Occurrence And Fate Of Phosphorus Flame Retardants In Sewage Treatment System In Guangzhou

Phosphorous flame retardants?PFRs?,as flame retardants,are widely used in chemical industry,electronic/electrical appliances,building materials and textile products.As the application has been growing steadily,PFRs will enter sewage treatment system through domestic sewage,industrial wastewater,the runoff and dry and wet deposition from the atmosphere.There are fewer researchs on the removal effeciency of PFRs and it is necessary to study the occurrence and fate of PFRs in sewage treatment system.This study focused on the occurrence,distribution and fate of nine PFRs in wastewater and sludge in the wastewater treatment plant and the municipal landfill leachate treatment system in Guangzhou.Solid-phase extraction and GC-MS were used in analysis.?1?For the wastewater treatment plant,the occurrence of the PFRs in each process was detected.The results showed that seven of nine targets were detected with TCPP and TEP as the primary components.Through the treatment system,the?₇PFRs was reduced from1076.15-3349.98 ng/L to 804.79-2828.93 ng/L.The PFRs pollution of sewage in this study was at the moderate level compared with other countries.Only 28%of the PFRs-including 39%of the alkyl PFRs and 15%of the chlorinated PFRs-were removed from the wastewater.The range of PFRs'concentrations in dewatered sludge was 122.37-893.52 ng/g dw,of which TCPP was the significant constitute?58.28%?,followed by TEHP?18.36%?.The PFRs in sewage were only TCPP for low ecological risk.?2?It was found that there were three main fates of the PFRs flowing into sewage treatment plants,with outflow of effluent,adsorption and biodegradation or volatilization.Most of the PFRs were flowed out with the effluent.?3?For the landfill leachate,only five of nine targets were detected with TCPP and TCEP,both chlorinated PFRs,as the primary components.Through the treatment system,the?₅PFRs was reduced from 4807.02 ng/L to 103.91 ng/L,with close to 98%was removed from the wastewater.TCPP dominated through the treatment process and accounted for over 80%and50%of?PFRs at the influent and the effluent,respectively.TCPP was most efficiently removed?99%?followed by TCEP?97%?and TPP?89%?.?4?Microfiltration/reverse osmosis was critical for the removal of PFRs while A²/O and MBR played a minor role towards their removal.Chlorinated PFRs and TEHP were difficult to be removed by biodegradation due to the steric effects.This study revealed the occurrence,distribution and fate of PFRs in municipal sewage and landfill leachate,which will provide a reference for the efficient removal of PFRs.