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Bioremediation through the use of Biochar

May 20, 2014
  • Bioremediation through the use of Biochar

‘Biochar’ is a term used for charcoal when it is used for particular purposes, namely as a soil amendment. Biochar is created by the pyrolysis of biomass (firing biomass without oxygen). In this context, we have used refused tea as biomass. Biochar can increase soil fertility, increase agricultural productivity and provide protection against some foliar and soil-bourne diseases. Biochar is a stable solid, rich in carbon and can endure in soil for thousands of years. Biochar is also under investigation as an approach towards carbon sequestration, to produce negative carbon dioxide emissions. Thus, Biochar has the potential to help mitigate climate change by way of carbon sequestration.

As part of Dilmah Conservation’s Biomediation Programme, a new machine was invented to convert waste tea generated from our own factories into Biochar.

With the creation of a prototype, the tea waste was successfully and efficiently converted and Dilmah will place these machines in some of our plantations and main agriculture hubs to improve productivity. This machine can additionally convert paddy husk and sawmill waste into Biochar. This machine uses Dilmah’s waste oil (a by-product of tea bagging machines) to ignite the process and to produce the energy required for the conversion.

We have installed suction methods to forcibly take the toxic syn gas out of the machine, in order to reduce air pollution at this stage and purify the gas using a few layers of water screens. At a later stage, this gas is used to fuel the machine and dry the biomass. Dilmah has also taken steps to modify its resource consumption practices in order to achieve a state of carbon neutrality in the coming years.

‘Biochar’ has resulted in the reduction of chemical fertilizer intake within our tea gardens by 50%, ensuing improvement in the quality, taste and colour of the tea leaves cultivated. Dilmah will continue to develop and expand its commitment to serving the community and the environment through best practices and strengthening its tradition of sustainable and ethical business.