Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, East China University of Science and Technology, Shanghai, China.
National Engineering Laboratory for High-concentration Refractory Organic Wastewater Treatment Technologies (NELHROWTT), East China University of Science and Technology, Shanghai, China.
J Environ Sci Health A Tox Hazard Subst Environ Eng. 2020;55(14):1563-1570. doi: 10.1080/10934529.2020.1826773. Epub 2020 Dec 24.
As a common pretreatment process for coal chemical wastewater, the conventional one-stage coagulation process has the problem of poor removal of small size oil, which will inhibit the subsequent biological treatment. Measures to improve oil removal efficiency based on the development of new coagulants and the addition of composite processes are common in the literature, but two-stage coagulation to improve coagulation efficiency has not been reported to date. Here, we optimized coagulation parameters and compared the oil removal efficiency of two-stage coagulation and one-stage coagulation. Under the same total dosage of coagulant (PAC), the optimum removal of oil in two-stage coagulation was achieved 90% which increased by 11% compared to one-stage process. P10 and P 1 μm were proposed to evaluate the oil removing effect of two-stage coagulation. In addition, SEM scanning was used to conduct flocs analysis and two-stage coagulation process simulation, revealing the principle of the excellent oil removal performance of two-stage coagulation. Finally, coagulant in filter residue was recovered by acidification method and the recovered coagulant was used again in the two-stage coagulation process of coal chemical wastewater. These results suggest that two-stage coagulation is a cost-effective alternative oil removal technique with high energy efficiency and environmental benign. This research may offer helpful insights to develop an advanced oil removal process.
作为煤化工废水的一种常见预处理工艺，传统的一级混凝工艺存在去除小粒径油效果差的问题，这将抑制后续的生物处理。基于开发新型混凝剂和添加复合工艺来提高除油效率的措施在文献中很常见，但迄今为止尚未报道两级混凝来提高混凝效率。在这里，我们优化了混凝参数，并比较了两级混凝和一级混凝的除油效率。在相同的总混凝剂（PAC）剂量下，两级混凝的最佳除油率达到 90%，比一级工艺提高了 11%。提出 P10 和 P1μm 来评估两级混凝的除油效果。此外，还进行了 SEM 扫描以进行絮体分析和两级混凝工艺模拟，揭示了两级混凝具有优异除油性能的原理。最后，通过酸化法从滤渣中回收混凝剂，并将回收的混凝剂再次用于煤化工废水的两级混凝过程。这些结果表明，两级混凝是一种具有高能源效率和环境友好性的具有成本效益的替代除油技术。这项研究可能为开发先进的除油工艺提供有益的见解。
