The 6th International Conference on Biomass Energy (ICBE2018)

457 / 2018-09-05 09:19:28

The effects of trace elements addition on the anaerobic co-digestion performance of chicken manure and maize silage

Plenary track > E.Gaseous Biofuel

In order to verify the regulating effect of trace elements (TEs) deficiency/addition on the performance of the anaerobic digestion (AD) from nitrogen and fiber-rich feedstocks, chicken manure mixed with maize silage was used as co-feedstock to promote ammonia and total solid (TS) surplus in digestate. The long-term AD was conducted for 297 days in the 5L continuous stirred tank reactor, so as to observe the variations of total ammonia nitrogen (TAN), volatile fatty acids, biogas production and other indicators of AD performance. The results showed that the threshold value of Ni, Se and Co of 0.30, 0.10 and 0.10 mg/L or less could trigger propionic acid accumulation. The addition of the lacking TEs did not show significant effect on preventing acetic acid accumulation, but could exert positive effect on restraining propionic acid accumulation on the premise of the TAN level and TS content below 7000 mg/L and 18%, respectively. By facilitating the competitiveness of acetoclastic pathway, the TEs addition could relieve the instable AD process brought by ammonia and TS surplus to a certain degree. However, the beneficial effects of TEs addition on biogas production were restricted by multiple inhibitions from low mass migration and utilization as well as high free ammonia level.