Use of a rotating biological contactor for removal of ammonium from mining effluents

Mine and mill effluents often contain appreciable quantities of ammonia. The discharge of effluents containing ammonia to aquatic systems can have significant environmental effects because ammonia is toxic to fish and other organisms. The Rotating Biological Contactor (RBC) technology has been in use for several years for the treatment of municipal and industrial wastewater. This study evaluates the application of RBC technology for the removal of ammonia from mining industry effluents. The research shows that the RBC is very effective in the removal of ammonium (NH4-N) from simulated mining effluents in the temperature range of 4.5 to 24C and pH values ranging from 7.5 to 8.0. The RBC was able to remove more than 95% of the influent NH4-N (at a concentration of 45mg/l) at a hydraulic retention time (HRT) of 1.7h and a hydraulic loading rate (HLR) of 0.04m/md at 8C. At 4.5C the RBC produced an effluent with NH4N and NO2-N concentrations of 0.1 and 0.7mg/l, respectively, at HRT of 3.2h and HLR of 0.02m/md. The results show that RBC biological treatment systems are capable of treating mine effluents at cold temperature conditions (4 to 5C) for ammonia removal. The RBC was observed to recover approximately 50% to 75% of normal ammonia removal process efficiency in about a day after process upsets. © 2003 SDU. All rights reserved.