Occurrence and removal of bis(2-ethylhexyl) phthalate in landfill leachate from Tianjin, China

Landfill leachates of two municipal solid waste (MSW) landfills in Tianjin were analysed for semivolatile organic priority pollutants. Bis(2-ethylhexyl) phthalate (DEHP) was the pollutant occurring at highest concentrations (up to 1024.5 mu g/L) and it Was present in all leachates; concentrations of other phthalates were usually below 10.8 mu g/L. DEHP is priority pollutant and endocrine disruptor. The efficiency of ozonation to remove DEHP was investigated and GC and UV were used to follow the intermediate and ultimate oxidation products produced in the ozonation of DEHP. Furthermore, the effects of pH and concentrations of DEHP on the ozonation of DEHP were also studied. Results revealed that excess 95% DEHP could be removed after being ozonated for 30min at O-3 dose of 16.76mg/L, and under the condition of high pH and low contration of DEHP, the removal rate of DEHP rose greatly. In the presence of scavenger of the hydroxyl free radical, the results showed that DEHP was degraded greatly by center dot OH generated from O-3 decomposition except for the direct ozonation.