The poorly controlled discharge of coffee husks in Ethiopia causes severe environmental pollution and is a waste of resources. The volatile solid and carbon content in coffee husks waste indicates that it is rich in organic matter and has huge potential to produce biogas. This study investigated the feasibility of coffee husks to produce biomass through anaerobic digestion, based on temperature, initial pH, inoculum/substrate (I/S) ratio and carbon/nitrogen (C/N) ratio. The study demonstrated that the maximum production of biogas and methane reached 3359.6 ml and 2127.30 ml, respectively, under the conditions of mesophilic temperature (35±1°C), an initial pH of 7, an I/S ratio of 0.75 and a C/N ratio of 30. Based on this result, the effects of trace elements (Fe²⁺, Ni²⁺, Co²⁺) on biogas production and methane content were also explored. Compared with the group with no addition of trace elements, the experiment adding trace elements had significant enhancement effects on the production of biogas and methane, in which Fe²⁺ played a leading role (p<0.05). Fe²⁺ promoted the hydrolysis and acidification of coffee husks, resulting in the production of a series of intermediates such as volatile fatty acids and the other kinds of dissolved organic matter. Furthermore, the cooperation of Ni²⁺, Co²⁺ and Fe²⁺ enhanced the activity of the enzyme system in methanogens, promoting methane production. The results in this paper show that coffee husks have clear biogas potential through anaerobic digestion, and its effective utilization could fulfill the dual purpose of solid waste reclamation and local environmental protection in Ethiopia.

埃塞俄比亚的咖啡壳排放控制不善，造成了严重的环境污染，浪费了资源。咖啡果皮废料中的挥发性固体和碳含量表明它富含有机物，具有产生沼气的巨大潜力。这项研究基于温度，初始pH，接种物/底物（I / S）和碳/氮（C / N）的比例，研究了咖啡壳通过厌氧消化生产生物质的可行性。研究表明，在中温温度（35±1°C），初始pH为7，I / S比为0.75和C的条件下，沼气和甲烷的最大产量分别达到3359.6 ml和2127.30 ml。 / N比为30。基于此结果，微量元素（Fe 2 ⁺，Ni 2 ⁺，Co还探讨了沼气产量和甲烷含量的²⁺）。与不添加微量元素的组相比，添加微量元素的实验对沼气和甲烷的产生具有显着的增强作用，其中Fe ²⁺起主要作用（p <0.05）。Fe ²⁺促进了咖啡果壳的水解和酸化，导致产生了一系列中间体，例如挥发性脂肪酸和其他种类的溶解有机物。此外，Ni 2 ⁺，Co ²⁺和Fe ^2+的配合增强了产甲烷菌中酶系统的活性，促进了甲烷的产生。本文结果表明，咖啡果皮通过厌氧消化具有明显的沼气潜力，其有效利用可以满足埃塞俄比亚固体废物填埋和当地环境保护的双重目的。