原水碳源分子量分布及DPB效能对酸化时间的响应

摘要

采用超滤-纳滤膜法对污水中碳源分子量(MW)进行切割试验,并测定各区间总有机碳(TOC)浓度以了解污水碳源组成特性；同时采用污水酸化技术,研究在不同酸化时间,碳源分子量分布的变化及对厌氧-膜好氧-反硝化(A2N)工艺中反硝化聚磷菌(DPB)用碳和净污效能的影响.结果表明,试验原水TOC为(58.3±2.83) mg /L,其中颗粒有机碳(POC)为(38.05±1.65)mg /L,占65.27%,剩余溶解有机碳(DOC)在分子量0.5kDa以上区间呈现“W”型分布,其中 MW>100kDa、10k~5kDa、1k~0.5kDa、MW<0.5kDa区间碳源分别占36.20%、12.05%、13.68%和29.83%.在不同酸化时间下,POC含量与DOC分布存在显著差异,在12h内酸化,可以有效将POC转化为DOC,且在14mg/L左右趋于平衡；DOC在大于0.5kDa区间上的分布呈现随时间而整体后移的趋势,在8h时碳源质量最优,其中MW<1kDa的小分子有机物高达17.30mg/L；此时,DPB污泥在厌氧池与缺氧池中的碳源利用率分别为83.48%、79.59%,比0h时分别提高了23.56%、18.03%；TN、TP去除率分别提高了14.63%、16.98%.%In order to know the features of carbon source composition, nanofiltration-ultrafiltration membranes was used to determine fractionation of the molecular weight in wastewater carbon source. Then we studied the influence of molecular weight distribution on the carbon utilization by denitrifying phosphorous removing bacteria(DPB) and related treatment performance of wastewater in the anaerobic-nitrification-anoxic (A2N) process, by employing acidification method with different acidification time. The averaged concentration of the total organic carbon (TOC) in raw wastewater was (58.3±2.83) mg/L, among which there is an averaged concentration of the particulate organic carbon (POC) in (38.05±1.65) mg/L with 65.27% to TOC. The dissolved organic carbon (DOC) presents a "W" type distribution on the molecular weigh with ranges of less than 0.5kDa (Dalton). And the molecular in weight ranges of “bigger than 100kDa”, “10kDa~5kDa”, “1kDa~0.5kDa” and “less than 0.5kDa” has contributed 36.20%, 12.05%, 13.68% and 36.20% to the total DOC, respectively. Acidification time has significantly impact on the allocation between POC and DOC. A 12-h acidification could effectively transformed POC to DOC, reaching a balanced concentration of 14mg/L. DOC decreased with increased acidification time. Best quality of carbon sources was expected at 8h, when DOC in low molecule weight organic matter (LMWOM, <1kDa) was 17.30mg/L. As a result, carbon utilization rate of DPB sludge in anaerobic tank and anoxic tank were 83.48% and 79.59%, increased by 23.56% and 18.03% from the 0-h acidification time, respectively. Meanwhile, the removal rate of total nitrogen (TN) and total phosphorus (TP) increased by 14.63% and 16.98%, respectively.