Study On The Enhancement Of Cooking Fume Purification By Biological Scrubber

Biological scrubber has many disadvantages such as low removal of fine particles（PM2.5and PM10）and volatile organic compounds（VOCs）from cooking fume and low degradation by biochemistry,based on these problems,a study on the technology to enhance the performance of the biological scrubber will be carried out.In this paper,the domesticated activated sludge was used as the washing solution,the effects of contact between gas and liquid（including airflow velocity,contact angle and distance）on the removal rate of PM2.5（VOCs）from cooking fumes and mass transfer rate of gas-liquid will be investigated,the relation function of between gas-liquid contact and mass transfer coefficient will be found in order to define the parameters that can improve the properties of biological scrubber;the effects of the adding nutrients（Nitrogen source,Nitrogen source and oxygen）into the scrubbing solution on the degradation rate of pollutants from cooking fumes,the relation between the species of superiority strains,nutrients proportion and bio-removal rate,the coefficient of degradation rate of pollutants from cooking fumes will be examined to determine the dominant strains and nutrients proportion which can improve their biochemical degradation properties.In the mean time,VOCs and metabolite that from biodegrading cooking fume in bioscrubbing solution were analyzed by GC-MS to determine treatment efficiency by different components.After the acclimation of activated sludge by 25d,The MLSS and MLVSS of activated sludge were stabilized at about 3.00 g2L^-1 and 1.80 g2L^-1,respectively.And with good settlement performance,SV and SVI returned to the normal level,which were about 40%and 130,respectively.The removal rate of the fine particles in the oil smoke was stable and the removal rate of PM2.5 and PM10 was about 70%.The degradation rate of H-1 in the first 3h was the fastest,and the degradation rate of 6h remained stable after 0.08 mg2L^-12h^-1.The results showed that the best gas-liquid contact velocity,distance and angle were 24.49 m2h^-1,20 cm and 0°,corresponding to the mass transfer coefficient were0.1962 h^-1,0.1704 h^-1,0.1530 h^-1,and cooking fumes removal rates were 85.51%,85.36%,84.50%.The nutrient elements and dissolved oxygen of activated sludge microbial purification cooking oil fume were optimized by orthogonal experiment method.the study found that the various factors on the degradation rate of impact factor from big to small in turn for dissolved oxygen,ammonium nitrate,potassium dihydrogen phosphate,adding starch,trace elements.The best degradation experiment group was A₂B₄C₂D₃E₄:adding starch solution 20mL,NH₄NO₃ 6mL,KH₂PO₄ 1mL,trace element(0.03 g2L^-1CuSO₄·5H₂O,0.1 g2L^-1 ZnSO₄·7H₂O,0.043 g2L^-1 MnSO₄2H₂O)2mL and control of dissolved oxygen concentration 7.1 mg2L^-1.and the best carbon nitrogen phosphorus ratio was 44:9:1.In the optimal culture conditions,the activated sludge microbial reactor in good degradability of oil fume pollutants,the degradation rate and degradation rate of maximum 24h,respectively 46.1%and 0.54 mg2L^-12h^-1,with the increase of the degradation time,carbon source and nitrogen source gradually reduced,the microbial quantity increases gradually,within 7 days of training in the process of increasing the carbon nitrogen ratio decreased first and then.Through the analysis of gas and liquid oil fume pollutants by GC/MS,it was found that most of the aldehydes,alcohols,alkanes and esters were absorbed completely.The degradation process of liquid smoke pollutants in the main components of chloro compounds（42.98%）,followed by acids（33.53%）,alcohol（15.98%）and hydrocarbons（7.5%）,third days of most of the material degradation completely only partially chlorinated compounds and hydrocarbons and residues,except for three to fifth days outside most of vinyl chloride has not detected.Through the high-throughput sequencing of activated sludge,activated sludge microbial diversity found in bacteria than fungi,bacteria in the genus level was Spartobacteria（14.6%）,Cellvibrio（14.5%）,Planctomicrobium（12.2%）,Microbacterium（9.9%）and Steroidobacter（4.5%）and Luteolibacter（3.8%）.The fungi were mainly Nectriaceae（14.2%）,Trichocomaceae（13.2%）,Trichoderma（10.4%）,Davidiellaceae（9.4%）,Yarrowia（5.7%）and Aspergillus（4.7%）.In the 5 day of degradation,the bacteria which can degrade the oil fume pollutants were Microbacterium,Steroidobacter and Luteolibacter of the genus Bacillus.The fungi belonged to Aspergillus,Trichoderma and Yarrowia.