2)比间接耦合系统(R3)具有更高的脱氮效能、污泥比活性以及NO_(3)^(-)-N还原能力.

The effects of NaHCO3 dosage on the nitrogen removal efficiency of the waste iron scraps-assisted anammox systems were investigated.The results show that,with a decrease in NaHCO3 dosage gradually from 250 to 125mg/L,the TN removal efficiency and sludge specific anammox activity of the conventional anammox system(R1)reduced to below 65%and by 16%,respectively.In contrast,the TN removal efficiency of the waste iron scraps(WIS)-assisted anammox systems(R2 and R3)increased to 76.9%~82.2%,while the sludge specific anammox activities of R2 and R3 were 39.5%~51.4%higher than that of R1.The decrease in the NaHCO3 dosage also led to an increase in theΔNO_(3)^(-)-N/ΔNH_(4)^(+)-N ratio of R1(to 0.34).However,theΔNO_(3)^(-)-N/ΔNH_(4)^(+)-N ratio of both R2 and R3 was 0.20~0.21.The inorganic carbon limitation(rather than pH or alkalinity)was the main reason for the deterioration of nitrogen removal efficiency of R1.The WIS-assisted anammox systems could effectively deal with the adverse effects of the inorganic carbon limitation and enhance the nitrogen removal efficiency.Moreover,the direct coupling system of iron scrap and anammox(R2)possessed a higher nitrogen removal efficiency,sludge specific anammox activity and NO_(3)^(-)-N reduction ability than that of the indirect coupling system(R3)under the conditions of inorganic carbon limitation(IC/TN=0.04).