Solubilization of organic matter by electrochemical treatment of sludge: Influence of operating conditions

Pérez-Rodrı́guez, Martı́n; Cano, A.; Durán, U.; Barrios, J.A.

doi:10.1016/j.jenvman.2019.01.105

Cited by 20 publications

(14 citation statements)

References 29 publications

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“…In contrast to VS removal, the maximum soluble COD removal efficiencies were reached with the high TS concentration and with current densities of 21.4 and 28.6 mA/cm 2 , which were between 52.7 and 53.4%. In all cases, COD removal were higher for the solubilized, demonstrating that, the process is controlled by mass transfer [16]. The observed result is similar to that of results reported in the literature [26].…”

Section: Vs Reduction and Cod Removalsupporting

confidence: 90%

“…This is because high capacity of electrochemical hydrolysis is provided by short-lived and energy rich free radicals that carry out disintegrating microbial cell walls. As recently proposed by Pérez-Rodríguez et al [16], hydrolysis rate can be improved if the critical engineering aspects of reactors used for this purpose are identified. The primary drawback of EOP is associated to high-energy consumptions, due to operating inefficiencies [17].…”

Section: Introductionmentioning

confidence: 99%

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Efficiency of an integrated process of electrooxidation and anaerobic digestion of waste activated sludge

Barrios¹,

Cano²,

Rivera³

et al. 2020

Preprint

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Background Most of the organic content of waste activated sludge (WAS) comprises microbial cells hard to degrade, which must be pre-treated for the energy recovery by anaerobic digestion (AD). Electrooxidation pre-treatment (EOP) with a 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 solubilise 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 effect of current density (CD) during EOP and the initial total solids concentration [TS] from WAS on methane (CH4) production by AD was investigated. Results In the present work, biogas production from WAS conversion are comprehensively affected by CD and [TS]. The highest COD and VS removal by 60 and 39% respectively, were achieved with WAS at 3% of [TS] pre-treated at CD of 24.1 mA/cm2, and with a maximum CH4 production of 305 N-L/kg VS and a positive energy balance of 0.83 kWh/kg VS. Therefore, the low current densities used in boron-doped diamond (BDD) electrode are adequate to produce the strong oxidant ●OH radical on the electrode surface, allow the oxidation of organic compounds that favours the solubilization of COD from WAS. Conclusions The improvement of VS removal indicates that EOP help to disintegrating cell walls from WAS. This allows a decomposition reaction that leads to biodegrade more compounds during AD. The energy balance was positive, suggesting that even without any optimization the energy used as electricity could be approximately recovered as energy from the increased methane production. However, this kind of analysis have not been sufficiently studied so far, therefore, is important to understand how critical parameters can influence the pre-treatment and AD performances. The current study highlights that the mathematical optimization and energy analysis can get the whole process more convenient and feasible.

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Section: Vs Reduction and Cod Removalsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Efficiency of an integrated process of electrooxidation and anaerobic digestion of waste activated sludge

Barrios¹,

Cano²,

Rivera³

et al. 2020

Preprint

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“…1,2 WAS disposal and treatment, which is one of the foremost critical problems, takes about 50%-60% of the total operating cost in WWTPs and may pose a serious threat to the environment, if not managed properly. 3,4 WAS consists of a complex and rigid floc structure containing a high concentration of organics, microorganisms, and some nutrients, mainly nitrogen and phosphorus. 5,6 The anaerobic digestion (AD) is the most preferred method for the stabilization and destruction of WAS.…”

Section: Introductionmentioning

confidence: 99%

“…23 EO pretreatment of WAS by using different metal electrode pairs has been investigated to enhance sludge disintegration and dewaterability all. 1,4,[24][25][26][27] Mainly, Ti-Ti, Ti/RuO 2 , or Ti/IrO 2 mesh plate electrodes were used in these studies, and disintegration degrees in terms of CODs were improved significantly in the range of 1.6%-30.2%. [24][25][26]28,29 It was noted that the TiO 2 coated with RuO 2 , IrO 2 , or platinum electrodes were used as an anode in these studies in order to enhance the electro-catalytic ability and to generate hydroxyl radicals (•OH) at their surface.…”

Section: Introductionmentioning

confidence: 99%

Highlighting the cathodic contribution of an electrooxidation pretreatment study on waste activated sludge disintegration

Erkan

Turan

Engin

2021

Env Prog and Sustain Energy

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In this study, the effect of the cathodic contribution in the performance of electrooxidation (EO) pretreatment of waste activated sludge (WAS) was investigated using different electrode pairs, namely titanium dioxide (TiO 2 )/TiO 2 , TiO 2 /TiO 2 coated Platine (Pt) and TiO 2 /TiO 2 coated ruthenium dioxide (RuO 2 ) and main operational parameters such as dosage of electrolyte solution (Na 2 SO 4 ), initial pH, applied current, and electrolysis time were optimized. Disintegration degree (DD) in terms of soluble chemical oxygen demand (CODs) increased with an increase in initial pH of WAS, applied current, and electrolysis time for all pairs of electrodes. Under the optimized conditions (5 g/L Na 2 SO 4 , pH 10, 3 A of current, and 100 min of e time), a maximum DD value of 23.93 and 14.26% was obtained using TiO 2 /RuO 2 and Pt/TiO 2 electrodes, respectively. However, lower DD COD value of 12.85% was obtained for TiO 2 /TiO 2 electrodes at similar conditions except for 4 A current. Soluble extracellular polymeric substances analysis and their protein and polysaccharide concentrations confirmed the disintegration of WAS flocs by the EO process. The operational cost (OC) of applied processes was also calculated and OC values were found in the following order: TiO 2 /RuO 2 (46.54 €/m 3 ) > TiO 2 /TiO 2 (41.77 €/m 3 ) > TiO 2 /Pt (32.99.54 €/m 3 ) from the point of energy consumption.

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“…The electrooxidation experiments of Feki et al (2015) improved the solubilisation of COD in 28% where the experiments were conducted at pH 7 under a current density of 2.5 A/dm 2 for 2 h. The studies of showed a reduction of the total COD and an increase in soluble COD for the best pre-treatment conditions applied (28.6 mA cm -2 ) leading to higher methane production (up to76 -80%) after anaerobic digestion. In contrast, the studies of Pérez- Rodríguez et al (2019) with different operating conditions for sludge electrooxidation (current density around 28.6 mA cm -2 for 30 min), resulted in a maximum degree of solubilisation of just 1.78%.…”

Section: Resultsmentioning

confidence: 89%

Estrategias para la mejora de la digestión anaerobia: integración de procesos electroquímicos y bioelectroquímicos = Strategies for improving anaerobic digestion: integration of electrochemical and bioelectrochemical processes

Sevillano¹,

Bernabé²

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Solubilization of organic matter by electrochemical treatment of sludge: Influence of operating conditions

Cited by 20 publications

References 29 publications

Efficiency of an integrated process of electrooxidation and anaerobic digestion of waste activated sludge

Efficiency of an integrated process of electrooxidation and anaerobic digestion of waste activated sludge

Highlighting the cathodic contribution of an electrooxidation pretreatment study on waste activated sludge disintegration

Estrategias para la mejora de la digestión anaerobia: integración de procesos electroquímicos y bioelectroquímicos = Strategies for improving anaerobic digestion: integration of electrochemical and bioelectrochemical processes

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