Int.J.Curr.Microbiol.App.Sci (2018) 7(7): 2317-2329 2317 Original Research Article https://doi.org/10.20546/ijcmas.2018.707.270 Effect of Slanted Soil Design and Filter Media Distribution on the Removal of Fecal Bacteria and Organic Matter from Greywater Ynoussa Maiga 1* , Awa Ndiaye 2 , Drissa Sangaré 3 , Emeline Bitié 4 and Ken Ushijima 5 1 University Ouaga 1 Pr Joseph KI-ZERBO, Laboratory of Microbiology and Microbial Biotechnology, 03 BP 7021 Ouagadougou 03, Ouagadougou, Burkina Faso 2 Biological Sciences, Peleforo Gon Coulibaly University, BP 1328 Korhogo, Côte d’Ivoire 3 University of Man, BP 20 Man, Côte d’Ivoire 4 International Institute for Water and Environmental Engineering, 01 BP 594 Ouagadougou 01, Ouagadougou Burkina Faso 5 Environmental Engineering and Science, Hokkaido University, kita13-nishi 8, Kita-ku, Sapporo-shi, Hokkaido 060–8628, Japan *Corresponding author ABSTRACT Introduction In 2015, it was estimated that 2.4 billion people globally still lack improved sanitation facilities and that the least developed countries did not meet the sanitation target. The use of improved sanitation facilities is particularly low in Sub-Saharan Africa (30% overall) and despite this, the disparity between urban and rural areas is striking. Indeed, seven out of ten people without improved sanitation facilities live globally in rural areas (WHO-UNICEF, 2015). International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 7 Number 07 (2018) Journal homepage: http://www.ijcmas.com Slanted Soil Treatment System (SSTS) was previously designed for onsite greywater treatment. In this study, several configurations were tested with granitic gravel in order to improve its efficiency. The lowest average removal efficiencies for fecal coliforms, enterococci and E. coli were 1.78, 2.15 and 2.21 log u. respectively and originated from case 3 (length 3 m, width 20 cm, grain size in second box 1-4 mm). The highest removal efficiencies originated from case 1 (length 5 m, width 20 cm, grain size in second box 1-2 mm) with values of 2.66, 2.56 and 2.51 log u. for fecal coliforms, enterococci and E. coli respectively. The average removal of suspended solids varied from 62% (case 3) to 92% (case 1). The comparison of the performances highlighted that the removal of indicator bacteria was more affected by the variations in the characteristics of the SSTS than that of organic matter. Based on these results, a SSTS with a length of 5 m, a width of 30 cm and a grain size of 1-4 mm (to avoid early clogging) is suggested in order to enhance the removal of indicator bacteria. However, for organic matter, further studies are necessary to improve the removal efficiency. Keywords Granit, Greywater, Indicator bacteria, Slanted soil system Accepted: 17 June 2018 Available Online: 10 July 2018 Article Info