焦化废水处理技术研究进展.doc

焦化废水处理技术研究进展
关键词:焦化废水、生化处理技术、化学处理技术、进展
Advancements in the Research on Coke Plant Wastewater Treatment
Wang Yeyao, Yuan Yanxiao, Tian Rensheng (Chinese Research Academy of Environmental Sciences, Beijing 100012)
Abstract: Wastewater from coke plants is a kind of anic ones with high concentration of ammonia pounds. In this paper advancements in coke plant wastewater treatment in recent years in China and overseas were systematically introduced. Bioaugmentation technique can greatly increase the treatment applicability and capability of the existing treatment equipment and is much suitable to wastewater treatment of the coke plants in China. Biological fluidized-bed technique, immobilized technique and ammonia removal by biological method are great improvements on traditional biological method and will find much wide applications in treatment of wastewater from coke plants. Compared with biological methods, chemical methods are simple in treatment process, high in reaction rate and removal efficiency. However, the investment and treatment cost of the latter are much higher than those of the former.
Key words: Coke plant wastewater, Biological treatment method, Chemical treatment method, Advancements
1 引言
焦化废水产生于炼焦、制气过程,废水排放量大、水质成份复杂,除含有氨、氰、硫氰根等无机污染物外,还含有酚、油类、萘、吡啶、喹啉、蒽等杂环及多环芳香族化合物(PAHs)。多环芳烃不但难以生物降解,通常还是致癌物质,因此焦化废水的大量排放,不但对环境造成严重污染,同时也直接危胁到人类的健康。
初期的焦化厂大多采用传统活性污泥法来处理焦化废水。但是,进入90年代后,随着人们环保意识的提高,我国逐渐增大了污染控制的力度,制定了更为严格的排放标准。96年颁布的《污水综合排放标准》(GB8978-1996)中不但增加了NH3-N指标(NH3-N<15mg/L ),而且CODcr的排放标准也更为严格(CODcr<150mg/L )。经传统活性污泥法处理后的焦化废水,特别是CODcr、NH3-N两项指标,已很难达到排放标准的要求。根据冶金部1997年的调查[1],90%以上的焦化厂处理后的CODcr、NH3-N 无法达标。为了提高CODcr及NH3-N的去除率,近年来人们从微生物、工艺流程及反应器几方面着手进行了大量的研究开发工作,这些工作主要集中于生化处理技术和化学处理技术的研究。
2 生物强化技术进展
生物强化技术,就是为了提高废水处理系统的处理能力,而向该系统中投加从自然界中筛选的优势菌种或通过基因组合技术产生的高效菌种,以去除某一种或某一类有害物质的方法。投入的菌种与底质之间的作用主要包括直接作用和共代谢作用[2]。
生物强化技术产生于20世纪70年代中期,由于它能在不扩充现有的水处理设施基础上,提高其水处理的范围和能力,因此近年来它在现代废水治理中的应用日益受到人们重视。针对目前我国焦化废水处理现状,将生物强化技术与普通生化工艺技术相结合无疑是一条比较实用的思路。
萘和吡啶是焦化废水中含量较高的典型难降解有机物。王