Characterization of microplastics from wastewater treatment plants in Kampala

Abstract

This study aimed to evaluate the presence, types, and removal efficiency of microplastics (MPs) in wastewater treatment processes at Lubigi and Bugolobi Wastewater Treatment Plants (WWTPs) in Uganda. Wastewater samples were collected from both influent and effluent points across two sampling campaigns at each plant. Microplastics were characterized based on shape, revealing that beads, fragments and fibers were the most dominant types across all samples. Quantitative analysis indicated that Bugolobi WWTP achieved consistently high MP removal efficiencies, ranging from 87.24% to 95.93%, while Lubigi WWTP exhibited a wider range of performance, from 30.99% to 94.10%. This inconsistency at Lubigi suggests possible operational fluctuations or infrastructural limitations. Supporting physicochemical analyses showed reductions in turbidity, BOD, COD, and nutrient levels between influent and effluent samples, validating the general effectiveness of the treatment processes. The findings highlight the need for improved treatment infrastructure, regular monitoring, and policy-level attention to microplastic pollution in wastewater management systems.