Enhancement of waste activated sludge aerobic digestion by electrochemical pre-treatment

Song, Lei; Zhu, Nanwen; Yuan, Haiping; Hong, Ying; Ding, Jin

doi:10.1016/j.watres.2010.05.052

Cited by 81 publications

(38 citation statements)

References 42 publications

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“…This implies that the enhancement of methane production in WAS from 2-chamber electrolysis is due to the effect of pH change rather than electrolytic effect on the sludge biomass. This finding appears to disagree with the finding of Song et al (2010) that electrolysis itself (in a single chamber without pH change) could disrupt cell membranes in WAS and therefore enhance biodegradation in subsequent aerobic digestion.…”

Section: Results Incontrasting

confidence: 87%

“…The VSS solubilisation obtained in this study is comparable to those obtained by thermo-chemical pretreatment (Valo et al 2004;Liu et al 2008). However, the results are significantly higher than that obtained by Song et al (2010) using single chamber electrolysis (no pH gradient) of around 9%. The solubilisation of about 31% VSS from WAS suggests that by simply employing a selective membrane between electrodes during electrolysis to enhance the electrolyitic pH gradient, WAS hydrolysis is significantly enhanced.…”

Section: Vss and Cod Solubilisation Of Was During Electrolysiscontrasting

confidence: 62%

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Enhancement of waste activated sludge anaerobic digestion by a novel chemical free acid/alkaline pretreatment using electrolysis

Charles

Cord‐Ruwisch

et al. 2013

Water Science and Technology

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Anaerobic digestion of waste activated sludge (WAS) is relatively poor due to hydrolysis limitations. Acid and alkaline pre-treatments are effective in enhancing hydrolysis leading to higher methane yields. However, chemical costs often prohibit full-scale application. In this study, 12V two-chamber electrolysis using an anion exchange membrane alters sludge pH without chemical dosing. pH dropped from 6.9 to 2.5 in the anode chamber and increased to 10.1 in the cathode chamber within 15 hours. The volatile suspended solids solubilisation of WAS was 31.1% in the anode chamber and 34.0% in the cathode chamber. As a result, dissolved chemical oxygen demand increased from 164 mg/L to 1,787 mg/L and 1,256 mg/L in the anode and cathode chambers, respectively. Remixing of sludge from the two chambers brought the pH back to 6.5, hence no chemical neutralization was required prior to anaerobic digestion. Methane yield during anaerobic digestion at 20 days retention time was 31% higher than that of untreated sludge. An energy balance assessment indicated that the non-optimized process could approximately recover the energy (electricity) expended in the electrolysis process. With suitable optimization of treatment time and voltages significant energy savings would be expected in addition to the benefit of decreased sludge volume.

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Section: Results Incontrasting

confidence: 87%

Section: Vss and Cod Solubilisation Of Was During Electrolysiscontrasting

confidence: 62%

Enhancement of waste activated sludge anaerobic digestion by a novel chemical free acid/alkaline pretreatment using electrolysis

Charles

Cord‐Ruwisch

et al. 2013

Water Science and Technology

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“…The undigested or semi-digested sludge can potentially cause land disposal problems and the leachates can contaminate the ground water if disposed in the same vicinity of a residential complex [15]. The most common methods of sludge stabilization are aerobic and anaerobic digestion to degrade complex substrates in waste sludge by microbial action [16][17][18] resulting in the reduction of the volatile solids content [3].…”

Section: Introductionmentioning

confidence: 99%

“…Aerobic digestion is popular for smaller treatment facilities due to its low investment cost, simpler operation and ease of management and control [17,19,20]. Aerobic digestion is the biochemical oxidative stabilization of waste sludge under endogenous conditions; when there is insufficient external substrate available, heterotrophic microorganisms are added to begin to digest their own cellular mass [3,21].…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of the Digestibility of Attached and Suspended Growth Sludge in an Aerobic Digester for a Small Community

Azizi

Kamika

Tekere

2018

Water

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Abstract:The aerobic sludge digestion process for waste sludge generated from suspended biomass (i.e., activated sludge process, ASP) and attached biomass (i.e., moving bed bioreactor, MBBR and modified packed bed biofilm, PBBR) reactors in a residential complex were analyzed. The rate of digestion with respect to different sludge characteristics generated through these various treatment processes were examined; the results revealed that waste sludge from ASP took 16 days to achieve complete digestion while MBBR and PBBR took nine and seven days, respectively. The most important factors influencing the sludge digestion such as sludge volume index (SVI), mixed liquor suspended solid (MLSS), and mixed liquor volatile suspended solid (MLVSS) were examined. The ASP which had the highest initial MLSS and MLVS took a longer time for digestion. Aerobic sludge digestion in all the treatment reactors was studied under laboratory scale conditions in batch experimentation to evaluate sludge characteristics and the rate of digestion as well as through a continuous bench scale pilot system to optimize the process parameters. Removal efficiencies of volatile solids (VS) 90.71% in ASP, 84.27% in MBBR and 84.07% in PBBR in aerobic digestion during batch mode were also observed. The study revealed that the aerobic sludge digestion process utilized in curbing sludge is not feasible application for a small community due to very long digestion times and a large amount of space although Packed Bed Biofilm (PBBR) used the lowest time (seven days) compared to the other systems.

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Highly Efficient, Ultra‐Low Energy Consumption Process for Phenol Wastewater Treatment with Ultra‐Low Carbon Emission

Zhang

et al. 2013

CLEAN Soil Air Water

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Phenol is one of the main pollutants in phenol wastewater and has been proved non‐biodegradable. In this study, based on strongly ring‐opening capability of boron doped diamond film electrode, a highly efficient and energy‐saving method with ultra‐low carbon emission is established through a combination of electrochemical oxidation and biological degradation. On one hand, electrochemical oxidation as pretreatment can solve the critical problem that phenol wastewater is a biological recalcitrant. On the other hand, the relatively low current efficiency during the late stage of electrochemical oxidation can be solved by follow‐up biological treatment, thus reduce the energy consumption and the cost significantly. More importantly, the carboxylic acids (oxidized from phenol) can be fully used as carbon source (no additional carbon source is added) for microbial growth instead of being oxidized to carbon dioxide and water through selecting optimizing sequencing batch reactor access time, so the carbon emission is greatly reduced. The results showed that it can save about 76.5% energy consumption and about 51.2% chemical oxygen demand can be used to maintain microorganism self‐reproduction. This is significant that this combined technology not only runs highly effectively at low cost, but also reduces the emission of greenhouse gas, carbon dioxide, thus environment friendly with wide application prospects.

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Enhancement of waste activated sludge aerobic digestion by electrochemical pre-treatment

Cited by 81 publications

References 42 publications

Enhancement of waste activated sludge anaerobic digestion by a novel chemical free acid/alkaline pretreatment using electrolysis

Enhancement of waste activated sludge anaerobic digestion by a novel chemical free acid/alkaline pretreatment using electrolysis

Evaluation of the Digestibility of Attached and Suspended Growth Sludge in an Aerobic Digester for a Small Community

Highly Efficient, Ultra‐Low Energy Consumption Process for Phenol Wastewater Treatment with Ultra‐Low Carbon Emission

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