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Biogas plant
- Thread starter smimran
- Start date
Hi
Biogas technology provides an alternate source of energy in rural India, and is hailed as an archetypal appropriate technology that meets the basic need for cooking fuel in rural areas. Using local resources, viz. cattle waste and other organic wastes, energy and manure are derived. Realization of this potential and the fact that India supports the largest cattle wealth led to the promotion of National Biogas Programme in a major way in the late 1970s as an answer to the growing fuel crisis. Biogas is produced from organic wastes by concerted action of various groups of anaerobic bacteria. An attempt has been made in this review on the work done by our scientists in understanding the microbial diversity in biogas digesters, their interactions, factors affecting biogas production, alternate feedstocks, and uses of spent slurry.
Microbial conversion of organic matter to methane has become attractive as a method of waste treatment and resource recovery. This process is anaerobic and is carried out by action of various groups of anaerobic bacteria.
Three basic points about this process are:
(i) that most of the important bacteria involved in biogas production process are anaerobes and slow growing;
(ii) that a greater degree of metabolic specialization is observed in these anaerobic microorganisms; and
(iii) that most of the free energy present in the substrate is found in the terminal product methane. Since less energy is available for the growth of organism, less microbial biomass is produced and, consequently, disposal of sludge after the digestion may not be a major problem.
Complex polymers are broken down to soluble products by enzymes produced by fermentative bacteria which ferment the substrate to short-chain fatty acids, hydrogen and carbon dioxide. Fatty acids longer than acetate are metabolized to acetate by obligate hydrogen-producing acetogenic bacteria . The major products after digestion of the substrate by these two groups are hydrogen, carbon dioxide, and acetate. Hydrogen and carbon dioxide can be converted to acetate by hydrogen-oxidizing acetogens or methane by carbon-dioxide-reducing, hydrogen-oxidizing methanogens . Acetate is also converted to methane by aceticlastic methanogens . Nearly seventy per cent of methane from biogas digesters fed with cattle dung is derived from acetate.
FActors affecting biogas production
Various factors such as biogas potential of feedstock, design of digester, inoculum, nature of substrate, pH, temperature, loading rate, hydraulic retention time (HRT), C : N ratio, volatile fatty acids (VFA), etc. influence the biogas production.
REgards
Ashwini
Biogas technology provides an alternate source of energy in rural India, and is hailed as an archetypal appropriate technology that meets the basic need for cooking fuel in rural areas. Using local resources, viz. cattle waste and other organic wastes, energy and manure are derived. Realization of this potential and the fact that India supports the largest cattle wealth led to the promotion of National Biogas Programme in a major way in the late 1970s as an answer to the growing fuel crisis. Biogas is produced from organic wastes by concerted action of various groups of anaerobic bacteria. An attempt has been made in this review on the work done by our scientists in understanding the microbial diversity in biogas digesters, their interactions, factors affecting biogas production, alternate feedstocks, and uses of spent slurry.
Microbial conversion of organic matter to methane has become attractive as a method of waste treatment and resource recovery. This process is anaerobic and is carried out by action of various groups of anaerobic bacteria.
Three basic points about this process are:
(i) that most of the important bacteria involved in biogas production process are anaerobes and slow growing;
(ii) that a greater degree of metabolic specialization is observed in these anaerobic microorganisms; and
(iii) that most of the free energy present in the substrate is found in the terminal product methane. Since less energy is available for the growth of organism, less microbial biomass is produced and, consequently, disposal of sludge after the digestion may not be a major problem.
Complex polymers are broken down to soluble products by enzymes produced by fermentative bacteria which ferment the substrate to short-chain fatty acids, hydrogen and carbon dioxide. Fatty acids longer than acetate are metabolized to acetate by obligate hydrogen-producing acetogenic bacteria . The major products after digestion of the substrate by these two groups are hydrogen, carbon dioxide, and acetate. Hydrogen and carbon dioxide can be converted to acetate by hydrogen-oxidizing acetogens or methane by carbon-dioxide-reducing, hydrogen-oxidizing methanogens . Acetate is also converted to methane by aceticlastic methanogens . Nearly seventy per cent of methane from biogas digesters fed with cattle dung is derived from acetate.
FActors affecting biogas production
Various factors such as biogas potential of feedstock, design of digester, inoculum, nature of substrate, pH, temperature, loading rate, hydraulic retention time (HRT), C : N ratio, volatile fatty acids (VFA), etc. influence the biogas production.
REgards
Ashwini