Sustainable Coffee Production Research Articles

Soil bioengineering for sustainable coffee farming in Way Besai sub-watersheds, Lampung, Indonesia

Soil bioengineering is part of vegetative land conservation activities, including covering all use of plants to maintain the carrying capacity of the land. The sustainability of coffee farming achievement in the upstream watershed area is closely related to the application of soil bioengineering technology. This study conducted to identify the recent studies of soil bioengineering technology and its application in coffee farming toward increasing the land productivity in the upstream watershed. The research location is a smallholder coffee plantation upstream of the Way Besay sub-watershed, spread over 3 sub-districts, Air Hitam, Way Tenong, and Sumber Jaya sub-District, West Lampung, Lampung, Indonesia. Coffee farmers as many as 167 people as respondents. The data analysis method used exploration of the applicability of soil bioengineering technology at the micro-level. The mapping of the role of soil bioengineering trace using the VosViewer tool. The results of the analysis show that the readiness level application of soil bioengineering technology in coffee farming includes the production and use of organic fertilizers made from local materials, the use of mulch as soil cover, agroforestry with a variety of tall canopy plants/MPTS, the planting of multiple cropping (planting various yielding crops), and plant diversification with alley planting. Soil bioengineering technology has a very high potential to increase land productivity to support sustainable coffee production in the upstream area of the Lampung watershed.

Potential Application of Rhizobacteria Isolated from the Central Highland of Vietnam as an Effective Biocontrol Agent of Robusta Coffee Nematodes and as a Bio-Fertilizer

Robusta coffee is a major commercial crop in the Central Highland of Vietnam with high economic and export value. However, this crop is adversely affected by various pathogens, particularly nematodes. This study aimed to screen active anti-nematode rhizobacterial strains for sustainable coffee production. Among more than 200 isolates, the isolate TUN03 demonstrated efficient biocontrol with nearly 100% mortality of J2 coffee nematodes Meloidogyne spp. and 84% inhibition of nematode egg hatching. This active strain was identified as Pseudomonas aeruginosa TUN03 based on its 16S rRNA gene sequence and phylogenetic analysis. In greenhouse tests, the strain TUN03 significantly reduced the coffee nematode population in the rhizome-soil with an 83.23% inhibition rate and showed plant growth-promoting effects. Notably, this is the first report of the nematicidal effect of P. aeruginosa against coffee nematodes. This potent strain further showed an antifungal effect against various crop-pathogenic fungi and was found to be the most effective against Fusarium solani F04 (isolated from coffee roots) with a 70.51% inhibition rate. In addition, high-performance liquid chromatography analysis revealed that this bacterial strain also secretes plant growth regulators including indole acetic acid (IAA), gibberellic acid (GA3), kinetin, and zeatin in significant amounts of 100, 2700, 37, and 9.5 µg/mL, respectively. The data from this study suggest that P. aeruginosa TUN03 may be a potential biocontrol agent and biofertilizer for the sustainable production of Robusta coffee and other crops.

Genomic and transcriptomic inventory of membrane transporters in coffee: Exploring molecular mechanisms of metabolite accumulation

The genus Coffea (Rubiaceae) encompasses a group of perennial plant species, including a commodity crop from which seeds are roasted, ground, and infused to make one of the most appreciated beverages in the world. As an important tropical crop restricted to specific regions of the world, coffee production is highly susceptible to the effects of environmental instabilities (i.e., local year-to-year weather fluctuations and global climate change) and threatening pest pressures, not to mention an increasing quality rigor by consumers in industrialized countries. Specialized metabolites are substances that largely affect plant-environment interactions as well as how consumers experience agricultural products. Membrane transporters are key targets, albeit understudied, for understanding and tailoring the spatiotemporal distribution of specialized metabolites as they mediate and control molecular trafficking and substance accumulation. Therefore, we analyzed the transportome of C. canephora encoded within the 25,574 protein-coding genes annotated in the genome of this species and identified 1847 putative membrane transporters. Following, we mined 152 transcriptional profiles of C. canephora and C. arabica and performed a comprehensive co-expression analysis to identify transporters potentially involved in the accumulation of specialized metabolites associated with beverage quality and bioactivity attributes. In toto, this report points to an avenue of possibilities on Coffea genomic and transcriptomic data mining for genetic breeding strategies, which can lead to the development of new, resilient varieties for more sustainable coffee production systems.

Plant Growth-Promoting Microorganisms in Coffee Production: From Isolation to Field Application

Coffee is an important, high-value crop because its roasted beans are used to produce popular beverages that are consumed worldwide. Coffee plantations exist in over 70 countries and constitute the main economic activity of approximately 125 million people. Currently, there is global concern regarding the excessive use of agrochemicals and pesticides in agriculture, including coffee crops. This situation has motivated researchers, administrators, and farmers to seek ecologically friendly alternatives to decrease the use of synthetic fertilizers and pesticides. In the last decades, multiple studies of the rhizosphere, at the chemical, physical and biological levels, have improved our understanding of the importance of beneficial microorganisms to plant health and growth. This review aims to summarize the state of the use of plant growth-promoting microorganisms (PGPM) in coffee production, where the most extensively studied microorganisms are beneficial plant growth-promoting rhizobacteria (PGPR) and arbuscular mycorrhizal fungi (AMF). This review also contains information on PGPM, in regard to plantations at different latitudes, isolation techniques, mass multiplication, formulation methods, and the application of PGPM in nurseries, monoculture, and coffee agroforestry systems. Finally, this review focuses on relevant research performed during the last decade that can help us improve sustainable coffee production.

Coffee income and its determinants: A case of Deusa village, Nepal

Understanding economic contribution of coffee production and influencing socioeconomic and environmental factors for coffee income are vital for its promotion. The primary aim of this study was therefore to assess the contribution of coffee income to the household total cash income and identify influencing socioeconomic and environmental factors for coffee income in Deusa, Solukhumbu district of Nepal. A semi-structured questionnaire survey gather data from 55 coffee-growing households. We used Ordinary Least Square regressions (OLS) for identifying influencing factors for coffee income. Household annual gross income, from farm and off-farm income sources, estimated was around NPR 161 thousand, and the median value was 57.4 thousand. On average, coffee farming contributed almost 9% of the total household income in the study area. The OLS regression showed that sufficient labor availability (p<0.05), access to coffee-related trainings (p<0.05), and access to irrigation facilities (p<0.05) significantly increased coffee earnings. Likewise, environmental variables - elevation (negatively, p<0.05) and shade trees availability for coffee farming (positively, p<0.05) also influenced earnings from the coffee farming. We recommend provisions of trainings, improved irrigation facilities and tree saplings for shade management for sustainable coffee production in the study area.

A Competitive Perspective of Sustainable Coffee Production Practices

Background: This study analyzes sustainable coffee production and its competitive perspectives. The present study explains the understanding of sustainable production practices with a triple bottom line approach examining the relationship between production practices and competitiveness. The adoption of a sustainable development strategy has become important for companies as they cannot only be environment friendly but also gain a competitive advantage. The recent studies even found that environmental sustainability has a direct and positive relationship with competitiveness. Objective: The main objective of this study is to find out sustainable coffee production practices and competitive perspectives. Method: The research is descriptive. It explains the data and their characteristics statistically without manipulation. A structured questionnaire was used to collect the data using a survey method.Result: The most significant observation of the study is that the strenuous working condition of coffee production changes the living standard of the people in the community in the future. In this study, the majority of farmers responded that they were practicing sustainable coffee production. They were aware of the environmental aspect of coffee production practices and sustainable way of production leads to competitiveness in international markets. Conclusion: The research concluded that the independent variables economic aspect, social aspect, and environmental aspect of sustainable production practices have a significant positive relationship with competitiveness.Implication: The findings of the paper imply that the adoption of a sustainable development strategy has become more important for the companies as they cannot only be environment friendly but also gain a competitive advantage.

Optimization of ecosystems services for sustainable coffee production under changing climate

Legume cover crops have previously been evaluated for green manure, weed control and soil moisture conservation, this study includes further evaluation of biomass of the legume fodder. Our research was to compare soil nutrients and moisture concentration at different times in the treatment plots in the coffee plantation after the establishment of a desmodium legume cover crop with quantification of the resulting biomass as fodder for livestock. This case study conducted at the University of Nairobi coffee plantation evaluating different weed control methods in coffee using hand weeding, glyphosate (1.0 kg ha-¹ of acid equivalent) based herbicide and desmodium spp legume cover crop compared weeding costs and implications to farmers’ incomes in coffee production. Using completely Randomized Block Design 3 treatments replicated 3 times were analyzed for the annual weeding labour costs, soil nutrients, soil moisture and biomass production. Statistical analysis of soil moisture content and nutrients was evaluated among the treatments. Results indicated that coffee intercropped with desmodium had higher moisture retention of 36 % on average being higher than other treatment and desmodium legume fresh biomass production was extrapolated to 17,000 kgs per hectare per year. Desmodium spp planted was able to establish providing groundcover (90%) 18 weeks after planting inhibiting weed growth thus reducing the need for weeding as well as conserve soil moisture. There were significant savings on the cost of manual weeding with additional earnings or savings of 750 $ US from sales or utilization of the desmodium fodder per hectare. The study concludes that cover crops can enhance farmers’ resilience to changing climate utilizing the same size of land while enhancing output and increasing revenue. Policymakers need to realign extension services to introduce legume cover crops in coffee production to reduce the labour costs and the high doses of synthetic fertilizers which emit

Effect of Integrated Use of Coffee Husk Compost and NPS Fertilizer on Soil Physicochemical Properties and Yield of Coffee (<i>Coffea arabica L</i>.) at Haru, Ethiopia

Integrated application of inorganic and organic fertilizers is the main sources for replenishing plant nutrients in agricultural soils. However, selecting the optimum combination of these resources based on soil type and crop species is necessary. In this context, field experiment was conducted at Haru research center to assess the effect of coffee husk Compost and NPS Fertilizer on soil physicochemical properties and Yield of coffee in 2018/2019. The treatments were the different rates of both compost and NPS fertilizers laid out in randomized complete block design. The results of the study showed that combined application of coffee husk compost and NPS fertilizers were improved soil moisture and total porosity over control, while, bulk density was decreased below the control. Combined application of coffee husk compost at (7.5 t ha^-1) and mineral NPS fertilizer at (50 kg ha^-1) has better improved yield of coffee crop. The experimental yield of Manasibu variety for present study from the station was 1.59 t ha^-1. Therefore, based on the result of the study it can be concluded that under condition of low soil pH of study area the availability of essential nutrients (e.g. P, N, K, Ca, Mg, and Mo) are critically affected. This indicates that the strong acid pH values at Haru Research sub-center require more attention. Moreover, the low levels of CEC, organic carbon, total nitrogen, and available P contents at study area soils confirm that soil fertility is among the constraints for sustainable coffee production in the Haru district. In response to this application of integrated NPS fertilizer and coffee husk compost with different rates improved soil physicochemical properties and coffee yield. The study recommended that the use of 7.5 t ha^-1 coffee husk compost and 50 kg ha^-1 of NPS fertilizer can be the best alternative integrated soil fertility management option in place of the sole application of inorganic fertilizers at study area tentatively. Nevertheless, in order to give conclusive recommendation further research studies are needed for more soil types and coffee crop varieties.

Life cycle assessment synthesis of the carbon footprint of Arabica coffee: Case study of Brazil and Vietnam conventional and sustainable coffee production and export to the United Kingdom

Over 9.5 billion kg of coffee is produced annually and demand is expected to triple by 2050. Hence, the identification and quantification of the greenhouse gas emission footprint of coffee is essential if it is to become a more sustainable crop. We have produced a detailed life cycle assessment of the carbon equivalent footprint of coffee produced in Brazil and Vietnam and exported to the United Kingdom. The average carbon footprint of Arabica coffee from both countries was calculated as 15.33 (±0.72) kg of carbon dioxide equivalent per 1 kg of green coffee (kg CO2e kg−1) for conventional coffee production and 3.51 (±0.13) kg CO2e kg−1 for sustainable coffee production. The 77% reduction in carbon footprint for sustainable coffee production in comparison to conventional production was due to exportation of coffee beans via cargo ship rather than freight flight and the reduction of agrochemical inputs. Based on our results, further reductions could be made through optimal use of agrochemicals; reduced packaging; more efficient water heating; renewable energy use; roasting beans before exportation; and carbon offsetting. Applying these recommendations correctly through certification schemes could mitigate other environmental impacts of coffee cultivation.

Primary Metabolism Is Distinctly Modulated by Plant Resistance Inducers in Coffea arabica Leaves Infected by Hemileia vastatrix.

Epidemics of coffee leaf rust (CLR) leads to great yield losses and huge depreciation of coffee marketing values, if no control measures are applied. Societal expectations of a more sustainable coffee production are increasingly imposing the replacement of fungicide treatments by alternative solutions. A protection strategy is to take advantage of the plant immune system by eliciting constitutive defenses. Based on such concept, plant resistance inducers (PRIs) have been developed. The Greenforce CuCa formulation, similarly to acibenzolar-S-methyl (ASM), shows promising results in the control of CLR (Hemileia vastatrix) in Coffea arabica cv. Mundo Novo. The molecular mechanisms of PRIs action are poorly understood. In order to contribute to its elucidation a proteomic, physiological (leaf gas-exchange) and biochemical (enzymatic) analyses were performed. Coffee leaves treated with Greenforce CuCa and ASM and inoculation with H. vastatrix were considered. Proteomics revealed that both PRIs lead to metabolic adjustments but, inducing distinct proteins. These proteins were related with photosynthesis, protein metabolism and stress responses. Greenforce CuCa increased photosynthesis and stomatal conductance, while ASM caused a decrease in these parameters. It was further observed that Greenforce CuCa reinforces the redox homeostasis of the leaf, while ASM seems to affect preferentially the secondary metabolism and the stress-related proteins. So, the PRIs prepare the plant to resist CLR but, inducing different defense mechanisms upon pathogen infection. The existence of a link between the primary metabolism and defense responses was evidenced. The identification of components of the plant primary metabolism, essential for plant growth and development that, simultaneously, participate in the plant defense responses can open new perspectives for plant breeding programs.

Understanding the Perceptions of Sustainable Coffee Production: A Case Study of the K’Ho Ethnic Minority in a Small Village in Lâm Đồng Province of Vietnam

This case study used anthropological and culture concept methodologies to evaluate the perceptions of sustainable coffee production of the K’Ho ethnic minority in Di Linh district, Lâm Đồng province in the Central Highlands of Vietnam. Sustainable production is a means of mitigating the increasing impacts of climate change upon the region. The Central Highlands is a major coffee production hub and Di Linh is the largest coffee growing region of Lâm Đồng province. The case study included in-depth interviews with farmers based on open-ended questions and a questionnaire about sustainable coffee indicators. The survey invited farmers to quantify the current status of their social, economic, and environmental sustainability. Our study revealed that the unique, government sponsored development of coffee farms led to fast production rates and quick economic prosperity. But, it also resulted in a prolonged monoculture system of coffee production and high chemical use; causing farm productivity to decline and social, economic, and environmental vulnerability to increase. The K’Ho farmers in a small village are noticing the devastating long-term effects of agrochemicals, but have had some initial success exploring the potential benefits of reverting to traditional farming methods.

Toward a more sustainable coffee production

This paper contributes to the literature on the emerging trend of Southern sustainability standards and certifications as a reaction to the Northern-based private standards by businesses and NGOs. It particularly analyzes the implementation capacity of ISCoffee as a public standard and certification initiated by the Indonesian government. We analyze the opportunities and barriers in the process of implementing ISCoffee and examine whether ISCoffee can become a viable alternative to Northern-based private standards and certification. We first conclude that the implementation capacity of ISCoffee is low, because of weak administrative structures, and communication and coordination deficiencies. Second, we conclude that ISCoffee will unlikely being able to solve smallholder-related problems in the coffee sector such as limited access to market, insufficient capital, and underdeveloped farmer organizations. Finally, we conclude that ISCoffee - on the short term - will not manage to become a viable alternative to Northern-based private standards and certifications.

Kinerja Usahatani Kopi di Hulu DAS Sekampung, Tanggamus, Lampung

Most of the coffee production areas in Lampung are in the vicinity of production forests andprotected forests, also a catchment area for watersheds in Lampung, namely Sekampung andWay Seputih watersheds. Continuity of sustainable coffee production lines is an importantdemand that needs to be done. The application of coffee production systems with shade(agroforestry) in the catchment area is very important in ensuring environmentalsustainability. This study aims to analyze the income performance of agroforestry coffeebased on the land status in Hulu Das Sekampung. The research uses survey methods. Fielddata exploration conducted in April-November 2016 is located in Datar Lebuay and SinarJawa Villages. Air Naningan, Tanggamus, Lampung. The descriptive statistical analysismethod is used to explain the performance of agroforestry coffee production at the researchlocation. Based on the results and discussion it was concluded that farmers with landownership status had the highest level of coffee farming income compared to the land statusof HKm and non-HKm. Agroforestry coffee farmers obtain sources of income from coffeeproduction, MPTS production, and other crop production (multiple cropping). The averagecontribution of coffee farming income is 22% of the total farm income. Coffee contributes22% to the total income of farmer households. Farmer's household income with the status ofland ownership is the highest compared to the land status of HKm and Non-HKm. Thediversity of income sources of upstream farmers in the watershed. The villages that comefrom various vegetation plants are important in maintaining land cover as a catchment area.The practice of agroforestry coffee is an adaptation of sustainable production in the upperwatershed Sekampung. The pattern of agroforestry coffee production in the area aroundprotected and watershed forests needs to be continuously developed.

Sustainable Production of Robusta Coffee under a Changing Climate: A 10-Year Monitoring of Fertilizer Management in Coffee Farms in Vietnam and Indonesia

Assessing and prescribing fertilizer use is critical to profitable and sustainable coffee production, and this is becoming a priority concern for the Robusta coffee industry. In this study, annual survey data of 798 farms across selected Robusta coffee-producing provinces in Vietnam and Indonesia between 2008 and 2017 were used to comparatively assess the fertilizer management strategies in these countries. Specifically, we aimed to characterize fertilizer use patterns in the key coffee-growing provinces and discuss the potential for improving nutrient management practices. Four types of chemical (NPK, super phosphate, potassium chloride and urea) and two of natural (compost and lime) fertilizers were routinely used in Vietnam. In Indonesia, NPK and urea were supplemented only with compost. Farmers in Vietnam applied unbalanced quantities of chemical fertilizers (i.e., higher rates than recommended) and at a constant rate between years whereas Indonesian farmers applied well below the recommended rates because of poor accessibility and financial support. The overuse of chemical fertilizers in Vietnam threatens the sustainability of Robusta coffee farming. Nevertheless, there is a potential for improvement in both countries in terms of nutrient management and sustainability of Robusta coffee production by adopting the best local fertilizer management practices.

Fluctuating asymmetry and feather growth bars as biomarkers to assess the habitat quality of shade coffee farming for avian diversity conservation.

Shade coffee farming has been promoted as a means of combining sustainable coffee production and biodiversity conservation. Supporting this idea, similar levels of diversity and abundance of birds have been found in shade coffee and natural forests. However, diversity and abundance are not always good indicators of habitat quality because there may be a lag before population effects are observed following habitat conversion. Therefore, other indicators of habitat quality should be tested. In this paper, we investigate the use of two biomarkers: fluctuating asymmetry (FA) of tarsus length and rectrix mass, and feather growth bars (average growth bar width) to characterize the habitat quality of shade coffee and natural forests. We predicted higher FA and narrower feather growth bars in shade coffee forest versus natural forest, indicating higher quality in the latter. We measured and compared FA in tarsus length and rectrix mass and average growth bar width in more than 200 individuals of five bird species. The extent of FA in both tarsus length and rectrix mass was not different between the two forest types in any of the five species. Similarly, we found no difference in feather growth between shade coffee and natural forests for any species. Therefore, we conclude our comparison of biomarkers suggests that shade coffee farms and natural forests provide similar habitat quality for the five species we examined.

Exploring drivers’ interaction influencing the adoption of sustainable coffee production system through a qualitative system dynamics modelling, case study : smallholder coffee plantation in Pangalengan, Bandung, Indonesia

As one of complex socio-ecological systems, a coffee production system comprises dynamic interactions between social, economic, and ecological factors. This type of production system which is managed by smallhoder farmers not only provides economic gain, but also social equity and may has a potential to influence environmental quality. A study focused on identifying dynamics interaction between emerged drivers (economics, social quality, environmental quality, technology) and analyzing the polarity dominance of feedback process in order to find the most influental drivers in the adoption of sustainable production system has been carried out in smallholder coffee plantation in Pangalengan, Bandung, Indonesia. Within this approach, a qualitative system dynamics modelling namely causal loop diagram (CLD) were used as a system visualization tool. These analyses resulted insight into the behaviour that may cause a potentially grown or destructive (reinforcing loops), or conversely a stabilizing (balancing loop) behaviour. A polarity loop analysis found that each main driver may has a potential to influence the system to be grown or deteriorated due to its reinforcing loop dominance. The reinforcing feedbacks would tend to escalate the process and result in a sustainable state of the system. However, conversely this behaviour also would tend to declince the feedback process and result in an unsustainable state of the system. It indicates that instability of the process are most likely existed in the system. The most influental driver in this behaviour would be social quality, regarding its highest loop polarity differences. A management and intervention strategies are needed to prevent deterioration of the system, particularly with involving the social quality driver.

Using the yield-SAFE model to assess the impacts of climate change on yield of coffee (Coffea arabica L.) under agroforestry and monoculture systems

Ethiopia economy depends strongly on Coffea arabica production. Coffee, like many other crops, is sensitive to climate change and recent studies have suggested that future changes in climate will have a negative impact on its yield and quality. An urgent development and application of strategies against negative impacts of climate change on coffee production is important. Agroforestry-based system is one of the strategies that may ensure sustainable coffee production amidst likelihood future impacts of climate change. This system involves the combination of trees in buffer extremes thereby modifying microclimate conditions. This paper assessed coffee production under: (1) coffee monoculture and (2) coffee grown using agroforestry system, under: (a) current climate and (b) two different future climate change scenarios. The study focused on two representative coffee growing regions of Ethiopia under different soil, climate and elevation conditions. A process-based growth model (yield-SAFE) was used to simulate coffee production for a time horizon of 40 years. Climate change scenarios considered were: representative concentration pathways (RCP) 4.5 and 8.5. The results revealed that in monoculture systems, the current coffee yields are between 1200 and 1250 kg ha−1 year−1, with expected decrease between 4–38 and 20–60% in scenarios RCP 4.5 and 8.5, respectively. However, in agroforestry systems, the current yields are between 1600 and 2200 kg ha−1 year−1, the decrease was lower, ranging between 4–13 and 16–25% in RCP 4.5 and 8.5 scenarios, respectively. From the results, it can be concluded that coffee production under agroforestry systems has a higher level of resilience when facing future climate change and reinforce the idea of using this type of management in the near future for adapting climate change negative impacts on coffee production.

Agroecological coffee management increases arbuscular mycorrhizal fungi diversity.

Agroecology aims to maintain ecosystem services by minimizing the impact of agriculture and promoting the use of biological potential. Arbuscular mycorrhizal fungi (AMF) are elements which are key to improving crop productivity and soil quality. It is pertinent to understand how agricultural management in the tropics affects the AMF spatio-temporal community composition, especially in crops of global importance, such as coffee (Coffea arabica L.). Soil and root samples were collected from three localities under three management systems (agroecological, conventional and forest fragment), during the phenological stages of coffee (flowering, grain filling, harvesting). Spores were extracted for morphological identification and molecular community analysis by PCR–DGGE. Dendrograms were prepared and the bands were sequenced and analyzed by bioinformatics. No differences were observed in the richness of morphospecies between management systems, localities and period, but little is known about tropical species. Molecular analysis showed that the agroecological management system was similar to natural forest and with a higher diversity indices than conventional management. Locality and period of sample affect AMF community composition. It is necessary to associate classical taxonomic evaluations with molecular biological techniques because different approaches can lead to different outcomes. This study contributes to the understanding of the impact of agriculture management systems on AMF and provides evidence that agroecology is a management system applicable to sustainable coffee production.

CalcuCafé

Many smallholder coffee farmers in Latin America join cooperatives for increased access to global markets. This requires them to understand their costs relative to a complex sustainable coffee production process. To that end, we designed CalcuCafé, a web-based application for cooperative technicians and coffee farmers to calculate a farmer's costs of coffee production. We iteratively developed and evaluated CalcuCafé's design with members of two coffee cooperatives in Peru. Our research uncovered different expectations about the application between technicians and farmers, stemming from differing backgrounds, goals, and perspectives. Learning to use the application in a group setting helped overcome these differences and facilitated collaboration, resulting in a strong buy-in for the application. Our paper contributes a research and design effort to support smallholder coffee farmers, an underrecognized group at the intersection of HCI for sustainable agriculture and HCI for development.

Assessment of the effluent quality of wet coffee processing wastewater and its influence on downstream water quality

The objective of this study was to evaluate the impact of effluents from traditional wet coffee processing plants on the downstream water quality in Ethiopia. Composite water samples were collected from 11 rivers/streams associated with wet coffee processing plants at the peak hours of coffee processing, and water quality parameters were measured for the wastewater discharged as well as for the river water upstream and downstream of the discharge point. Acidic pH values were recorded for all plant effluents. The organic content of the effluents varied from one plant to another but was considerably high overall, with maximum values of 7200mg/L and 871mg/L for COD and BOD5, respectively. This high level of organic content in the effluents depleted the oxygen content to the level of 0.25mg/L. The organic load and the presence of nutrients invoke a large risk of eutrophication. We found that variations in coffee bean soaking time, pulp fermentation, and the absence of appropriate treatment facilities were the major factors affecting the water pollutant parameters. In general, the measured values of effluent parameters significantly deviated from both the Ethiopian-EPA and US-EPA guidelines. Thus, water bodies and ecosystems located downstream of the traditional wet coffee processing plants are at an alarming risk of ecological disruption, and there may also be severe health consequences for the nearby residents. These findings raise the need for further research into the design and implementation of coffee waste valorization and treatment in view of sustainable coffee production.