Title:
Towards Developing an Optimum Anaerobic Co-Digestion from Wastewater Sewage Sludge as Biogas Production Enhancement Technique: Physicochemical Characteristics and Microbial Community of Methanogens of the Feedstock
Author(s):
Mudzanani, K.E. , Van Heerden, E. , Mbhele, R.N., Daramola, M.O.
Document(s):
Paper
Poster
Abstract:
This study aims to report physicochemical, microbiological analysis and the biochemical methane potential of the sewage sludge from the two different municipal WWTPs in Johannesburg, South Africa. Furthermore, deliver the recommendation of either mono digestion is sufficient for the required CHP engine loading or co-digestion is recommended. The standard methods were used for physicochemical microbiological analysis. The physicochemical characterization was performed on the wastewater treatment plant sewage sludge, along with the microbial community composition to reveal functional traits in a typical full-scale anaerobic digester. The physical characterization of the feed material was carried out using standard wastewater analysis techniques in which parameters such as pH, total solids (TS), volatile solids (VS), COD & TOC amongst others was analysed. The microbiological characterization was done by extracting DNA from WWT sewage sludge, and conducting high-throughput metagenomics sequencing on the Illumina HiSeq 2000 platform and a usearch database. The results presented shows that WWTW contain a high potential methane production, 28.6 & 27.8 g CH4/kg feed in COT2 PS and JW1 NW sewage sludge, respectively. However, it should be noted that extremely high COD may lead to accumulation of volatile fatty acids, making a delay in biogas production or reducing pH of bioreactors. Thus, a well-balanced high COD with C/N ratio and VS concentration of the ranges of 10-100 g/kg feed, C/N of 17–36, and VS 80–98% TS is recommended. The characterization of sewage sludge as a feedstock for biogas production showed that most sludges shortlisted contain reasonable of COD, organic matter, total solids (TS), volatile solid (VS) along with the inhibitory parameters which shows a potential of high yield of methane in biogas production, as long as the stability of AD is maintained at throughout the process. The microbiology data showed that the high-throughput sequencing analysis showed clear differences in microbial communities available in the sewage sludge along with the AD inhibiting microbes. From the present study, it was demonstrated that sewage sludge from COT and JW WWTP can be a suitable substrate for efficient anaerobic digestion. However, depending on the operating conditions such as pH, temperature and organic loading rate, the process can be improved or deteriorated in terms of the methane yield. Different operational strategies can be put into practice to find the most stable environment and to avoid inhibitory effects.
Keywords:
anaerobic digestion, microbial community, methanogenesis, physicochemical, chemical oxygen demand
Topic:
Biomass Conversion for Bioenergy
Subtopic:
Anaerobic Digestion for Biogas and Biomethane Production
Event:
29th European Biomass Conference and Exhibition
Session:
2CV.7.13
Pages:
623 - 630
ISBN:
978-88-89407-21-9
Paper DOI:
10.5071/29thEUBCE2021-2CV.7.13
Price:
FREE
