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Direct Research Journals
Vol.3 (1), pp. 17-25, January 2015 
ISSN: 2354-4147

An assessment of the quality of rooftop rainwater harvested at Nhlambeni, Swaziland
Article Number: DRJA17086157
DOI:

Original Research Article


*1Vilane, B.R.T. and 2Mtshali, C.S.


1Agricultural and Biosystems Engineering, Faculty of Agriculture, University of Swaziland, P.O. Luyengo, M25, Luyengo,Swaziland.
2Nhlambeni, Zone 2, P.O. Box 824, Manzini, Swaziland.


date Received: November 19, 2015     date Accepted: December 13, 2014     date Published: January 30, 2015

Abstract

Rooftop rainwater could be safe provided safety precautions are taken during the capture, storage and distribution. Despite the precautions taken, rooftop rainwater can be polluted, hence this study. An experiment was conducted to purposively target the quality of rooftop rainwater harvested by 81 households in Nhlambeni. It was designed to determine the storage facilities and catchment materials used for rooftop rainwater harvesting, and to determine the physical and biological quality of the rooftop rainwater harvested.It had four treatments; corrugated iron, corrugated iron with concrete blocks, painted corrugated iron and tiles with two replications. The Swaziland Water Services Cooperation (SWSC) treated tapwater was used as a control. The parameters investigated were Biological and physical. Rainwater samples were collected at the top and bottom of the storage tanks using two sterilised glass bottles. Rainwater analysis results were compared to the SWSC drinking water guidelines. Data were analyzed using Microsoft Excel computer software, utilizing standard error bars. The results indicated that the rooftop rainwater storage facilities used by the 81 households were mostly (98.8%) PVC tanks and one (1.2%) metal storage tank. The catchment materials were corrugated iron sheets (95.1%) and Tiles (4.9%). The biological quality of the harvested rainwater was within the acceptable level (> 100 counts per 100 ml). Total and faecal coliforms had total mean levels of 15.46/100 ml and 11.63/100 ml, respectively. It was concluded that the Physical rainwater quality reflected that the rainwater was within acceptable quality ranges (>25NTU for turbidity and between 6.5 and 8.5 for pH). Turbidity, pH and temperature had total averages of 12.23 NTU, 6.54 and 12.3OC, respectively. It was recommended that the rooftop rainwater storage tanks should be flushed during the dry season when they are empty to minimize contamination during the subsequent rainwater harvesting season.


Key words: Rainwater harvesting, Rooftop catchments, Water quality.