Lukhabi, Khasisi, Wairimu Muia, and Julius Kipkemboi. 2022. “Investigating the Efficiency of Vertical Sub-Surface Flow Constructed Wetlands in the Reduction of Faecal Indicator Bacteria and Organic Matter Under Varied Sizes of Gravel Substrate Aggregates”. PAN AFRICA SCIENCE JOURNAL 2 (01):187-214. https://doi.org/10.47787/pasj.v1i02.15.