Grey water treatment in urban slums by a filtration system: Optimisation of the filtration medium

A. Y. Katukiza*, M. Ronteltap, C. B. Niwagaba, F. Kansiime, P. N.L. Lens

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

38 Citations (Scopus)


Two uPVC columns (outer diameter 160cm, internal diameter 14.6cm and length 100cm) were operated in parallel and in series to simulate grey water treatment by media based filtration at unsaturated conditions and constant hydraulic loading rates (HLR). Grey water from bathroom, laundry and kitchen activities was collected from 10 households in the Bwaise III slum in Kampala (Uganda) in separate containers, mixed in equal proportions followed by settling, prior to transferring the influent to the tanks. Column 1 was packed with lava rock to a depth of 60cm, while column 2 was packed with lava rock (bottom 30cm) and silica sand, which was later replaced by granular activated carbon (top 30cm) to further investigate nutrient removal from grey water. Operating the two filter columns in series at a HLR of 20cm/day resulted in a better effluent quality than at a higher (40cm/day) HLR. The COD removal efficiencies by filter columns 1 and 2 in series amounted to 90% and 84% at HLR of 20cm/day and 40cm/day, respectively. TOC and DOC removal efficiency amounted to 77% and 71% at a HLR of 20cm/day, but decreased to 72% and 67% at a HLR of 40cm/day, respectively. The highest log removal of Escherichia coli, Salmonella sp. and total coliforms amounted to 3.68, 3.50 and 3.95 at a HLR of 20cm/day respectively. The overall removal of pollutants increased with infiltration depth, with the highest pollutant removal efficiency occurring in the top 15cm layer. Grey water pre-treatment followed by double filtration using coarse and fine media has the potential to reduce the grey water pollution load in slum areas by more than 60%.

Original languageEnglish
Pages (from-to)131-141
Number of pages11
JournalJournal of Environmental Management
Publication statusPublished - 15 Dec 2014
Externally publishedYes


  • Filter columns
  • Granular activated carbon
  • Grey water
  • Lava rock
  • Slum sanitation
  • Treatment


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