R.Ramabhadran Pillai

NGO initiative to make use of water hyacinth, a menace for many

KOCHI: Water hyacinth, which is considered a menace by the inland water transport agencies, could become a boon to many others. It is being used in various processes for producing bio-gas, vermi-compost and fibre-based materials.

The Kottapuram Integrated Development Society (KIDS), a non-governmental organisation, in collaboration with the India-Canada Environmental Facility, is utilising water hyacinth for producing biogas. The project has been running successfully, according to Sunny George, a scientist who is associated with the project.

Water hyacinth has more than 85 per cent water. It is homogenised using a special machine. Special mechanisms are provided for maintaining constant temperature and pressure in a digester. Variations in the temperature are avoided by heating the inside of the digester through a hot water circulating system.

Biogas is collected in a conventional biogas plant. The slurry is ejected out of the digester once every fortnight.

A tank that is fed with 700 litres of homogenised water hyacinth yields 3,600 litres of biogas (i.e. 150 litres an hour). The entire requirement of cooking in the college canteen of KIDS is met by biogas from the water hyacinth project, according to Mr.George. The slurry generated from this processes is extensively used for organic farming among the self-help groups, according to P.Johnson, Director of KIDS.

Another project of KIDS involves production of vermi-compost from water hyacinth. The process involves several steps. The water hyacinth is chopped manually. Cowdung is used to absorb excess water from water hyacinth. A layer of coconut husk is prepared at the bottom of the vermi-compost tank followed by a layer of cowdung. Then, the chopped water hyacinth is spread over it, after which worms are put into the tank.

Each worm is expected to eat one gm of water hyacinth per day and excretes one gm. About 2 kg of worms are introduced into each tank.