EVALUATION OF WASTE MANAGEMENT SYSTEMS IN A KENYAN TEA FACTORY: A CASE STUDY OF MARAMBA TEA FACTORY IN KIAMBU COUNTY

Abstract

This paper evaluates the effectiveness of waste management systems in Maramba Tea Factory in Kiambu County, Kenya.   Performance of the already existing systems is therefore critical in sustaining our environment. Tea processing generates different types of wastes. A waste management system design should at least begin from a clear characterization of these wastes, the quantities and qualities of the wastes and identification of sources. This study attempted to bring these challenges to the fore. It evaluated the waste management systems for Maramba Tea factory in Kiambu County, Kenya.  Primary data and secondary data, Purposively and Convenience sampling techniques, Benchmarking evaluation technique were utilised. The types of wastes identified were organic solid wastes, inorganic solid wastes, Liquid wastes and Thermal wastes. The quantities of wastes were determined by weighing. The Organic solid wastes from tea processing stages was 486.47 kilograms per month and inorganic solid wastes (sacks and polythene bags) was 15.38 kilograms per month.  The amount of liquid wastes generated for the study period were estimated. The highest with major cleaning done weekly averaged of 139.4m³ and least with minor cleaning done daily averaged at 52.8m³. The thermal wastes generated was due to heat loss from the wood fuel used as a source of energy. The total amount of heat loss was 1145.51kcal/kg representing 37.45%. of the Gross Calorific Value (GCV) of wood fuel. The highest heat loss was due to dry flue gas with a 22.09% of GCV of wood fuel representing 675.85kcal/kg and the least due to moisture present in the combustion air at 24.78kcal/kg representing 0.810 % of the total GCV of wood fuel. The qualities of wastewater were achieved through analysing the BOD₅, COD, pH and Electrical conductivity and comparing the values to the standards recommended by National Environment Management Authority (NEMA). The BOD₅ at 83.7mg/L and COD at 106.63mg/L exceeded the NEMA limits of 30mg/L and 50mg/L respectively. The thermal waste systems were evaluated by determining the boiler efficiency. Boiler efficiency at Maramba Tea Factory was 62.55%. The boiler efficiency of 62.55% is lower compared to the set values of 75.01% and 75%. The analysis with ANOVA showed significant differences in the water parameter values from source through the lagoon to the river. The coefficient of determination (R²) for most of the parameter analysed were above 97%.  It was concluded that the waste management systems are only partially effective at Maramba Tea Factory.  More targeted studies need to be carried out in other food industries to make a general conclusion on the state of waste management systems in Kenya.