Sludge fermentation

Figure 9.12 Alarge-scale sludge fermenter for the biogas production and sludge treatment in a public sewage treatment plant. The scaffolding illustrates the size of the fermenter, which is about 30 m high. (Source Fischer fixing systems, Germany)...

A penicillin-insensitive, cell wall-less mycoplasma-like methanogen has been isolated from a sewage sludge fermenter and named Methanoplasma elizabethii 5y. However, no pure culture has been deposited in a cultiue collection, and no further data on this organism are so far available. 

Boil yeast nutrient and gypsum in IV2 gallons wato , add honey and simmer for about 15 minutes, skimmingoff any yellow scum thatforms.Tum off heatand add blueberries. Steep for about 20-30 minutes. Pour 3V gaUons cold water in fermenter. Add hot must. Let cool, and then pitch rehydrated yeast. Rack off to a secondary fermenter after 1-2 weeks, leaving behind settled finit sludge. Ferment another 8 weeks in secondary. Bottle and age 10-18 months. 

Sludge stabilization is a process of destruction of the microbial, easily available organic component. In practice it takes place most frequently via the sludge fermentation under aerobic or anaerobic conditions. 

Mengmeng, C., Hong, C., Qingliang, Z., Shirley, S. N., Jie, R. Optimal production of polyhydroxyalkanoates (PHA) in activated sludge fed by volatile fatty acids (VFAs) generated from alkaline excess sludge fermentation. Bioresour Technol 2009,100,1399-1405. 

A pilot plant ia India has been estabUshed to extract fiber, pulp, and juice from the leaves of sisal plants. The fiber is sold direcdy or used to manufacture rope, the cmshed pulp is used ia paper processiag, and the juice is an excellent source of hecogenin. During a three- to five-day fermentation of the juice, partial enzymatic hydrolysis causes hecogenin to precipitate as the hemisaponin ia the form of a fine sludge. This sediment is hydrolyzed with aqueous hydrochloric acid, neutralized, and filtered. This filter cake is washed with water and extracted with alcohol. The yield of hecogenin varies between 0.05 and 0.1% by the weight of the leaf (126). 

Sludge Stabilization. Organic sludges need to be stabilized before ultimate disposal except in the case of incineration. This is usually achieved by either aerobic or anaerobic digestion. In aerobic digestion, the degradable volatile soHds are Hquefted and oxidized to CO2 and H2O. In anaerobic digestion the soHds are Hquefted and fermented to CH and CO2. 

Treatment of the Wort. The hot wort produced in the brewhouse cannot be transferred directly to the fermenting room. If natural hops are used they must be separated by a hop strainer as shown in Figure 8. During boiling, protein—tannin complexes are precipitated in the form of warm sludge. 

Biochemical processes, such as fermentation, oxidation of sludges, production of proteins, biochemical oxidations, and so on... 

Dispersing a gas m a liquid as fine bubbles (e.g., oxygen from air m a suspension of microorganism for fermentation or for activated sludge treatment). 

For waste treatment rather than fermentation for product formation, again few examples of process economics exist in the literature. Those that do, favor fluidization. Badot et al. (1994) described an industrial prototype fluidized bed reactor that competed favorably on an economical basis with activated sludge processes for treating carbon pollution and was estimated to be economically comparable to fixed bed processes for denitrification. Schneeberg (1994) described the successful and economically-sound implementation of fluidization as an upgrade to an existing wastewater treatment plant. The restricted space available for extension of the wastewater plant made fluidization particularly advantageous in this case. 

Irradiation shortens the composting period, because it is not necessary to keep an elevated fermentation temperature to reduce the pathogens in the sludge. 

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