燃机电厂循环水排污水处理工艺研究

Research on Treatment Process of Sewage Discharged from Circulating Water in Gas Turbine Power Plants

[目的]在国家水资源重复利用的节水政策引导下,越来越多的电厂采用中水作为循环水补充水,增加了电厂循环水排污水的处理难度,文章针对循环水排污水中COD、总氮、总磷等污染物超标问题,提出了生物处理法结合高级氧化法的处理工艺。[方法]以广东某燃机电厂为例,介绍了以中水为补充水的循环水排污水的水质特征,整理了近年来不同新建燃机电厂循环水排污水排放标准,针对超标污染物的种类和特性,提出了“反硝化池+二沉池+高级氧化+曝气生物滤池+砂滤”工艺,并深入分析了各级处理工艺的原理、功能及优缺点。[结果]反硝化池在缺氧条件下,进行反硝化反应可实现总氮的脱除,芬顿和臭氧高级氧化可分解和氧化废水中难生物降解的COD,曝气生物滤池作为二级生化池,不仅有生物吸附和氧化作用,还有固液分离的过滤作用,可将前端工艺中剩余的COD和过量的外加碳源一起处理,实现COD的达标,通过混凝澄清和过滤可去除总磷和悬浮物。该工艺是一种高效稳定的循环水排污水深度处理工艺。[结论]为实现电厂的循环水排污水稳定达标排放处理工艺提供参考。

[Introduction]Under the guidance of the national water-saving policy for water resource reuse,more and more power plants are using reclaimed water as make-up water for circulating water,which increases the difficulty of treating sewage discharged from circulating water in power plants.This paper proposes a treatment process that combines biological treatment with advanced oxidation to address the issue relatd to excessive COD,total nitrogen,and total phosphorus pollutants in sewage discharged from circulating water.[Method]Taking a gas turbine power plant in Guangdong province as an example,this paper described the water quality characteristics of sewage discharged from circulating water using reclaimed water as make-up water,and sorted out the discharge standards for sewage discharged from circulating water in different newly-built gas turbine power plants in recent years.Based on the types and characteristics of pollutants exceeding the standard,a"denitrification tank+secondary sedimentation tank+advanced oxidation+aerated biological filter+sand filter"process was proposed,and a thorough analysis of the principles,functions,advantages and disadvantages of various treatment processes was conducted.[Result]Under anaerobic conditions in the denitrification tank,denitrification reaction can remove the total nitrogen.Fenton and ozone advanced oxidation can decompose and oxidize COD that is difficult to biodegrade in wastewater.As a secondary biochemical tank,the aerated biological filter not only has biological adsorption and oxidation effects but also has solidliquid separation filtration effects.It can treat the remaining COD in the front-end process together with excess external carbon sources,achieving COD compliance.Total phosphorus and suspended solids can be removed through coagulation,clarification and filtration.This process is an efficient and stable in-depth treatment process for sewage discharged from circulating water.[Conclusion]It can provide reference for the stable and standard discharge treatment process of sewage discharged from circulating water in power plants.