scholarly journals Comparison between Thermo-Alkaline and Electro-Fenton Disintegration Effect on Waste Activated Sludge Anaerobic Digestion

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Emna Feki ◽  
Sami Sayadi ◽  
Slim Loukil ◽  
Abdelhafidh Dhouib ◽  
Sonia Khoufi
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Continuous Fermentation ◽  
Waste Activated Sludge ◽  
Sludge Reduction ◽  
Continuous Stirred Tank Reactor ◽  
Biogas Yield ◽  
Anaerobic Biodegradability ◽  
Continuous Stirred Tank ◽  
Better Than

Disintegration of municipal waste activated sludge (WAS) using thermo-alkaline (TA) and electro-Fenton (EF) methods was investigated and compared in terms of the efficiency of sludge solubilisation and enhancement of anaerobic biodegradability. Performance of organic matter solubilisation (soluble COD, proteins, polysaccharides) of sludge pretreated with EF was proved to be better than that with TA pretreatment, which resulted in the enhancement of anaerobic biodegradability. Comparison of results indicated that percentages of PN and PS release obtained after EF pretreatment (68.95 and 65.22%) were higher than those obtained by TA method (45.25 and 35.22%) respectively. An improvement of biogas potential about 2 and 1.6 times was achieved respectively by EF and TA pretreatment in comparison to raw sludge. During semi-continuous fermentation study in continuous stirred tank reactor, EF pretreated sludge gave the best biogas yield (0.6 L biogas/g COD) at an OLR of 2.5 g COD/L. d in comparison to TA pretreated sludge (0.3 L biogas/g COD), where low biogas yield about 0.1 L biogas/g COD was registered by raw sludge in the same CSTR. Therefore, the integration of EF process to anaerobic digestion might be a promising process for sludge reduction and biogas recovery.

scholarly journals High-Rate Anaerobic Digestion of Waste Activated Sludge by Integration of Electro-Fenton Process

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 626 ◽  
Author(s):  
Emna Feki ◽  
Audrey Battimelli ◽  
Sami Sayadi ◽  
Abdelhafidh Dhouib ◽  
Sonia Khoufi
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Volatile Fatty Acids ◽  
Continuous Fermentation ◽  
Removal Rate ◽  
High Rate ◽  
Organic Loading Rate ◽  
Waste Activated Sludge ◽  
Capillary Suction ◽  
Biogas Yield

Anaerobic digestion (AD), being the most effective treatment method of waste activated sludge (WAS), allows for safe disposal. The present study deals with the electro-Fenton (EF) pretreatment for enhancing the WAS biogas potential with low-cost iron electrodes. The effect of pretreatment on the physicochemical characteristics of sludge was assessed. Following EF pretreatment, the pH, conductivity, soluble chemical oxygen demand (SCOD), and volatile fatty acids (VFA) increased to 7.5, 13.72 mS/cm, 4.1 g/L, and 925 mg/L, respectively. Capillary suction time (CST) analysis highlighted the dewaterability effect of EF on WAS, as demonstrated by the decrease in CST from 429 to 180 s following 30 min of pretreatment. Batch digestion assays presented an increase in the biogas yield to 0.135 L/g volatile solids (VS) after 60 min of EF pretreatment in comparison to raw sludge (0.08 L/g VS). Production of biogas was also found to improve during semi-continuous fermentation of EF-pretreated sludge conducted in a lab-scale reactor. In comparison to raw sludge, EF-pretreated sludge produced the highest biogas yield (0.81 L biogas/g VS) with a high COD removal rate, reaching 96.6% at an organic loading rate (OLR) of 2.5 g VS/L. d. Results revealed that the EF process could be an effective WAS disintegration method with maximum recovery of bioenergy during AD.

scholarly journals Comparison of the impacts of thermal pretreatment on waste activated sludge using aerobic and anaerobic digestion

2018 ◽  
Vol 78 (8) ◽  
pp. 1772-1781 ◽  
Author(s):  
Hyungjun (Brian) Jo ◽  
Wayne Parker ◽  
Peiman Kianmehr
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Oxygen Demand ◽  
Waste Activated Sludge ◽  
Thermal Pretreatment ◽  
Decay Products ◽  
Anaerobic Biodegradability ◽  
Pretreatment Conditions ◽  
The Impact ◽  
Aerobic And Anaerobic

Abstract A range of thermal pretreatment conditions were used to evaluate the impact of high pressure thermal hydrolysis on the biodegradability of waste activated sludge (WAS) under aerobic and anaerobic conditions. It was found that pretreatment did not increase the overall extent to which WAS could be aerobically biodegraded. Thermal pretreatment transformed the biodegradable fraction of WAS (XH) to readily biodegradable chemical oxygen demand (COD) (SB) (16.5–34.6%) and slowly biodegradable COD (XB) (45.8–63.6%). The impact of pretreatment temperature and duration on WAS COD fractionation did not follow a consistent pattern as changes in COD solubilization did not correspond to the observed generation of SB through pretreatment. The pretreated WAS (PWAS) COD fractionations determined from aerobic respirometry were employed in anaerobic modeling and it was concluded that the aerobic and anaerobic biodegradability of PWAS differed. It was found that thermal pretreatment resulted in as much as 50% of the endogenous decay products becoming biodegradable in anaerobic digestion. Overall, it was concluded that the COD fractionation that was developed based upon the aerobic respirometry was valid. However, it was necessary to implement a first-order decay process that reflected changes in the anaerobic biodegradability of the endogenous products through pretreatment.

Improved methane production from waste activated sludge with low organic content by alkaline pretreatment at pH 10

2013 ◽  
Vol 68 (7) ◽  
pp. 1591-1598 ◽  
Author(s):  
L. Y. Feng ◽  
L. Q. Yang ◽  
L. X. Zhang ◽  
H. L. Chen ◽  
J. Chen
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Methane Production ◽  
Organic Content ◽  
Alkaline Pretreatment ◽  
Waste Activated Sludge ◽  
Digestion Time ◽  
Anaerobic Microorganisms ◽  
Anaerobic Biodegradability ◽  
Pretreatment Time

Sludge with low organic content always results in an unsatisfactory performance, even failure of anaerobic digestion. The alkaline pretreatment effect on anaerobic digestion of sludge with low organic content has seldom been studied although it gives many benefits for sludge with high organic content. In this study the influence of alkaline pretreatment (pH 10, an effective alkaline pH) on the solubilization and methane production from waste activated sludge (WAS) with low organic content was investigated. Results from biochemical methane potential (BMP) experiments showed that anaerobic biodegradability of WAS was greatly improved by alkaline pretreatment at pH 10. Methane production from the current WAS under conditions of pretreatment time 4 h and digestion time 15 d was 139.6 mL/g VS (volatile solids), much higher than that from the unpretreated WAS with digestion time of 20 d (75.2 mL/g VS). Also, the solubilization of WAS was significantly accelerated by alkaline pretreatment. Mechanism exploration indicated that the general activities of anaerobic microorganisms, specific activities of key enzymes and the amounts of methanogens were enhanced by alkaline pretreatment at pH 10, showing good agreement with methane production.

scholarly journals Toward bioenergy recovery from waste activated sludge: improving bio-hydrogen production and sludge reduction by pretreatment coupled with anaerobic digestion–microbial electrolysis cells

RSC Advances ◽  
2015 ◽  
Vol 5 (60) ◽  
pp. 48413-48420 ◽  
Author(s):  
Zhangwei He ◽  
Aijuan Zhou ◽  
Chunxue Yang ◽  
Zechong Guo ◽  
Aijie Wang ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Hydrogen Production ◽  
Activated Sludge ◽  
Waste Activated Sludge ◽  
Sludge Reduction ◽  
Microbial Electrolysis Cells ◽  
Electrolysis Cells ◽  
Microbial Electrolysis

A novel and attractive technology for renewable bioenergy recovery from WAS and sludge reduction has been investigated.

Occurrence, effect, and fate of residual microplastics in anaerobic digestion of waste activated sludge: A state-of-the-art review

2021 ◽  
pp. 125035
Author(s):  
Zhang-Wei He ◽  
Wen-Jing Yang ◽  
Yong-Xiang Ren ◽  
Hong-Yu Jin ◽  
Cong-Cong Tang ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
State Of The Art ◽  
Waste Activated Sludge

Modified ADM1 disintegration/hydrolysis structures for modeling batch thermophilic anaerobic digestion of thermally pretreated waste activated sludge

2009 ◽  
Vol 43 (14) ◽  
pp. 3479-3492 ◽  
Author(s):  
Ivan Ramirez ◽  
Alexis Mottet ◽  
Hélène Carrère ◽  
Stéphane Déléris ◽  
Fabien Vedrenne ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Waste Activated Sludge ◽  
Thermophilic Anaerobic Digestion
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