|Biogas - Biogas is an organic gas refers to methane produced by the fermentation of organic matter including manure, wastewater sludge, municipal solid waste, or any other biodegradable feedstock, under anaerobic conditions. Biogas is also called digester gas, swamp gas, landfill gas and marsh gas, depending on where it is produced. Each variant has different levels of methane and carbon dioxide with other minor gases. The process is popular for treating many types of organic waste because it provides a convenient way of turning waste into electricity, decreasing the amount of waste to be disposed of, and of destroying disease causing pathogens which can exist in the waste stream.|
|The use of biogas is encouraged in waste management because it does not increase the amount of carbon dioxide in the atmosphere, which is responsible for much of the greenhouse effect, if the biomass it is fueled on is regrown. Also, methane burns relatively cleanly compared to coal. Processing of the biodegradable feedstock occurs in a anaerobic digester, which must be strong enough to withstand the buildup of pressure and must provide anaerobic conditions for the bacteria inside. Digesters are usually built near the source of the feedstock, and several are often used together to provide a continuous gas supply. Products put into the digester are composed mainly of carbohydrates with some lipids and proteins. Bananas produce a large amount of biogas in a short amount of time.|
|More recently, developed countries have been making increasing use of gas generated from both wastewater and landfill sites. Landfill gas production is incidental and usually nothing is done to increase gas production or quality. There are indications that slightly wetting the waste with water when it is deposited may increase production, but there is a concern that gas production would be large at first and then drop sharply. Even if not used to generate heat or electricity, landfill gas must be disposed of or cleaned because it contains trace volatile organic compounds (VOCs), many of which are known to be precursors to photochemical smog. Because landfill gas contains these trace compounds, the United States Clean Air Act, and Part 40 of the Federal Code of Regulations, requires landfill owners to estimate the quantity of VOCs emitted. If the estimated VOC emissions exceeds 50 metric tons, then the landfill owner is required to collect the landfill gas, and treat it to remove the entrained VOCs. Usually, treatment is by combustion of the landfill gas. Because of the remoteness of landfill sites, it is sometimes not economically feasible to produce electricity from the gas.|
|Biogas digesters take the biodegradable feedstock, and convert it into two useful products: gas and digestate. The biogas can vary in composition typically from 50-80% methane, with the majority of the balance being made up of carbon dioxide. The digestate comprises of lignin and cellulose fibres, along with the remnants of the anaerobic microorganisms. This digestate can be used on land as a soil amendment, to increase moisture retention in soil and improve fertility. If biogas is cleaned up sufficiently, biogas has the same characteristics as natural gas. More frequently, it is burned with less extensive treatment on site or nearby. If it is burned nearby, a new pipeline can be built to carry the gas there. If it is to be transported long distances, laying a pipeline is probably not economical. It can be carried on a pipeline that also carries natural gas, but it must be very clean to reach pipeline quality. Water (H2O), hydrogen sulfide (H2S) and particulates are removed if present at high levels or if the gas is to be completely cleaned. Carbon dioxide is less frequently removed, but it must also be separated to achieve pipeline quality gas. If the gas is to be used without extensively cleaning, it is sometimes cofired with natural gas to improve combustion. Feeding biogas into the natural gas network is particularly interesting for climates where the waste heat of a biogas powered power plant cannot be used during the summer.|
|In some cases, landfill gas contains siloxanes. Burning converts them to silica particles, which tend to clog conventional combustion engines. Stirling engines are more resistant against them. Biogas cleaned up to pipeline quality is called renewable natural gas, and in this form can be used in any application that natural gas is used for. Such applications include distribution via the natural gas grid, electricity production, space heating, water heating and process heating. If compressed, it can replace compressed natural gas for use in vehicles, where it can fuel an internal combustion engine or fuel cells.|
|Benefits of biogas - Biogas permit generate electricity, and clean gas for cooking
allowing some savings by decreasing the use of fuel petroleum derivates, gasoline, diesel, propane gas, and it is a great way for waste treatment.
Biogas technology makes optimal utilization of the valuable natural resource of dung;
it provides nearly three times more useful energy that dung directly burnt, and also produces nutrient-rich manure.
|| Direct Burning = 10460 kcal gross energy = With a 10 % Efficiency produces 1046 kcal Useful Energy None
|| Biogas = Produce 1 m3 of biogas 4713 kcal (55 % efficiency) 2592 kcal Useful Energy
|| Manure - 10 kg air dried manure
As a cooking fuel, it is cheap and extremely convenient.
Based on the effective heat produced, a 2cu m biogas plant could replace, in a month, fuel
equivalent of 26 kg if LPG (nearly two standard cylinders), or 37 litres of kerosene, or
88kg of charcoal, or 210 kg of fuelwood, or 740 kg of animal dung. In terms of cost, biogas is cheaper, on a life cycle basis, than conventional biomass fuels (dung, fuelwood, crop wastes, etc.) as well as LPG, and is only fractionally more expensive than kerosene;
the commercial fuels like kerosene and LPG, however, have severe supply constraints in the
||To the housewife, a biogas is easy to use and saves time
in the kitchen; biogas stove has an efficiency of about 55% which is comparable to that of
an LPG stove. Cooking on biogas is free from smoke and soot, and can substantially reduce
the health problems, which are otherwise quite common in most rural areas in India where
biomass is the chief source of fuel . The use of biogas is helpful to improve the quality
of life in household.
||However, the use of biogas is by no means confined to cooking alone. It can be used, through a specially designed mantle, for lightning, too.
Further, biogas can partially replace diesel to run IC (internal combustion) engines for
water pumping; small industries like floor mill, saw mill, oil mill etc. This would not
only reduce dependence on diesel, but also help in reducing carbon pollutants which
adversely affect the atmosphere. Dual – fuel engines (80% biogas and 20% diesel) are
now commercially manufactured in India. Biogas can be similarly used to produce
electricity, though this has not been attempted on a large scale in the country so far.
Nevertheless, the versatility of biogas is its greatest advantage as a source of energy
for the rural areas.
||While biogas has multiple benefits at the individual
family level, it also has several qualitative and quantitative benefits at the societal
level. Firstly, a shift to biogas from traditional biomass fuels results in less
dependence on natural resources such as forests, in less dependence on natural resources
such as forests, checking their indiscriminate and unsustainable exploitation. Since dung
is collected systematically when used in biogas, environment can be kept clean and
The other advantage is that, unlike centralized systems
such as thermal power plants and fertilizer factories, which entail huge capital
investments and need elaborate distribution networks, biogas plants are decentralized
systems which can be installed even in remote areas with very low investments.
||Experiences and Potential of biogas in India -
In India, the dissemination of large–scale
biogas plants has began in the mid-seventies and the process has become consolidated with
the advent of the National Project on Biogas Development (NPBD) in 1981, which has been
continuing since. Against the estimated potential of 12 million biogas plants, 2.9 million
family type and 2700 community, institutional and nightsoil-based plants have been set up
till December 1999.
This is estimated to have helped in a saving of 3 million tonnes of fuelwood per year and manure containing nitrogen equivalent to 0.7 million tonnes of urea.
|However, in terms of total dung that is available in the
country, the potential is much more. The bovine population in India is 260 millions. As
adult bovine produces an average of 10 kg of dung per day. Since grazing is a common
practice in India, all the dung produced cannot be collected. If it is assumed that 75% of
the dung is collected, nearly 2 millions tonnes of dung would be available everyday. At 25
kg per one cubic metre, this dung can feed as many as 40 millions - biogas plants of
2 cubic metre capacity, which can be considered the ultimate potential for biogas
But even this high potential of biogas is based on animal
dung only. However, all organic matter can technically be used to generate methane; if the
scientific experiments that are going on in the country under the patronage of MNES to
develop alternative feedstocks (such as water hyacinth, kitchen waste, and poultry waste)
come to fruition, potential for biogas generation could be virtually unlimited. It can be
mentioned in this context that human waste is an excellent source of biogas which would
enhance the potential; substantially. With such high potential, which can be routed to
hitherto unemphasized applications of shaft power and electricity generation, biogas can
make a significant contribution to the development of small industries and agriculture, and thus to the overall advancement of the rural areas.
||Biogas and bioenergy links and websites
||Biogas plant models
||Biogas: a source of rural employment. New Delhi: Tata Energy Research Institute.
|| Experience in India
shows an estimated potential of 12 millions family type biogas plants
over 3 millions family type biogas plants has been installed in the country .
|| Non-Conventional Energy Sources The policies
from the Ministry of Non-Conventional Energy Sources from the Indian Government
have some financing incentives for biogas production, WIND ENERGY , SOLAR PHOTOVOLTAICS, SOLAR THERMAL
||A system approach to biogas technology
Biogas technology: a training manual for extension (FAO/CMS)
Adding value to the residue from biogas plants
Rural Energy in India - NATIONAL BIOGAS MANAGEMENT PROGRAMME - Technologies have been developed indigenously to produce modern biomass fuel, such as biogas from cattle dung and other organic wastes and to burn biomass in an efficient manner.
Ease the construction of plant compared of biogas ofr ($214.4) nearly the same as the cost others charge for the installation !.
Energy from biowaste The modular fabrication and production of quality controlled elements.
|| Biogas overview Renewing India
Biogas Technology in India: More than Gandhi's Dream?
||Renewable energy devices
||Flat plat solar collectors
||Concentrating and pipe type solar collectors
||Solar water heaters and systems
||Air / gas / fluid heating systems
||Solar crop driers and systems
||Solar refrigeration, cold storage and air-conditioning systems
||Solar steels and desalination systems
||Solar power generating systems
||Solar pumps based on solar thermal and solar photovoltaic conversion
||Solar photovoltaic modules and panels for water pumping and other applications
||Wind mills and any specially designed devices which run on wind mills
||Any special devices including electric generators and pumps running on wind energy
||Biogas plant and biogas engines
||Electrically operated vehicles including battery powered or fuel-cell powered vehicles
||Agricultural and municipal waste conversion devices producing energy
||Equipment for utilizing ocean waste and thermal energy
||Machinery and plant used in the manufacture of any of the above sub-items