Fermentation, methane

Fig. 4. Microbial phases in anaerobic digestion A, hydrolysis B, acidification C, methane fermentation.

Table 12. Comparison of Methane Fermentation Performance Under High Rate Mesophillic Conditions ...

Considerable laboratory work has also been done to develop pre- and post-digestion treatments that improve biodegradabiUty. A plateau of about 50—60% volatile soHds destmction efficiencies and energy recoveries in the product gas seems to exist for most methane fermentation systems. 

Some of the other research studies have addressed topics such as high soHds biomass digestion (154), utilization of superthermophilic organisms (155), advanced reactor designs (156), landfill gas enhancement (157), and microbiology of the mixed cultures involved in methane fermentation (158). 

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. 

Chou, W., Speece, R., Siddiqi, R., and McKeon, R., The effect of petrochemical structure on methane fermentation toxicity, Program Water Technol., 10, 545-550, 1987. 

Bhattacharya, S.K. and Parkin, G.F., Fate and effect of methylene chloride and formaldehyde in methane fermentation systems, J. Water Pollut. Control Fed., 60, 531-536, 1988. 

Aerobic respiration Denitrification Mn(IV) reduction Fe(III) reduction Sulfate reduction Methane fermentation Nitrogen fixation... 

The Marine Biotechnology Institute (MBI) was founded in 1987 for the study and applications of biodiversity in marine environments. Currently, and within the scope of the present book, the research area of relevance is industrial applications of microbiology . The institute also performs research in C02 fixation. The Applied Microbiology Laboratory is searching cost-effective utilization of microbes for environmental conservation and restoration. In particular, the decontamination of areas polluted with petroleum-related compounds has been addressed. Attention has been paid to removal of polycyclic hydrocarbons. They are also developing processing methods for the conversion of biomass and organic wastes by methane fermentation. 

Methane fermentation may be considered a reduction of C02 to CH4 accompanied by oxidation of any one of the intermediate oxidation states to C02. Since all of the latter have pE°(W) less than —6.2 (this for... 

Study on Methane Fermentation and Production of Vitamin B12 from Alcohol Waste Slurry... 

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... 

Fig. 15.11 Methane fermentation of organic sludge after WEO treatment...

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