College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China.
College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China.
J Hazard Mater. 2019 Feb 5;363:99-108. doi: 10.1016/j.jhazmat.2018.09.072. Epub 2018 Sep 29.
The chemical p-nitrophenol (PNP) is a priority pollutant, and PNP wastewater is highly toxic and resistant to biodegradation. The traditional physical and chemical methods (adsorption, extraction, and oxidation) for treating PNP wastewater have the disadvantages of complicated processes, high costs and secondary pollution generation. In this study, two integrated membrane-aerated bioreactor systems (RA and RB) with anoxic and aerated zones were constructed to enhance PNP biodegradation. The results showed that a helical silicone rubber membrane module displayed a high oxygen supply rate under a low membrane aeration pressure, and the hydraulic flow state of the reactor approached ideal mixing. At an influent PNP concentration of 500 mg/L, the average removal rates of PNP, chemical oxygen demand (COD) and total nitrogen (TN) reached 95.86%, 89.77%, and 94.81%, respectively, for RA and 89.48%, 74.26% and 64.78%, respectively, for RB, indicating efficient simultaneous PNP and nitrogen removal. Compared with that of RB, the pre-anoxic zone in RA not only performed detoxification pretreatment but also enhanced PNP degradation and denitrification effects, which relieved the biological treatment burden of the subsequent aerated zone. Based on these comprehensive analyses of reactor performance, the hydroquinone pathway might be the main route in the aerobic degradation of PNP.
化学物质对硝基苯酚（PNP）是一种优先污染物，PNP 废水毒性高且难以生物降解。传统的物理化学方法（吸附、萃取和氧化）处理 PNP 废水存在工艺复杂、成本高和产生二次污染等缺点。本研究构建了两个具有缺氧和好氧区的集成膜曝气生物反应器系统（RA 和 RB），以增强 PNP 的生物降解。结果表明，螺旋硅橡胶膜模块在低膜曝气压力下具有较高的供氧量，且反应器的水力流动状态接近理想混合。在进水 PNP 浓度为 500mg/L 时，RA 的 PNP、化学需氧量（COD）和总氮（TN）的平均去除率分别达到 95.86%、89.77%和 94.81%，RB 的分别达到 89.48%、74.26%和 64.78%，表明能够高效同步去除 PNP 和氮。与 RB 相比，RA 中的预缺氧区不仅进行了解毒预处理，还增强了 PNP 降解和脱氮效果，减轻了后续曝气区的生物处理负担。基于对反应器性能的综合分析，对苯二酚途径可能是 PNP 好氧降解的主要途径。
