Study On Treatment To The Coal-Gasification Wastewater With Extraction, Fenton Oxidization And Anammox

High toxicity is the major hazard issues in coal-gasification wastewater.There are many toxic substances in this wastewater such as phenol, cyanogen and coal tar.The COD, phenol, ammonia and cyanide were usually about 12000-20000mg/L, 2300-5000mg/L,500-800mg/Land80-150mg/L.Currently, most coal-gasification wastewater treatment systems are based on the primary treatment or secondary treatment process, and the treated wastewater discharge standards can not be done. Based on the constituents of coal-gasification wastewater, in this experiment we combined the extraction, fenton oxidization and anammox technologies to treat coal-gasification wastewater.By assayed the quality of coal-gasification wastewater after each stage, to find the best operating condition in this craft.The experiment was displayed as follows:The extraction experiment showed that the concentration of COD, phenol and ammonia in coal-gasification wastewater can be decreased to 700mg/L,31mg/L and 540mg/L from 14000mg/L,3100mg/L and 650mg/L, while pH was 3-3.5, concentration, temperature and time of the extraction were 70%,30℃and 10 min separately, with an oil-water ratio of 3:1. Extractants has not losen efficacy after reused 100 times.2. Fenton oxidation was used to deal with the extracted water.In this treatment, the concentrations of COD and ammonia can be decreased to 210mg/L and 513mg/L, the phenol was not detected while pH was 3, the value of H2O2 was 1000mg/L, the value of Fe2SO4 was 100mg/L, the reaction time was 10min.Those conditions were confirmed by orthogonal experiment.3. After 145 days domestication in, the mature ANAMMOX bacteria has been found in synthetic coal-gasification wastewater in UASB process. The coal-gasification wastewater was stably treated by mature ANAMMOX bacteria in 40 days.The concentrations of COD and ammonia were decreased to 40mg/L from 210mg/L and 300mg/L from 513mg/L.The anammox reaction was under the condition that temperature was 30℃,pH value was 7.8,HRT was 24 h.The study results indicated that coal-gasification wastewater through the treated by the extraction, fenton oxidization and anammox technologies.The outflow of COD and phenol can meet nation discharge,the concentration of ammonia has also been markedly decreased and all the medicaments used to treat one ton coal-gasification wastewater will be cost 12.5RMB.