Key Operating Parameters Of Anaerobic Fluidized Bed Reactor Treating Amino Acids Wastewater

Anaerobic Fluidized Bed (AFB) is a highly efficient combination of anaerobic fermentation technology with bio-film process. In an AFB reactor, biological particles, formed by microorganism adhesion to the carrier surface, is a complex microbial system. Practically, the operating conditions are easily changed, such as the concentration of substrate, temperature, hydraulic retention time (HRT), pH and organic loading rate (OLR) etc. Macroscopically, the removal efficiency of organic matters will be changed. However, microcosmically, the microbial structure, the biomass amount and their activity will be varied. Among them, the operating temperature and OLR are the most important and difficult to be controlled. In this study, the effect of OLR and operating temperature on removal efficiency of AFB with a kind of new carrier from waste tires treating the stimulated amino acids and bio-film properties was investigated. The main contents and results are summarized as follows:Firstly, the effect of OLR on performance characteristics of AFB was investigated. As OLR increased, COD removal had little change, the concentration of extracellular polymeric substances (EPS) decreased and the polysaccharides were the main components. With OLR of 15.0 kg/(m~3·d), COD removal, suspended sludge (SS) concentration, the contents of proteins and polysaccharides were about 93%, 5.13 g/L, 14.58 mg/gVSS and 102.57 mg/gVSS, respectively. In addition, the dehydrogenase activity and coenzyme F420 of SS were 3.55μgTF/gVSS and 0.45μmol/gVSS.Secondly, the effect of OLR on biofilm properties of AFB was studied. With OLR increased, the activity of microorganism and the ratio of proteins to polysaccharides also went up. However, EPS concentration was firstly decreased and then increased. SS of biofilm was 1.44g/L and VSS/SS ratio was 0.73. The proteins were its main components. The contents of proteins and polysaccharides were 42.53 mg/gMLVSS and 39.58 mg/gMLVSS. The dehydrogenase activity was 3.82μgTF/gVSS and the coenzyme F420 was 0.55μmol/gVSS when the OLR is 15.0 kg/(m~3·d).Thirdly, the effect of operating temperature on performance characteristics of AFB was studied. The results showed that, the optimal temperature of AFB reactor was 35℃. COD removal was about 90% and the biogas productivity was 0.33 (m~3/kgCOD). The ratio of proteins to polysaccharides was less. SS, VSS/SS ratio, the dehydrogenase activity and the coenzyme F420 were 7.33 g/L, 0.73, 3.46μgTF/gVSS and 0.32μmol/gVSS, respectively.Finally, the effect of operating temperature on biofilm characteristics in AFB was investigated. Under 35℃, the content of EPS was the least, the ratio of proteins to polysaccharides in EPS was the maximum. SS, the VSS/SS ratio, the dehydrogenase activity and the coenzyme F420 in biofilm were 0.90 g/L, 0.72, 3.81μgTF/gVSS, 0.36μmol/gVSS, respectively.