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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.
Emna Feki; Sami Sayadi; Abdelhafidh Dhouib; Sonia Khoufi; Audrey Battimelli. High-Rate Anaerobic Digestion of Waste Activated Sludge by Integration of Electro-Fenton Process. Molecules 2020, 25, 626 .
AMA StyleEmna Feki, Sami Sayadi, Abdelhafidh Dhouib, Sonia Khoufi, Audrey Battimelli. High-Rate Anaerobic Digestion of Waste Activated Sludge by Integration of Electro-Fenton Process. Molecules. 2020; 25 (3):626.
Chicago/Turabian StyleEmna Feki; Sami Sayadi; Abdelhafidh Dhouib; Sonia Khoufi; Audrey Battimelli. 2020. "High-Rate Anaerobic Digestion of Waste Activated Sludge by Integration of Electro-Fenton Process." Molecules 25, no. 3: 626.
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.
Emna Feki; Sami Sayadi; Slim Loukil; Abdelhafidh Dhouib; Sonia Khoufi. Comparison between Thermo-Alkaline and Electro-Fenton Disintegration Effect on Waste Activated Sludge Anaerobic Digestion. BioMed Research International 2019, 2019, 1 -10.
AMA StyleEmna Feki, Sami Sayadi, Slim Loukil, Abdelhafidh Dhouib, Sonia Khoufi. Comparison between Thermo-Alkaline and Electro-Fenton Disintegration Effect on Waste Activated Sludge Anaerobic Digestion. BioMed Research International. 2019; 2019 ():1-10.
Chicago/Turabian StyleEmna Feki; Sami Sayadi; Slim Loukil; Abdelhafidh Dhouib; Sonia Khoufi. 2019. "Comparison between Thermo-Alkaline and Electro-Fenton Disintegration Effect on Waste Activated Sludge Anaerobic Digestion." BioMed Research International 2019, no. : 1-10.
Disintegration of municipal waste-activated sludge (WAS) is regarded as a prerequisite of the anaerobic digestion process to reduce sludge volume and improve biogas yield. Pretreatment of WAS using thermo-alkaline (TA), H2O2 oxidation, electrolysis and electro-oxidation (EO) processes were investigated and compared in term of COD solubilization and biogas production. For each pretreatment, the influences of different operational variables were studied in detail. At optimum conditions, EO gave the maximum COD solubilization (28 %). The effects of pretreatments under the optimum conditions on anaerobic digestion were experienced with biochemical methane potential assay. Significant increases in biogas yield up to 78 and 40 % were observed respectively in the EO and TA pretreated samples compared to raw sludge. Results clearly revealed that the application of EO is a significant alternative method for the improvement of WAS anaerobic digestion.
Emna Feki; Sonia Khoufi; Slim Loukil; Sami Sayadi. Improvement of anaerobic digestion of waste-activated sludge by using H2O2 oxidation, electrolysis, electro-oxidation and thermo-alkaline pretreatments. Environmental Science and Pollution Research 2015, 22, 14717 -14726.
AMA StyleEmna Feki, Sonia Khoufi, Slim Loukil, Sami Sayadi. Improvement of anaerobic digestion of waste-activated sludge by using H2O2 oxidation, electrolysis, electro-oxidation and thermo-alkaline pretreatments. Environmental Science and Pollution Research. 2015; 22 (19):14717-14726.
Chicago/Turabian StyleEmna Feki; Sonia Khoufi; Slim Loukil; Sami Sayadi. 2015. "Improvement of anaerobic digestion of waste-activated sludge by using H2O2 oxidation, electrolysis, electro-oxidation and thermo-alkaline pretreatments." Environmental Science and Pollution Research 22, no. 19: 14717-14726.
Anaerobic co-digestion of olive mill wastewater (OMW) with liquid poultry manure (LPM) was investigated in a jet-loop reactor (JLR) as a new approach for upgrading the efficiency of bioprocess. Optimum proportion of LPM was evaluated by determining biochemical methane potential. Methane yields were compared by applying one way ANOVA method followed by post hoc Tukey’s test with a 0.05 significance level. Results demonstrated that the addition of LPM at proportion of 10% and 30% (v/v) improved methane yield of OMW digestion but differences between these mixtures and raw OMW are not significant. JLR results confirmed that the proportion 30% LPM gives the optimum condition for excellent stability of digester. Methane production was significantly high until an organic loading rate of 9.5 g COD/L reactor/day. Overall; this study indicates the technical feasibility and effectiveness of using JLR as one-stage anaerobic system for the co-digestion of OMW and LPM.
Sonia Khoufi; Assawer Louhichi; Sami Sayadi. Optimization of anaerobic co-digestion of olive mill wastewater and liquid poultry manure in batch condition and semi-continuous jet-loop reactor. Bioresource Technology 2015, 182, 67 -74.
AMA StyleSonia Khoufi, Assawer Louhichi, Sami Sayadi. Optimization of anaerobic co-digestion of olive mill wastewater and liquid poultry manure in batch condition and semi-continuous jet-loop reactor. Bioresource Technology. 2015; 182 ():67-74.
Chicago/Turabian StyleSonia Khoufi; Assawer Louhichi; Sami Sayadi. 2015. "Optimization of anaerobic co-digestion of olive mill wastewater and liquid poultry manure in batch condition and semi-continuous jet-loop reactor." Bioresource Technology 182, no. : 67-74.
Enzymatic hydrolysis of olive mill wastewater compounds (OMW) using culture broth of Aspergillus niger, Trichoderma atroviride and Trametes trogii was tested in order to release free simple phenolic compounds having high antioxidant activity. HPLC analysis of treated and untreated OMW indicated the release of large amounts of free hydroxytyrosol (HT). Enzymatic pre-treatment of OMW by A. niger and T. atroviride broth cultures which are rich in β-glucosidase increased the amount of HT respectively from 0.05 up to 1.1 and 0.50 g/L. However, the use of T. trogii broth culture showed an oxidation of phenolic compounds due to its high laccase activity. The ethyl acetate extract of OMW treated by A. niger broth culture with IC50 of 45 μg/mL showed the strongest antioxidant potency compared to untreated OMW with IC50 of 501 μg/mL.
Manel Hamza; Sonia Khoufi; Sami Sayadi. Fungal enzymes as a powerful tool to release antioxidants from olive mill wastewater. Food Chemistry 2011, 131, 1430 -1436.
AMA StyleManel Hamza, Sonia Khoufi, Sami Sayadi. Fungal enzymes as a powerful tool to release antioxidants from olive mill wastewater. Food Chemistry. 2011; 131 (4):1430-1436.
Chicago/Turabian StyleManel Hamza; Sonia Khoufi; Sami Sayadi. 2011. "Fungal enzymes as a powerful tool to release antioxidants from olive mill wastewater." Food Chemistry 131, no. 4: 1430-1436.
Aspergillus niger broth culture on wheat bran was assessed for olive wastewater (OW) hydrolysis in order to release hydroxytyrosol (HT). The enzyme profiles of this culture broth gave essentially (IU/L): 3000 β-glucosidase and 100 esterase. Hydrolysis activity of A. niger enzyme preparation was evaluated by using three substrates: raw OW, phenolic fraction extracted from OW by ethyl acetate and its corresponding exhausted fraction. Large amounts of free simple phenolics were released from exhausted fraction and raw OW after enzymatic treatment. HPLC analyses show that HT was the main phenolic compound. One step of ethyl acetate extraction of hydrolysed OW allowed the recovery of 0.8 g of HT per litre of OW. The antioxidant activity of extracts from OW and exhausted fraction, measured by DPPH method, was drastically enhanced after hydrolysis treatment. This study demonstrates that hydrolysed OW is a potential source of bioactive phenolic compounds with promising applications in food and pharmaceutical industries.
Sonia Khoufi; Manel Hamza; Sami Sayadi. Enzymatic hydrolysis of olive wastewater for hydroxytyrosol enrichment. Bioresource Technology 2011, 102, 9050 -9058.
AMA StyleSonia Khoufi, Manel Hamza, Sami Sayadi. Enzymatic hydrolysis of olive wastewater for hydroxytyrosol enrichment. Bioresource Technology. 2011; 102 (19):9050-9058.
Chicago/Turabian StyleSonia Khoufi; Manel Hamza; Sami Sayadi. 2011. "Enzymatic hydrolysis of olive wastewater for hydroxytyrosol enrichment." Bioresource Technology 102, no. 19: 9050-9058.