State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin 150090, China.
School of Engineering, South China Agricultural University, Guangzhou 510642, China.
Sci Total Environ. 2018 Oct 1;637-638:1-8. doi: 10.1016/j.scitotenv.2018.04.404. Epub 2018 May 8.
Even though coal gasification wastewater (CGW) treated by various biochemical treatment processes generally met the national discharge standard, its potential biotoxicity was still unknown. Therefore, in this study, bioassay with Tetrahymena thermophila (T. thermophila) was conducted to comprehensively evaluate the variation of biotoxicity in raw CGW and the treated effluent from lab-scale micro-electrolysis integrated with biological reactor (MEBR), single iron-carbon micro-electrolysis (ICME) and conventional activated sludge (CAS) processes. The results illustrated that raw CGW presented intensive acute toxicity with 24 h EC value of 8.401% and toxic unit (TU) value of 11.90. Moreover, it performed significant cell membrane destruction and DNA damage even at 10% dilution concentration. The toxicant identification results revealed that multiple toxic polar compounds such as phenolic, heterocyclic and polycyclic aromatic compounds were the main contributors for biotoxicity. Furthermore, these compounds could accelerate oxidative stress, thereby inducing oxidative damage of cell membrane and DNA. As for treated effluent, TU value was decreased by 90.58% in MEBR process. An effective biotoxicity reduction was achieved in MEBR process owing to high removal efficiency in polar organic toxicants. In contrast, effluent from ICME and CAS processes presented relatively high acute toxicity and genotoxicity, because various heterocyclic and polycyclic aromatic compounds were difficult to be degraded in these processes. Therefore, it was suggested that MEBR was a potential and feasible process for improving CGW treatment and minimizing ecological risk.
尽管经过各种生化处理工艺处理的煤气化废水（CGW）通常符合国家排放标准，但它的潜在生物毒性仍然未知。因此，在这项研究中，使用嗜热四膜虫（T. thermophila）进行了生物测定，以综合评估原始 CGW 和经过实验室规模的微电解与生物反应器（MEBR）、单一铁碳微电解（ICME）和传统活性污泥（CAS）工艺处理后的废水的生物毒性变化。结果表明，原始 CGW 具有强烈的急性毒性，24 小时 EC 值为 8.401%，毒性单位（TU）值为 11.90。此外，即使在 10%稀释浓度下，它也会对细胞造成明显的膜破坏和 DNA 损伤。毒性鉴定结果表明，多种有毒极性化合物，如酚类、杂环和多环芳烃化合物是生物毒性的主要贡献者。此外，这些化合物会加速氧化应激，从而导致细胞膜和 DNA 的氧化损伤。对于处理后的废水，MEBR 工艺使 TU 值降低了 90.58%。由于对极性有机毒物具有高去除效率，MEBR 工艺实现了有效的生物毒性降低。相比之下，ICME 和 CAS 工艺的出水则表现出相对较高的急性毒性和遗传毒性，因为这些工艺中各种杂环和多环芳烃化合物难以降解。因此，建议采用 MEBR 工艺来改善 CGW 处理并最小化生态风险。
