Biofilms systems

A laboratory-scale anaerobic-anoxic-oxic fixed biofilm system treating coking wastewater... 

Heterotrophic bacterial processes dominate transformations in the sewer. There are similarities with the corresponding processes in biological treatment plants. It is, however, from the very beginning, important to emphasize that transformations of wastewater under sewer conditions and in activated sludge or biofilm systems proceed differently. The processes in sewers, treatment plants and receiving waters must be dealt with as an entity however, they must also be considered with their own specific characteristics. 

Arcangeli,J. P. Arvin, E. (1994). Biodegradation of BTEX compounds in a biofilm system under nitrate-reducing conditions. In Hydrocarbon Bioremediation, ed. R. E. Hinchee, B. C. Alleman, R. E. Hoeppel R. N. Miller, pp. 374—82. Boca Raton, FL Lewis Publishers. 

The use of an immobilized biofilm system is recommended, since the oxidation products often are only slowly biodegradable. Biomass, especially slow growing microorganisms, can efficiently be kept in the system using support material. This is especially important in continuously operated systems where the liquid phase is completely mixed. In such a system suspended biomass would be washed out when the hydraulic retention time is less than or equal to the population doubling time (i. e. the reciprocal of the specific growth rate Grady, 1985). In several studies materials such as polyurethane foams (Moerman et al., 1994 Jochimsen, 1997) or quartz sand particles (Stem etal., 1995 and 1996 Heinzle et al, 1995 Saupe and Wiesmann, 1998) have been used for immobilization. 

Bouwer, E. J. 1987. Theoretical investigation of particle deposition in biofilm systems. Water Research 21 1489—1498. 

Stoodley, P. deBeer, D. Lewandowski, Z. Liquid flow in biofilm systems. Appl. Environ. Microbiol. 1994, 60, 2711-2716. 

Pang, H. Zhang, T.C. (1998) Fabrication of redox potential microelectrodes for studies in vegetated soils or biofilm systems. Environ. Sci. Tech., 32, 3646-3652. 

The other biofilm systems such as the rotating biological contactor (RBC) and the aerobic upflow sludge bed reactor (AUSB) shown in Fig. 2 could possibly be applied for MTBE removal, and may posses some unique advantages. However, to our knowledge these reactors have never been appHed for MTBE removal so far. 

Some aspects of solvents in these organic-aqueous biofilm systems are studied. Solvents can occur in water systems emitted from surrounding organic materials. It was shown that solvents are important concerning microbial biocorrosion and biofouling processes, e.g., by swelling and hydrolysis of materials. ... 

Mathematical models of biofibns systems, which are layers of usually nonresistant microorganisms such as bacteria that attach to a surface, are critical to the medical and technical industries. Biofibn systems can cause infections in humans and corrosion and deterioration in technical systems. Biomathematics can be used to model biofilms systems to help understand and prevent their formation. 

Peak potentials and peak currents are useful diagnostic parameters to calculate in CV. In diffusing, reversible systems such as ferri/ferrocyanide, the straightforward relations in Table 5.2 can be used to extract estimates of formal potential, reversibility, and even diffusion coefficients. Understanding how to extract parameters from known electrochemical systems will help users identify trends in less well-known biofilm systems. 

After defined exposure times, the test substrata can be removed from the system and treated with biocide, or they remain in the system and are analysed at the end of the experiment to determine biocide efficacy. Other, new variations of the CSTR can be suitable as test systems. These include the Calgary Biofilm Device, which utilises shaken microtitre plates (Ceri et al., 1999 Ceri et al., 2001), the flow-cell (Stoodley et al., 2001), the artificial biofilm system (Harkonen et al., (1999), the colony biofihn system (Anderl et al., 2000) and the drip flow reactor (Xu et al., 1998). 

Chen, C. I., Griebe, T. and Characklis, W. G., 1993a. Biocide action of monochloramine on biofilm systems of Pseudomonas aeruginosa. Biofouling 7, 1-17. 

Nielsen PH, Lee W, Lewandowshi Z, Morison M, Characklis WG (1993) Corrosion of mild steel in an alternating oxic and anoxic biofilm system. Biofouling 7 267-284... 

Conceptual model for biofilm structure proposed at the 1988 Dahlem conference (Wilderer 1989). The model divides the biofilm system into specific compartments the substratum, the biofilm, the bulk liquid, and a possible headspace. The biofilm compartment was further subdivided into a base film and a surface film. Although the model recognized a certain degree of biofilm roughness, it was essentially a planar layered model... 

Chayen J, Bitensky L, Butcher R (1973) Practical histochemistry. Whey, New York ChenC-I, Griebe T, Charaddis WG (1993) Biodde action of monochloramine on biofilm systems of Pseudomonas aeruginosa. Biofouhng 7 1—17 Christensen BE, Characklis WG (1990) Physical and chemical properties of biofilms. In Charaddis WG, Marshall KC (eds) Biofilms. Whey, New York, pp 93-130... 

Zhang TC, Bishop PL (1996) Evaluation of microelectrode performance and applicability in biofilm systems. In 69th annual conference water environment federation, Dallas TX, pp 967-2007... 

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