Preparation And Characterization Of Biofilm In Biochemical Oxygen Demand Detector

The biochemical oxygen demand (BOD) is the most basic indicators of water pallution for the enviromental monitoring, now the standard method for determination the biochemical oxygen demand(BOD) is called BOD5 for short, BOD is conventionally determined by taking a sample of water, aerating it well, placing it in a sealed bottle, incubating for a standard period of time at 20±1?C in the dark, and determining the oxygen consumption in the water at the end of incubation ,which is called BOD5 for short.But there are some shortcomings for this method, such as time-consuming, labor-intensive, poor reproducibility and so on, a fast estimation of BOD is required to circumvent the disadvantages of the conventional test. The test time of microbial sensors is 20-30min, the test results printed directly, this method is convenient and to achieve online monitoring.This paper introduced the research status and development of microbial sensor for BOD determination .It also analies the determination mechanism of BOD microbial biosensors (BODS) as well as the advantages and disadvantages of BODs during the application to watery detecting. Based on that the study focused on immobilization and microorganisms selecting.The recent researches on microorganism-immobilized technology for wastewater treatment were reviewed. And classification of microorganism immobilization was introduced and the capabilities of diferent immobilized microorganism technology were compared. Three different kinds of immobilized carrier were applied in the after study, for its stability and keeping the microorganism alive for a long time. The incubation temperature fot the microbe was 25℃,30℃,32℃,35℃,37℃, the proportion of bacteria and sensitive material selected two different ratio, and the compared the capabilities of different immobilized microorganism.Isolation three kinds of bacteria from water samples , separately used as the sensitive material for the BOD sensor(BODs) after being immobilized by immobilized carrier. The results showed that the BOD values were reproducible within 6.3% . And the response time of the BOD sensor was only 8 min. furthermore, BODs could be kept stable for up to 10 days without significant loss in their activity.Germ No.3 ,which has the best degradability to organic ,identification the bacterria using the BIOLOG automated microbial analysis system ,analysis the utilization on the carbon source ,thu research their metabolia characteristics. The strain was Aeromonas hydrophila.