Selection and Study of High-yield Aerobic Strains of Treating the Closed Circulation Wastewater for

Efficient and reliable removal of cellulose,hemicellulose and lignin,that are the major organic pollutants in the wastewater from regenerated fiber,is critically important to prevent toxicity discharge.Low-and high-pH stresses sometimes occur in the effluent treatment systems due to the use of a large amount of acid and alkaline in the pulping process.Using flat separation method to select high-yield strains from bio-contact oxidation basin,seeing configuration of the strains and doing some physiological experiments,we found that the strains contain two kinds of main bacteria,Zoogloea sp.and Pseudomona sp.We also discovered the best growing time by spectrophotometer.The best growing time is at 0～32h,the logarithmic phase is about at 12～32 h,and the stable growth phase is about 32～60 h.Furthermore,we concluded that the disposal ability of high-yield strain is better than the ordinary one by doing parallel experiment.Through onhogonal test we also confirmed that the best growing temperature and pH value are 29℃ and 7.3 respectively,The COD removal rate is about 93% when the biomembrane is in good condition.