Pseudomonas Sp.LZ-Q Continuously Degrades Phenanthrene In A Membrane Bioreactor Using Ceramics As Carriers And The Application Of Hybrid Membrane Bioreactor(HMBR)in Refinery Wastewater Treatment

Phenanthrene is one of the most recalcitrant components of crude oil contaminated wastewater.An efficient phenanthrene-degrading bacterium Pseudomonas sp.sixain named LZ-Q was isolated from oil-contaminated soil near the sewage outlet of a petrochemical company.P.sp.LZ-Q is capable of growing in Bushnell-Hass mineral salt medium containing 1 g/L phenanthrene.LZ-Q can use other polycyclic aromatic hydrocarbons as the sole carbon sources such as naphthalene,anthracene,pyrene,petrol and diesel.LZ-Q is able to degrade PAHs at broad ranges of salinities of 0.5-7.5%,PHs of 5.0-9.0 and temperatures of 10-42 ?.Therefore,LZ-Q could be a good candidate for remediation of oil contaminated wastewater.A membrane bioreactor(MBR)was applied to study the remediation ability of LZ-Q.Results show that LZ-Q is capable of biodegrading 20 mg/L phenanthrene with a removal rate of 90.68%within 6 hours in hyperhaline wastewater at pH 8.0.The degradation of phenanthrene fitted to the exponential function and followed a pseudo-first order reaction.The rate constants increased from 0.290h-1 to 0.372h-1 when using ceramics as carriers.MBRs with immobilized LZ-Q degraded 96%phenanthrene and 94%COD continuously for 60 days when HRT was 3h.The refinery wastewater from PetroChina Lanzhou Petrochemical Company consists of complex ingredients.High concentration of pollutants is toxic to organisms and is hard to be treated.Activated sludge plays an important role in refinery wastewater treatment,but this process is not effective.Membrane bioreactor(MBR)is a new type of wastewater treatment system which includes microbial communities,membrane,influent system,effluent system and aeration system.Applications of ultrafiltration membrane can help get pure water.In view of important role of biofilm in degradation of toxic refractory wastewater,the research uses a MBR coupling sctivated sludge to treat the refinery wastewater.The results indicated that the removal efficiency of COD and organic pollutants by MBR is much more efficient than by conventional activated sludge process.And MBR is efficient for solid-liquid separation.In short,this study is useful in improving the removal efficiency of refinery wastewater.