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

Abstract

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.

Pretreatment of Slaughterhouse Effluent Treatment Plant Sludge Using Electro-Fenton Process for Anaerobic Digestion

“…A vast range of H 2 O 2 concentrations has been studied and significantly diverse results have been reported in the literature. Studies conducted by Feki et al 2019 [39] found an optimal H 2 O 2 concentration of 1.8 g/L for municipal sludge. To assess the impact of H 2 O 2 concentration, the other operating parameters were held constant (current density = 40 mA/cm 2 and time = 60 min) and the H 2 O 2 dosage was varied from 25 to 1000 mg/g-TS.…”

Electrochemical treatment of sewage sludge and pathogen inactivation

“…As the electrolysis time increases from 1 to 4 h operation, the amount of nitrate, phosphorous, ammonia, and chemical oxygen demand increased from 3.83 to 4.89 mg L −1 , 102 to 160 mg L −1 , 72 to 88 mg L −1 and 2521 to 4745 mg L −1 , respectively which indicates solubilization of biosolids, and the production of chemicals such as ammonia. The increase in the soluble chemical oxygen demand is originated from the damage of the sludge structure and membrane cell wall and releasing the extracellular and intracellular organic matters into liquid phase [33]. The amount of ammonia released during electrolysis was higher than biosolid digestion, which specified that the applied voltage could accelerate the rate of protein hydrolysis [20].…”