Unexpected heroes: invasive macrophytes boost performance of faltering waste stabilization ponds
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Date
2026
Journal Title
Journal ISSN
Volume Title
Publisher
Water Practice & Technology
Abstract
Waste stabilization ponds (WSPs) are a widely used technology for removing organic matter and pathogens from wastewater.
However, their effectiveness is often hindered by hydraulic overload, sludge accumulation, and the proliferation of invasive
macrophytes–the impacts of these challenges are not fully understood. In this study, standard methods were used to
assess WSPs under these operational challenges for the removal efficiency of physical, nutrient, and organic pollutants, as
well as faecal indicator bacteria (FIB); the extent of macrophyte occupancy; and the level of FIB colonizing invasive macrophyte
−
3−
roots. Results indicated high removal efficiencies (73.38–99.67%) for turbidity, total nitrogen, NO−
3 , NO2 , NH3, PO4 , BOD5, total
coliforms, Escherichia coli, enterococci, and Clostridium perfringens, whereas total dissolved solids, electrical conductivity,
and total phosphorus showed considerably lower removal (33.5–45.2%). Significant correlations (r = 0.47–0.96, P < 0.05)
were found between the removal efficiencies of physical, nutrient, and organic pollutants, as well as FIB, and macrophyte
occupancy. Furthermore, high densities of FIB colonizing the macrophyte roots suggest that these roots may have positively
contributed to the performance of the WSPs. The final effluent complied with East African standards for all pollutants except
turbidity, BOD5, and FIB. This study reveals that ignoring WSP maintenance significantly compromises treatment performance,
with potential implications for public health, and underscores the role of macrophytes in enhancing the performance of
faltering WSPs.
Description
Journal Article
Keywords
effluent quality, invasive macrophytes, removal efficiency, waste stabilization ponds, wastewater treatment, WSPs maintenance