The Contaminating Effects of Coffee Processing Honey Water, Case of Othaya Coffee Society, Nyeri County, Kenya

Abstract

The release of untreated honey water from green coffee processing poses a significant threat to surface water contamination, directly impacting the livelihoods of downstream communities. This study aimed to evaluate the contaminating effects of honey water emissions from coffee processing on surface waters. Specifically, the study sought to determine the levels of contaminants in honey water from coffee processing, assess the degree of pollution caused by these emissions, and examine the socio-economic impacts on affected populations. A mixed-methods research design was employed for this study. The research site was divided into experimental units, with four blocks (I–IV) and three treatments (K–M) per block, each containing three sub-samples (1–3). To minimize variability across tests from the same target area, the study employed a total squares randomized design with four combined replicates to create a test turnover table, which was used to determine variability between test objectives (p < 0.05). The study collected a total of sixteen samples: twelve surface water samples from upstream, midstream, and downstream locations, and four untreated honey water samples from coffee processing lagoons. The physicochemical properties of these samples were thoroughly analyzed. In addition, the study incorporated qualitative data through open and closed-ended questionnaires. Descriptive statistics were used to analyze responses from 79 members of the Othaya Coffee Society Management and 30 nearby households, focusing on their perceptions of the contaminating effects of honey water on surface waters. The findings revealed that coffee processing operations by the Othaya Coffee Society had detrimental effects on the local communities by polluting nearby surface waters with untreated coffee waste. The physicochemical analysis indicated that the water sources had elevated acidity, high organic matter content, increased chemical oxygen demand, and elevated concentrations of nutrients (nitrates, phosphates), as well as suspended solids—all of which contributed to deteriorating water quality. The analysis further confirmed that the effluents discharged by the wet coffee processing industry did not meet the World Health Organization's standards for treated effluent released into surface waters. Based on these findings, the study recommended that the Othaya Coffee Society and other coffee industries in the region implement proper wastewater treatment facilities to ensure that only treated effluent is discharged into water bodies. Furthermore, continuous enforcement of wastewater discharge regulations by authorities such as the National Environmental Management Authority is essential. The study also called for further research to examine the effects of coffee pulp on water contamination and to evaluate the role of urban planning policies in managing industrial wastewater in areas like Othaya town.