There exist problems in treating with semi-coking wastewater,such as difficult to treat,low removal rate of toxic pollutants in wastewater,and high treatment cost.It is necessary to develop treatment technologies with low cost,high stability and whole process zero emission.Oil substances in wastewater are removed by pretreatment,and the high-efficiency recovery of phenol-ammonia resource is realized through an enhanced phenol-removing and ammonia-evaporating treatment.The contents of COD and ammoniacal nitrogen in the treated effluent are less than 6 000 mg·L-1 and 50-100 mg·L-1,respectively.Through strengthening the biochemical treatment technology,the contents of COD,ammoniacal nitrogen and total cyanide in wastewater can reach below 120-150 mg·L-1,5 mg·L-1 and 0.2 mg·L-1,respectively.The content of COD in the treated effluent can stably be less than 40 mg·L-1 after using high-efficient ozone catalytic oxidation+MBR process.Enhanced desalination pretreatment,multi-grade gradient desalination and salt splitting treatment are integrated to realize a water yield of more than 90％from wastewater.About 10％-15％of acid solution and alkali solution is recovered after the concentrated water has been separated by nanofiltration,and the fresh water has been concentrated by bipolar membrane electrodialysis.High-quality ammonium sulfate(nitrogen content ≥21％)and sodium carbonate(a purity of about 97％)salts are obtained from concentrated nanofiltration water by short-range double decomposition and crystallization processes with the addition of ammonium bicarbonate.High-efficient recovery of valuable resources in wastewater achieves low-cost zero-discharge wastewater treatment.
关键词
兰炭废水/脱酚蒸氨预处理/生化及深度处理/膜脱盐及零排放
Key words
semi-coking wastewater/phenol removal and ammonia distillation pretreatment/biochemical and in-depth treatment/membrane desalination and zero emission
维普
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