Sustainable biogas from water-hyacinth
15 May 2013, 18:00 PM
UPDATED
15 May 2013, 21:00 PM
WATER-hyacinth or kochuripana (Eichhornia Crassipes) is an ecofriendly renewable natural resource for production of biofuel and other useful products. Biofuel as biogas from this non-food aquatic plant has different uses and it can be produced or cultivated in any water body with many environmental and socioeconomic benefits.
As an abundantly available source of biomass, the plant can be used as feedstock for local energy production as well as a resource input for various important products with environmental and socioeconomic benefits. Besides using the biomass for biogas production, many other eco-friendly biodegradable items can be fashioned from the plant and hence increase employment opportunity and generate income among the rural and agrarian population. Items include fiber boards, furniture, crafts and paper, to name a few.
Sustainability generally depends on socio-economic development and availability and consumption of energy. Because of diminishing natural resources and energy supply, the focus must be shifted to other forms of renewable energy sources. Bioenergy is a cheap source of energy.
Aquatic plants, especially water hyacinth, have the benefit of not requiring fertile land to grow, and thus do not take precious space away from food crops. Also, the harvest frequency tends to be on the order of days. Plentiful availability, low cost, and rapid growth of water hyacinths make them ideal for biofuel production. The concept of using aquatic plants for conversion to energy (methane) is gaining attention in tropical and sub-tropical regions of the world where warm climate is conductive to plant growth throughout the year.
As a flowering aquatic plant, it can live and reproduce by floating freely on the surface. It originated in South America, but is abundantly found in India, Bangladesh, and other South East Asian countries and also in the Philippines Islands. Plant size ranges from a few inches to around a meter in height. It grows in mats up to 2 meters thick, which can significantly reduce light and oxygen, change water chemistry, affect flora and fauna underneath, and cause significant increase in water loss due to evapotranspiration. Roots are variable in length and are superb micro-sites for bacterial communities. Two types of water hyacinth are abundantly available, the long type and the dwarf type. The former type is mostly available in stagnant water having high effluent absorbing capacity while the later is available mostly in paddy fields.
It grows readily without any need for sowing, weeding or fertilising, so it costs nothing. It is rich in nitrogen, phosphorus and potassium, so can be used as organic fertiliser. The plant has a fibrous tissue and a high energy and protein content, and can be used for a variety of useful applications. It has tough, fibrous roots that purify water by absorbing the nitrogen, phosphorus and potassium on which it thrives. The plant is extremely tolerant towards and has high capacity of up taking heavy metals as cadmium, chromium, cobalt, nickel, lead and mercury, among others, and often takes up these metals and toxic materials from waste water for its metabolic use.
Due to vegetative reproduction and extremely high growth rate water hyacinth spread rapidly. Its availability in large amount throughout the year and everywhere makes it an especially desirable biofuel feedstock. It also causes practical problems for marine transportation, fishing and at intakes for hydro power and irrigation schemes, so occasional displacement is locally advantageous.
Biogas produced from water hyacinth is similar to that from cow dung, a locally practiced energy production process. The easily biodegradable matter, particularly hemi-cellulose, is higher in water hyacinth than in cow dung. Biogas is produced by anaerobic digestion which takes place in a reactor or digester (an airtight container usually sited below ground) and the usable product is methane gas which can be used as a fuel for cooking, lighting or for powering an engine to provide shaft power. The residue from the digestion process provides a fertilizer rich in nutrients.
A plant with the capacity of about 6 cubic meters can be used to produce the gas. To reach an optimum condition for the production of a maximum amount of biogas from water hyacinth, the hyacinth should be collected from lakes or water bodies and delivered to a processing site. It should then be shredded to make slurry with cow dung and catalysts and processed into as many saleable products as possible.
In this method, water hyacinth is shred into slurry and digested in a continuous process, as cow dung is customarily used. A digestion tank (known as the digester), shredders, gas holders, pipes and fittings, a supply of water hyacinth, cow dung and catalyst are needed in the biogas energy production process. Animal farm should be a part of the project or associated with it as animal manure also acts as an important catalyst and increases the production of biogas.
Many nations are also currently using water hyacinth as compost for growing mushrooms and also to clean pollutants including toxic heavy metals. Recently, it is being used in waste water treatment plants due to its ability to tolerate high levels of pollution. To make rope, furniture and paper, the stem of water hyacinth is used by processing the plants; ashes are used for making soap. Water hyacinth briquettes are used as fuel. Due to scarcity of land, crops/vegetables are also grown on hyacinth rafts. Dried water hyacinth is used as a fuel, for making mat from the plant, as cattle food and compost, and for producing biogas. This technique is very much helpful for farmers using biogas plants.
the writer is Assistant Professor, Department of Environmental Science & Management,
North South University.
Email: nahar@northsouth.edu
WATER-hyacinth or kochuripana (Eichhornia Crassipes) is an ecofriendly renewable natural resource for production of biofuel and other useful products. Biofuel as biogas from this non-food aquatic plant has different uses and it can be produced or cultivated in any water body with many environmental and socioeconomic benefits.
As an abundantly available source of biomass, the plant can be used as feedstock for local energy production as well as a resource input for various important products with environmental and socioeconomic benefits. Besides using the biomass for biogas production, many other eco-friendly biodegradable items can be fashioned from the plant and hence increase employment opportunity and generate income among the rural and agrarian population. Items include fiber boards, furniture, crafts and paper, to name a few.
Sustainability generally depends on socio-economic development and availability and consumption of energy. Because of diminishing natural resources and energy supply, the focus must be shifted to other forms of renewable energy sources. Bioenergy is a cheap source of energy.
Aquatic plants, especially water hyacinth, have the benefit of not requiring fertile land to grow, and thus do not take precious space away from food crops. Also, the harvest frequency tends to be on the order of days. Plentiful availability, low cost, and rapid growth of water hyacinths make them ideal for biofuel production. The concept of using aquatic plants for conversion to energy (methane) is gaining attention in tropical and sub-tropical regions of the world where warm climate is conductive to plant growth throughout the year.
As a flowering aquatic plant, it can live and reproduce by floating freely on the surface. It originated in South America, but is abundantly found in India, Bangladesh, and other South East Asian countries and also in the Philippines Islands. Plant size ranges from a few inches to around a meter in height. It grows in mats up to 2 meters thick, which can significantly reduce light and oxygen, change water chemistry, affect flora and fauna underneath, and cause significant increase in water loss due to evapotranspiration. Roots are variable in length and are superb micro-sites for bacterial communities. Two types of water hyacinth are abundantly available, the long type and the dwarf type. The former type is mostly available in stagnant water having high effluent absorbing capacity while the later is available mostly in paddy fields.
It grows readily without any need for sowing, weeding or fertilising, so it costs nothing. It is rich in nitrogen, phosphorus and potassium, so can be used as organic fertiliser. The plant has a fibrous tissue and a high energy and protein content, and can be used for a variety of useful applications. It has tough, fibrous roots that purify water by absorbing the nitrogen, phosphorus and potassium on which it thrives. The plant is extremely tolerant towards and has high capacity of up taking heavy metals as cadmium, chromium, cobalt, nickel, lead and mercury, among others, and often takes up these metals and toxic materials from waste water for its metabolic use.
Due to vegetative reproduction and extremely high growth rate water hyacinth spread rapidly. Its availability in large amount throughout the year and everywhere makes it an especially desirable biofuel feedstock. It also causes practical problems for marine transportation, fishing and at intakes for hydro power and irrigation schemes, so occasional displacement is locally advantageous.
Biogas produced from water hyacinth is similar to that from cow dung, a locally practiced energy production process. The easily biodegradable matter, particularly hemi-cellulose, is higher in water hyacinth than in cow dung. Biogas is produced by anaerobic digestion which takes place in a reactor or digester (an airtight container usually sited below ground) and the usable product is methane gas which can be used as a fuel for cooking, lighting or for powering an engine to provide shaft power. The residue from the digestion process provides a fertilizer rich in nutrients.
A plant with the capacity of about 6 cubic meters can be used to produce the gas. To reach an optimum condition for the production of a maximum amount of biogas from water hyacinth, the hyacinth should be collected from lakes or water bodies and delivered to a processing site. It should then be shredded to make slurry with cow dung and catalysts and processed into as many saleable products as possible.
In this method, water hyacinth is shred into slurry and digested in a continuous process, as cow dung is customarily used. A digestion tank (known as the digester), shredders, gas holders, pipes and fittings, a supply of water hyacinth, cow dung and catalyst are needed in the biogas energy production process. Animal farm should be a part of the project or associated with it as animal manure also acts as an important catalyst and increases the production of biogas.
Many nations are also currently using water hyacinth as compost for growing mushrooms and also to clean pollutants including toxic heavy metals. Recently, it is being used in waste water treatment plants due to its ability to tolerate high levels of pollution. To make rope, furniture and paper, the stem of water hyacinth is used by processing the plants; ashes are used for making soap. Water hyacinth briquettes are used as fuel. Due to scarcity of land, crops/vegetables are also grown on hyacinth rafts. Dried water hyacinth is used as a fuel, for making mat from the plant, as cattle food and compost, and for producing biogas. This technique is very much helpful for farmers using biogas plants.
the writer is Assistant Professor, Department of Environmental Science & Management,
North South University.
Email: nahar@northsouth.edu
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