Thermal pre-treatment: Getting some insights on the formation of recalcitrant compounds and their effects on anaerobic digestion

2021 ◽  
Vol 282 ◽  
pp. 111940
Author(s):  
E. Ortega-Martínez ◽  
R. Chamy ◽  
D. Jeison
Keyword(s):  
Anaerobic Digestion ◽  
Recalcitrant Compounds ◽  
Pre Treatment

scholarly journals Efficiency of integrated electrooxidation and anaerobic digestion of waste activated sludge

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
J. A. Barrios ◽  
A. Cano ◽  
F. F. Rivera ◽  
M. E. Cisneros ◽  
U. Durán
Keyword(s):  
Anaerobic Digestion ◽  
Current Density ◽  
Methane Production ◽  
Energy Recovery ◽  
Energy Analysis ◽  
Mathematical Optimization ◽  
Waste Activated Sludge ◽  
Bdd Electrode ◽  
Vs Removal ◽  
Pre Treatment

Abstract Background Most of the organic content of waste activated sludge (WAS) comprises microbial cells hard to degrade, which must be pre-treated for energy recovery by anaerobic digestion (AD). Electrooxidation pre-treatment (EOP) with boron-doped diamond (BDD) electrode have been considered a promising novel technology that increase hydrolysis rate, by the disintegrating cell walls from WAS. Although electrochemical oxidation could efficiently solubilize organic substances of macromolecules, limited reports are available on EOP of WAS for improving AD. In this endeavour, the mathematical optimization study and the energy analysis of the effects of initial total solids concentrations [TS] of WAS and current density (CD) during EOP on the methane production and removal of chemical oxygen demand (COD) and volatile solids (VS) were investigated. Because limited reports are available on EOP of WAS for improving biogas production, it is not well understood; however, it has started to attract interest of scientists and engineers. Results In the present work, the energy recovery as biogas and WAS conversion were comprehensively affected by CD and [TS], in an integrated EOP and AD system. When working with WAS at 3% of [TS] pre-treated at current density of 24.1 mA/cm2, the highest COD and VS removal were achieved, making it possible to obtain the maximum methane (CH4) production of 305 N-L/kg VS and a positive energy balance of 1.67 kWh/kg VS. Therefore, the current densities used in BDD electrode are adequate to produce the strong oxidant (hydroxyl radical, ·OH) on the electrode surface, allow the oxidation of organic compounds that favours the solubilization of particulate matter and VS from WAS. Conclusions The improvement of VS removal and COD solubilization were due to the effects of pre-treatments, which help to break down the microbial cells for faster subsequent degradation; this allows a decomposition reaction that leads to biodegrade more compounds during AD. The balance was positive, suggesting that even without any optimization the energy used as electricity could be recovered from the increased methane production. It is worth noting that this kind of analysis have not been sufficiently studied so far. It is therefore important to understand how operational parameters can influence the pre-treatment and AD performances. The current study highlights that the mathematical optimization and energy analysis can make the whole process more convenient and feasible.

Alkali pre-treatment of Sorghum Moench for biogas production

2013 ◽  
Vol 67 (9) ◽  
Author(s):  
Karina Michalska ◽  
Stanisław Ledakowicz
Keyword(s):  
Anaerobic Digestion ◽  
Chemical Oxygen Demand ◽  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Total Phenolic ◽  
Methane Generation ◽  
Pre Treatment ◽  
Alkali Hydrolysis ◽  
Almost All

AbstractThis work studies the influence of the alkali pre-treatment of Sorghum Moench — a representative of energy crops used in biogas production. Solutions containing various concentrations of sodium hydroxide were used to achieve the highest degradation of lignocellulosic structures. The results obtained after chemical pre-treatment indicate that the use of NaOH leads to the removal of almost all lignin (over 99 % in the case of 5 mass % NaOH) from the biomass, which is a prerequisite for efficient anaerobic digestion. Several parameters, such as chemical oxygen demand, total organic carbon, total phenolic content, volatile fatty acids, and general nitrogen were determined in the hydrolysates thus obtained in order to define the most favourable conditions. The best results were obtained for the Sorghum treated with 5 mass % NaOH at 121°C for 30 min The hydrolysate thus achieved consisted of high total phenolic compounds concentration (ca. 4.7 g L−1) and chemical oxygen demand value (ca. 45 g L−1). Although single alkali hydrolysis causes total degradation of glucose, a combined chemical and enzymatic pre-treatment of Sorghum leads to the release of large amounts of this monosaccharide into the supernatant. This indicates that alkali pre-treatment does not lead to complete cellulose destruction. The high degradation of lignin structure in the first step of the pre-treatment rendered the remainder of the biomass available for enzymatic action. A comparison of the efficiency of biogas production from untreated Sorghum and Sorghum treated with the use of NaOH and enzymes shows that chemical hydrolysis improves the anaerobic digestion effectiveness and the combined pre-treatment could have great potential for methane generation.

Study of thermal pre-treatment on anaerobic digestion of slaughterhouse waste by TGA-MS and FTIR spectroscopy

2013 ◽  
Vol 31 (12) ◽  
pp. 1195-1202 ◽  
Author(s):  
Ángela Rodríguez-Abalde ◽  
Xiomar Gómez ◽  
Daniel Blanco ◽  
María José Cuetos ◽  
Belén Fernández ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Ftir Spectroscopy ◽  
Pre Treatment

Recalcitrant compounds formation, their toxicity, and mitigation: Key issues in biomass pretreatment and anaerobic digestion

Chemosphere ◽  
2021 ◽  
pp. 132930
Author(s):  
Gowtham Balasundaram ◽  
Rajesh Banu ◽  
Sunita Varjani ◽  
A.A. Kazmi ◽  
Vinay Kumar Tyagi
Keyword(s):  
Anaerobic Digestion ◽  
Biomass Pretreatment ◽  
Recalcitrant Compounds ◽  
Key Issues

Drivers of microbial community composition in mesophilic and thermophilic temperature-phased anaerobic digestion pre-treatment reactors

2013 ◽  
Vol 47 (19) ◽  
pp. 7098-7108 ◽  
Author(s):  
Hasina M. Pervin ◽  
Paul G. Dennis ◽  
Hui J. Lim ◽  
Gene W. Tyson ◽  
Damien J. Batstone ◽  
...  
Keyword(s):  
Microbial Community ◽  
Anaerobic Digestion ◽  
Community Composition ◽  
Microbial Community Composition ◽  
Pre Treatment

scholarly journals Kinetics of Anaerobic Digestion of Dairy Fat Waste with Saponification Pre-Treatment

2019 ◽  
Vol 13 (2) ◽  
pp. 112 ◽  
Author(s):  
Rifki Wahyu Kurnianto ◽  
Wiratni Budhijanto ◽  
Rochim Bakti Cahyono
Keyword(s):  
Anaerobic Digestion ◽  
Lipid Content ◽  
Alternative Energy ◽  
Organic Waste ◽  
High Lipid Content ◽  
Dairy Fat ◽  
High Lipid ◽  
Pre Treatment ◽  
Kinetics Of ◽  
Floating Layer

Anaerobic digestion has been an attractive field of research in the era of energy crisis. Biogas, which is the product of anaerobic digestion, provides alternative energy, while at the same time it also prevents pollution due to organic waste accumulation. Among various organic wastes, dairy fat waste is a potential substrate for anaerobic digestion. Fat waste has high theoretical biogas potential because of its high lipid content. However, anaerobic digestion of organic waste with high lipid content is quite challenging. The main obstacle in anaerobic digestion of fat waste is its tendency to form insoluble floating layer on top of the liquid phase. This phenomenon hinders the access of hydrolytic bacteria to the substrate. Saponification is one of the methods to increase the solubility of the floating layer and hence to improve the availability of substrate for the bacteria. Saponification changes the lipid content into soap which has both polar and non-polar functional groups and the polar side will increase the solubility of the substrate in water. This study evaluated the effect of different dosage of base added as the reactant during saponification pre-treatment on the productivity of anaerobic digestion of dairy fat waste. The kinetics of the anaerobic digestion process was analyzed by mean of mathematical model. The variations of the alkaline dosages studied for saponification pre-treatment were 0.04 mol base/g sCOD; 0.02 mol base/g sCOD; and no pre-treatment for control reactor. This study proved that saponification increased the solubility of dairy fat waste. This result was confirmed by the hydrolysis constant value (kH) of 0.00782/day for reactor with saponification, which was twenty times of magnitude higher than the kH value of 0.00032/day in the reactor without saponification. However, the exposure to high pH during the saponification pre-treatment might somewhat inhibit indigenous acidogenic bacteria in the waste which results in lower methane yield in the reactors with saponification to be compared to the control reactor. A B S T R A KPeruraian anaerobik merupakan salah satu bidang riset yang sangat menarik perhatian dalam era krisis energi. Biogas tidak hanya menyediakan energi alternatif, tetapi juga dapat mencegah pencemaran akibat limbah organik. Limbah lemak susu adalah substrat yang potensial untuk proses peruraian anaerobik karena memiliki potensi biogas teoritis yang tinggi akibat kandungan lemaknya yang tinggi. Namun, peruraian anaerobik dari limbah organik dengan kandungan lemak yang tinggi memiliki tantangan tersendiri. Hambatan utama dalam peruraian anaerobik dari limbah lemak susu adalah kecenderungan untuk membentuk lapisan padatan yang tidak larut dan mengapung di bagian atas fase cair. Fenomena ini menghambat akses bakteri hidrolisis terhadap substrat. Saponifikasi adalah salah satu cara untuk meningkatkan kelarutan lapisan padatan tersebut, sehingga meningkatkan ketersediaan substrat untuk bakteri. Saponifikasi akan mengubah kandungan lemak menjadi sabun yang memiliki gugus fungsi polar maupun non-polar. Gugus fungsi yang bersifat polar akan meningkatkan kelarutan substrat dalam air. Studi ini mengevaluasi pengaruh dari berbagai dosis larutan basa yang ditambahkan sebagai reaktan selama perlakuan awal saponifikasi terhadap peruraian anaerobik limbah lemak susu. Kinetika proses peruraian anaerobik dianalisis dengan menggunakan model matematika. Variasi dosis yang diamati pengaruhnya untuk perlakuan awal saponifikasi adalah 0,04 mol basa/g sCOD; 0,02 mol basa/g sCOD; dan nol (tanpa perlakuan awal saponifikasi). Dari penelitian ini, terbukti bahwa saponifikasi berhasil meningkatkan kelarutan limbah lemak susu dan juga ditunjukkan oleh nilai konstanta hidrolisis (kH) 0,00782/hari lebih tinggi dua puluh kali lipat dibandingkan dengan nilai kH 0,00032/hari pada reaktor tanpa saponifikasi. Akan tetapi, penelitian ini juga mengindikasikan bahwa bakteri asidogenik bawaan substrat terhambat kinerjanya oleh paparan pH yang tinggi selama perlakuan awal saponifikasi berlangsung sehingga hasil gas metan yang diperoleh lebih rendah daripada reaktor kontrol.

scholarly journals Influence of a steam-explosion pre-treatment on the methane yield and kinetics of anaerobic digestion of two-phase olive mil solid waste or alperujo

2016 ◽  
Vol 102 ◽  
pp. 361-369 ◽  
Author(s):  
Bárbara Rincón ◽  
Guillermo Rodríguez-Gutiérrez ◽  
Lucía Bujalance ◽  
Juan Fernández-Bolaños ◽  
Rafael Borja
Keyword(s):  
Anaerobic Digestion ◽  
Solid Waste ◽  
Steam Explosion ◽  
Methane Yield ◽  
Two Phase ◽  
Pre Treatment ◽  
Kinetics Of
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