Low Temperature Biofilm And Its Microbial Characteristics

Low temperature may cause low efficiency of sewage treatment in winter of cold area. As temperature drops to around 4℃, the mesophilic microorganisms would lose most ability to metabolize allogenic materials, thus the principal source to decompose organic wastes in sewage is psychrotrophs which only exist a little amount in natural condition. In past works, we have isolated some strains of psychrotroph and have applied them to low temperature sewage treatment. The results showed that the treatment efficiency could be improved significantly by adding psychrotrophs into the activated sludge, unfortunately the effect could not last for long period because the amount of psychrotroph would be decreased with the time being, this has made great consumption by adding psychrotroph repeatedly during the low-temperature sewage treatment.6 strains of psychrotrophs were isolated from activated sludge and identified as Achromobacter,Comamonas, Flavobacterium, Micrococcus, Bacillus and Pseudomonas .These psychrotrophs were combined together in order to treat low-temperature sewage efficiently . Cold-active enzymes are able to integrate with substrates at low temperature and catalyze the decomposition of organic compounds such as starch, protein, fibrin and fat. This study detected that the mixed psychrotrophs could hydrolyze starch, protein, fibrin and fat at 4℃, and the proper pH for catalysis was at neutral or a little alkaline condition.This study aims to improve the treatment of low-temperature sewage by fixing a certain amount of psychrotrophs in treatment system. Based on immobilized technology, psychrotrophs were immobilized on polyurethane foams, fragmentized aglites and cylinder active carbon, The results showed that the immobilization effects were decided by the density of pores and surface properties of carriers, the effect of immobilization was polyurethane foams﹥fragmentized aglites﹥cylinder active carbon. Adding amounts suggested is 1g/mL wet weight and the adding amount of carriers is 30% v/v of the volume of the experimental equipment.A combined low-temperature sewage bioreactor was design and developed, in order to apply and immobilize psychrotrophs, the biofilm unit was added on the...