Evaluation of biomethane yields from high-energy organic waste and sewage sludge: a pilot study for a wastewater treatment plant
1 Institute of Food Technology of Plant Origin, Poznan University of Life Sciences, ul. Wojska Polskiego 28, 60-637, Poznan, Poland
2 Institute of Biosystems Engineering, Poznan University of Life Sciences, ul. Wojska Polskiego 28, 60-637, Poznan, Poland
3 Institute of Chemical Wood Technology, Poznan University of Life Sciences, ul. Wojska Polskiego 28, 60-637, Poznan, Poland
4 Poznan City Hall, 61-847, Poznan, Poland
5 Centre of Advanced Technologies, Adam Mickiewicz University, ul. Umultowska 89C, 61-614, Poznan, Poland
2 Institute of Biosystems Engineering, Poznan University of Life Sciences, ul. Wojska Polskiego 28, 60-637, Poznan, Poland
3 Institute of Chemical Wood Technology, Poznan University of Life Sciences, ul. Wojska Polskiego 28, 60-637, Poznan, Poland
4 Poznan City Hall, 61-847, Poznan, Poland
5 Centre of Advanced Technologies, Adam Mickiewicz University, ul. Umultowska 89C, 61-614, Poznan, Poland
Abstract
The article describes a pilot study on a wastewater treatment plant operating a biogas plant (2.793 MW). The authors of the experiment used organic waste material, including: chicken fat with feathers (FF), molasses (M), glycerol (GL), raw sewage sludge (SS) and digested sewage sludge as an inoculum. The parameters of raw and digested sludge were compared, e.g. changes in the concentrations of ammonium nitrogen (N-NH4+), alkalinities, chemical oxygen demand (COD) and light metal ions. Potential biodegradation pathways for the organic waste used in the experiments were also proposed. The proposed sequences of chemical reactions are a useful tool for further biochemical analyses and for the mathematical modeling of anaerobic digestion. The results showed that fat with feathers was the most valuable high-energy substrate as it gave a cumulative methane yield of 822 m3/mg VS (VS volatile solids). There were comparable values of cumulative methane yield from molasses (350 m3/mg VS) and glycerol (342 m3/mg VS), whereas sewage sludge gave the lowest yield (246 m3/mg VS).
Keywords
anaerobic digestion; biodegradation pathways; biomethane efficiency; high-energy waste; sewage sludge