Application of CANON-SBR process for ammonium removal from old municipal old landfill leachate

Abstract

CANON (Completely Autotrophic Nitrogen-removal Over Nitrite) is the process combined Partial Nitritation and Anammox in a single reactor to remove ammonium from wastewater. This study used a lab-scale SBR Sequencing Bach Reactor for CANON process (CANON-SBR) to treat ammonium from old municipal solid waste landfill leachate. The reactor was run at two phases: (i) In adaptation phase, the synthetic wastewater containing 139 9 mg/l as NH4 +-N was fed into the reactor, and (ii) In operation phase, the reactor was fed with leachate taken from the Go Cat municipal lanfill which was closed since 2007. The reactor was run at ammonium loading rate of 0.2 kgN/m3.day and HRT of 0.6 day in the adaptation phase. pH and DO values in the reactor were controled in the ranges of 7.4 – 7.6 and 0.1 – 0.2 mg/l, respectively. After 15 days of adaptation, total nitrogen removal of 72% was obtained. Then, the leachate containing 3,000 mg/l NH4 +-N and 100 mg/l TSS was fed into the SBR. DO and pH were the key operation parameters for CANON process control. CANON-SBR obtained stable treatment efficiciency at DO ranging from 0.05-0.2 mg/l and pH values of 7.5 – 7.6. The obtained TN and COD removals were above 93% and 40%, respectively, when SBR was run at nitrogen loading rate of 0,4 kgN/m3.day and HRT of 7.43 day. TN concentration of the final batch was 34 mg/l that is met with column B1 QCVN 25:2009/BTNMT (TN< 60 mg/l), while nitrite and nitrate were not detected in the supernatant. This shows that co-existence of denitrifiers which consume nitrate produced from Anammox was available in biomass of the reactor. Numerous Anammox granules in dark red color happened after 20 days of running with leachate. Size of Anammox granules ranged from 5 - 800 μm, among that 73% of granule with size of 20 - 200 μm. The average granule diameter was 97.57 μm.