Effluent fermenters

Figure 12.4 Simplified schematic of a large (10 000 1) scale batch effluent heat sterilisation plant. 1981 design. All stainless steel construction pressure vessels, with full automatic control. F, PRV, D, FD, S-sources of effluent (fermenter, pressure relief, drains, floor drains, sinks) VF, vent filter FL, fill line VB, vacuum break VL, vent line.

Elevated cell concentrations can be achieved by separating cells from the effluent and recycling them to the fermenter. This has been... 

Initially fermentation broth has to be characterised on the viscosity of the fluid. If the presence of the biomass or cells causes trouble, they have to be removed. Tire product is stored inside the cells, the cells must be ruptured and the product must be freed. Intracellular protein can easily be precipitated, settled or filtered. In fact the product in diluted broth may not be economical enough for efficient recovery. Enrichment of the product from the bioreactor effluents for increasing product concentration may reduce the cost of product recovery. There are several economical methods for pure product recovery, such as crystallisation of the product from the concentrated broth or liquid phase. Even small amounts of cellular proteins can be lyophilised or dried from crude solution of biological products such as hormone or enzymes.2,3... 

Fig. 10.5. Continuous stirred tank fermenter, experimental setup with instrumentations and controllers, effluent.

The most widespread biological application of three-phase fluidization at a commercial scale is in wastewater treatment. Several large scale applications exist for fermentation processes, as well, and, recently, applications in cell culture have been developed. Each of these areas have particular features that make three-phase fluidization particularly well-suited for them Wastewater Treatment. As can be seen in Tables 14a to 14d, numerous examples of the application of three-phase fluidization to waste-water treatment exist. Laboratory studies in the 1970 s were followed by large scale commercial units in the early 1980 s, with aerobic applications preceding anaerobic systems (Heijnen et al., 1989). The technique is well accepted as a viable tool for wastewater treatment for municipal sewage, food process waste streams, and other industrial effluents. Though pure cultures known to degrade a particular waste component are occasionally used (Sreekrishnan et al., 1991 Austermann-Haun et al., 1994 Lazarova et al., 1994), most applications use a mixed culture enriched from a similar waste stream or treatment facility or no inoculation at all (Sanz and Fdez-Polanco, 1990). 

Distillers Spent Grains. Distillers spent grain is the solid residue left after the grain has been fermented to make spirits, typically whisky. This residue is the unfermentable parts of the grain and is high in fibre. Traditionally, the only outlet for this material was as cattle food or as an effluent. In addition to the fibre, protein, fat and the insoluble vitamins and minerals are present. 

BIOKOP A process for treating liquid effluents containing wastes from organic chemical manufacture. It combines aerobic fermentation, in special reactors known as BIOHOCH reactors, with treatment by powdered activated carbon. Developed originally for treating the effluent from the Griesheim works of Hoechst, it was engineered by Uhde and is now offered by that company. See also PACT. 

Ensio-Fenox A process for removing chlorinated phenols from pulp-bleaching effluents. It combines anaerobic and aerobic fermentation processes. 

When a pilot-scale fermenter is run in continuous mode with a fresh feed flowrate of 65 1/h, the effluent from the fermenter contains 12 mg/1 of the original substrate. The same fermenter is then connected to a settler-thickener which has the ability to concentrate the biomass in the effluent from the tank by a factor of 3.2, and from this a recycle stream of concentrated biomass is set up. The flowrate of this stream is 40 1/h and the fresh feed flowrate is at the same time increased to 100 1/h. Assuming that the microbial system follows Monod kinetics, calculate the concentration of the final clarified liquid effluent from the system. /x, = 0.15 h-1 and Ks = 95 mg/1. 

When a continuous culture is fed with substrate of concentration 1.00 g/1, the critical dilution rate for washout is 0.2857 h-1. This changes to 0.0983 h-1 if the same organism is used but the feed concentration is 3.00 g/1. Calculate the effluent substrate concentration when, in each case, the fermenter is operated at its maximum productivity. 

Two continuous stirred-tank fermenters are arranged in series such that the effluent of one forms the feed stream of the other. The first fermenter has a working volume of 100 1 and the other has a working volume of 50 1. The volumetric flowrate through the fermenters is 18 h-1 and the substrate concentration in the fresh feed is 5 g/1. If the microbial growth follows Monod kinetics with //, = 0.25 h-1, Ks = 0.12 g/1, and the yield coefficient is 0.42, calculate the substrate and biomass concentrations in the effluent from the second vessel. What would happen if the flow were from the 50 1 fermenter to the 100 1 fermenter ... 

A primary sedimentation tank has been designed for the pretreatment of 0.312 MOD of fermentation waste generated from the pharmaceutical industry. The raw waste SS concentration is 1660 mg/L. At a detention time of 2 hours the effluent SS concentration is reduced to 260 mg/L. Determine (i) the SS removal efficiency of the sedimentation tank and (ii) the quantity of sludge generated per day. Assume the specific gravity of sludge (5si) is 1.03, which contains 6% solids. 

Ko3Tincu, I. Yalcin, F. Ozturk, I. Color removal of high strength paper and fermentation industry effluents with membrane technology. Water Sci. Technol. 1999, 40 (11-12), 241-248. 

The situation with regard to ethanol is much clearer there is long industrial experience in the manufacture of ethanol from wood, by fermentation of the sugars in the waste effluents of pulp mills, or of the sugars made by wood hydrolysis ( ). In the years following World War II, wood hydrolysis plants have been unable to compete economically with petroleum-based ethanol synthesis, mainly by hydration of ethylene, and they have been shut down in most countries. However, in the Soviet Union, we understand, there are still about 30 wood hydrolysis plants in operation (10). Many of these are used for fodder yeast production (11) but the wood sugars are also available for ethanol production. 

Real Madeira wine is made only on the island of Madeira, and it is made by fermentation in ten 50-gallon casks with fresh juice continuously poured into the first, and the effluent passing successively into each cask and the product from the tenth bottled. 

Solid-state fermentation Less effluent generation Heat and mass-transfer limitations... 

Environmental process analysis requires the characterization of chemical process and waste streams in order to evaluate their environmental abuse potential and treatability characteristics. An integral part of this analysis, as well as environmental fate determinations, is the isolation of organic compounds and metabolic products from very complex matrices such as waste water effluents, process streams, biological reactors, and fermentation broths. Generally, the organics involved are fairly polar, water-soluble compounds that must be ex-... 

It is frequently desirable, particularly in the field of waste-water treatment, to operate a continuous fermenter at high dilution rates. With a simple stirred-tank this has two effects—one is that the substrate concentration in the effluent will rise, and the other is that such a system in practice tends to be unstable. One solution to this problem is to use a fermenter with a larger working volume, but an alternative strategy is to devise a method to retain the biomass in the fermenter whilst allowing the spent feed to pass out. There are several methods by which this may be achieved (see Fig. 5.60), and the net effect is the same in each case, but the analysis might... 

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