Karachi: Cattle dung can run 38MW power plant

[Naveed Yaseen]

Karachi has 0.5m cattle heads producing 5,000 tonnes manure daily that can be used to produce biogas to run power plants, vehicles, steam boilers

Wednesday, December 31, 2008
By Fasahat Mohiuddin

KARACHI: The mega-polis of Karachi is facing its worst power crisis that could be partially allayed with the help of buffalo dung.

Dung from 200,000 buffaloes housed in the Landhi Cattle Colony can power a 38MW electricity generation plant running on biogas.

Amanullah Khan an alternate energy expert and consultant for ATCO a firm based in Texas USA in his feasibility study of a biogas plant in Landhi Cattle Colony says that a 38MW power plant can be installed by using dung from cattle pens of Landhi.

The plant would be capable of supplying power to 50,000 houses and run on waste material that would be converted into energy making the area a pollution free environment.

This biogas plant will be able to supply natural gas to ten filling stations at half the price. These stations will generate their own CNG independent of utility services. Carbon credit available through the United Nations Organisation will cut cost to half.

Another advantage of this plant is that presently when the 200,000 cattle are washed all the water mixed with dung goes in to the sea polluting the coastline and destroying the seafood of Pakistan.

Amanullah Khan says the biogas plant would collect this dung contaminated water recycle it to recover gas and send back clean water to the cattle colony.

Clean water is an expensive commodity in the cattle colony and at present CDGK is supplying water to Landhi Cattle Colony on subsidized rate so that cost of the milk does not go high.

Amanullah Khan had given a presentation to the City Nazim Syed Mustafa Kamal and asked only for the land to set up plant and the buffalo dung for the American firm. Kamal gave him the green signal. It seems that the red tape blocked this vital project.

The city needs alternative energy sources such as biogas, wind power and solar energy to substitute natural gas.

Of the above sources mentioned the most appropriate one, which can be easily substituted in place of natural gas is biogas. This source can be generated from a variety of biomass material easily available around us.

Primary among the sources of biogas is buffalo dung, municipal solid waste and sewage sludge. The process of biogas conversion is simple and yields a gaseous product having 55-60 per cent methane and the balance is carbon dioxide.

The heating value of biogas is approximately 600-800 Btu/ft3. Biogas of this quality can be used to generate electricity; it may be used as fuel for a steam boiler, space heater, or refrigeration equipment; it can also be directly combusted as a cooking and lighting fuel. It can be used in vehicles using CNG as fuel. Biogas can be produced in every city and village of the country.

Electricity from Biogas can be generated for on-farm use or for sale to the local electric power grid. The most common technology for generating electricity is an internal combustion engine with a generator.

Landhi Cattle Colony houses around 200,000 cattle heads the total cattle population of Karachi is more than 500,000 heads producing 5,000 tonnes of dung daily.

This buffalo manure emits into atmosphere large quantities of methane, carbon dioxide and hydrogen sulphide, which pollute the surrounding air and the Atmosphere in the vicinity of Cattle Colony has exceeded the pollutants levels laid down by NEQS (National Environmental Quality Standards).

Urgent Action is needed to attend to this matter because Pakistan being one of the Earliest Signatories to the Kyoto Protocol, under which it is necessary to decrease the quantum of Green House Gases generated in our Country to the levels laid down by Kyoto Protocol.

How Biogas is made: Bio Gas is produced by anaerobic (in absence of oxygen) decomposition of Organic Matter (cattle dung). Decomposition of cattle dung is carried out by bacteria in two phases. In first phase the bacteria decompose the Organic matter i.e. proteins and fats to form acidic compounds thereafter in the second phase Methane-forming bacteria further decompose these acidic compounds to produce Methane (CH4), Carbon Dioxide (CO2) Water Vapors (H2O), Ammonia (NH3) and Hydrogen Sulfide (H2S) the last three components in trace quantities.

The smell and odour, which we feel in animal dung is due to the emissions of ammonia and hydrogen sulphide gases while all other components of biogas i.e. methane and carbon dioxide are absolutely odourless and tasteless.

Methane produced from cattle dung can be recovered in a biogas plant and used for power generation. This not only helps to meet the power shortage but also reduces the Green House Gas emissions.

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