The impact of traditional coffee processing on river water quality in Ethiopia and the urgency of adopting sound environmental practices

Abstract

Although waste from coffee processing is a valuable resource to make biogas, compost, and nutrient-rich animal food, it is usually dumped into nearby water courses. We carried out water quality assessment at 44 sampling sites along 18 rivers that receive untreated waste from 23 coffee pulping and processing plants in Jimma Zone, Ethiopia. Twenty upstream sampling sites free from coffee waste impact served as control, and 24 downstream sampling sites affected by coffee waste were selected for comparison. Physicochemical and biological results revealed a significant river water quality deterioration as a result of disposing untreated coffee waste into running water courses. During coffee-processing (wet) season, the highest organic load (1,900 mg/l), measured as biochemical oxygen demand, depleted dissolved oxygen (DO) to a level less than 0.01 mg/l, and thus curtailed nitrification. During off season, oxygen started to recuperate and augmented nitrification. The shift from significantly elevated organic load and reduced DO in the wet season to increased nitrate in the off season was found to be the determining factor for the difference in macroinvertebrate community structure as verified by ordination analysis. Macroinvertebrate diversity was significantly reduced in impacted sites during the wet season contrary to the off season. However, there was a significant difference in the ratio of sensitive to pollution-tolerant taxa in the off season, which remained depreciated in the longer term. This study highlights the urgency of research exploring on the feasibility of adopting appropriate pollution abatement technologies to implement ecologically sound coffee-processing systems in coffee-growing regions of Ethiopia.

Biogas Potential of Coffee Processing Waste in Ethiopia

“…The by-products are known to be rich in organic pollutants (e.g., proteins, sugars, and pectin), tannins, and phenolic compounds harmful to plants, humans, and aquatic biota [9,10]. Globally, coffee processing generates about 15 × 10 6 Mg (dry weight basis) of coffee residues, of which 9.4 × 10 6 Mg is pulp [11].…”

Experimental evaluation of anaerobic digestion for coffee wastewater treatment and its biomethane recovery potential

“…Several studies reported that untreated waste from traditional and modern industries is threatening surface waters worldwide, and it is severe in developing countries (Beyene et al 2011). Water pollution is the gloomy setback for the development in coffee producing countries (Mwaura and Mburu 1998;Varunprasath and Daniel 2010), and this also appears to be the case in Ethiopia (Haddis and Devi 2008;Beyene 2010).…”

“…Traditional shedding coffee plantation system, which has social and economic value (Vergara and Badano 2009) with minimal impact on biodiversity and environment (Perfecto et al 1996;Gordon et al 2007;López-Gómez et al 2008), prevails in Jimma Zone. Nevertheless, untreated waste materials from coffee processing are routinely discharged into local streams without treatment and caused a severe ecological disruption (Beyene et al 2011). Coffee processing is vilified for the production of byproducts such as parchment husks, coffee pulp and coffee husks all of which contribute to environmental pollution unless treated or recycled (Mburu and Mwaura 1996).…”

Overview of Coffee Waste and Utilization for Biomass Energy Production in Vietnam

“…Currently in vietnam, coffee waste management systems are not well established. Several studies reported that untreated waste from traditional and modern industries is threatening surface waters worldwide, and it is severe in developing countries (6) . Water pollution is the gloomy setback for the development in coffee producing countries (7,8) , and this also appears to be the case in Ethiopia and Vietnam (9)(10)(11) .…”