Composting of Coffee Husk and Pulp and Co-Digest With Other Organic Wastes (The Case of Dale Woreda)
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Date
2016-06
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Addis Ababa University
Abstract
Coffee processing firms generate huge amount of solid wastes (coffee pulp and husk). Because of their abundance, chemical composition and physical characteristics, these residues should be handled in an appropriate way in order to avoid environmental impact as these wastes are easily dumped in to water bodies and unsanitary landfills due to their threat to the environment. Hence, this work was undertaken to transform these waste to bio-fertilizer using windrow composting technique with the intention to alleviate environmental impacts while to produce soil conditioner. In this study, the samples were placed in (6*3) treatments in RCBD in which 6 is the treatment and 3 is the replication. coffee pulp + coffee husk (pile 1), coffee pulp + coffee husk + cow dung (pile 2), coffee pulp + coffee husk + khat waste (pile 3), coffee pulp + coffee husk + cow dung + khat waste (pile 4), coffee pulp + cow dung (pile 5) and coffee husk + cow dung (pile 6) were used to prepare compost. The compost base area was 1m2 and 1m long (1m3in volume), above 20cm height bricks bed with the composting material in layers till the height of the piles become 1m long. Essential parameters were measured during the 80 day composting. Samples were collected on days 0, 45, 80 for Physico-chemical analysis. The compost maturity tests (germination and plant bioassay) were conducted using maize (BH540). The mean physicochemical results of matured compost found within the range of acceptable limits set by most countries guidelines except total potassium content which is out of the range recommended by many countries. Mean range specific values of pH, EC, %MC, OM, TKN, TP, K and C/N ratios for matured compost were:7.85-8.2, 2.66-4.4 dS/m, 39-49.6%, 39-42.7%, 1.28-2.06%, 0.25-1.02%,0.25-1.48 and 11-20.8 respectively. While a germination index of 100%, 125%, 121%, 150%, 112.5% and 118.75% was obtained respectively which depicted the compost maturity. Parameters like OC, OM, and C/N ratio decreases throughout the composting period while other parameters like pH, EC, and plant macronutrients TN, TP and TK increases as composting process progressed till maturity.
Comparing the compost samples, the physic-chemical characteristics, germination and plant bio-assay the compost produced by coffee residue with other organic amendment has high nutrient value which can be used effectively as bio-compost.
Key words: coffee residue, composting, compost quality, macronutrient and Germination Index
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Keywords
Coffee residue, Composting, Compost quality, Macronutrient and Germination Index