[Bioavailability of nickel and its complexes during anaerobic digestion]

The biouptake of nickel and its complexes for methanogenic enrichment in the presence of different chelators during batch methane fermentation were investigated in this paper. The results showed that the chelators had obvious effects on anaerobic digestion. At sodium acetate concentration of 85 mmol/L, sulfides concentration of 1 mmol/L, nickel concentration of 200 micromol/L and temperature was 35 degrees C, methane production in the NTA added system were 15% and 9% which was higher than that in CA and EDTA amended ones. While nickel concentration was 100 micromol/L, methane production in NTA added system were 43% and 57% which was higher than that in CA and EDTA amended ones. The biouptake of nickel for methanogenic enrichment related to the species of nickel complexes. NTA was the best chelator for stimulating nickel biouptake in the anaerobic reactors, and EDTA was the better one. The biouptake of Ni-CA complexes was the minimum for the methanogenic enrichment.