Native biofilm cultured under controllable condition and used in mediated method for BOD measurement

In this article, we developed a native biofilm (NBF) bioreactor used for biochemical oxygen demand mediated method (BOD(Med)). There were two innovations differed from previous BOD(Med) assay. Firstly, the immobilization of microorganisms was adopted in BOD(Med). Secondly, the NBF was introduced for BOD measurement. The NBF bioreactor has been characterized by optical microscopy. A culture condition of NBF with 24h, 35°C and pH 7 was optimized. Furthermore, a measuring condition with 35°C, pH 7 and 55 mM ferricyanide in 1h incubation were optimized. Based on the optimized condition, the real wastewater samples from local sewage treatment plant had been measured. Performances of the NBFs proposed at different culture conditions were recorded for 110 d, and the results indicated that long-term storage stability was obtained. With the proposed method, an uncontaminated native microbial source solution can be obtained from a wastewater treatment plant. In this way, we can ensure that the microbial species of all in the NBF are same as that in the target to be measured.