scholarly journals Energy recovery from biowaste: influence of hydraulic retention time on biogas production in dry-anaerobic digestion

2021 ◽  
Vol 238 ◽  
pp. 01007
Author(s):  
Elena Rossi ◽  
Isabella Pecorini ◽  
Renato Iannelli

The hydraulic retention time (HRT) is a key parameter in dry-anaerobic digestion to set during the reactor configuration in order to achieve the optimal biogas production. For this reason, the study compared the results of two experimental tests operating with an HRT of 23 and 14 days. During the tests, the feedstock was organic fraction of municipal solid waste with a solid content of 33% and the digester was a pilot-scale plug-flow reactor operating in thermophilic condition. The highest specific biogas production of 311.91 Nlbiogas kg-1 d-1 was achieved when the HRT was set to 23 days. On the contrary, the highest methane production rate of 1.43 NlCH4 l-1 d-1 was achieved for an HRT of 14 days. In addition, the volatile solids removal (49.15% on average) and the energy content o(4.8 MJ kg-1 on average) were higher for HRT 23 days than for HRT14 days. The results indicated that in dry-anaerobic digestion of organic fraction of municipal solid waste, 23 days is a suitable HRT for energy recovery.

Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 195
Author(s):  
Elena Rossi ◽  
Simone Becarelli ◽  
Isabella Pecorini ◽  
Simona Di Gregorio ◽  
Renato Iannelli

The aim of this study is to investigate the performance of a pilot-scale plug-flow reactor (PFR) as a biorefinery system to recover chemicals (i.e., volatile fatty acids (VFAs)), and biogas during the dry thermophilic anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW). The effects of the hydraulic retention time (HRT) on both outputs were studied, reducing the parameter from 22 to 16 days. In addition, VFA variation along the PFR was also evaluated to identify a section for a further valorization of VFA-rich digestate stream. A particular focus was dedicated for characterizing the community responsible for the production of VFAs during hydrolysis and acidogenesis. The VFA concentration reached 4421.8 mg/L in a section located before the end of the PFR when the HRT was set to 16 days. Meanwhile, biogas production achieved 145 NLbiogas/d, increasing 2.7 times when compared to the lowest HRT tested. Defluviitoga sp. was the most abundant bacterial genus, contributing to 72.7% of the overall bacterial population. The genus is responsible for the hydrolysis of complex polysaccharides at the inlet and outlet sections since a bimodal distribution of the genus was found. The central zone of the reactor was distinctly characterized by protein degradation, following the same trend of propionate production.


1993 ◽  
Vol 27 (2) ◽  
pp. 133-143 ◽  
Author(s):  
M. Kayhanian ◽  
G. Tchobanoglous

An innovative system for stabilizing the organic fraction of municipal solid waste (OFMSW) has been documented on a pilot scale at the Civil Engineering Department of the University of California at Davis. The system involves the combined methods of high-solids anaerobic digestion and aerobic composting for the recovery of energy and the production of compost from the OFMSW. The performance of the high-solids anaerobic reactor was monitored for three mass retention times. The anaerobic digester was operated under extreme as well as normal conditions. The performance of the aerobic compost unit was monitored based on the physical and chemical characteristics of the final humus by-product. In general, the combined process was very stable at a 30 d retention time and is capable of removing essentially all of the biodegradable fraction of the organic fraction of MSW. A biogas production level of up to 6 liters per liter of active volume of reactor was achieved. The process stability and gas production decreased slightly when the retention time was reduced to 15 d. The output from the second stage is a fine humus-like material with a thermal content of about 14.80 MJ/kg.


2013 ◽  
Vol 295-298 ◽  
pp. 1834-1839
Author(s):  
Jian Chang Li ◽  
Ya Ge Yuan ◽  
Juan He ◽  
Rui Xu

Hydrolytic enzymes, which are very key enzymes in hydrolytic step of anaerobic digestion, have an important effect on substrate hydrolysis and biogas production. To research those effect, this paper have investigated the relationship between lipase activity and biogas rate with organic fraction of municipal solid waste (OFMSW) as substrate, at the mesophilic temperature and batch fermentation. The results showed that in the process of AD, the curve of lipase activity was similar as that of biogas rate. With the increase and drop of enzyme activity, biogas rate increased and dropped. When biogas rate was at its peak period, enzyme activity of lipase was at its peak period, too.


Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 475
Author(s):  
Omid Norouzi ◽  
Animesh Dutta

With the implementation of new policies supporting renewable natural gas production from organic wastes, Canada began replacing traditional disposal methods with highly integrated biogas production strategies. Herein, data from published papers, Canadian Biogas Association, Canada’s national statistical agency, and energy companies’ websites were gathered to gain insight into the current status of anaerobic digestion plants in recovering energy and resource from organic wastes. The availability of materials prepared for recycling by companies and local waste management organizations and existing infrastructures for municipal solid waste management were examined. Governmental incentives and discouragements in Canada and world anaerobic digestion leaders regarding organic fraction municipal solid waste management were comprehensively reviewed to identify the opportunities for developing large-scale anaerobic digestion in Canada. A range of anaerobic digestion facilities, including water resource recovery facilities, standalone digesters, and on-farm digesters throughout Ontario, were compared in terms of digestion type, digester volume, feedstock (s), and electricity capacity to better understand the current role of biogas plants in this province. Finally, technology perspectives, solutions, and roadmaps were discussed to shape the future in terms of organic fraction municipal solid waste management. The findings suggested that the biogas industry growth in Canada relies on provincial energy and waste management policies, advanced technologies for diverting organic waste from landfills, improving biogas yield using existing pretreatment methods, and educating farmers regarding digester operations.


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