State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China.
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China.
Water Res. 2020 Jun 1;176:115741. doi: 10.1016/j.watres.2020.115741. Epub 2020 Mar 20.
The addition of sludge alkaline fermentation liquid (SAFL) to biological nutrient removal (BNR) processes has been widely shown to reduce the dissolved inorganic nitrogen (DIN) in the effluent. However, knowledge regarding the effect of using SAFL in a BNR as an additional carbon source on the characteristics of dissolved organic nitrogen (DON) in the effluent is limited. This study investigated the effect of SAFL addition on effluent DON features and microbial community dynamics in a BNR process treating municipal wastewater. The performance of SAFL was compared with other two reactors (i.e., without an external carbon source and with the addition of sodium acetate). The results showed that the addition of SAFL can significantly reduce effluent DON (p < 0.05). The effluent DON was slightly higher with SAFL than with sodium acetate, but the bioavailable DON of the two reactors was similar (1.06 ± 0.11 vs 1.04 ± 0.12 mg/L, respectively, p > 0.05). The SAFL addition led to a decreased percentage of low molecular weight DON (p < 0.05) as well as an increased ratio of fulvic-like and humic-like substances to proteins-like substances. Moreover, the SAFL addition resulted in a lower percentage of substances resembling proteins/amino sugars and a higher percentage of lignin-like molecules than sodium acetate. These features accounted for the low DON bioavailability. The SAFL promoted the increased abundance of Bacteroidetes, Chloroflexi, Comamonadaceae and Rhodocyclaceae, which could be associated with the decreased effluent DON and its bioavailability. This study indicates that using SAFL as a BNR carbon source not only improves the removal of DIN but also reduces effluent DON and specifically DON bioavailability. These results facilitate the acquisition of comprehensive knowledge regarding the use of SAFL as an alternative external carbon source in the BNR process.
污泥碱性发酵液（SAFL）在生物脱氮（BNR）工艺中的添加已被广泛证明可以降低出水的溶解无机氮（DIN）。然而，关于将 SAFL 作为 BNR 的额外碳源添加对出水溶解有机氮（DON）特性的影响的知识是有限的。本研究考察了 SAFL 对处理城市污水的 BNR 过程中出水 DON 特性和微生物群落动态的影响。比较了 SAFL 的性能与其他两个反应器（即无外加碳源和添加乙酸钠）。结果表明，添加 SAFL 可显著降低出水 DON（p<0.05）。与乙酸钠相比，SAFL 的出水 DON 略高，但两个反应器的可生物利用 DON 相似（分别为 1.06±0.11 和 1.04±0.12mg/L，p>0.05）。SAFL 的添加导致低分子量 DON 的比例降低（p<0.05），富里酸样和腐殖酸样物质与蛋白质样物质的比例增加。此外，SAFL 的添加导致类似于蛋白质/氨基糖的物质比例降低，而类似于木质素的分子比例升高，这是 DON 可生物利用性低的原因。这些特征解释了低 DON 可生物利用性。SAFL 促进了拟杆菌门、绿弯菌门、食酸菌科和红环菌科的丰度增加，这可能与降低出水 DON 及其可生物利用性有关。本研究表明，将 SAFL 作为 BNR 碳源不仅可以提高 DIN 的去除率，还可以降低出水 DON，特别是 DON 的可生物利用性。这些结果有助于全面了解将 SAFL 作为 BNR 工艺中的替代外加碳源的应用。
