Effects of copper and zinc on three stages-anaerobic fermentation of organic wastes

In order to reveal fermentation microorganism changes in the anaerobic fermentation (AF) of organic wastes at three stages resulted from heavy metals, the samples of control group and three stage of AF + copper (Cu) or zinc (Zn) were set, respectively. The results showed that Cu could significantly inhibit Hydrogenispora and Ruminofilibacter at hydrolysis stage then affect whole fermentation. Whereas Zn mainly promoted the growth of SBR1031 in the early stage of AF then promoted macromolecular degradation. Then, the growth and biodiversity of SBR1031 and Ruminofilibacter were further inhibited by the Cu while the SBR1031 and C10-SB1A promoted by the Zn at acidification stage. Finally, the addition of Cu or Zn promoted microorganisms' activity at the methanogenesis. These results illustrated the effect of Cu and Zn on microorganisms was varied with fermentation stage, and the mechanisms of Cu and Zn on microorganisms were concluded at three stages of AF accordingly.