scholarly journals Enhancing Anaerobic Digestion: The Effect of Carbon Conductive Materials

2018 ◽  
Vol 4 (4) ◽  
pp. 59 ◽  
Author(s):  
Judith González ◽  
Marta Sánchez ◽  
Xiomar Gómez

Anaerobic digestion is a well-known technology which has been extensively studied to improve its performance and yield biogas from substrates. The application of different types of pre-treatments has led to an increase in biogas production but also in global energy demand. However, in recent years the use of carbon conductive materials as supplement for this process has been studied resulting in an interesting way for improving the performance of anaerobic digestion without greatly affecting its energy demand. This review offers an introduction to this interesting approach and covers the different experiences performed on the use of carbon conductive materials proposing it as a feasible alternative for the production of energy from biomass, considering also the integration of anaerobic digestion and thermal valorisation.

Author(s):  
Kai Schumüller ◽  
Dirk Weichgrebe ◽  
Stephan Köster

AbstractTo tap the organic waste generated onboard cruise ships is a very promising approach to reduce their adverse impact on the maritime environment. Biogas produced by means of onboard anaerobic digestion offers a complementary energy source for ships’ operation. This report comprises a detailed presentation of the results gained from comprehensive investigations on the gas yield from onboard substrates such as food waste, sewage sludge and screening solids. Each person onboard generates a total average of about 9 kg of organic waste per day. The performed analyses of substrates and anaerobic digestion tests revealed an accumulated methane yield of around 159 L per person per day. The anaerobic co-digestion of sewage sludge and food waste (50:50 VS) emerged as particularly effective and led to an increased biogas yield by 24%, compared to the mono-fermentation. In the best case, onboard biogas production can provide an energetic output of 82 W/P, on average covering 3.3 to 4.1% of the total energy demand of a cruise ship.


2021 ◽  
Vol 11 (24) ◽  
pp. 11660
Author(s):  
Rubén González ◽  
Marcos Ellacuriaga ◽  
Alby Aguilar-Pesantes ◽  
Daniela Carrillo-Peña ◽  
José García-Cascallana ◽  
...  

Anaerobic digestion is a biological process with wide application for the treatment of high organic-containing streams. The production of biogas and the lack of oxygen requirements are the main energetic advantages of this process. However, the digested stream may not readily find a final disposal outlet under certain circumstances. The present manuscript analyzed the feasibility of valorizing digestate by the hydrothermal carbonization (HTC) process. A hypothetical plant treating cattle manure and cheese whey as co-substrate (25% v/w, wet weight) was studied. The global performance was evaluated using available data reported in the literature. The best configuration was digestion as a first stage with the subsequent treatment of digestate in an HTC unit. The treatment of manure as sole substrate reported a value of 752 m3/d of biogas which could be increased to 1076 m3/d (43% increase) when coupling an HTC unit for digestate post-treatment and the introduction of the co-substrate. However, the high energy demand of the combined configurations indicated, as the best alternative, the valorization of just a fraction (15%) of digestate to provide the benefits of enhancing biogas production. This configuration presented a much better energy performance than the thermal hydrolysis pre-treatment of manure. The increase in biogas production does not compensate for the high energy demand of the pre-treatment unit. However, several technical factors still need further research to make this alternative a reality, as it is the handling and pumping of high solid slurries that significantly affects the energy demand of the thermal treatment units and the possible toxicity of hydrochar when used in a biological process.


2021 ◽  
Vol 47 (1) ◽  
pp. 174-180
Author(s):  
Henrique Sousa do Nascimento ◽  
Geísa Vieira Vasconcelos Magalhães ◽  
José Demontier Vieira de Souza-Filho ◽  
Ronaldo Stefanutti ◽  
Ari Clecius Alves de Lima ◽  
...  

This study evaluated the use of two anaerobic bioreactors in the production of biogas from malt bagasse waste. Bioreactor B1 was loaded with a mixture of 600mL of anaerobic sludge, 300g of organic waste, taken from an upflow anaerobic sludge blanket (UASB) reactor, and 300g of malt bagasse residue. Bioreactor B2 was loaded with a mixture of 600g of organic waste and 600mL of anaerobic sludge taken from an UASB reactor. The anaerobic digestion processes lasted for 10 weeks and the produced methane fraction was measured in 5 occasions. Bioreactor B1 presented low methane production (7.2%) but Bioreactor B2 showed a much more signif- icant percentage, reaching up to 48.3%. The experiments were capable of reproducing largescale operational conditions, enabling increased results in biogas capturing and processing, strengthening sustainability and energy efficiency. The experiment also showed the importance of studying different types of organic waste, seeking optimization of anaerobic digestion pro- cesses.


2021 ◽  
Vol 13 (12) ◽  
pp. 6746
Author(s):  
Obianuju Patience Ilo ◽  
Mulala Danny Simatele ◽  
S’phumelele Lucky Nkomo ◽  
Ntandoyenkosi Malusi Mkhize ◽  
Nagendra Gopinath Prabhu

Anaerobic digestion has been identified as a feasible fragment of a bioeconomy, yet numerous factors hinder the adoption of the technology in South Africa. Apart from its energy recovery, other nonmarket advantages support the technology. Though it may be challenging to have a price tag, they provide clear added worth for such investments. With a growing energy demand and global energy transitions, there is a need to sustainably commercialise the biogas industry in South Africa. Most studies are at laboratory scale and under specific conditions, which invariably create gaps in using their data for commercialising the biogas technology. The key to recognising these gaps depends on knowing the crucial technical phases that have the utmost outcome on the economics of biogas production. This study is a meta-analysis of the optimisation of anaerobic digestion through methodological approaches aimed at enhancing the production of biogas. This review, therefore, argues that regulating the fundamental operational parameters, understanding the microbial community’s interactions, and modelling the anaerobic processes are vital indicators for improving the process stability and methane yield for the commercialisation of the technology. It further argues that South Africa can exploit water hyacinth as a substrate for a self-sufficient biogas production system in a bid to mitigate the invasive alien plants.


2021 ◽  
Vol 13 (17) ◽  
pp. 9488
Author(s):  
Addam Claes ◽  
Lucy Melchi ◽  
Sibel Uludag-Demirer ◽  
Goksel N. Demirer

Due to its high water and organic contents, management of apple pomace (AP) poses several waste management challenges on the apple juice and cider producing industries. Bioconversion of AP into biogas provides an excellent possibility to reduce the environmental challenge faced in the management of AP waste along with producing renewable energy in the form of methane. This study investigated the effect of carbon-based conductive materials (biochar and graphene) and trace metals supplementation to improve biogas production from AP. The results indicate that supplementation of biochar, trace metals, and graphene significantly improves the biogas production from AP. Trace metal and biochar supplementation at a COD concentration of 6000 mg/L resulted in 7.2% and 13.3% increases in the biogas production, respectively. When trace metals and biochar were supplemented together, the biogas production increased by 22.7%. This synergistic effect was also observed at the COD concentration of 12,000 mg/L. The improvement in the biogas formation was significantly higher for graphene supplemented reactors (27.8%). Moreover, biochar and trace metals supplementation also led to 19.6% and 23.0% increases in the methane yield relative to the reactor fed only with AP, respectively. These results suggest anaerobic digestion supplemented with carbon-based conductive materials and trace metals is a viable option for valorizing apple pomace.


Author(s):  
Ajcharapa Chuanchai ◽  
Sawitree Tipnee ◽  
Yuwalee Unpaprom ◽  
Keng-Tung Wu

Recently, biogas production through anaerobic digestion technology has advanced massively. At the moment, caused by high energy demand and environmental concerns as the world’s population increases, the drive for anaerobic digestion processes is achievement drive within research and the industry for sustainable energy generation. The study evaluated biogas production from anaerobic mono-digestion of para grass in laboratory scale studies. In addition, improvement of the biogas yield from the grass via chemical pretreatment and leaching bed reactors was studied. Methane content of biogas was 54.36 % by mono- substrate. The results revealed that para grass can be treated anaerobically and are a good source of biogas.


2020 ◽  
Vol 7 (3) ◽  
pp. 80 ◽  
Author(s):  
Prativa Mahato ◽  
Bernard Goyette ◽  
Md. Saifur Rahaman ◽  
Rajinikanth Rajagopal

Globally, livestock and poultry production leads to total emissions of 7.1 Gigatonnes of CO2-equiv per year, representing 14.5% of all anthropogenic greenhouse gas emissions. Anaerobic digestion (AD) is one of the sustainable approaches to generate methane (CH4) from manure, but the risk of ammonia inhibition in high-solids AD can limit the process. Our objective was to develop a two-stage (liquid–solid) AD biotechnology, treating chicken (CM) + dairy cow (DM) manure mixtures at 20 °C using adapted liquid inoculum that could make livestock farming more sustainable. The effect of organic loading rates (OLR), cycle length, and the mode of operation (particularly liquid inoculum recirculation-percolation mode) was evaluated in a two-stage closed-loop system. After the inoculum adaptation phase, aforementioned two-stage batch-mode AD operation was conducted for the co-digestion of CM + DM (Total Solids (TS): 48–51% and Total Kjeldahl Nitrogen (TKN): 13.5 g/L) at an OLR of 3.7–4.7 gVS/L.d. Two cycles of different cycle lengths (112-d and 78-d for cycles 1 and 2, respectively) were operated with a CM:DM mix ratio of 1:1 (w/w) based on a fresh weight basis. Specific methane yield (SMY) of 0.35 ± 0.11 L CH4g/VSfed was obtained with a CH4 concentration of above 60% for both the cycles and Soluble Chemical Oxygen Demand (CODs) and volatile solid (VS) reductions up to 85% and 60%, respectively. For a comparison purpose, a similar batch-mode operation was conducted for mono-digestion of CM (TS: 65–73% and TKN: 21–23 g/L), which resulted in a SMY of 0.52 ± 0.13 L CH4g/VSfed. In terms of efficiency towards methane-rich biogas production and ammonia inhibitions, CM + DM co-digestion showed comparatively better quality methane and generated lower free ammonia than CM mono-digestion. Further study is underway to optimize the operating parameters for the co-digestion process and to overcome inhibitions and high energy demand, especially for cold countries.


2016 ◽  
Vol 24 (4) ◽  
pp. 426-459 ◽  
Author(s):  
Biswabandhu Chatterjee ◽  
Debabrata Mazumder

Anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW) has gained great interest in the last few decades. Presently, among the various municipal solid waste management (MSWM) techniques, such as sanitary land-filling, aerobic or anaerobic composting, and thermal incineration, AD is being considered as the most techno-economically viable method owing to its many advantages. AD not only serves to efficiently manage and treat an enormous quantity of OFMSW but also acts as a convenient source of non-conventional energy. The methane generated via AD of OFMSW serves as a potent substitute for fossil-based fuels. Given the current global energy crisis, this technology may be a welcome boost to the global energy demand. In this review an attempt has been made to provide a comprehensive understanding of: (i) the origin and scope of AD of OFMSW; (ii) the potential of AD for OFMSW stabilization; (iii) various pilot and bench-scale studies conducted hitherto; (iv) the process design aspects of AD of OFMSW; (v) the potential of energy recovery from AD of OFMSW; and (vi) the past experiences of AD of OFMSW. This review also delves into the critical issues that govern the process of AD in stabilizing OFMSW. In addition, the compatibility of AD for MSWM in the Indian scenario compared to other classical methodologies, such as landfilling, composting, thermal incineration, and pyrolysis or gasification, is highlighted. An overview of the overall future prospect of AD of OFMSW is discussed.


2004 ◽  
Vol 49 (10) ◽  
pp. 163-169 ◽  
Author(s):  
J. la Cour Jansen ◽  
C. Gruvberger ◽  
N. Hanner ◽  
H. Aspegren ◽  
 Svärd

Anaerobic digestion of sludge has been part of the treatment plant in Malmö for many years and several projects on optimisation of the digestion process have been undertaken in full scale as well as in pilot scale. In order to facilitate a more sustainable solution in the future for waste management, solid waste organic waste is sorted out from households for anaerobic treatment in a newly built city district. The system for treatment of the waste is integrated in a centralised solution located at the existing wastewater treatment plant. A new extension of the digester capacity enables separate as well as co-digestion of sludge together with urban organic waste from households, industry, restaurants, big kitchens, food stores, supermarkets, green markets etc. for biogas production and production of fertiliser. Collection and pre-treatment of different types of waste are in progress together with examination of biogas potential for different types of organic waste. Collection of household waste as well as anaerobic digestion in laboratory and pilot scale has been performed during the last year. It is demonstrated that organic household waste can be digested separately or in combination with sludge. In the latter case a higher biogas yield is found than should be expected from digestion of the two materials separately. Household waste from a system based on collection of organic waste from grinders could be digested at mesophilic conditions whereas digestion failed at thermophilic conditions.


Sign in / Sign up

Export Citation Format

Share Document