Methane fermentation yields

Although from theoretical considerations biomass yields from methane could be as high as 1.4, in laboratory-scale cultures values of about 1.0 were obtained, and in larger scale systems values were around 0.3-0.6. Methane fermentation also incurs high aeration and cooling costs. 

The BOD/COD ratio is an indicator of biodegradability for an aerobic process but the WEO was also found to increase the biodegradability for anaerobic treatment. The filtrate from WEO treatment of organic sludge at 250°C was submitted to a methane fermentation test. Figure 15.11 shows the methane yield for the filtrate of WEO, in which different electrical charges were applied. A clear increase in the methane yield was observed with the increase in the electrical charge of WEO. The... 

Methane fermentation in natural ecosystems is usually described as a two-stage system in which nonmethanogenic bacteria ferment organic matter such as carbohydrate yielding such products as acetate, formate, hydrogen, and carbon dioxide. The methanogenic bacteria are restricted... 

To illustrate the influence of reaction energetics on cellular yield and other characteristics of the methane fermentation, and to simplify the analysis, a few assumptions will be made. 

The reaction with the lowest yield of standard free energy is methane fermentation with the products carbonate, methane, ammonia and phosphate. For details of these reactions, see Chapter 4. 

Biological—Biochemical Processes. Fermentation is a biological process in which a water slurry or solution of raw material interacts with microorganisms and is enzymatically converted to other products. Biomass can be subjected to fermentation conditions to form a variety of products. Two of the most common fermentation processes yield methane and ethanol. Biochemical processes include those that occur naturally within the biomass. 

The following describes the process of mannre and straw mixtnre digestion. For the first 3 days, the methane yield is almost 0% and carbon dioxide generation is roughly 100%. In this period, digestion occius as aerobic fermentation to carbon... 

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