Floes bacterial

Depending upon the physical properties of a surfactant (component), removal from the mixed liquor is further possible through precipitation of insoluble salts and adsorption onto solids or bacterial floes, which, in turn, are subsequently withdrawn with the excess sludge [53]. In particular, intact or partly degraded low water-soluble surfactants are eliminated by this route. 

Low power ultrasound offers the possibility of enhancing the effects of chlorine. The results of a study of the combined effect of low power ultrasound and chlorination on the bacterial population of raw stream water are shown (Tab. 4.2). Neither chlorination alone nor sonication alone was able to completely destroy the bacteria present. When sonication is combined with chlorination however the biocidal action is significantly improved [10]. The effect can be ascribed partly to the break-up and dispersion of bacterial clumps and floes which render the individual bacteria more susceptible to chemical attack. In addition cavitation induced damage to bacterial cell walls will allow easier penetration of the biocide. 

Van Omman Kloeke, F., and G. G. Geesey. 1999. Localization and identification of populations of phosphatase-active bacterial cells associated with activated sludge floes. Microbial Ecology 38 201-214. 

The UASB type of digester consists of a bottom layer of packed sludge, a sludge blanket, and an upper liquid layer. Wastewater flows upward through a sludge bed that is covered by a floating blanket of active bacterial floes. Settler screens separate the sludge floes from the treated water, and gas is... 

Zhang B, Yamamoto K, Ohgaki S, and Kamiko N. Floe size distribution and bacterial activities in membrane separation activated sludge processes for small-scale wastewater treatment/reclamation. Water Sci Technol. 1997 35 37 14. 

B. Zhang, K. Yamamoto, S. Ohgaki, and N. Kainiko, Floe Size Distribution and Bacterial Activities in Membrane Separation Activated Sludge Processes for Small-scale Waste-water Treatment/Reclamation, Water Science and Technology, 35(6), 37-44 (1997). 

Treated water (biological treatment) 5-100 mg/L Homogeneous solids (bacterial floes) Turbidimetry (nephelometry) +/-... 

The reason for this good performance of the sludge could be attributed to the ramification of the floe surface due to the specific protozoa, whereas the poor performance of the swimming type especially in terms of the bacterial removal in settling might be ascribed to a less possibility of entrapping the bacteria due to the free swimming... 

The fractal nature of bacterial aggregates (floes) has implications for transport processes, including movement of dissolved respiratory gases to and from the outside of the aggregate, and for movement of dissolved nutrient sources and metabolic products. Several methods have been employed to estimate fractal dimensions of floes in three dimensions. One approach is to measure light scattering of suspended floes [17,18]. The two-slopes method calculates fractal dimensions A from the slope of the cumulative size distribution for maximum length / and the slope of the cumulative solid volume F [17] ... 

Confocal optical microscopy can be used to take a sequence of randomly chosen images through a bacterial floe. Methodologies for calculation of three-dimensional fractal dimensions have been described for this approach [18-20]. One method determines the fractal dimension of each section 7)f using a two-point correlation function C(r) [20] ... 

Increased SS in settled water relatively proportional to salinity have often been attributed to saline water. In fact the deterioration of SS, which is common in the petrochemical and pharmaceutical industries, may have several causes related to poor quality bacterial floe ... 

Figure 6.6 Energy Flow Through the Activated Sludge Process. The ecosystem Is less complex than that of the filter bed (Figure 6.4). There are fewer trophic levels and the protozoa play only a minor role in purification. The bulk of the organic matter of the settled sewage is converted into bacterial biomass which is aggregated into polysaccharide based floes, removed by sedimentation, I.e. most of the available energy does not pass along the food chain, but is removed and dumped.

Additional applications of DOTM include observing deposition and critical fluxes for yeast, algae and bacterial cells [10, 15-17], and particle deposition patterns that occur when spacers are used in the membrane channels [18]. Spacers were shown to increase the critical flux by up to two times [19]. Observations of the deposition and removal of submicron bacteria required the use of fluorescence. Removal of the bacterial cake when the flux was reduced below the critical value was observed to occur in floes [16]. In a recent application of DOTM, Zhang, Fane and Law [20] showed that the presence of larger particles increased the critical flux of smaller particles in a mixture and that only the smaller particles selectively deposited from a mixture when the imposed permeate flux was above this critical flux. This finding is consistent with the earlier observation of Li et al. ]10] that the smaller particles are preferentially deposited from a feed distribution of particle sizes. 

Wastewater treatment 10 to 10 Mixed bacterial and fungal communities, biofiims, aggregates, and floes Lemmers and Griebe (1995)... 

Wuertz, S. Muller, E. Spaeth, R. Pfleiderer, P Flemming, H. C. Detection of heavy metals in bacterial biofilms and microbial floes with the fluorescent complexing agent Newport Green. J. Ind. Microbiol. Biotechnol. 2000, 24, 116-123. 

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