Upflow anaerobic sludge bed reactor

Anaerobic treatment of CP-containing liquids has been reported in fixed-film reactors (Hend riksen et al., 1991) and upflow anaerobic sludge bed reactors (UASB) with anaerobic granular sludge, resulting in less-chlorinated phenols (Hendriksen etal., 1992 Mohn Kennedy, 1992 Woods etal., 1989) or mineralization (Wu et al., 1993). WithMCPs, the UASB treatment resulted in mineralization (Krumme Boyd, 1988). UASB had better PCP removal efficiency and stability than anaerobic fixed-film reactors (Hendriksen Ahring, 1993). Anaerobic remediation always requires the addition of an external electron donor. 

Diaz EE, Stams AJM, Amils R, Sanz JL (2006) Phenotypic properties and microbial diversity of methanogenic granules from a full-scale upflow anaerobic sludge bed reactor treating brewery wastewater. Appl Environ Microbiol 72 4942 949... 

Table 1 reports a wide spectrum of typologies of biofilm reactor upflow anaerobic sludge bed (UASB), fluidized bed, airlift, fixed bed with and without recycle, mechanically agitated vessel, rotating drum and rotating biological contactor. Each reactor is characterized by positive features and drawbacks. 

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. 

FBBR, fluidized-bed biofilm reactor CFSTR, completely mixed stirred tank reactor PUR, polyurethane immobilized cells UASB, upflow anaerobic sludge blanket reactor NS, not specified. 

If the fermentation contains sohds, then special precautions may be required to prevent sedimentation. One is a fluidized bed, where a dense slurry phase in the bottom of the tank is kept in gentle motion via upflow of the hquid or some induced gas/liquid momentum. The upflow anaerobic sludge bed (UASB) reactor is an example. In biogas installations, sohds may sediment and bacterial consortia may take several months to convert ah the material into methane and CO2. Because of the slow reaction rates, these instahations can be extremely large, up to 20 000 m. Other devices are packed-bed bioreactors, where ceUs are immobihzed on a solid support and the liquid is percolated or trickled down to supply nutrients and remove products. These can be found in specific antibiotic or food fermentations. Because of the lack of free fluid flow, the performance characteristics of such vessels are usually poor compared to suspensions. 

A third type of reactor system is the upflow anaerobic sludge blanket (UASB) reactor system. The UASB is a continuous-flow system that maintains a dense flocculated biomass that is granular. The waste-water passes through this dense sludge blanket to achieve desired treatment efficiency. The UASB, anaerobic filter, and fluidized-bed systems have all been applied successfully to treat a variety of industrial waste streams. Table 22-44 summarizes some of the applications of these treatment technologies. 

FIGURE 3.5 Processes used for FVW anaerobic treatment (A) continuously stirred tank reactor (CSTR) (B) tubular reactor (C) two-phase integrated anaerobic solid bed hydrolyser (SBH) and upflow anaerobic sludge blanket (UASB) (D) two-phase integrated anaerobic CSTR and fixed film reactor (FFR) and (E) two-phase integrated anaerobic sequencing batch reactor and FFR (Bouallagui ef ai, 2005). 

RBCs have been used widely used for wastewater treatment in the past and are well understood furthermore, abundant information is available in the literature on their operation and design [54], The upflow sludge bed reactor has also been apphed successfully in the past. However, experience is only widely available on its apphcation to anaerobic wastewater treatment [55,56]. One of the key requirements for apphcation of the AUSB for MTBE bioremediation, however, depends on the abihty of the MTBE bacteria to agglomerate and form dense granules [57]. The granules also need to attain a settling velocity in the range of 40-100 m/h to function properly inside a reactor [58]. 

Partial anaerobic digestion of aerobic sludge Acid orange 7 Upflow packed bed reactor Batch and continuous... 

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