WASET
    Moatlhodi Wise Letshwenyo and  Lesedi Lebogang,  Pilot Scale Investigation on the Removal of Pollutants from Secondary Effluent to Meet Botswana Irrigation Standards Using Roughing and Slow Sand Filters.   journal   = {International Journal of Environmental and Ecological Engineering}, [online]. World Academy of Science, Engineering and Technology.
    April 2018, vol. 137(5). 376 - 384
    [viewed 28 March 2024]. Available from: https://publications.waset.org/pdf/10008983.