CH4 production potential of autotrophic nitrification bacteriaproduced in the submerged nitrification bioreactor in thelaboratory and kinetic analysis

In this study, CH4 production capacity of nitrification bacteria (NB) obtainedfrom the submerged biofilter in the laboratory was investigated. Biochemicalmethane potential (BMP) test was carried out with the NB amount of zero(control, CR), 5% (R1), 10% (R2), and 15% (R3) at a temperature of about 37 ±0.5°C. Compared to the CR, significantly higher cumulative CH4 volume ofabout 290, 490, and 715 mL were determined in the R1, R2, and R3, respec-tively. All the applied kinetic models gave good results (R2 ≥0.97), while theTransference Function and First-order models provided the better R2 values.The delay phase (λ) was not observed in the AD process, and CH4 productionstarted immediately on the first day of operation. The predicted k value of0.133 day−1 was high in CR, while it was approximately between 0.078 and0.112 day−1 for the higher amount of NB containing BMP units, which indi-cated that the AD required long reaction time.