College of Environmental Science and Engineering, Nanjing Tech University, Nanjing, Jiangsu 211816, China; Bioenergy Research Institute, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, Jiangsu 211816, China.
Bioenergy Research Institute, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, Jiangsu 211816, China.
Sci Total Environ. 2023 Jul 1;880:163241. doi: 10.1016/j.scitotenv.2023.163241. Epub 2023 Apr 1.
Coal chemical wastewater (CCW) containing toxic and hazardous matters requires to be treated prior to discharge. Promoting the in-situ formation of magnetic aerobic granular sludge (mAGS) in continuous flow reactor process has a great potential for CCW remediation. However, long granulation time and low stability limit the application of AGS technology. In this study, FeO/sludge biochar (FeO/SC) with biochar matrix derived from coal chemical sludge were applied to facilitate the aerobic granulation in two-stage continuous flow reactors, containing separated anoxic and oxic reaction units (abbreviated as A/O process). The performance of A/O process was evaluated at various hydraulic retention times (HRTs) (42 h, 27 h, and 15 h). Magnetic FeO/SC with porous structures, high specific surface area (BET = 96.69 m/g), and abundant functional groups was successfully prepared by ball-milled method. Adding magnetic FeO/SC to A/O process could promote aerobic granulation (85 days) and the removal of chemical oxygen demand (COD), ammonia nitrogen (NH-N) and total nitrogen (TN) from CCW at all tested HRTs. Since the formed mAGS had high biomass, good settling ability, and high electrochemical activities, mAGS-based A/O process had high tolerance to the decrease of HRT from 42 h to 15 h for CCW treatment. The optimized HRT for A/O process was 27 h, at which FeO/SC addition can result in the increase of COD, NH-N and TN removal efficiencies by 2.5 %, 4.7 % and 10.5 %, respectively. Based on 16S rRNA genes sequencing, the relative abundances of genus Nitrosomonas, Hyphomicrobium/Hydrogenophaga and Gaiella in mAGS accounting for nitrification, denitrification as well as COD removal were increased during aerobic granulation. Overall, this study proved that adding FeO/SC to A/O process was effective for facilitating aerobic granulation and CCW treatment.
含毒有害物质的煤化工废水（CCW）在排放前需要进行处理。在连续流反应器工艺中促进原位形成磁性好氧颗粒污泥（mAGS）对于 CCW 修复具有很大的潜力。然而，长的颗粒化时间和低稳定性限制了 AGS 技术的应用。在本研究中，以煤化工污泥为生物炭基质的 FeO/污泥生物炭（FeO/SC）被应用于在两个阶段连续流反应器中促进好氧颗粒化，该反应器包含分离的缺氧和好氧反应单元（简称 A/O 工艺）。在不同水力停留时间（HRT）（42 h、27 h 和 15 h）下评估了 A/O 工艺的性能。通过球磨法成功制备了具有多孔结构、高比表面积（BET=96.69 m/g）和丰富官能团的磁性 FeO/SC。在 A/O 工艺中添加磁性 FeO/SC 可以促进好氧颗粒化（85 天）和在所有测试的 HRT 下从 CCW 中去除化学需氧量（COD）、氨氮（NH-N）和总氮（TN）。由于形成的 mAGS 具有高生物量、良好的沉降能力和高电化学活性，mAGS 基 A/O 工艺对 CCW 处理的 HRT 从 42 h 降低到 15 h 具有很高的耐受性。对于 A/O 工艺的优化 HRT 为 27 h，在此条件下，添加 FeO/SC 可使 COD、NH-N 和 TN 的去除效率分别提高 2.5%、4.7%和 10.5%。基于 16S rRNA 基因测序，在好氧颗粒化过程中，mAGS 中硝化、反硝化和 COD 去除的优势属硝化单胞菌属、氢单胞菌属/氢噬胞菌属和盖氏菌属的相对丰度增加。总的来说，本研究证明了在 A/O 工艺中添加 FeO/SC 对于促进好氧颗粒化和 CCW 处理是有效的。
