AWWA JAW34180

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 3.5C, the system has shown superior performance compared with conventional fixed-film 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. Includes 62 references, tables, figures.