scholarly journals A Review of the Processes, Parameters, and Optimization of Anaerobic Digestion

2018 ◽  
Vol 15 (10) ◽  
pp. 2224 ◽  
Author(s):  
Jay Meegoda ◽  
Brian Li ◽  
Kush Patel ◽  
Lily Wang
Keyword(s):  
Anaerobic Digestion ◽  
Operating Conditions ◽  
Process Efficiency ◽  
Maximum Efficiency ◽  
Anaerobic Sludge ◽  
Operating Parameters ◽  
Anaerobic Digesters ◽  
Efficient Operation ◽  
Significant Research ◽  
Recent Developments

Anaerobic digestion is a technology that has been used by humans for centuries. Anaerobic digestion is considered to be a useful tool that can generate renewable energy and significant research interest has arisen recently. The underlying theory of anaerobic digestion has been established for decades; however, a great deal of current research is directed towards the optimization of anaerobic digestion under diverse digestion conditions. This review provides a summary of the processes underlying anaerobic digestion, commonly-utilized measurements of anaerobic sludge, operating parameters of anaerobic digesters, and methods of acceleration and optimization used to improve process efficiency. Recent developments in addition to older research are considered to provide a general but comprehensive summary of accumulated knowledge in the theory of anaerobic digestion, as well as considerations in the efficient operation of digesters. We have determined that the numerous factors pertinent to the design and operation of batch-based anaerobic digesters must each be considered to ensure the maximum efficiency and cost-effectiveness of a digester provided its respective operating conditions.

Anaerobic digestion of waste activated sludge combined with ozone post-treatment and recycling

2003 ◽  
Vol 48 (4) ◽  
pp. 61-68 ◽  
Author(s):  
A. Battimelli ◽  
C. Millet ◽  
J.P. Delgenès ◽  
R. Moletta
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Removal Rate ◽  
Operating Conditions ◽  
Cod Removal ◽  
Process Efficiency ◽  
Recycling Rate ◽  
Waste Activated Sludge ◽  
Digested Sludge ◽  
Combined Process

The aim of the study was to determine the performances of a combined ozone/anaerobic digestion system for waste activated sludge reduction. The objective was the estimation of the process efficiency and stability when keeping constant influent flow while increasing recycled chemically treated flow. The ozonation step consisted in a partial oxidation (0.16 g O3/g SS) of the anaerobic mesophilic digested sludge. Chemical treatment of digested sludge resulted in a threefold COD solubilization and a decrease of SS of 22%. Some of the advantages of digested sludge ozonation were: deodorization, better settlement and a reduction in viscosity. However there were drawbacks: foaming during ozonation and, at high ozone doses, poorer filterability. The anaerobic digestion was carried out over 6 months with an increasing recycling of ozonated flow. Suspended solids removal rate and COD removal rate were compared with initial operating conditions for the biological reactor and the whole combined process. The optimum recycling rate was 25% with increases of SS removal and COD removal of 54% and 66% respectively when considering the combined process; corresponding to a decrease of the hydraulic retention time from 24 days to 19 days.

scholarly journals Insights on anaerobic digestion foaming via association between bacterial metabolism and variations in microbiota

2020 ◽  
Author(s):  
Jian-Lu Duan ◽  
Yue Feng ◽  
Li-Juan Feng ◽  
Jing-Ya Ma ◽  
Xiao-Dong Sun ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Loading Rate ◽  
Short Chain Fatty Acids ◽  
Process Efficiency ◽  
Metabolic Phenotype ◽  
Bacterial Metabolism ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Anaerobic Digesters ◽  
Global Concern

Abstract Background: Foaming in anaerobic digesters is considered a global concern due to significant impacts on process efficiency and operational costs. Although the importance of the organic loading rate on anaerobic foaming is now widely recognized, little is known about the key bacteria among the hundreds of species inducing foaming, especially the metabolite-microbiota correlation that influences foaming in anaerobic digesters.Results: Here, we show that the organic loading rate promotes foaming and decreases the performances of bench-scale batch digesters. Metabolomics analysis revealed distinct changes in the metabolic phenotype, including mainly short-chain fatty acids and amino acids, decreasing the surface tension and inducing foaming. Furthermore, the correlation analysis revealed that Clostridium clusters were the main microbes contributing to these metabolite foaming incidents.Conclusions: We provide the foaming microbes and metabolites in anaerobic digestion. Our findings elucidate the complex formation of foaming in anaerobic digestion and provide an effective early-warning for the control of foaming in full-scale digesters.

Lessons learnt from 15 years of ICA in anaerobic digesters

2006 ◽  
Vol 53 (4-5) ◽  
pp. 25-33 ◽  
Author(s):  
J.P. Steyer ◽  
O. Bernard ◽  
D.J. Batstone ◽  
I. Angelidaki
Keyword(s):  
Wastewater Treatment ◽  
Anaerobic Digestion ◽  
Energy Production ◽  
Control Strategies ◽  
Operating Conditions ◽  
High Rate ◽  
Anaerobic Digesters ◽  
Treatment Processes ◽  
On Line ◽  
Rate Processes

Anaerobic digestion plants are highly efficient wastewater treatment processes with inherent energy production. Despite these advantages, many industries are still reluctant to use them because of their instability confronted with changes in operating conditions. There is therefore great potential for application of instrumentation, control and automation (ICA) in the field of anaerobic digestion. This paper will discuss the requirements (in terms of on-line sensors needed, modelling efforts and mathematical complexity) but also the advantages and drawbacks of different control strategies that have been applied to AD high rate processes over the last 15 years.

Experience with UASB reactor start-up under different operating conditions

1996 ◽  
Vol 34 (5-6) ◽  
pp. 421-428 ◽  
Author(s):  
M. M. Ghangrekar ◽  
S. R. Asolekar ◽  
K. R. Ranganathan ◽  
S. G. Joshi
Keyword(s):  
Steady State ◽  
Operating Conditions ◽  
Cod Removal ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Operating Parameters ◽  
Reactor Performance ◽  
Loading Rates ◽  
Start Up ◽  
Sludge Production

Four laboratory upflow anaerobic sludge blanket (UASB) reactors were operated at different operating parameters viz., hydraulic retention time (HRT), upflow velocity, organic concentration, and Ca2+ concentration in the wastewater. These operating parameters gave different values of organic loading rates (OLRs) and sludge loading rates (SLRs). The reactor performance during start-up was evaluated at different values of the above listed parameters. Also, the effects of these parameters on the granule characteristics were investigated. It was observed that COD removal efficiency at steady state was profoundly influenced by SLR. The reactor started with SLR of 0.6 kgCOD/ kg VSS.d could result in about 50% COD removal at steady state. The reactor performance could not improve even after three months of operation. Up to 0.3 kgCOD/ kgVSS.d the reactor performance was good with more than 90% COD removal at steady state. The OLD and SLR also determine time required for the reactor to achieve steady state. Different operating conditions also have the bearing on the strength of the granules cultivated. The methanogenic activity measured on acetate for each reactor was observed between 0.259 and 0.909 kg CH4 COD/ kgVSS.d. The sludge production in all the reactors was between 0.087 and 0.13 kgVSS/ kgCODin. The mathematical model was developed in order to predict sludge production.

scholarly journals Tree-based automated machine learning to predict biogas production for anaerobic co-digestion of organic waste

2021 ◽  
Author(s):  
Yan Wang ◽  
Tyler Huntington ◽  
Corinne Donahue Scown
Keyword(s):  
Machine Learning ◽  
Anaerobic Digestion ◽  
Organic Waste ◽  
Municipal Wastewater ◽  
Biogas Production ◽  
Treatment Plant ◽  
Operating Conditions ◽  
Operating Parameters ◽  
Time Lags ◽  
Biogas Yield

The dynamics of microbial communities involved in anaerobic digestion of mixed organic waste are notoriously complex and difficult to model, yet successful operation of anaerobic digestion is critical to the goals of diverting high-moisture organic waste from landfills. Machine learning (ML) is ideally suited to capturing complex and nonlinear behavior that cannot be modeled mechanistically. This study uses 8 years of data collected from an industrial-scale anaerobic co-digestion (AcoD) operation at a municipal wastewater treatment plant in Oakland, California, combined with a powerful automated ML method, Tree-based Pipeline Optimization Tool, to develop an improved understanding of how different waste inputs and operating conditions impact biogas yield. The model inputs included daily input volumes of 31 waste streams and 5 operating parameters. Because different wastes are broken down at varying rates, the model explored a range of time lags ascribed to each waste input ranging from 0 to 30 days. The results suggest that the waste types (including rendering waste, lactose, poultry waste, and fats, oils, and greases) differ considerably in their impact on biogas yield on both a per-gallon basis and a mass of volatile solids basis, while operating parameters are not useful predictors in a carefully operated facility.

Simulation of the Impact of Higher Ammonia Recycle Loads Caused by Upgrading Anaerobic Sludge Digesters

2005 ◽  
Vol 40 (4) ◽  
pp. 491-499 ◽  
Author(s):  
Jeremy T. Kraemer ◽  
David M. Bagley
Keyword(s):  
Anaerobic Digestion ◽  
Biogas Production ◽  
Treatment Plant ◽  
Anaerobic Sludge ◽  
Content Increase ◽  
Limited Information ◽  
Dynamic Simulations ◽  
Treatment Train ◽  
Temperature Liquid ◽  
The Impact

Abstract Upgrading conventional single-stage mesophilic anaerobic digestion to an advanced digestion technology can increase sludge stability, reduce pathogen content, increase biogas production, and also increase ammonia concentrations recycled back to the liquid treatment train. Limited information is available to assess whether the higher ammonia recycle loads from an anaerobic sludge digestion upgrade would lead to higher discharge effluent ammonia concentrations. Biowin, a commercially available wastewater treatment plant simulation package, was used to predict the effects of anaerobic digestion upgrades on the liquid train performance, especially effluent ammonia concentrations. A factorial analysis indicated that the influent total Kjeldahl nitrogen (TKN) and influent alkalinity each had a 50-fold larger influence on the effluent NH3 concentration than either the ambient temperature, liquid train SRT or anaerobic digestion efficiency. Dynamic simulations indicated that the diurnal variation in effluent NH3 concentration was 9 times higher than the increase due to higher digester VSR. Higher recycle NH3 loads caused by upgrades to advanced digestion techniques can likely be adequately managed by scheduling dewatering to coincide with periods of low influent TKN load and ensuring sufficient alkalinity for nitrification.

Relationships between Population Dynamics and Operating Parameters in an Activated Sludge-Plant by Statistical Analysis

1992 ◽  
Vol 25 (4-5) ◽  
pp. 399-400 ◽  
Author(s):  
L. Cingolani ◽  
M. Cossignani ◽  
R. Miliani
Keyword(s):  
Population Dynamics ◽  
Statistical Analysis ◽  
Activated Sludge ◽  
Treatment Plant ◽  
Operating Conditions ◽  
Statistical Analyses ◽  
Operating Parameters ◽  
Aerobic Treatment

Statistical analyses were applied to data from a series of 38 samples collected in an aerobic treatment plant from November 1989 to December 1990. Relationships between microfauna structure and plant operating conditions were found. Amount and quality of microfauna groups and species found in activated sludge proved useful to suggest the possible causes of disfunctions.

"Recent Patents on the Triboelectrostatic Separation of Fly Ash"

2019 ◽  
Vol 13 ◽  
Author(s):  
Haisheng Li ◽  
Wenping Wang ◽  
Yinghua Chen ◽  
Xinxi Zhang ◽  
Chaoyong Li
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
High Efficiency ◽  
Separation Efficiency ◽  
High Reliability ◽  
Operating Conditions ◽  
Security Requirements ◽  
Unburned Carbon ◽  
Efficient Operation ◽  
Triboelectrostatic Separation

Background: The fly ash produced by coal-fired power plants is an industrial waste. The environmental pollution problems caused by fly ash have been widely of public environmental concern. As a waste of recoverable resources, it can be used in the field of building materials, agricultural fertilizers, environmental materials, new materials, etc. Unburned carbon content in fly ash has an influence on the performance of resource reuse products. Therefore, it is the key to remove unburned carbon from fly ash. As a physical method, triboelectrostatic separation technology has been widely used because of obvious advantages, such as high-efficiency, simple process, high reliability, without water resources consumption and secondary pollution. Objective: The related patents of fly ash triboelectrostatic separation had been reviewed. The structural characteristics and working principle of these patents are analyzed in detail. The results can provide some meaningful references for the improvement of separation efficiency and optimal design. Methods: Based on the comparative analysis for the latest patents related to fly ash triboelectrostatic separation, the future development is presented. Results: The patents focused on the charging efficiency and separation efficiency. Studies show that remarkable improvements have been achieved for the fly ash triboelectrostatic separation. Some patents have been used in industrial production. Conclusion: According to the current technology status, the researches related to process optimization and anti-interference ability will be beneficial to overcome the influence of operating conditions and complex environment, and meet system security requirements. The intelligent control can not only ensure the process continuity and stability, but also realize the efficient operation and management automatically. Meanwhile, the researchers should pay more attention to the resource utilization of fly ash processed by triboelectrostatic separation.

scholarly journals Tanning Wastewater Treatment by Ultrafiltration: Process Efficiency and Fouling Behavior

Membranes ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 461
Author(s):  
Fu Yang ◽  
Zhengkun Huang ◽  
Jun Huang ◽  
Chongde Wu ◽  
Rongqing Zhou ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Shear Rate ◽  
Membrane Surface ◽  
Filtration Efficiency ◽  
Operating Conditions ◽  
Process Efficiency ◽  
Transmembrane Pressure ◽  
Leather Industry ◽  
Pore Blocking ◽  
The Impact

Ultrafiltration is a promising, environment-friendly alternative to the current physicochemical-based tannery wastewater treatment. In this work, ultrafiltration was employed to treat the tanning wastewater as an upstream process of the Zero Liquid Discharge (ZLD) system in the leather industry. The filtration efficiency and fouling behaviors were analyzed to assess the impact of membrane material and operating conditions (shear rate on the membrane surface and transmembrane pressure). The models of resistance-in-series, fouling propensity, and pore blocking were used to provide a comprehensive analysis of such a process. The results show that the process efficiency is strongly dependent on the operating conditions, while the membranes of either PES or PVDF showed similar filtration performance and fouling behavior. Reversible resistance was the main obstacle for such process. Cake formation was the main pore blocking mechanism during such process, which was independent on the operating conditions and membrane materials. The increase in shear rate significantly increased the steady-state permeation flux, thus, the filtration efficiency was improved, which resulted from both the reduction in reversible resistance and the slow-down of fouling layer accumulate rate. This is the first time that the fouling behaviors of tanning wastewater ultrafiltration were comprehensively evaluated, thus providing crucial guidance for further scientific investigation and industrial application.

scholarly journals Latest Developments in Insect Sex Pheromone Research and Its Application in Agricultural Pest Management

Insects ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 484
Author(s):  
Syed Arif Hussain Rizvi ◽  
Justin George ◽  
Gadi V. P. Reddy ◽  
Xinnian Zeng ◽  
Angel Guerrero
Keyword(s):  
Sex Pheromone ◽  
Pest Management ◽  
Interdisciplinary Approach ◽  
Pheromone Biosynthesis ◽  
Insect Pheromones ◽  
Agricultural Pest ◽  
Practical Applications ◽  
The Past ◽  
Significant Research ◽  
Recent Developments

Since the first identification of the silkworm moth sex pheromone in 1959, significant research has been reported on identifying and unravelling the sex pheromone mechanisms of hundreds of insect species. In the past two decades, the number of research studies on new insect pheromones, pheromone biosynthesis, mode of action, peripheral olfactory and neural mechanisms, and their practical applications in Integrated Pest Management has increased dramatically. An interdisciplinary approach that uses the advances and new techniques in analytical chemistry, chemical ecology, neurophysiology, genetics, and evolutionary and molecular biology has helped us to better understand the pheromone perception mechanisms and its practical application in agricultural pest management. In this review, we present the most recent developments in pheromone research and its application in the past two decades.

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