scholarly journals A Review of the Chemistry of Anaerobic Digestion: Methods of Accelerating and Optimizing Process Efficiency

Processes ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 504 ◽  
Author(s):  
Anthony Anukam ◽  
Ali Mohammadi ◽  
Muhammad Naqvi ◽  
Karin Granström
Keyword(s):  
Anaerobic Digestion ◽  
Energy System ◽  
Process Efficiency ◽  
Process Conditions ◽  
Future Directions ◽  
Digestion Process ◽  
Process Chemistry ◽  
Depth Analysis ◽  
Sustainable Energy System ◽  
Digestion Methods

The anaerobic digestion technology has been in existence for centuries and its underlying theory established for decades. It is considered a useful technology for the generation of renewable energy, and provides means to alleviate problems associated with low access to energy. However, a great deal of current research is targeted towards the optimization of this technology under diverse digestion process conditions. This review presents an in-depth analysis of the chemistry of anaerobic digestion and discusses how process chemistry can be used to optimize system performance through identification of methods that can accelerate syntrophic interactions of different microorganisms for improved methanogenic reactions. Recent advances in addition to old research are discussed in order to offer a general but comprehensive synopsis of accumulated knowledge in the theory of anaerobic digestion, as well as an overview of previous research and future directions and opportunities of the AD technology. Achieving a sustainable energy system requires comprehensive reforms in not just economic, social and policy aspects, but also in all technical aspects, which represents one of the most crucial future investments for anaerobic digestion systems.

Full scale experience of two stage thermophilic/mesophilic sludge digestion

1997 ◽  
Vol 36 (6-7) ◽  
pp. 449-456 ◽  
Author(s):  
Jürgen Oles ◽  
Norbert Dichtl ◽  
Hans-hermann Niehoff
Keyword(s):  
Degradation Process ◽  
Pilot Scale ◽  
Full Scale ◽  
Process Efficiency ◽  
Anaerobic Sludge ◽  
Process Conditions ◽  
Two Stage ◽  
Operational Conditions ◽  
Digestion Process ◽  
General Goals

The general goals of anaerobic sludge stabilisation are degradation of organic substances, reduction of solids, decrease of pathogenic bacterias, improvement of dewatering capabilities and production of biogas. The anaerobic degradation process can be divided in several steps with different optimum operational conditions. This gives the possibility to design treatment plants as a two-stage process, optimizing the process conditions in each step and thereby leading to an overall increase in process efficiency. Research results in lab scale and pilot scale have shown that a two-stage digestion process with a high loaded first thermophilic (50-55°C) stage and a second stage under mesophilic (35-37°C) conditions with sufficient retention time will lead to the best results. After giving a short summary of the development of the two-stage thermophilic/mesophilic digestion process the paper will present full scale experiences with this system in Germany.

scholarly journals Organic Power Generation and Utilization Using Anaerobic Digestion Process

2020 ◽  
pp. 126-132
Keyword(s):  
Anaerobic Digestion ◽  
Organic Materials ◽  
Energy System ◽  
Developed Countries ◽  
Water Tank ◽  
Digestion Process ◽  
Synthetic Materials ◽  
End Products ◽  
Organic Fuels ◽  
Tank Water

Organic power is produced by using both solids and liquid organic materials like wastage of industries, agriculture fields, and other synthetic materials. In recent days, many developed countries have given incentives for the production of bio-fuel and injected into the natural gas grid. The existing anaerobic digestion plants are upgraded to produce organic power efficiently. The objective of this paper is to introduce an innovative energy system for consuming organic materials. The proposed system is an anaerobic digestion system that consists of a digestion process tank, water tank, temperature controller for the digestion process, and other accessories to complete that process. An anaerobic digestion plant is developed as a function of the percentage of the organic materials sent to the upgrading system and the amount of organic power produced. The end products of the proposed system are biogas, biomethane, carbon dioxide, and clean fertilizer. The optimized parameters are taken as ammonia CODp, sugar TAN, proteins TOC, and organic inserts NORg. Furthermore, the comparison of organic fuels is discussed with other energy fuels.

scholarly journals Triangulation of microbial fingerprinting in anaerobic digestion reveals consistent fingerprinting profiles

2021 ◽  
Author(s):  
Jo De Vrieze ◽  
Robert Heyer ◽  
Ruben Props ◽  
Lieven Van Meulenbroek ◽  
Karen Gille ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Microbial Community ◽  
Anaerobic Digestion ◽  
Diversity Analysis ◽  
Fast Method ◽  
Anaerobic Digestion Process ◽  
Digestion Process ◽  
Α Diversity ◽  
Depth Analysis ◽  
Community Fingerprinting

The anaerobic digestion microbiome has been puzzling us since the dawn of molecular methods for mixed microbial community analysis. Monitoring of the anaerobic digestion microbiome can either take place via a non-targeted holistic evaluation of the microbial community through fingerprinting or by targeted monitoring of selected taxa. Here, we compared four different microbial community fingerprinting methods, i.e., amplicon sequencing, metaproteomics, metabolomics and cytomics, in their ability to characterise the full-scale anaerobic digestion microbiome. Cytometric fingerprinting through cytomics reflects a, for anaerobic digestion, novel, single cell-based approach of direct microbial community fingerprinting by flow cytometry. Three different digester types, i.e., sludge digesters, digesters treating agro-industrial waste and dry anaerobic digesters, each reflected different operational parameters. The α-diversity analysis yielded inconsistent results, especially for richness, across the different methods. In contrast, β-diversity analysis resulted in comparable profiles, even when translated into phyla or functions, with clear separation of the three digester types. In-depth analysis of each method's features i.e., operational taxonomic units, metaproteins, metabolites, and cytometric traits, yielded certain similar features, yet, also some clear differences between the different methods, which was related to the complexity of the anaerobic digestion process. In conclusion, cytometric fingerprinting through flow cytometry is a reliable, fast method for holistic monitoring of the anaerobic digestion microbiome, and the complementary identification of key features through other methods could give rise to a direct interpretation of anaerobic digestion process performance.

scholarly journals Process optimization of dry batch anaerobic digestion of municipal solid waste

2007 ◽  
pp. 357-366
Author(s):  
Jeanger P. Juanga
Keyword(s):  
Particle Size ◽  
Anaerobic Digestion ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Biogas Production ◽  
Process Efficiency ◽  
Particle Size Reduction ◽  
Digestion Process ◽  
Waste Stabilization ◽  
Substrate Particle

Optimizing anaerobic digestion aims to maximize organic waste stabilization at shortdigestion period with higher biogas production. This paper presents different strategies tooptimize the anaerobic digestion of organic fraction of municipal solid waste in combinedprocess in which early flushing and microaeration were conducted during pre-stage, Also, theinfluence of substrate particle size reduction and the advantage of thermophilic system overmesophilic in the overall digestion process are presented, Additionally, an attempt was takento employ sequential staging concept by using a mature (old) reactor which underwent acombined digestion process. Importantly, process evaluation between an optimized combinedprocess and sequential staging concept were evaluated with the main objective of optimizingthe process, Process efficiency evaluation was based on biochemical methane potential(BMP) test The overall result suggest that the combined anaerobic digestion process can beoptimized by conducting shorter duration of pre-stage at reduced volume of flushing waterwith microearation, under thennophilic condition at reduced substrate particle size of 30 mm,Nevertheless, the sequential staging concept offers an improved operation over the combinedanaerobic digestion wherein the higher specific methane yield of 11.9 L CH4/kg VS.day wasachieved, Improved waste stabilization with 86% and 79% mass and volume reduction whichcorresponds to 84% process efficiency was obtained by sequential staging process,

scholarly journals Two-Stage Anaerobic Digestion Process Combining Pre-digestion with Methanization

2015 ◽  
Vol 9 (2) ◽  
pp. 55-60
Author(s):  
Mohammed Mohaibes
Keyword(s):  
Anaerobic Digestion ◽  
Detectable Level ◽  
Process Efficiency ◽  
Two Stage ◽  
Biogas Yield ◽  
Digestion Process ◽  
Vs Removal ◽  
Mesophilic Digestion ◽  
Thermophilic Digestion ◽  
Biogas Process

Anaerobic digestion of a mixture of manure and sewage sludge by combination of the biological predigestion at 73°C with methanization at 55°C was studied with regard to the biogas process efficiency,energy balance and sanitation effect. Performance of the two-stage digestion was compared with theconventional, one-stage moderate thermophilic digestion at 55°C and mesophilic digestion at 37°C,respectively. The best performance was achieved by the two-stage treatment both in terms of VolatileSolids (VS) removal and biogas yield. Up to 60% of VS was removed and a specific methane yield of 300ml CH4 gVS-1 was achieved. Sanitation effect was measured as inactivation of the indicators of bacterialpathogens - the faecal enterococci and spores of Clostridium perfringens. Elimination of faecal enterococcito non-detectable level occurred only during treatments at 73°C and 55°C. Numbers of Clostridiumperfringens spores were reduced solely by the combined 73°C/55°C treatment.

A Mathematical Model for the Anaerobic Digestion Process Applied to a Mixture of Night Soil and Septic Tank Sludge

1986 ◽  
Vol 18 (7-8) ◽  
pp. 239-248 ◽  
Author(s):  
Sung Ryong Ha ◽  
Dwang Ho Lee ◽  
Sang Eun Lee
Keyword(s):  
Mathematical Model ◽  
Anaerobic Digestion ◽  
Biomass Concentration ◽  
Gas Production ◽  
Septic Tank ◽  
Volatile Acid ◽  
Hydraulic Residence Time ◽  
Anaerobic Digestion Process ◽  
Digestion Process ◽  
Proposed Model

Laboratory scale experiments were conducted to develop a mathematical model for the anaerobic digestion of a mixture of night soil and septic tank sludge. The optimum mixing ratio by volume between night soil and septic tank sludge was found to be 7:3. Due to the high solids content in the influent waste, mixed-liquor volatile suspended solids (MLVSS) was not considered to be a proper parameter for biomass concentration, therefore, the active biomass concentration was estimated based on deoxyribonucleic acid (DNA) concentration in the reactor. The weight ratio between acidogenic bacteria and methanogenic bacteria in the mixed culture of a well-operated anaerobic digester was approximately 3:2. The proposed model indicates that the amount of volatile acid produced and the gas production rate can be expressed as a function of hydraulic residence time (HRT). The kinetic constants of the two phases of the anaerobic digestion process were determined, and a computer was used to simulate results using the proposed model for the various operating parameters, such as BOD5 and volatile acid concentrations in effluent, biomass concentrations and gas production rates. These were consistent with the experimental data.

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