Title: Tertiary treatment of abattoir wastewater in a horizontal subsurface flow-constructed wetland under tropical conditions

Authors: Robinson Odong; Frank Kansiime; John Omara; Joseph Kyambadde

Addresses: Department of Biological Sciences, College of Natural Sciences, Makerere University, P.O. Box 7062, Kampala, Uganda ' Department of Environmental Management, College of Agricultural and Environmental Sciences, Makerere University, P.O. Box 7062, Kampala, Uganda ' Department of Biochemistry and Sports Science, College of Natural Sciences, Makerere University, P.O. Box 7062, Kampala, Uganda ' Department of Biochemistry and Sports Science, College of Natural Sciences, Makerere University, P.O. Box 7062, Kampala, Uganda

Abstract: A horizontal subsurface flow-constructed wetland (HSSF-CW) system planted with Cyperus papyrus was used to polish abattoir wastewater pre-treated in anaerobic and aerobic sequencing batch reactors at City Abattoir, Kampala. The HSSF-CW was 13 m long, 5 m wide, and was filled with gravel up to a depth of 0.6 m, of which 0.55 m was saturated with wastewater at hydraulic retention time (HRT) of 1.16 days. The percentage removals for turbidity, ammonium-nitrogen (NH₄-N), total nitrogen (TN), orthophosphate (o-PO₄-P), total phosphorus (TP), chemical oxygen demand (COD) and faecal coliform were 76, 48, 46, 74, 63, 60, and 100, respectively. Among different plant tissues investigated (roots, culm, sheath and umbel), nitrogen concentration was highest in the sheath. The different parts of plants also had different concentrations of phosphorus, with the culm having the highest concentration. Compared to literature, the percentage removals for organic matter, nutrients and faecal coliforms reported in this paper were high. Therefore, C. papyrus based constructed wetlands could potentially be used for tertiary treatment of abattoir effluents.

Keywords: abattoir wastewater; nutrients; constructed wetland systems; anaerobic-aerobic SBRs; sequencing batch reactors; C. papyrus; wastewater treatment; tropical conditions; Uganda; turbidity; ammonium-nitrogen; total nitrogen; orthophosphate; total phosphorus; chemical oxygen demand; COD; faecal coliform; tertiary treatment; abattoir effluent.

DOI: 10.1504/IJEWM.2015.069160

International Journal of Environment and Waste Management, 2015 Vol.15 No.3, pp.257 - 270

Accepted: 29 Jul 2014
Published online: 30 Apr 2015 *

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