Title: Assessing quality wastewater for irrigation in Swaziland (eSwatini) using multivariate statistical analyses: organics and nutrients

Authors: Thabani Ivor Mamba; Julius Musyoka Ndambuki; Williams Kehinde Kupolati; Adesola Olutayo Olaleye

Addresses: Department of Civil Engineering, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa ' Department of Civil Engineering, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa ' Department of Civil Engineering, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa ' Department of Crop Production, University of Eswatini, Private Bag 4, Kwaluseni, Luyengo, Eswatini

Abstract: Data is sparse on the quality of wastewater (WW) discharged into rivers. The objective was to assess the quality of WW variables (organics and nutrients) using multivariate statistical analyses and compare these with international WW quality standards for irrigation. Samples were collected for 22 months and were analysed in the laboratory. Data were analysed statistically. Results showed WW variables (nutrients) were within the normal standards and guidelines for water quality for irrigated agriculture and aquatic lives. The principal component analysis (PCA) showed four components accounted for about 79.40% of the variations in the properties of the WW effluents. The PC-1 was 31% and associated with coliforms and chemical oxygen demand (COD). The results of the cluster analysis showed that the 11 WWTPs could be grouped into four clusters for ease of management. The elevated levels of total coliforms (TC), FC and COD from these treatment plants may pose risks to aquatic lives.

Keywords: Eswatini; irrigation; multivariate statistics; organics; wastewater treatment; Southern Africa; Swaziland.

DOI: 10.1504/IJEWM.2025.144221

International Journal of Environment and Waste Management, 2025 Vol.36 No.2, pp.140 - 167

Accepted: 06 Jul 2022
Published online: 03 Feb 2025 *

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