Landfill Leachate Ammonia Removal in Submerged Aerated Filter: A Full Scale Study Under Non-Alkalinization Condition

This study presents the performance of submerged aerated filter technology in landfill leachate treatment. The main objective was to evaluate ammonia removal. The investigation proposes the filter, without the use of chemical agents to alter the pH, as an applicable mechanism for nitrogen removal in the treatment. The research was developed in real-scale. The efficiencies obtained, for a hydraulic retention time of 56 days, were: 83% removal of ammoniacal nitrogen (influent concentration of 2,653 mg/L) and 78% removal of total Kjeldahl nitrogen (influent of 3,058 mg/L). The pH variation range was from 8.3 to 9.3. The alkalinity showed a reduction from 12,338 mg/L to 4,015 mg/L. The dissolved oxygen concentration ranged from 0 to 8.3 mg/L. Additionally, the efficiencies in removal organic matter were: 35% removal of COD (influent of 5,022 mg/L), 45% BOD removal (influent of 2,400 mg/L) and 40% TOC removal (influent of 2,141 mg/L). The expulsion of ammonia was great. The oxidation of organic matter, even after the establishment of a very favorable aerobic condition and despite the long liquid retention time, encountered difficulty in the extremely varied and complex composition of the leachate. The research hypothesis was positively confirmed: there is no need to alkalize the medium to obtain high ammonia expulsion in the leachate. The removal, in terms of load, was quite significant: 2.6 tons.