School of Environmental Health, Jimma University, P.O. Box 378, Jimma, Ethiopia.
Environ Monit Assess. 2012 Nov;184(11):7053-63. doi: 10.1007/s10661-011-2479-7. Epub 2011 Dec 9.
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.
尽管咖啡加工废料是生产沼气、堆肥和营养丰富的动物饲料的宝贵资源，但通常会被倾倒到附近的水道中。我们在埃塞俄比亚吉马地区的 18 条河流的 44 个采样点进行了水质评估，这些河流接收了 23 家咖啡浆和加工厂未经处理的废物。20 个上游采样点没有受到咖啡废料的影响，作为对照，选择了 24 个下游采样点进行比较，这些采样点受到了咖啡废料的影响。理化和生物结果表明，由于将未经处理的咖啡废料排入流水道，河水水质显著恶化。在咖啡加工（湿）季节，最高的有机负荷（1900 毫克/升），以生化需氧量（BOD）衡量，消耗了溶解氧（DO）至低于 0.01 毫克/升的水平，从而阻止了硝化作用。在淡季，氧气开始恢复并增加了硝化作用。湿季有机负荷显著升高和 DO 降低，而淡季硝酸盐增加，这被证明是确定大型无脊椎动物群落结构差异的决定因素，这一差异通过排序分析得到了验证。在湿季，受影响的地点的大型无脊椎动物多样性明显减少，而在淡季则相反。然而，在淡季，对污染敏感和耐受的分类群的比例存在显著差异，而且这种情况在长期内仍然存在。本研究强调了研究的紧迫性，需要探索采用适当的污染减排技术的可行性，以在埃塞俄比亚的咖啡种植地区实施生态合理的咖啡加工系统。
