Impact of Ammonia Nitrogen on COD Removal Efficiency in Anaerobic Hybrid Membrane Bioreactor Treating Synthetic Leachate

In this study, anaerobic hybrid membrane bioreactor (An-HMBR) was operated for the treatment of synthetic leachate combining suspended growth, attached growth system and membrane system integrated in single unit. The treatment efficiency was examined under different ratios of synthetic leachate along with enrichment feed. Ammonia nitrogen (NH4-N) removal was limited compared to COD degradation due to anaerobic condition. The aim of the study is to examine nitrogen dynamics in An-HMBR and inhibition effect of NH4-N on the COD removal percentage. The nitrogen loading rate increased from 0.12 to 1.27kg/m(3)day and NH4-N concentration increased from 250 to 2500mgL(-1). The results showed that lower NH4-N concentration does not affect COD removal efficiency, while with increase in NH4-N concentration the COD removal efficiency decreased from 96 to 82%. The process inhibition of ammonia nitrogen was evaluated by Monod, Yano-Koga and Haldane model. Among the inhibition models, Yano-Koga model showed best fit correlation coefficient (R-2 0.97) compared to other models. Article HighlightsHigh concentration of ammoniacal nitrogen reduces the COD removal efficiency.Mass balance study shows that accumulation of ammoniacal nitrogen takes place at high leachate concentration.Yano-Koga model describes the specific growth rate very well.The maximum specific growth rate was 0.006h(-1) and substrate inhibition constant was 761.