Innovative Two-Stage Process for the Recovery of Energy and Compost from the Organic Fraction of Municipal Solid Waste (MSW)

1993 ◽  
Vol 27 (2) ◽  
pp. 133-143 ◽  
Author(s):  
M. Kayhanian ◽  
G. Tchobanoglous
Keyword(s):  
Municipal Solid Waste ◽  
Solid Waste ◽  
Retention Time ◽  
Biogas Production ◽  
Pilot Scale ◽  
Gas Production ◽  
High Solids ◽  
Organic Fraction ◽  
Active Volume ◽  
Engineering Department

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.

Rheology of sludge from double phase anaerobic digestion of organic fraction of municipal solid waste

2000 ◽  
Vol 41 (3) ◽  
pp. 51-59 ◽  
Author(s):  
P. Battistoni ◽  
P. Pavan ◽  
J. Mata-Alvarez ◽  
M. Prisciandaro ◽  
F. Cecchi
Keyword(s):  
Anaerobic Digestion ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Pilot Scale ◽  
Gas Production ◽  
Organic Loading Rate ◽  
Second Phase ◽  
Organic Fraction ◽  
Double Phase ◽  
Long Term Experiment

In this paper experimental results on the anaerobic digestion of sewage sludge and organic fraction of municipal solid waste (OFMSW) by using a double phase process are reported. The long-term experiment has been carried out on a pilot scale plant, performed in different sets of operative conditions, during which granulometric distributions of particles in sludges and rheological properties of sludges were monitored. A significant fluidification of sludge was evidenced in the meso-thermo process, especially taking into account the variation in sludge behaviour from the first to the second phase. In the thermo-thermo process a fluidification higher than that shown in meso-thermo conditions is not observed, this suggesting that better results in terms of sludge conditioning can be obtained in a long time spent in thermophilic anaerobic digestion. Total volatile solids (TVS) and total fixed solids (TFS) become the most important parameters when mathematical modelling is applied to these processes.In the acidogenic phase, hydraulic retention time (HRT) and temperature are used to determine rigidity coefficient (RC), while only temperature is needed for yield stress (YC). Organic loading rate (OLR) and specific gas production (SGP) exert an important role in methanogenic phase description.

scholarly journals Anaerobic Co-digestion of Organic Fraction of Municipal Solid waste and Septage for Sustainable Waste Treatment: A Case Study from Goa, India

2021 ◽  
Vol 1 (3) ◽  
pp. 1-8
Author(s):  
Ravikiran Shet ◽  
Srikanth Mutnuri
Keyword(s):  
Municipal Solid Waste ◽  
Solid Waste ◽  
Waste Treatment ◽  
Biogas Production ◽  
Pilot Scale ◽  
Anaerobic Digester ◽  
Full Scale ◽  
Organic Fraction ◽  
Set Up

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.

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
Keyword(s):  
Anaerobic Digestion ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Retention Time ◽  
Energy Recovery ◽  
Hydraulic Retention Time ◽  
Flow Reactor ◽  
Biogas Production ◽  
Organic Fraction ◽  
Dry Anaerobic Digestion

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.

Strategies for the anaerobic digestion of the organic fraction of municipal solid waste: an overview

2006 ◽  
Vol 53 (8) ◽  
pp. 7-22 ◽  
Author(s):  
H. Hartmann ◽  
B.K. Ahring
Keyword(s):  
Anaerobic Digestion ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Biogas Production ◽  
C:N Ratio ◽  
Cost Benefit ◽  
Single Stage ◽  
High Solids ◽  
Organic Fraction ◽  
Multi Stage

Different process strategies for anaerobic digestion of the organic fraction of municipal solid waste (OFMSW) are reviewed weighing high-solids versus low-solids, mesophilic versus thermophilic and single-stage versus multi-stage processes. The influence of different waste characteristics such as composition of biodegradable fractions, C:N ratio and particle size is described. Generally, source sorting of OFMSW and a high content of food waste leads to higher biogas yields than the use of mechanically sorted OFMSW. Thermophilic processes are more efficient than mesophilic processes in terms of higher biogas yields at different organic loading rates (OLR). Highest biogas yields are achieved by means of wet thermophilic processes at OLRs lower than 6 kg-VS·m−3 d−1. High-solids processes appear to be relatively more efficient when OLRs higher than 6 kg-VS·m−3 d−1 are applied. Multi-stage systems show in some investigations a higher reduction of recalcitrant organic matter compared to single-stage systems, but they are seldom applied in full-scale. An extended cost-benefit calculation shows that the highest overall benefit of the process is achieved at an OLR that is lower and a hydraulic retention time (HRT) that is longer than those values of OLR and HRT, at which the highest biogas production is achieved.

Anaerobic digestion of co-mingled municipal solid waste and sewage sludge

1998 ◽  
Vol 38 (2) ◽  
pp. 127-132 ◽  
Author(s):  
N. Hamzawi ◽  
K. J. Kennedy ◽  
D. D. McLean
Keyword(s):  
Sewage Sludge ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Biogas Production ◽  
Empirical Models ◽  
Organic Fraction ◽  
Primary Sludge ◽  
Digestion Process ◽  
Solids Concentration ◽  
Anaerobic Biodegradability

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.

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