Clean Water and Sanitation (SDG 6), Climate Action (SDG 13)
Characterisation of Natural Organic Matter (NOM) and Efficiency of its removal in Drinking Water Treatment Plants (DWTPs) of the Kingdom of Eswatini Cynthia Chear 1* , Welldone Moyo 2 , Thabo Nkambule 2 , Thabile Ndlovu 1 1 Department of Chemistry, Faculty of Science and Engineering, University of Eswatini, Kwaluseni, Eswatini 2 Institute for Nanotechnology and water sustainability (iNanoWs), College of Engineering, Science and Technology, University of South Africa, Johannesburg, South Africa Natural organic matter (NOM) is a complex mixture of organic compounds derived from the decomposition of animal and plant material in water sources and surrounding environments. The source, climatic conditions and land use influence NOM concentrations and its reactivity in the water. NOM influences the quality and treatability of water, as its presence reduces the efficiency of conventional drinking water treatment plants (WTPs). Its presence is a precursor for the formation of disinfection by-products (DBPs) and acts as a substrate for bacterial growth and mobilises toxic metals and other organic pollutants. Even though NOM characteristics and removal performances of various WTPs have been investigated in the SADC region (e.g., South Africa and Zimbabwe), this has not been done in the Kingdom of Eswatini. This research sought to assess the nature of NOM in Eswatini and to evaluate the NOM removal efficiency in WTPs. Four treatment plants were sampled at all the stages of the treatment train to determine the efficiency of each treatment stage in removing NOM. The NOM was characterised using total organic carbon,dissolved organic carbon, ultraviolet-visible and fluorescence excitation- emission matrix). Key results show that water in the Middleveld and Lowveld agro-ecological regions of Eswatini show the presence of hydrophobic fractions, while the Highveld region mainly show the presence of transphilic fractions. In addition, it was found that all the treatment plants in Eswatini have low concentrations of organic matter, and these decrease along the treatment train, showing efficiency of the NOM removal processes. Key words: Agro-ecological zone, Natural organic matter, Water treatment plant, Eswatini, Treatability
P01
© The Author(s), 2023
Made with FlippingBook Learn more on our blog