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The purpose of this research is to eval ate the removing
efficiency 、degradation mechanism and cometabolism degradation
of benzene、toluene and xylene by various types
of biofilter system.The pig waste compost and neutral peat
seeding with activatedsludge were used as the materials of
biofilter.Pure benzene、toluene and xylene(BTX)were used either
individual or mixed to pass through the various types of
biofilter to estimate the removing efficience of BTX.The
efficiency of inoculting BTX degradingbacteria or mixed with
acclimated biofilter to the removal of BTX were also
investigated.For the individual gas removing experiments,it has
shown that the removing efficiency of pig waste compost
biofilter was better than the peat biofilter while the inlet
concentrationof benzene and toluene was limited at and ppm,
respectively.In these experiments,themaximum removing capacity
of benzene、toluene and xylene in pig waste compost
biofilterwere found at 827、1820 and 2076 mg BTX/Kg-media/day
and the CO2 conversion rate were foundat 80%、30% and
70%,respectively.Consequenly,the biodegradation rate by pig
compost biofilter were followed in the order of toluene>xylene>
benzene.For mixed with benzene and toluene or toluene and xylene
removing experiments,the pig wastecompost seeding with activated
suldge or mixed with the acclimated compost were used as
thematerial of biofilter.During the operation period of time,the
mixed with acclimated compostbiofilter has shown better removing
efficiency than the seeding with activated sludgecompost
biofilter.Additionally,when the inlet concentration of benzene
was higher than tolueneor over the loading capacity of the
biofilter,the degradation rate of toluene will be inhibited.
However,while the presence of toluene in the biofilter which
indicated that apparentlyimprove the degration rate of xylene.
For mixed benzene、toluene and xylene removing experiments,the
pig waste compost 、and compost seeding with activated sludge、
mixed with acclimated compost、seeding with the BTX
degradingbacteria and reused compost were used as the materials
of biofilter.During the 100 days operationperiod time,the mixed
with acclimated compost biofilter was the best removing
efficiencyamong the others,and the maximum removing capacity
were found at 2390 mg BTX/Kg-media/day.Futhermore,for the
compost biofilter which without seeding had not apparent
biological reactionduring the operation period of time,but the
seeding with activated sludge、or seeding withBTX degrading
bacteria biofilter and reused compost biofilter have shown the
semiliar removingefficiency:the removing efficiency could arrive
to 70%-80% under the loading of 2390 mg BTX/Kg-media/day.In
addition,the presence of toluene will improve the degradation
rate ofxylene when inlet concentration of benzene was not over
the critical loading capacity.However,when inlet concentration
of benzene was over the critical loading capacity,benzenehad
apparent inhibition effect on the degradation of xylene than the
addition effect oftoluene had on xylene degradation.
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