ARTI develops a novel biogas plant

Though remembered for its success in converting sugar-cane leaf trash and similar organic waste into charcoal briquettes, Dr Arvind Karve's Appropriate Rural Technology Institute [ARTI] in Phaltan near Pune, Maharashtra, is working on many other innovations as well. The charcoal briquette process won it the Ashden Award for 2002. Now here's news of ARTI's 'compact biogas plant'. It is small. It will accept a wide range of farm wastes—not just cow dung—as its input. It will digest them and yield gas in 6 hours.

The following note received from ARTI elaborates it further:

Appropriate Rural Technology Institute [ARTI], has been working on biomass based improved fuels and cooking systems for the last 8 years. ARTI received, in February 2002, the Ashden Award for Renewable Energy, 2002, for developing the technology of making charcoal briquettes from agricultural waste and the Sarai cooker [see note below], which uses these briquettes as fuel.

In January 2003, ARTI received from Shell Foundation, London, a grant of Rs.15 million, for commercialising improved biomass based fuels and cooking systems in India. This work was being conducted till 2002, by the Ministry of Non-Conventional Energy Sources, Government of India, under a government sponsored welfare programme called the National Programme on Improved Cookstoves [NPIC]. This programme was terminated by the Government of India, because it failed to have any impact at all.

Under the Shell funded project, ARTI distributes charcoal briquettes, Sarai cooker and various models of energy efficient cookstoves that were developed under NPIC, through small-scale commercial enterprises based on these technologies. The prices of the fuel and the devices have not been subsidised. The customers have to pay the full price. Under this programme, about 100 artisans have already started small rural enterprises under the guidance of ARTI.

About two years ago, ARTI developed, under the guidance of its President, Dr.A.D.Karve, a compact biogas system, which uses starch or sugar as feedstock. Just one kg of starch or sugar yields the same amount of methane as 40 kg of cattle dung. Whereas cattle dung requires about 40 days to get converted into gas, the starch/sugar based biogas plant delivers the gas in just 6 to 8 hours. Waste starch in the form of rain damaged grain, banana rhizomes, non-edible seeds of various tree species, oilcake of non-edible oilseeds, etc.Êis plentifully available in the rural areas. While the smallest traditional domestic biogas plant has a volume of about 2 cubic meters, the new compact biogas system is just as large as a household refrigerator.

This invention was publicised by Dr. Karve under the title "The Blue Flame Revolution". Papers based on this concept were also presented by him in international seminars held in October 2003 in Yogyakarta, Indonesia, and in January 2004 in Seattle, U.S.A. A short note on this technology was also published in the premier scientific journal "Science".

The smoke and soot generated by traditional cookstoves using traditional fuels like stalks of cotton or pigeonpea, maize cobs, dung cakes, etc. cause indoor air pollution in rural households. Because the improved fuels and improved cookstoves mitigate this problem, the United States Environmental Protection Agency [USEPA] had already accorded the status of a partner organisation to ARTI under its programme called "Partnership for Clean Indoor Air". Under the same programme, the USEPA has sanctioned to ARTI a grant amounting to about Rs. 6 million, for standardising and commercialising the compact biogas technology. The project, having a duration of two years, would be conducted under the leadership of Dr. A.D.Karve.

For those that may not know what a Sarai cooker is, here is a note on it by Dr Karve himself:

Sarai is a stainless steam cooker. It is a non-pressurised vessel, into which you put about 150 ml of water and then lower into it, a wire cage, which carries three cook-pots, one on top of another. The steam pot has a lid which is kept closed while the food is being cooked. The heat is provided by a charcoal burner, designed to hold just 100 g of charcoal or a single honeycomb briquette of 100 g. After the coal has caught fire, the pot assembly containing the food to be cooked is placed on the stove.

A hollow cylinder, also made of stainless steel, encloses the entire assembly. The surrounding annular gap is just 5 mm. Flue gases generated by the charcoal escape through this gap. In this way, the pot is heated on all sides, instead of just from the bottom. The boiling and evaporation test showed the efficiency of this gadget to be 70%. Beans, rice and vegetables for a family of 4 to 5 are cooked with just 100 g of charcoal briquettes. It takes between 45 minutes to an hour to cook the meal. At present we are advocating it for food that needs to be steamed or boiled. We have not attempted roasting or frying