Synergistic effects of sono-alkaline pretreatment on anaerobic biodegradability of waste activated sludge

Şahinkaya, Serkan; Sevimli, Mehmet Faik

doi:10.1016/j.jiec.2012.08.002

Cited by 38 publications

(22 citation statements)

References 23 publications

(31 reference statements)

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“…Şahinkaya et al [17] investigated under similar conditions the effects of disintegrations using NaOH and they achieved sludge disintegration -24.4%. Similar results using this method had Zhang et al [18].…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, pH start of the anaerobic digesters should be monitored at a pH lower than 8.0 after the alkali-treated sludge is fed into the digesters. Mostly, alkalization is used witch some other disintegration methods (sonification [10,17], thermal pretreatment [10], high pressure homogenization [18]) to increase the efficiency of whole process but usually this is financially unfavorable cause of a high energy expending process.…”

Section: Resultsmentioning

confidence: 99%

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Impact of Alkalization of Surplus Activated Sludge on Biogas Production

Grűbel¹,

Machnicka²

2013

Ecological Chemistry and Engineering S

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Large amounts of sludge are produced in biological wastewater treatment plants. Since the sludge is highly contaminated, it has to undergo proper stabilization before it is disposed or utilized in an environmentally safe way. On the whole, the aim of bacterial cell disintegration is the release of cell contents in the form of an aqueous extract. Chemical disintegration of surplus activated sludge by alkalization results in destruction and disruption of the flocs and microorganisms as well as increase concentration of organic matter in supernatant. The mesophilic anaerobic sewage sludge digestion is an established process, most often applied at medium and large municipal sewage treatment plants. Four major steps of anaerobic digestion are distinguished. The first hydrolysis step leads to solubilization of insoluble particulate matter and biological decomposition of organic polymers to monomers or dimers. The hydrolysis step is recognized as the rate-limiting step of the following second and third steps, the processes of acidogenesis and acetogenesis. Chemical disintegration activates biological hydrolysis and, therefore, it can significantly increase the stabilization rate of the secondary sludge. It has been shown that when the activated sludge was subjected to alkalization to pH 9.0 value, the COD concentration increased from 101 to 530 mg/dm 3 in sludge supernatant. The paper presents a potential application of chemical disintegration for sewage sludge (mainly activated sludge) to upgrading biogas production.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Impact of Alkalization of Surplus Activated Sludge on Biogas Production

Grűbel¹,

Machnicka²

2013

Ecological Chemistry and Engineering S

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“…While maximum substrate usage in the pretreated reactors happened in the first week of the incubation period; it was seen in the reactor with raw sludge in the third week. This result was expected due to the considerable increment in the solubilization of WAS via the pre-treatment application, prior to the anaerobic digestion (Pilli et al, 2011;Şahinkaya and Sevimli, 2013b;Wu et al, 2015). In addition, it was observed that there was no toxic effect on the anaerobic digestion of sludge.…”

Section: Effect Of Pre-treatment Methods On Anaerobic Sludge Digestionmentioning

confidence: 79%

“…However, its most important disadvantage is its consumption of high amounts of electrical energy. In order to reduce its capital and operating costs, sonication can be combined with acidification (Şahinkaya, 2015), alkalization (Şahinkaya and Sevimli, 2013b), the Fenton process (Şahinkaya et al, 2015) and thermal pretreatment (Şahinkaya and Sevimli, 2013a). The present work presents a new approach combining sonication with an advanced oxidation method using potassium ferrate (K2FeO4).…”

Section: Introductionmentioning

confidence: 99%

Sono-Oxidative Pre-Treatment of Waste Activated Sludge Before Anaerobic Biodegradation

Şahinkaya

2017

Braz. J. Chem. Eng.

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-The effects of sonication, potassium ferrate (K2FeO4) oxidation and their simultaneous combination (called "sono-oxidative pre-treatment") on chemical properties and anaerobic digestion of waste activated sludge (WAS) were investigated and compared comprehensively. Based on chemical parameters, the optimum operating conditions were found to be 0.3 g K2FeO4/g total solids (TS) dosage for 2-h individual K2FeO4 oxidation, 0.50 W/mL ultrasonic power density for 10-min individual sonication and, lastly, the combination of 2.5-min sonication at 0.75 W/mL ultrasonic power density with 2-h chemical oxidation at 0.3 g K2FeO4/g TS dosage for sono-oxidative pre-treatment. The disintegration efficiencies of these methods under the optimized conditions were in the following descending order: 37.8% for sono-oxidative pretreatment > 26.3% for sonication > 13.1% for K2FeO4 oxidation. The influences of these methods on anaerobic biodegradability were tested with the biochemical methane potential assay. It was seen that the cumulative methane production increased by 9.2% in the K2FeO4 oxidation reactor, 15.8% in the sonicated reactor and 18.6% in the reactor with sono-oxidative pre-treatment, compared to the control (untreated) reactor.

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“…This leads to delignification and swelling of the biomass, which increases surface area and exposes cells to AD microorganisms [57,72]. Some of the advantages of alkaline pre-treatment include the simplicity of the technologies and ease of operation as well as their high efficiency [73,74].…”

Section: Alkaline Pre-treatmentmentioning

confidence: 99%