焦化废水处理过程中固相物质的形成及处置方法评价

Formation and treatment methods evaluation of solid⁃phase substances in coking wastewater treatment

焦化废水处理过程中产生的焦油、污泥和结晶杂盐等固相物质,既有资源属性,又有污染特性,但目前缺乏基于能源、经济及环境影响方面的评估.本研究阐述了3类固相物质的形成机制,建立了质量当量计算及处置方法评价模型.以宝武集团韶关钢铁股份有限公司焦化厂(二期)焦化废水处理工程的A/O/H/O(厌氧/好氧/水解/好氧)流化床工艺作为考察对象,利用工程运行参数和水质统计数据进行固相物质的产量推算,结果发现,焦油、物化污泥、生物污泥(含水率为80%)和工业杂盐的产率分别为0.186、5.80、4.24和1.97 kg·m^-3.通过处置方法评价模型明确了焦油焚烧、污泥热解、结晶杂盐分盐提纯后工业应用是最佳处置方案,在60 m^3·h^-1废水处理规模的固相物质处置过程中,每年约产生1177 MWh的能源,获得135.0万元的经济效益,排放627.0 t CO2,表明能源回收、经济效益和环境影响的协同存在.

A variety of solid⁃phase substances,including tar,sludge and salt,were produced during coking wastewater treatment process.These substances are pollutants,but also have the potential to be resources.At present,there is a lack of assessment on energy,economic and environmental aspects of solid⁃phase substances disposal technologies.In this study,the formation mechanism of three kinds of solid⁃phase substances was systematically proposed.A model for output calculation and treatment method evaluation was established.Taking the A/O/H/O(Anaerobic/Aerobic/Hydrolysis/Aerobic)fluidized bed process for coking wastewater treatment in Baowu Group Guangdong Shaoguan Iron&Steel Co.,Ltd.as the research object,the actual production of solid⁃phase substances was estimated by using the engineering operation parameters and water quality statistical data.The yields of tar,inorganic sludge,biological sludge(moisture content is 80%)and salts were 0.186,5.80,4.24 and 1.97 kg·m^-3,respectively.Based on the evaluation model,it was clear that tar incineration,sludge pyrolysis and salt purification and recovery were the best scheme for the disposal of solid⁃phase substances.In the disposal of solid⁃phase substances produced in a wastewater treatment plant with a treatment capacity of 60 m^3·h^-1,1177 MWh energy might be generated annually,with an economic benefit of 1.35 million yuan and carbon dioxide emissions of 627.0 tons,showing the co⁃occurrence of energy recovery,economic benefits and environmental impact.