Removing Nitrate With a Methylotrophic Fluidized Bed: Technology and Operating Performance

A pilot biological fluidized‐bed plant with a capacity of 40 m3/h has been in operation since January 1988 at De Blankaart drinking water production center for removing nitrate from surface water. Methanol is used as the reductant. With a nitrate removal efficiency of 9.0 kg NO3−/m3 reactor.day at 3.5°C, the system has shown superior performance compared with conventional fixed‐bed biofilm reactors. With an influent concentration of 75 mg NO3−/L, complete nitrate removal was achieved at an empty bed contact time of 15 min. Nitrite was not detected in the effluent, provided there was a slight excess of methanol (1–2 mg/L). Residual methanol was easily removed by the existing downstream drinking water treatment processes.