碳源类型对A2O系统脱氮除磷的影响

采用52.5 L的A²O反应器，以乙酸和丙酸分别作为进水唯一碳源，系统研究了进水碳源类型对脱氮除磷和代谢过程的影响.结果表明，在进水COD为250 mg/L左右，NH⁺₄-N为52 mg/L左右的条件下，原水碳源类型对TN的去除影响不大，系统TN去除率均在65%左右.进水碳源类型对TP的去除及相应污泥中PHA的类型、含量和代谢及糖原的变化影响较大.乙酸为唯一碳源时，厌氧区放磷浓度较高，污泥中PHA的成分主要为PHB和PHV，两者在厌氧区的合成量差别不大，PHB在随后的反应过程中变化较大，对除磷代谢过程起主要作用，而PHV的变化较小.丙酸作为进水唯一碳源时，厌氧区的放磷浓度偏低，主要合成PHV，几乎不含PHB，PHV在随后吸磷过程中浓度变化较大，对除磷代谢起主要作用，而且出水TP浓度偏低.碳源类型对污泥中糖原的代谢也有影响，乙酸为碳源时糖原的含量高，变化范围也较大，丙酸为碳源时糖原的变化幅度较小.在同步脱氮除磷系统中，与乙酸相比，丙酸是一种更合适的碳源.

Influence of Carbon Source on Biological Nutrient Removal in A2O Process

A 52.5 L pilot-scale biosystem, based on A²O configaration, was employed to investigate the effect of carbon source on biological nutrient removal and its metabolism process. Acetic acid and propionic acid were selected as the sole carbon source in different step.The COD was about 250 mg/L and NH⁺₄-N was about 52 mg/L in the influent. The results showed that the removal efficiency of TN was about 65% and without any relationship to the carbon source. The TP viariation along the reactor, PHA formation and content were determined by diffirent carbon source. When acetic acid was the sole carbon source, more phosphate was released in the anaerobic phase compared to propionic acid as the carbon source and the content of PHA was mainly PHB and PHV. The amount of PHB and PHV was almost equal. PHB was depleted in the following anoxic and aerobic phase for phosphorus removal but PHV was almost constant along the reactor. When propionic acid was the sole carbon source, less phosphate was released in the anaerobic phase and the content of PHA was mainly PHV. Almost no PHB and PH2MV were formed. PHV was depleted in the following anoxic and aerobic phase for phosphate uptake. Besides, the glycogen formation, variation and amount were different when different carbon source was dosed. More glycogen was depleted and formed in anaerobic and anoxic/aerobic phase when acetic acid was used as carbon source. Compared to acetic acid, propionic acid was more suitable for biological nutrient removal in wastewater treatment systems.