[1] Univ Cape Town, Fac Engn & Built Environm, Dept Chem Engn, ZA-7701 Rondebosch, South Africa
[2] Univ Cape Town, Fac Engn & Built Environm, Ctr Res Engn Educ, ZA-7701 Rondebosch, South Africa
[3] Moi Univ, Sch Engn, Dept Chem & Proc Engn, Eldoret, Kenya
[4] Univ Dar Es Salaam, Coll Engn & Technol, Dept Chem & Min Engn, Dar Es Salaam, Tanzania