Coupling anaerobic digestion and pyrolysis processes for maximizing energy recovery and soil preservation according to the circular economy concept

2021 ◽  
Vol 279 ◽  
pp. 111632
Author(s):  
Saida Tayibi ◽  
Florian Monlau ◽  
Frederic Marias ◽  
Guillaume Cazaudehore ◽  
Nour-Elhouda Fayoud ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Circular Economy ◽  
Energy Recovery ◽  
Pyrolysis Processes

scholarly journals Enhancing Energy Recovery in Form of Biogas, from Vegetable and Fruit Wholesale Markets By-Products and Wastes, with Pretreatments

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1298
Author(s):  
Carlos Morales-Polo ◽  
María del Mar Cledera-Castro ◽  
Marta Revuelta-Aramburu ◽  
Katia Hueso-Kortekaas
Keyword(s):  
Anaerobic Digestion ◽  
Circular Economy ◽  
Energy Recovery ◽  
Structural Characteristics ◽  
Complete Analysis ◽  
Generation Process ◽  
Positive Effects ◽  
Digestion Process ◽  
By Products

Residues and by-products from vegetables and fruit wholesale markets are suitable for recovery in the form of energy through anaerobic digestion, allowing waste recovery and introducing them into the circular economy. This suitability is due to their composition, structural characteristics, and to the biogas generation process, which is stable and without inhibition. However, it has been observed that the proportion of methane and the level of degradation of the substrate is low. It is decided to study whether the effect of pretreatments on the substrate is beneficial. Freezing, ultrafreezing and lyophilization pretreatments are studied. A characterization of the substrates has been performed, the route of action of pretreatment determined, and the digestion process studied to calculate the generation of biogas, methane, hydrogen and the proportions among these. Also, a complete analysis of the process has been performed by processing the data with mathematical and statistical methods to obtain disintegration constants and levels of degradation. It has been observed that the three pretreatments have positive effects, when increasing the solubility of the substrate, increasing porosity, and improving the accessibility of microorganisms to the substrate. Generation of gases are greatly increased, reaching a methane enrichment of 59.751%. Freezing seems to be the best pretreatment, as it increases the biodegradation level, the speed of the process and the disintegration constant by 306%.

pH regulation of the first phase could enhance the energy recovery from two‐phase anaerobic digestion of food waste

2021 ◽  
Author(s):  
Qing Zhao ◽  
Samuel Gyebi Arhin ◽  
Ziyi Yang ◽  
Haopeng Liu ◽  
Zongye Li ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Food Waste ◽  
Energy Recovery ◽  
Ph Regulation ◽  
Two Phase

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.

scholarly journals Recent Approaches for the Production of High Value-Added Biofuels from Gelatinous Wastewater

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4936
Author(s):  
Ahmed Tawfik ◽  
Shou-Qing Ni ◽  
Hanem. M. Awad ◽  
Sherif Ismail ◽  
Vinay Kumar Tyagi ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Energy Recovery ◽  
Protein Concentration ◽  
Volatile Fatty Acids ◽  
Low Cost ◽  
Large Fraction ◽  
Value Added ◽  
Organic Loading Rate ◽  
Simultaneous Treatment ◽  
Factors Affecting

Gelatin production is the most industry polluting process where huge amounts of raw organic materials and chemicals (HCl, NaOH, Ca2+) are utilized in the manufacturing accompanied by voluminous quantities of end-pipe effluent. The gelatinous wastewater (GWW) contains a large fraction of protein and lipids with biodegradability (BOD/COD ratio) exceeding 0.6. Thus, it represents a promising low-cost substrate for the generation of biofuels, i.e., H2 and CH4, by the anaerobic digestion process. This review comprehensively describes the anaerobic technologies employed for simultaneous treatment and energy recovery from GWW. The emphasis was afforded on factors affecting the biofuels productivity from anaerobic digestion of GWW, i.e., protein concentration, organic loading rate (OLR), hydraulic retention time (HRT), the substrate to inoculum (S0/X0) ratio, type of mixed culture anaerobes, carbohydrates concentration, volatile fatty acids (VFAs), ammonia and alkalinity/VFA ratio, and reactor configurations. Economic values and future perspectives that require more attention are also outlined to facilitate further advancement and achieve practicality in this domain.

Sign in / Sign up

Export Citation Format

Share Document