scholarly journals An Unstructured Model for Anaerobic Treatment of Raw Cheese Whey for Volatile Fatty Acids Production

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1850
Author(s):  
Claudio B-Arroyo ◽  
Antonio Lara-Musule ◽  
Ervin Alvarez-Sanchez ◽  
Gloria Trejo-Aguilar ◽  
Juan-Rodrigo Bastidas-Oyanedel ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Dynamic Behavior ◽  
Volatile Fatty Acids ◽  
Cheese Whey ◽  
Value Added ◽  
Anaerobic Treatment ◽  
Operating Conditions ◽  
Model Parameters ◽  
Temperature Conditions ◽  
Proposed Model

The whey is a byproduct of the dairy industry that, if not treated properly, can cause serious environmental pollution problems. Anaerobic treatment is an alternative for its recovery, since, in addition to reducing the organic load. it allows the generation of value-added products such as volatile fatty acids (VFA) and biogas. However, the process is very complex and requires specific operating conditions that guarantee its stability and favor the production of value-added compounds. In this work, an unstructured mathematical model is proposed to evaluate the dynamic behavior of the stages of the anaerobic degradation process of the whey (i.e., hydrolysis, acidogenesis, acetogenesis and methanogenesis). The proposed model considers the dynamic variation in pH during the experiment. To validate the model, an experimental set was carried out at pH and temperature conditions that favor the production of VFAs. Experimental results show that the anaerobic treatment of the raw cheese whey favors pH = 5.5; for T = 40 °C, the maximum VFA production is obtained (30.71 gCOD L−1), and for T = 35 °C, a 45.81% COD degradation is reached. The proposed model considers the effect of pH and temperature and it is validated in the region where the experimental tests were carried out. The model parameters were estimated using the Levenberg–Marquardt method, obtaining coefficients of determination R2 > 0.94. The proposed model can describe the dynamic behavior of the key variables in the anaerobic treatment of raw cheese whey at different pH and temperature conditions, finding that VFA production is favored at pH ≥ 7, while the highest COD removal results in acidic conditions

scholarly journals Diagnosis and Monitoring of Volatile Fatty Acids Production from Raw Cheese Whey by Multiscale Time-Series Analysis

2021 ◽  
Vol 11 (13) ◽  
pp. 5803
Author(s):  
Antonio Lara-Musule ◽  
Ervin Alvarez-Sanchez ◽  
Gloria Trejo-Aguilar ◽  
Laura Acosta-Dominguez ◽  
Hector Puebla ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Time Series ◽  
Time Series Analysis ◽  
Multiscale Analysis ◽  
Volatile Fatty Acids ◽  
Cheese Whey ◽  
Anaerobic Treatment ◽  
Operating Conditions ◽  
Series Analysis ◽  
Key Variables

Anaerobic treatment is a viable alternative for the treatment of agro-industrial waste. Anaerobic digestion reduces organic load and produces volatile fatty acids (VFA), which are precursors of value-added products such as methane-rich biogas, biohydrogen, and biopolymers. Nowadays, there are no low-cost diagnosis and monitoring systems that analyze the dynamic behavior of key variables in real time, representing a significant limitation for its practical implementation. In this work, the feasibility of using the multiscale analysis to diagnose and monitor the key variables in VFA production by anaerobic treatment of raw cheese whey is presented. First, experiments were carried out to evaluate the performance of the proposed methodology under different operating conditions. Then, experimental pH time series were analyzed using rescaled range (R/S) techniques. Time-series analysis shows that the anaerobic VFA production exhibits a multiscale behavior, identifying three characteristic regions (i.e., three values of Hurst exponent). In addition, the dynamic Hurst exponents show satisfactory correlations with the chemical oxygen demand (COD) consumption and VFA production. The multiscale analysis of pH time series is easy to implement and inexpensive. Hence, it could be used as a diagnosis and indirect monitoring system of key variables in the anaerobic treatment of raw cheese whey.

scholarly journals Anaerobic treatment of high-sulfate wastes

1986 ◽  
Vol 13 (4) ◽  
pp. 423-428 ◽  
Author(s):  
Jan A. Oleszkiewicz ◽  
Barry L. Hilton
Keyword(s):  
Fatty Acids ◽  
Volatile Fatty Acids ◽  
Cheese Whey ◽  
Oxygen Demand ◽  
Anaerobic Treatment ◽  
Pulp And Paper ◽  
Anaerobic Sludge ◽  
Dairy Wastes ◽  
High Sulfate ◽  
Cooking Liquor

Six parallel upflow anaerobic sludge bed reactors were operated at chemical oxygen demand (COD) loads from 3 to 10 kg COD/(m3∙d). Four reactors (R1–R4) were fed sodium sulfate at loads of 1–3 kg S-SO4/(m3∙d). Reactors R1 and R2 were fed spent cheese whey with R1 being operated in an unstripped and R2 in a stripped mode. At COD loads below 5 kg/(m3∙d), the removal in R1 was 60–80% COD and generally trailed R2 by a margin of 0–15%. At higher COD loads and at higher SO4/COD ratios, the performance of R1 deteriorated significantly. A similar situation was found in the pair R3 (unstripped) and R4 (stripped), which was fed a mixture of spent whey and sulfite cooking liquor. Reactors R5 and R6 were subjected to the same feed as R3 and R4, but no sulfate was added. A comparison of R4 with R6 indicated slightly lower COD removal in R4 with similar amounts of volatile fatty acids accumulating in both reactors in cases of overloading. Key words: anaerobic treatment, sulfides, methanogenesis, inhibition, sludge bed reactor, dairy wastes, pulp and paper wastes, sulfate reduction.

Volatile fatty acids production from anaerobic treatment of cassava waste water: effect of temperature and alkalinity

2015 ◽  
Vol 36 (20) ◽  
pp. 2637-2646 ◽  
Author(s):  
Salah Din Mahmud Hasan ◽  
Citieli Giongo ◽  
Mônica Lady Fiorese ◽  
Simone Damasceno Gomes ◽  
Tatiane Caroline Ferrari ◽  
...  
Keyword(s):  
Waste Water ◽  
Fatty Acids ◽  
Volatile Fatty Acids ◽  
Anaerobic Treatment ◽  
Effect Of Temperature ◽  
Water Effect ◽  
Cassava Waste

scholarly journals Dynamic Emulation of a PEM Electrolyzer by Time Constant Based Exponential Model

Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 750 ◽  
Author(s):  
Damien Guilbert ◽  
Gianpaolo Vitale
Keyword(s):  
Dynamic Behavior ◽  
Proton Exchange Membrane ◽  
Exponential Model ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Experimental Investigations ◽  
Model Parameters ◽  
Dynamic Operating ◽  
Pem Electrolyzer ◽  
Current Interval

The main objective of this paper is to develop a dynamic emulator of a proton exchange membrane (PEM) electrolyzer (EL) through an equivalent electrical model. Experimental investigations have highlighted the capacitive effect of EL when subjecting to dynamic current profiles, which so far has not been reported in the literature. Thanks to a thorough experimental study, the electrical domain of a PEM EL composed of 3 cells has been modeled under dynamic operating conditions. The dynamic emulator is based on an equivalent electrical scheme that takes into consideration the dynamic behavior of the EL in cases of sudden variation in the supply current. The model parameters were identified for a suitable current interval to consider them as constant and then tested with experimental data. The obtained results through the developed dynamic emulator have demonstrated its ability to accurately replicate the dynamic behavior of a PEM EL.

scholarly journals Pengaruh sumber karbon terhadap produksi bioplastik polihidroksialkanoat (PHA) dengan ralstonia eutropha

2018 ◽  
Vol 9 (1) ◽  
pp. 28
Author(s):  
Martha Aznury ◽  
Tjandra Setiadi ◽  
Adi Pancoro
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Carbon Source ◽  
Fermentation Process ◽  
Volatile Fatty Acids ◽  
Ralstonia Eutropha ◽  
Operating Conditions ◽  
Batch Bioreactor ◽  
Pha Production ◽  
Fructose Fermentation

Bioplastic Polyhidroxyalknoate (PHA) is a polyester type bioplastic with physicochemical properties resemble to those of polypropilen from petroleum. PHA production was investigated to determine the effect of carbon source on the fermentation process by Ralstonia eutropha. Specifically, Ralstonia eutropha was cultivated in a batch bioreactor to show the dynamics of P(3HB-co-3HV) copolymer production from glucose or fructose as C source. In adition, the effect of volatile fatty acids addition, as stimulator to the copolymer production, was also studied. The operating conditions in a 7 L bioreactor were at temperature 30 oC and pH 7.0. The concentration of carbon source glucose or fructose was 40 g/L, and after 20 hour fermentation, volatile fatty acids were added. With volatile fatty acids addition, the resulting fructose fermentation had PHA content of 32.78%, in which the HV percentage was 11.78%. Meanwhile, the fermentation of glucose, stimulated by volatile fatty acids, gave PHA as much as 20.19% with HV percentage of 8.71%. Therefore,, the Ralstonia eutropha fermentation of fructose as the carbon source gave a higher yield than glucose. Keywords: Volatil Fatty Acid, Fructose, Glucose, PHA, P(3HB-co-3HV), Ralstonia eutropha AbstrakBioplastik polihidroksialkanoat (PHA) adalah bioplastik dari kelompok poliester dengan sifat fisikokimia mirip dengan plastik polipropilen dari minyak bumi. Penelitian ini bertujuan untuk mempelajari pengaruh sumber karbon terhadap poduksi PHA yang dilakukan dengan proses fermentasi menggunakan Ralstonia eutropha. Ralstonia eutropha dikultivasi dalam bioreaktor batch untuk mempelajari dinamika produksi kopolimer P(3HB-co-3HV) dari sumber karbon glukosa atau fruktosa, serta mempelajari pengaruh sumber stimulator asam lemak volatil. Kondisi operasional fermentasi menggunakan bioreaktor 7 L adalah pada temperatur 30 oC dan pH 7. Konsentrasi sumber karbon glukosa atau fruktosa yang digunakan adalah 40 gr/L, dan setelah 20 jam fermentasi ditambahkan asam lemak volatil yang berfungsi sebagai stimulator dalam produksi P(3HB-co-3HV). Panen sel Ralstonia eutropha dilakukan setelah 60 jam. Hasil penelitian menunjukkan fermentasi Ralstonia eutropha dengan substrat fruktosa dan asam lemak volatil sebagai stimulator mempunyai kandungan PHA sebesar 32,78%, dengan kadar HV 11,78%. Pada pemberian substrat glukosa dan asam lemak volatil menunjukkan kandungan PHA sebesar 20,19%, dengan kadar HV 8.71%. Jadi fermentasi Ralstonia eutropha dengan menggunakan substrat fruktosa memberikan yield yang lebih tinggi dibandingkan menggunakan substrat glukosa.Kata Kunci: Asam lemak volatil, fruktosa, glukosa, PHA, P(3HB-co-3HV), Ralstonia eutropha

scholarly journals Production Of Value-Added Products From Waste Derived Volatile Fatty Acids: A Review

2021 ◽  
Author(s):  
Matthew Donald Hinnecke
Keyword(s):  
Fatty Acids ◽  
Literature Review ◽  
Human Population ◽  
Volatile Fatty Acids ◽  
Value Added ◽  
Sustainable Society ◽  
Waste Streams ◽  
A Value ◽  
The World ◽  
Value Added Products

Due to the exponential growth of the human population and declining environmental quality in the world, waste derived volatile fatty acids (VFAs) have been identified as a source for the production of value-added products. Throughout this paper, different technologies for the production of value-added products from VFAs, various high content VFA waste streams and value-added products from each process will be discussed. Additionally, an in-depth literature review will be conducted on 5 value added products from VFAs. Highlights of various experiments will be identified as well as common trends in experiments to date. Some considerations will also be given to particular strategies and methods which may enhance the production of a value-added product in the future. Even through the uncertainty it has been proven that waste derived VFAs are a major candidate in contributing to a more environmentally and sustainable society in the immediate future.

scholarly journals Production Of Value-Added Products From Waste Derived Volatile Fatty Acids: A Review

2021 ◽  
Author(s):  
Matthew Donald Hinnecke
Keyword(s):  
Fatty Acids ◽  
Literature Review ◽  
Human Population ◽  
Volatile Fatty Acids ◽  
Value Added ◽  
Sustainable Society ◽  
Waste Streams ◽  
A Value ◽  
The World ◽  
Value Added Products

Due to the exponential growth of the human population and declining environmental quality in the world, waste derived volatile fatty acids (VFAs) have been identified as a source for the production of value-added products. Throughout this paper, different technologies for the production of value-added products from VFAs, various high content VFA waste streams and value-added products from each process will be discussed. Additionally, an in-depth literature review will be conducted on 5 value added products from VFAs. Highlights of various experiments will be identified as well as common trends in experiments to date. Some considerations will also be given to particular strategies and methods which may enhance the production of a value-added product in the future. Even through the uncertainty it has been proven that waste derived VFAs are a major candidate in contributing to a more environmentally and sustainable society in the immediate future.

Mathematical modeling of volatile fatty acids production from cheese whey: Evaluation of pH and substrate-inoculum ratio effects

Fuel ◽  
2021 ◽  
Vol 287 ◽  
pp. 119510
Author(s):  
J. Pérez-Morales ◽  
C. B.-Arroyo ◽  
E. Morales-Zarate ◽  
H. Hernández-García ◽  
H.O. Méndez-Acosta ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Fatty Acids ◽  
Volatile Fatty Acids ◽  
Cheese Whey

Valorization of sewage sludge in co-digestion with cheese whey to produce volatile fatty acids

2020 ◽  
Vol 118 ◽  
pp. 541-551
Author(s):  
Ruth Iglesias-Iglesias ◽  
Christian Kennes ◽  
María C. Veiga
Keyword(s):  
Fatty Acids ◽  
Sewage Sludge ◽  
Volatile Fatty Acids ◽  
Cheese Whey

scholarly journals Fatigue life assessment method of in-service mechanical structure

2021 ◽  
Vol 13 (2) ◽  
pp. 168781402199652
Author(s):  
Xiqiang Ma ◽  
Fang Yang ◽  
Jishun Li ◽  
Yujun Xue ◽  
Zhiqiang Guan
Keyword(s):  
Elastic Modulus ◽  
Fatigue Life ◽  
Modulus Of Elasticity ◽  
Evaluation Model ◽  
Assessment Method ◽  
Operating Conditions ◽  
Life Assessment ◽  
Model Parameters ◽  
Mechanical Structure ◽  
Proposed Model

The most usual failure mode of any mechanical structure is fatigue, which is characterized by an important feature of the decrease of elastic modulus of the material. In this paper, a fatigue life evaluation model based on equivalent elastic modulus is proposed for in-service mechanical structure. In the proposed model, parameters that represent the operating conditions of the mechanical structure, such as load, vibration, and shaft torque, etc., are used as the generalized load. To replace the fatigue stress, the statistical method is used here, which is also used in the conventional fatigue analysis method. The structural strain is also measured simultaneously. Using the statistical theory, the equivalent modulus of elasticity is formulated based on the relationship of stress, strain, and modulus of elasticity. To validate the proposed model, an online fatigue damage experiment has been conducted. The experimental results have been compared with that of the fatigue life prediction model with good agreement. It is expected that the methodology proposed in this paper will be widely used.

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