Jiang Zhao, Xia Zhiheng, Liu Shuai, Wei Qi, Fan Haitao, Qi Lu, Liu Guohua, Wang Hongchen
Low-carbon Water Environment Technology Research Center, School of Environment & Natural Resources, Renmin University of China, Beijing 100872, China.
Low-carbon Water Environment Technology Research Center, School of Environment & Natural Resources, Renmin University of China, Beijing 100872, China.
J Environ Sci (China). 2025 Jan;147:607-616. doi: 10.1016/j.jes.2023.10.032. Epub 2023 Nov 4.
This study embarks on an explorative investigation into the effects of typical concentrations and varying particle sizes of fine grits (FG, the involatile portion of suspended solids) and fine debris (FD, the volatile yet unbiodegradable fraction of suspended solids) within the influent on the mixed liquor volatile suspended solids (MLVSS)/mixed liquor suspended solids (MLSS) ratio of an activated sludge system. Through meticulous experimentation, it was discerned that the addition of FG or FD, the particle size of FG, and the concentration of FD bore no substantial impact on the pollutant removal efficiency (denoted by the removal rate of COD and ammonia nitrogen) under constant operational conditions. However, a notable decrease in the MLVSS/MLSS ratio was observed with a typical FG concentration of 20 mg/L, with smaller FG particle sizes exacerbating this reduction. Additionally, variations in FD concentrations influenced both MLSS and MLVSS/MLSS ratios; a higher FD concentration led to an increased MLSS and a reduced MLVSS/MLSS ratio, indicating FD accumulation in the system. A predictive model for MLVSS/MLSS was constructed based on quality balance calculations, offering a tool for foreseeing the MLVSS/MLSS ratio under stable long-term influent conditions of FG and FD. This model, validated using data from the BXH wastewater treatment plant (WWTP), showcased remarkable accuracy.
本研究对进水细砂（FG，悬浮固体中的不可挥发部分）和细碎屑（FD，悬浮固体中挥发性但不可生物降解部分）的典型浓度及不同粒径对活性污泥系统的混合液挥发性悬浮固体（MLVSS）/混合液悬浮固体（MLSS）比值的影响展开探索性调查。通过细致的实验发现，在恒定运行条件下，添加FG或FD、FG的粒径以及FD的浓度对污染物去除效率（以化学需氧量和氨氮去除率表示）没有实质性影响。然而，当典型FG浓度为20 mg/L时，观察到MLVSS/MLSS比值显著下降，FG粒径越小，这种下降越明显。此外，FD浓度的变化影响MLSS以及MLVSS/MLSS比值；FD浓度越高，MLSS增加，MLVSS/MLSS比值降低，表明系统中FD的积累。基于质量平衡计算构建了MLVSS/MLSS的预测模型，为预测FG和FD长期稳定进水条件下的MLVSS/MLSS比值提供了一种工具。该模型利用BXH污水处理厂的数据进行验证，显示出了很高的准确性。
