焦化废水处理技术进展与发展方向

Progress and perspectives of coking wastewater treatment technology

焦化作为传统煤化工产业发展迅速,而我国焦化企业大多分布在相对较缺水的华北地区,所以焦化废水的有效处理对焦化行业的持续稳定发展具有重要作用。从焦化废水的来源与水质特点着手,论述了焦化废水处理技术的研究进展,指出目前焦化废水处理技术存在的不足,并对其发展方向进行展望。焦化废水具有产生量大、有机污染物浓度高、处理难度大等特点,是典型的难处理工业废水。国内焦化企业对预处理工段重要性的认识相对比较淡薄,目前传统的预处理技术仍占主导地位,效率低、能耗高、二次污染等问题突出,但磁分离技术在今后的预处理工段会得到进一步应用;生化处理工段主要延用20世纪发展成熟的厌氧、缺氧、好氧技术,其发展成熟且效果理想因此被普遍采用,但生化处理技术对水质要求较高,尤其废水中的碳氮比(C/N)、有机碳源浓度等因素更是决定了生化处理的最终效果,生物强化技术及膜生物反应器未来将会有较大的发展与突破,厌氧技术因其能量利用率高再次引起广大学者关注,厌氧技术的应用有利于构建理想型的现代废水处理工厂;深度处理工段主要解决生化出水不达标的问题,在“零排放”工艺中对过膜水质有较高要求,所以深度处理工段为更精细、更针对性地降解一些有机物,高级氧化技术作为新兴的处理技术发展迅速且逐渐被更多焦化企业采用。研究表明,将多种处理技术进行优化耦合产生的协同作用可进一步加强处理效果而使焦化废水达到排放或满足回用标准;随着环保政策的日益严格、废水“零排放”的普及、企业可接受的处理成本以及焦化废水的水质特点等因素共同决定了以高级氧化技术、膜分离技术等相对成熟的深度处理技术的耦合连用将是今后发展的重点方向;提高资源回收利用率、提高处理能力与效率、降低能耗与运营成本将成为焦化废水处理的发展趋势。在焦化废水处理过程中膜分离技术得到广泛应用的同时会产生高浓度的含盐废水,含盐废水的有效处理关系到分盐产品的纯度,若不能有效处理浓盐水中的有机污染物会增加后续工段的处理成本甚至产生污染环境的危废,所以对高浓盐水的有效处理也是科研界亟待解决的焦点问题。

Coking,as a traditional coal chemical industry,has developed rapidly,and most of coking enterprises are distributed in North China where there is relatively little water.Therefore,the effective treatment of coking wastewater plays an important role in the sustainable and stable development of coking industry.In this paper,the research progress of coking wastewater treatment technology was discussed based on the source and water quality characteristics of coking wastewater.The shortcomings of the current coking wastewater treatment technology were pointed out,and its development direction was prospected.Coking wastewater is a typical industrial wastewater,which is difficult to be treated because of its characteristics such as large amount of production and high concentration of organic pollutants.Domestic coking enterprises have relatively weak understanding about the importance of pretreatment section,at present the traditional pretreatment technology is still dominant,and the problems such aslow efficiency,high energy consumption and secondary pollution are outstanding,but the magnetic separation technique in the pretreatment section can be of further application.The anaerobic,anoxic and aerobic technology developed in the 20th century are mainly used in the biochemical treatment section,which are mature and have been widely used.But the biochemical treatment technology has higher requirements for water quality,especially the wastewater carbon nitrogen ratio(C/N)and the concentration of organic carbon source determine to the final effect of biochemical treatment.Microorganis technology and the development of membrane bioreactor in the future will have great development and breakthrough,and anaerobic technology because of its high energy utilization has attracted the attention of many scholars,and the application of anaerobic technology is helpful to build the ideal type of modern wastewater treatment plants.Deep processing section mainly solves the problem of biochemical effluent substandard,and in the"zero emissions"process,there are higher requirements for the water quality of the membrane,so the depth of processing section is to degradate some organic matters more precisely and specifically,and advanced oxidation technology as a new processing technology is developing rapidly and is gradually adopted by more coking enterprises.The results show that the synergetic effect of the optimization coupling of several treatment technologies can further enhance the treatment effect and make the coking wastewater meet the discharge or reuse standards.With the increasingly strict environmental protection policy,factors such as the popularization of"zero discharge"of wastewater,the acceptable treatment cost of enterprises and the water quality characteristics of coking wastewater jointly determine that the coupling and combination of relatively mature deep treatment technologies such as advanced oxidation technology and membrane separation technology will be the key direction of future development.The development trend of coking wastewater treatment in the future is to improve the utilization rate of resources,improve treatment capacity and efficiency,and reduce energy consumption and operating cost.In the process of coking waste water treatment,membrane separation technology is widely used and at the same time,it can produce high concentrations of saline wastewater.The effective treatment of saline wastewater is related to the points and the purity of salt products,and if the organic pollutants in concentrated brine can not be effectively treated,the treatment cost of the follow-up section will be increased and even the hazardous waste of environmental pollution will be produced.Therefore,the effective treatment for high concentration brine is also the focus of the research community urgent problem.