scholarly journals Bio-Delignification of Green Waste (GW) in Co-Digestion with the Organic Fraction of Municipal Solid Waste (OFMSW) to Enhance Biogas Production

2021 ◽  
Vol 11 (13) ◽  
pp. 6061
Author(s):  
Bruno Semeraro ◽  
Daniela Summa ◽  
Stefania Costa ◽  
Federico Zappaterra ◽  
Elena Tamburini

The organic fraction of municipal solid waste (OFMSW) is recognized as a suitable substrate for the anaerobic digestion (AD) process and is currently considered a mature technology. A promising strategy to enhance biogas yield and productivity is the co-digestion of OFMSW with other organic biomass, such as green waste (GW), a mixture of leaves, grass, and woody materials originated from private yards and public greenspace management. The main limitation to the use of GW for biogas production is the high percentage of the lignocellulosic fraction, which makes necessary a pretreatment of delignification to dissolve the recalcitrant structure. In this study, a new strategy of sustainable bio-delignification using the white-rot fungi Bjerkandera adusta (BA) in comparison with other chemical pretreatments were investigated. Untreated and treated GW were, respectively, submitted to anaerobic co-digestion with OFMSW. AD processes were carried out in a lab-scale plant for 30 days in thermophilic conditions (55 °C). Biogas cumulative production was increased by about 100% in the case of treated GW compared with that of just OFMSW, from 145 to 289 Nm3 CH4/ton SV, and productivity almost doubled from 145 to 283 Nm3/ton FM * day. The measured average methane content values in the cumulative biogas were 55% from OFMSW and 54% from GW. Moreover, over 95% of the biogas was produced in 20 days, showing the potential opportunity to reduce the AD time.

2019 ◽  
Vol 37 (1_suppl) ◽  
pp. 27-39 ◽  
Author(s):  
Mohanakrishnan Logan ◽  
Chettiyappan Visvanathan

Anaerobic digestion has emerged as the preferred treatment for organic fraction of municipal solid waste. Digestate management strategies are devised not only for safe disposal but also to increase the value and marketability. Regulations and standards for digestate management are framed to address the pollution concerns, conserve vulnerable zones, prevent communicable diseases, and to educate on digestate storage and applications. Regulations and the desired end uses are the main drivers for the enhancement of digestate through pretreatment, in vessel cleaning, and post-digestion treatment technologies for solid and liquid fractions of digestate. The current management practice involves utilization of digestate for land application either as fertilizer or soil improver. Prospects are bright for alternative usage such as microalgal cultivation, biofuel and bioethanol production. Presently, the focus of optimization of the anaerobic digestion process is directed only towards enhancing biogas yield, ignoring the quality of digestate produced. A paradigm shift is needed in the approach from ‘biogas optimization’ to ‘integrated biogas–digestate optimization’.


1998 ◽  
Vol 38 (2) ◽  
pp. 127-132 ◽  
Author(s):  
N. Hamzawi ◽  
K. J. Kennedy ◽  
D. D. McLean

This study evaluated the technical feasibility of the anaerobic co-digestion process in the context of typical North American solid waste. Using biological activity tests, an optimal mixture was identified with 25% organic fraction of municipal solid waste (OFMSW) and 75% sewage sludge (65% raw primary sludge (RAW), 35% thickened WAS (TWAS)) based on biogas production. Also, based on the rate of biogas production, the most anaerobically biodegradable components of the OFMSW were paper and grass. The TWAS and the newspaper were found to be the least biodegradable components. Lab-scale testing indicated that alkaline pretreatment increased the biodegradability of the sewage sludge/OFMSW mixture the most, as compared to the untreated control. Thermochemically pretreated feedstocks inhibited anaerobic biodegradability as compared to the control, whereas the anaerobic biodegradability of thermally pretreated feed was not found to be significantly different from that of the control. Empirical models were developed based on alkaline dose, feed total solids concentration and particle size for biogas production and removal of TS and VS. All three experimental factors were found to be significant with respect to the response variables studied.


2021 ◽  
Vol 1 (3) ◽  
pp. 1-8
Author(s):  
Ravikiran Shet ◽  
Srikanth Mutnuri

India generates 0.15 million metric tons (MT) of solid waste per day out of which more than 80% is organic fraction. Apart from this, 38% of the households use septic tanks where proper disposal of faecal sludge is also need of the hour. Anaerobic co-digestion (ACD) of two different substrates has positive potential towards solving this problem. In the present study, ACD of organic fraction of municipal solid waste (OFMSW) and septage solids (SS) was studied at three different levels, i.e., lab-scale, pilot-scale (1 m3), and full scale- capacity (325 m3). A loading rate of 1.5 kg VS/m3 was selected. The bio-methanation potential (BMP) assay showed a maximum biogas generation, i.e., 120±20.6 mL/gmVS with 68% maximum methane concentration at a 5:1 OFMSW and SS ratio. Cumulative biogas production after 30 days was 1.6 L/gmVS. The ultimate biogas production in the pilot-scale plant was 1000±100.5 L/day with 71% methane. The plant was also efficient in removing 87% of COD and 61% of VS. The full-scale anaerobic digester was set up at Mormugao Municpal Council, Goa India wherein the objective was to co-digest OFMSW and SS. This digester showed a similar removal pattern like earlier studies i.e., 94% and 45% COD and VS removal, respectively. The average methane content of the biogas was 68%. Full-scale operation of the anaerobic digester did not show any operational problems at the chosen co-digestion conditions.


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.


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