WASET
    H.A. Gasim and  S.R.M. Kutty and  M.H. Isa and  M.P.M. Isa,  Treatment of Petroleum Refinery Wastewater by using UASB Reactors.   journal   = {International Journal of Environmental and Ecological Engineering}, [online]. World Academy of Science, Engineering and Technology.
    February 2012, vol. 62(2). 58 - 61
    [viewed 19 April 2024]. Available from: https://publications.waset.org/pdf/584.