Impact of nickel and cobalt on biogas production and process stability during semi-continuous anaerobic fermentation of a model substrate for maize silage

• Published in: Water research (Oxford) 2011-01, Vol.45 (2), p.781-787
• Main Authors: Pobeheim, Herbert, Munk, Bernhard, Lindorfer, Harald, Guebitz, Georg M.
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Anaerobic processes; Anaerobiosis; Applied sciences; Bioconversions. Hemisynthesis; Biofuels; Biogas; Biological and medical sciences; Biomass; Bioreactors; Biotechnology; Cellulose; Cobalt; Cobalt - administration & dosage; Cobalt - pharmacology; corn; corn silage; Energy; Exact sciences and technology; Fatty Acids, Volatile - metabolism; Fermentation; Fermentation - drug effects; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Hydrogen-Ion Concentration; Maize; Methods. Procedures. Technologies; Natural energy; Nickel; Nickel - administration & dosage; Nickel - pharmacology; propionic acid; Reactors; Silage; Stability; Use of agricultural and forest wastes. Biomass use, bioconversion; Volatile fatty acids; Zea mays - metabolism
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2010.09.001

The importance of nickel and cobalt on anaerobic degradation of a defined model substrate for maize was demonstrated. Five semi-continuous reactors were operated for 250 days at 35 °C and a well-defined trace metal solution was added to all reactors. Two reactors each were limited regarding the concentration of Ni2+ and Co2+, respectively, for certain time intervals. The required nickel concentration was depending on the organic loading rates (OLR) while, for example, above 2.6 g ODM L−1 d−1 nickel concentrations below 0.06 mg kg−1 FM in the process significantly decreased biogas production by up to 25% compared to a control reactor containing 0.8 mg Ni2+ kg−1 FM. Similarly, limitation of cobalt to 0.02 mg kg−1 FM decreased biogas production by about 10%. Limitations of nickel as well as cobalt lead to process instability. However, after gradual addition of nickel till 0.6 mg and cobalt till 0.05 mg kg−1 FM the OLR was again increased to 4.3 g ODM L−1 d−1 while process stability was recovered and a fast metabolisation of acetic and propionic acid was detected. An increase of nickel to 0.88 mg kg−1 FM did not enhance biogas performance. Furthermore, the increase of cobalt from 0.05 mg kg−1 FM up to 0.07 mg kg−1 FM did not exhibit a change in anaerobic fermentation and biogas production.