Bio CNG Plants

Gobar gas plant/Biogas plant

If the land is large enough, a biogas plant based on the conversion of dung should be built. This turns the dung into gas which can be used for lighting, cooking and be sold to farmers. The minimum land necessary for a biogas unit ranges from 10X10 m2 for 50 animals to 15X15 m2 for 1000 animals.

BIO CNG Plants

Location and Shape

Availability of water

Saving of water in the Gaushala


Sun exposure and wind protection

Loose house system


In Bhabha Atomic Research Center, Mumbai, a method is developed for treating biodegradable waste that is called as Nisargruna, a Sanskrit word, which literally means ‘retuning the loan of nature’. This is the first time when aerobic degradation of the waste is carried out for 72-96 hours as a pretreatment, prior to anaerobic degradation. The realization that resources are limited and the idea of refusing back to soil has provided important impetuses for development of Nisargruna system for treating organic waste.Nisargruna provides a simple system to handle biodegradable waste in most nature–friendly manner, which is economically very valuable. In this system there is no garbage, no effluent and energy is generated. Blending of aerobic and anaerobic phases has proven successful in terms of reduction in retention time, high process stability with a better methane yield and manure quality. It has also increased the scope from gobar or cattle dung to kitchen waste resource, animal residues and agricultural residues.

Biogas generator

A biogas generator is a reactor or chemical processing machine designed to organically breakdown biological source materials into gases such as methane and hydrogen that can then be combined with oxygen for use as source of fuel. A biogas generator is a sealed container with inlet for organic waste infusion with anaerobic bacteria. The bacteria break down the waste in the absence of oxygen into a gas mixture of about 60% methane and 40% carbon dioxide, which is siphoned off into another container. Industrial level systems are simply larger scale versions of the same process. They have an elevated waste-feeding chamber that channels the material into reactor chamber filled with digesting slurry. The biogas generator pipes transport gas out of the top of the chamber and treated slurry to the outside of the container. Methane from a biogas generator is the main component of the natural gas, which can be used to heat homes and for other uses such as cooking and hot water production. The slurry after drying acts as good organic manure It is easier to get a professional company to make the unit rather than attempting it on your own.

Self-reliant local energy generation from cow dung (biogas for cooking, lighting and electricity generation)

Purification of Biogas to Bio-CNG

Biogas to Bio-CNG Conversion Technology/Process: Biogas produced from anaerobic digestion of biodegradable biomass contains significant amount of impurities like water, N2, O2, H2S, NH3, and CO2 and so forth. Therefore, biogas has to be purified prior to the conversion into bio-CNG. Generally, pressurized water scrubbing, pressure swing adsorption, chemical absorption, membrane permeation, temperature swing adsorption, cryogenic approach, physical absorption, and biological filtration methods are used to purify the biogas before conversion. However, pressurized water scrubbing is the most commonly used method as it offers several advantages and higher percentages of CH4 purity compared to the other purifying methods. leaned biogas containing more than 97% CH4 and less than 2% O2 is considered for production of bio-CNG. Generally, two approaches named physical (compression and liquefaction) and chemical approach (catalytic reforming and Fischer–Tropsch synthesis) are applied for this conversion. Pure biogas then undergoes a high compression pressure between 20 and 25 MPa and converts into bio-CNG which occupies less than 1% of its normal volume. It is required to store bio-CNG as it affects vehicle filling time, filling completeness, and energy consumption. Typically, two storage systems such as buffer storage and cascade storage are used in filling station. The buffer storage system maintains the pressure of CNG in the range of 20–25 MPa and provides CNG with a maximum pressure of 20 MPa to a vehicle’s on-board cylinders. In this case, all filling station reservoirs are connected and maintained at the same pressure.

Self-reliant local energy generation from cow dung (biogas for cooking, lighting and electricity generation)