Cost-saving biological nitrogen removal from strong ammonia landfill leachate

The aim of the study was to develop an improved management mode in Ammassuo landfill (Finland) for leachate ammonium-nitrogen removal, to minimize the leachate management costs and secure compliance with the uptrend requirements of regulations for on-site leachate management. With a single sequential batch simulation reactor, the minimum C/N ratio was detected as 1.7 (adjusted by external carbon addition), to achieve the acceptable removal efficiency of 99, 62 and 74% in NH4-N, total nitrogen and chemical oxygen demand, respectively. Both total nitrogen removal and efficiency of carbon use were correlated with an increasing NO2-/NOx- ratio indicating higher performance with denitrification via nitrite. It was estimated that the leachate management cost could be reduced by 28 to 38%.