Anaerobic reactor, continuous flow stirred

Many wastewater flows in industry can not be treated by standard aerobic or anaerobic treatment methods due to the presence of relatively low concentration of toxic pollutants. Ozone can be used as a pretreatment step for the selective oxidation of these toxic pollutants. Due to the high costs of ozone it is important to minimise the loss of ozone due to reaction of ozone with non-toxic easily biodegradable compounds, ozone decay and discharge of ozone with the effluent from the ozone reactor. By means of a mathematical model, set up for a plug flow reactor and a continuos flow stirred tank reactor, it is possible to calculate more quantitatively the efficiency of the ozone use, independent of reaction kinetics, mass transfer rates of ozone and reactor type. The model predicts that the oxidation process is most efficiently realised by application of a plug flow reactor instead of a continuous flow stirred tank reactor. 

List of abbreviations BOD, biological oxygen demand CA, chloroanisol CCA, copper-chromate-arsenate CP, chlorophenol 2,4-D, dichlorophenoxyacetic acid DCP, dichlorophenol CFSTR, continuous-flow stirred tank reactor FBBR, fluidized-bed biofilm reactor MCP, monochlorophenol NAPL, non-aqueous phase liquid PAH, polycyclic aromatic hydrocarbon PCPP, polychlorinated phenoxyphenol PCDF, polychlorinated dibenzofuran PCDD, polychlorinated dibenzodioxin PCR, polymerase chain reaction PCP, pentachlorophenol PCA, pentachloroanisole TeCP, tetrachlorophenol TeCA, tetrachloroanisole TCC, trichlorocatechol TCP, trichlorophenol TOC, total organic carbon 2,4,5-T, trichlorophenoxyacetic acid UASB, upflow anaerobic sludge blanket reactor VSS, volatile suspended solids. 

Kim, S. H., Han, S. K., and Shin, H. S. 2005. Performance comparison of a continuous-flow stirred-tank reactor and an anaerobic sequencing batch reactor for fermentative hydrogen production depending on substrate concentration. Water Sci. Technol., 52 (10-11), 23-29. 

Reactions occur in a continuous flow stirred anaerobic reactor without recycle and operating under steady-state conditions. 

With the above constraints, a continuous flow stirred anaerobic reactor as illustrated in Figure 1 will be considered to operate under steady-state conditions dQ/dt = drii°/dt = dni /dt = dn /dt = 0), where Q is the flow rate in liters per day and nf, and represent the number of moles of component Ai per unit time entering the reactor, and leaving the reactor in the gas and aqueous phases, respectively. The system contains m components A (f = 1, 2,. m) interconnected by means of n biologically mediated reactions Bfc (fc = 1, 2,. n). There are more components than reactions so that n is less than m. Sf is the concentration of component A in the reactor in moles per hter. The reactor contains flnite concentrations of all components. 

Figure 1. Schematic of continuous flow stirred anaerobic reactor...

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