Chen Xiurong, Sun Xiaoli, Wang Xiaoxiao, Xu Peng, Yang Chenchen, Lu Quanling, Wang Shanshan
Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, East China University of Science and Technology, Shanghai 200237, China and National Engineering Laboratory for High-concentration Refractory Organic Wastewater Treatment Technologies (NELHROWTT), East China University of Science and Technology, Shanghai 200237, China E-mail:
Water Sci Technol. 2019 Jun;79(11):2185-2194. doi: 10.2166/wst.2019.219.
Coal gasification wastewater is mainly from gas washing, condensation and purification processes in the gas furnace with high NH-N (nitrogen in water in the form of free ammonia (NH) and ammonium ion (NH )), TN (total nitrogen) and refractory organics content, which will inhibit the subsequent biological treatment. The 'air stripping - hydrolysis acidification - air stripping' process was proposed as the pretreatment for coal gasification wastewater to improve the biodegradability and nitrogen removal, which could reduce the subsequent biological treatment load. The first-stage air stripping process before hydrolysis acidification could achieve a significant removal of NH-N (97.0%) and volatile phenol (70.0%), reducing the corresponding toxicity on hydrolysis acidification. The group with air stripping had more abundant microbial communities and a more effective organic degradation performance in hydrolysis acidification than that without air stripping. The second-stage air stripping removed NH-N released from hydrolysis acidification, and significantly reduced the TN concentration in effluent. The whole process achieved a TN removal from 2,000 ± 100 mg/L to 160 ± 80 mg/L, and a total phenols removal from 700 ± 50 mg/L to 80 ±20 mg/L.
煤气化废水主要来源于煤气发生炉的气体洗涤、冷凝和净化过程，其氨氮（水中以游离氨（NH）和铵离子（NH）形式存在的氮）、总氮（TN）和难降解有机物含量高，会抑制后续的生物处理。提出了“吹脱-水解酸化-吹脱”工艺作为煤气化废水的预处理工艺，以提高其可生物降解性和脱氮效果，从而降低后续生物处理的负荷。水解酸化前的第一阶段吹脱工艺可显著去除氨氮（97.0%）和挥发酚（70.0%），降低其对水解酸化的相应毒性。与未进行吹脱的组相比，进行吹脱的组在水解酸化过程中具有更丰富的微生物群落和更有效的有机降解性能。第二阶段吹脱去除了水解酸化释放的氨氮，并显著降低了出水的总氮浓度。整个工艺实现了总氮从2000±100mg/L降至160±80mg/L，总酚从700±50mg/L降至80±20mg/L。
