Emission Research Of CVMS And Concentration Level In Municipal Wastewater And Air

Cyclic volatile methylsiloxanes(cVMS)have been widely used in cosmetic&personal care products(C&PCPSs)、electronic products、furniture、biological products due to its special physical and chemical properties,the application into C&PCPSs is important,approximately 10%of cVMS will enter into municipal wastewater treatment plant when C&PCPSs was used by the general public.cVMS in wastewater will volatilize into air,sorbed to sludge,enter into recieving water with effluent finally;cVMS volatilized into the air will enter into different kind of environment matrixs by dry and wet deposition,it will have some threat to aquatic and land environment.Therefore,the research of cVMS behavior in wastewater and air is significant important,at present,domestic research about cVMS behavior in wastewatwer treatment plant is still scarce,how treatment process and open or closed style influence cVMS air concentration and emission is still not clear.We selected typical cVMS(D3-D6)as target compound,simultaneously monitored cVMS concentration in influent.effluent.air around the aeration tank in eight wastewater treatment plant in Dalian,analysed how cVMS concentration vary with cVMS loading,temperature,wind direction,wind speed et al,calculated cVMS emission rate with Gaussian dispersion model and Air pollution concentration in single room model.It turns out that,D3-D6 influent average concentration of W1-W8 is 190.64±61.92,396.61±379.61,2073.31±1714.44,857.90±788.00 ng/L,respectively,D5 concentration is 11、5、2.4 times of D3、D4、D6;cVMS concentration level in Dalian is lower than foreign studies for 1-2 order of magnitudes.cVMS concentration in influent is D5>D6>D4>D3,this is the same with cVMS concentration in C&PCPs at Shanghai and Canada.Most of effluent were not detected cVMS.D4-D6 air average concentration is 11645.58±1828.36,3540.43±5771.10,586.701±634.23ng/m3,respectively.D5 is the dominant compound,1%of ∑cVMS.cVMS air concentration in WWTP is apparently higher than field site for 1-3 order of magnitudes,it suggested that WWTP is an important emission source of cVMS.EcVMS emission rate of eight WWTP is 1343.12 kg/yr,outdoor ∑c VMS emission rate is 1343kg/yr,indoor EcVMS emission rate is 123 g/yr,indoor emission rate is significantly lower than outdoor,it suggested that stamped aeration tank can significantly decrease the emission of cVMS.