“…The rapid transformation of C, N and other elements can occur in RBF system under the stimulation of high hydrodynamic loading and strong chemical gradients (Runkel, Mcknight, & Rajaram, 2003). Iron (Fe 2+ ) and manganese (Mn 2+ ) exist widely in groundwater, especially in Northeast China (Hasan, Abdullah, Kamarudin, & Kofli, 2015), which can result in aesthetic and operational problems such as undesirable colour, odour and staining of laundry when the groundwater is intended for potable use (Qin, Ma, Huang, & Yang, 2009). In addition, ammonium (NH 4 + ) can react with chlorine to form disinfection by‐products, producing deteriorated taste and odour of water and damage to the human nervous system (Hasan, Abdullah, Kofli, & Kamarudin, 2012).…”