A mathematical model for the kinetics of concurrent volatile solids destruction and water evaporation during aerobic and anaerobic digestion of wastewater sludge under mesophilic and thermophilic temperatures

2022 ◽  
Vol 46 ◽  
pp. 102540
Author(s):  
Eskandar Poorasgari ◽  
Banu Örmeci
Keyword(s):  
Mathematical Model ◽  
Anaerobic Digestion ◽  
Wastewater Sludge ◽  
Water Evaporation ◽  
Volatile Solids ◽  
Kinetics Of ◽  
Aerobic And Anaerobic

Sludge electrooxidation as pre-treatment for anaerobic digestion

2016 ◽  
Vol 75 (4) ◽  
pp. 775-781 ◽  
Author(s):  
J. A. Barrios ◽  
U. Duran ◽  
A. Cano ◽  
M. Cisneros-Ortiz ◽  
S. Hernández
Keyword(s):  
Anaerobic Digestion ◽  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Wastewater Sludge ◽  
Boron Doped Diamond ◽  
Boron Doped ◽  
Treatment Conditions ◽  
Volatile Solids ◽  
Pre Treatment

Anaerobic digestion of wastewater sludge is the preferred method for sludge treatment as it produces energy in the form of biogas as well as a stabilised product that may be land applied. Different pre-treatments have been proposed to solubilise organic matter and increase biogas production. Sludge electrooxidation with boron-doped diamond electrodes was used as pre-treatment for waste activated sludge (WAS) and its effect on physicochemical properties and biomethane potential (BMP) was evaluated. WAS with 2 and 3% total solids (TS) achieved 2.1 and 2.8% solubilisation, respectively, with higher solids requiring more energy. After pre-treatment, biodegradable chemical oxygen demand values were close to the maximum theoretical BMP, which makes sludge suitable for energy production. Anaerobic digestion reduced volatile solids (VS) by more than 30% in pre-treated sludge with a food to microorganism ratio of 0.15 g VSfed g−1 VSbiomass. Volatile fatty acids were lower than those for sludge without pre-treatment. Best pre-treatment conditions were 3% TS and 28.6 mA cm−2.

Kinetics of Batch Anaerobic Digestion of Vegetable Oil Wastewater

2014 ◽  
Vol 2014 (2) ◽  
pp. 1-10 ◽  
Author(s):  
Chinenyenwa Nweke ◽  
◽  
Philomena Igbokwe ◽  
Joseph Nwabanne ◽  
◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Vegetable Oil ◽  
Kinetics Of ◽  
Oil Wastewater

Kinetics of Water Evaporation from Emulsions

2005 ◽  
Vol 36 (5) ◽  
pp. 425-430 ◽  
Author(s):  
A. M. Pavlenko ◽  
B. I. Basok
Keyword(s):  
Water Evaporation ◽  
Kinetics Of

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.

scholarly journals Innovations in anaerobic digestion: a model-based study

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Karol Postawa ◽  
Jerzy Szczygieł ◽  
Marek Kułażyński
Keyword(s):  
Mathematical Model ◽  
Anaerobic Digestion ◽  
Production Efficiency ◽  
Biogas Production ◽  
Biogas Plant ◽  
Methane Content ◽  
Pig Manure ◽  
Pig Slurry ◽  
Production Chain ◽  
The Impact

Abstract Background Increasing the efficiency of the biogas production process is possible by modifying the technological installations of the biogas plant. In this study, specific solutions based on a mathematical model that lead to favorable results were proposed. Three configurations were considered: classical anaerobic digestion (AD) and its two modifications, two-phase AD (TPAD) and autogenerative high-pressure digestion (AHPD). The model has been validated based on measurements from a biogas plant located in Poland. Afterward, the TPAD and AHPD concepts were numerically tested for the same volume and feeding conditions. Results The TPAD system increased the overall biogas production from 9.06 to 9.59%, depending on the feedstock composition, while the content of methane was slightly lower in the whole production chain. On the other hand, the AHPD provided the best purity of the produced fuel, in which a methane content value of 82.13% was reached. At the same time, the overpressure leads to a decrease of around 7.5% in the volumetric production efficiency. The study indicated that the dilution of maize silage with pig manure, instead of water, can have significant benefits in the selected configurations. The content of pig slurry strengthens the impact of the selected process modifications—in the first case, by increasing the production efficiency, and in the second, by improving the methane content in the biogas. Conclusions The proposed mathematical model of the AD process proved to be a valuable tool for the description and design of biogas plant. The analysis shows that the overall impact of the presented process modifications is mutually opposite. The feedstock composition has a moderate and unsteady impact on the production profile, in the tested modifications. The dilution with pig manure, instead of water, leads to a slightly better efficiency in the classical configuration. For the TPAD process, the trend is very similar, but the AHPD biogas plant indicates a reverse tendency. Overall, the recommendation from this article is to use the AHPD concept if the composition of the biogas is the most important. In the case in which the performance is the most important factor, it is favorable to use the TPAD configuration.

scholarly journals Co-Digestion of Rice Straw with Cow Manure in an Innovative Temperature Phased Anaerobic Digestion Technology: Performance Evaluation and Trace Elements

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2561
Author(s):  
Furqan Muhayodin ◽  
Albrecht Fritze ◽  
Oliver Christopher Larsen ◽  
Marcel Spahr ◽  
Vera Susanne Rotter
Keyword(s):  
Trace Elements ◽  
Anaerobic Digestion ◽  
Greenhouse Gas ◽  
Rice Straw ◽  
Methane Yield ◽  
Methane Formation ◽  
Cow Manure ◽  
Volatile Solids ◽  
Mass Fractions ◽  
Cu And Zn

Rice straw is an agricultural residue produced in abundant quantities. Open burning and plowing back the straw to the fields are common practices for its disposal. In-situ incorporation and burning cause emissions of greenhouse gas and particulate matter. Additionally, the energy potential of rice straw is lost. Anaerobic digestion is a technology that can be potentially used to utilize the surplus rice straw, provide renewable energy, circulate nutrients available in the digestate, and reduce greenhouse gas emissions from rice paddies. An innovative temperature phased anaerobic digestion technology was developed and carried out in a continuous circulating mode of mesophilic and hyperthermophilic conditions in a loop digester (F1). The performance of the newly developed digester was compared with the reference digester (F2) working at mesophilic conditions. Co-digestion of rice straw was carried out with cow manure to optimize the carbon to nitrogen ratio and to provide the essential trace elements required by microorganisms in the biochemistry of methane formation. F1 produced a higher specific methane yield (189 ± 37 L/kg volatile solids) from rice straw compared to F2 (148 ± 36 L/kg volatile solids). Anaerobic digestion efficiency was about 90 ± 20% in F1 and 70 ± 20% in F2. Mass fractions of Fe, Ni, Co, Mo, Cu, and Zn were analyzed over time. The mass fractions of Co, Mo, Cu, and Zn were stable in both digesters. While mass fractions of Fe and Ni were reduced at the end of the digestion period. However, no direct relationship between specific methane yield and reduced mass fraction of Fe and Ni was found. Co-digestion of rice straw with cow manure seems to be a good approach to provide trace elements except for Se.

scholarly journals Biochemical Methane Potential of Cork Boiling Wastewater at Different Inoculum to Substrate Ratios

2021 ◽  
Vol 11 (7) ◽  
pp. 3064
Author(s):  
Roberta Mota-Panizio ◽  
Manuel Jesús Hermoso-Orzáez ◽  
Luis Carmo-Calado ◽  
Gonçalo Lourinho ◽  
Paulo Sérgio Duque de Brito
Keyword(s):  
Anaerobic Digestion ◽  
Biogas Production ◽  
Treatment Plant ◽  
Organic Substrates ◽  
Biochemical Methane Potential ◽  
Volatile Solids ◽  
Working Volume ◽  
Methane Potential ◽  
Bmp Test ◽  
Cork Industry

The present study evaluates the digestion of cork boiling wastewater (CBW) through a biochemical methane potential (BMP) test. BMP assays were carried out with a working volume of 600 mL at a constant mesophilic temperature (35 °C). The experiment bottles contained CBW and inoculum (digested sludge from a wastewater treatment plant (WWTP)), with a ratio of inoculum/substrate (Ino/CBW) of 1:1 and 2:1 on the basis of volatile solids (VSs); the codigestion with food waste (FW) had a ratio of 2/0.7:0.3 (Ino/CBW:FW) and the codigestion with cow manure (CM) had a ratio of 2/0.5:0.5 (Ino/CBW:CM). Biogas and methane production was proportional to the inoculum substrate ratio (ISR) used. BMP tests have proved to be valuable for inferring the adequacy of anaerobic digestion to treat wastewater from the cork industry. The results indicate that the biomethane potential of CBWs for Ino/CBW ratios 1:1 and 2:1 is very low compared to other organic substrates. For the codigestion tests, the test with the Ino/CBW:CM ratio of 2/0.7:0.3 showed better biomethane yields, being in the expected values. This demonstrated that it is possible to perform the anaerobic digestion (AD) of CBW using a cosubstrate to increase biogas production and biomethane and to improve the quality of the final digestate.

scholarly journals Batch and Semi-Continuous Anaerobic Digestion of Industrial Solid Citrus Waste for the Production of Bioenergy

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 648
Author(s):  
Erik Samuel Rosas-Mendoza ◽  
Andrea Alvarado-Vallejo ◽  
Norma Alejandra Vallejo-Cantú ◽  
Raúl Snell-Castro ◽  
Sergio Martínez-Hernández ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Oxygen Demand ◽  
Continuous Mode ◽  
Citrus Industry ◽  
Batch Mode ◽  
Volatile Solids ◽  
Working Volume ◽  
Plant Level ◽  
Citrus Waste ◽  
Mesophilic Conditions

The aim of this paper is to describe a study of the anaerobic digestion of industrial citrus solid waste (ISCW) in both batch and semi-continuous modes for the production of bioenergy without the elimination of D-limonene. The study was conducted at the pilot plant level in an anaerobic reactor with a working volume of 220 L under mesophilic conditions of 35 ± 2 °C. Cattle manure (CM) was used as the inoculum. Three batches were studied. The first batch had a CM/ISCW ratio of 90/10, and Batches 2 and 3 had CM/ISCW ratios of 80/20 and 70/30, respectively. In the semi-continuous mode an OLR of approximately 8 g total chemical oxygen demand (COD)/Ld (4.43 gVS/Ld) was used. The results showed that 49%, 44%, and 60% of volatile solids were removed in the batch mode, and 35% was removed in the semi-continuous mode. In the batch mode, 0.322, 0.382, and 0.316 LCH4 were obtained at STP/gVSremoved. A total of 24.4 L/d (34% methane) was measured in the semi-continuous mode. Bioenergy potentials of 3.97, 5.66, and 8.79 kWh were obtained for the respective batches, and 0.09 kWh was calculated in the semi-continuous mode. The citrus industry could produce 37 GWh per season. A ton of processed oranges has a bioenergy potential of 162 kWh, which is equivalent to 49 kWh of available electricity ($3.90).

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