Bioreactors For Clean Coffee Effluent

Coffee is a major commercial crop in India with its cultivation being undertaken in hilly tracts of Karnataka, Kerala, TamilNadu, AndhraPradesh, Orissa, West Bengal and Northeastern states. The total area under coffee cultivation is about 0.305 mha with arabica and robusta being cultivated in about the same extent of land. India’s share in world production is about 4% with coffee exports contributing substantial foreign exchange to the national exchequer. Coffee cultivation is a source of direct employment for lakhs of people in the coffee-growing regions of the country. Coffee cultivation in the hilly tracts has been recognized as a contributory factor for the conservation of forest resources as coffee is grown under shade.

As part of the coffee post-harvest processing operations, coffee fruit is pulped and washed to obtain parchment. This process results in the discharge of effluents that is rich in organic content. This effluent, if treated in appropriate technological systems, can be utilized to generate biogas for supply to the diesel engine used for the pulper and to labour quarters (in the plantation) for use in cooking. The sludge can be used as a source of nutrients in the plantation thereby reducing the use of inorganic fertilizers. Water consumption during pulping can be reduced by recycling water.

Technology Informatics Design Endeavour (TIDE), Bangalore has been involved in the construction of bioreactor systems in coffee processing units in the Western Ghats region of Karnataka. Over the past year, TIDE has been working on a project supported by the Indo Norwegian Environment Programme (INEP) to promote bioreactor systems for treatment of coffee pulping and washing effluents. In this project, TIDE has been involved in the assessment of user requirements, formulation of technical specifications to address the needs, construction of the bioreactors and, training of adopters in utilizing and maintaining the bioreactor system. TIDE is technically assisted by center for ASTRA of the Indian Institute of Science that has been working on biogas technologies for over 2 decades. As part of this project, bioreactor systems were established at locations in Chickmagalur district in the year 2000 and demonstrated for their ability to reduce the organic load of the effluents and recover biogas. The biogas has been used for running diesel engines with up to 70 % diesel replacement. The biogas has also been used for cooking.

Read about success story of bioreactors at Mr Steven Rebello's coffee plantation