Ultrasound, thermal and alkali treatments affect extracellular polymeric substances (EPSs) and improve waste activated sludge dewatering

Ruiz-Hernando, Maria; Cabanillas, Esther; Labanda, Jordi; Llorens, Joan

doi:10.1016/j.procbio.2015.01.001

Cited by 79 publications

(24 citation statements)

References 30 publications

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“…The amount of EPS obtained by formaldehyde + NaOH, formamide + NaOH and Na 2 CO 3 + heat + mixing was higher than that of centrifugation, sonication and EDTA extraction. Similar results for these extraction techniques were also shown by previous studies [11][12][13]15 indicating that alkaline conditions enhance EPS solubility 26,27 . The amount of EPS recovered by Na 2 CO 3 was the highest, more than 20 times of that obtained only by centrifugation.…”

Section: Stability Test Of the Ionic Hydrogelsupporting

confidence: 88%

Extraction of Structural Extracellular Polymeric Substances from Aerobic Granular Sludge

Felz

Al-Zuhairy

Aarstad

et al. 2016

JoVE

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To evaluate and develop methodologies for the extraction of gel-forming extracellular polymeric substances (EPS), EPS from aerobic granular sludge (AGS) was extracted using six different methods (centrifugation, sonication, ethylenediaminetetraacetic acid (EDTA), formamide with sodium hydroxide (NaOH), formaldehyde with NaOH and sodium carbonate (Na 2 CO 3 ) with heat and constant mixing). AGS was collected from a pilot wastewater treatment reactor. The ionic gel-forming property of the extracted EPS of the six different extraction methods was tested with calcium ions (Ca 2+ ). From the six extraction methods used, only the Na 2 CO 3 extraction could solubilize the hydrogel matrix of AGS. The alginatelike extracellular polymers (ALE) recovered with this method formed ionic gel beads with Ca 2+. The Ca 2+ -ALE beads were stable in EDTA, formamide with NaOH and formaldehyde with NaOH, indicating that ALE are one part of the structural polymers in EPS. It is recommended to use an extraction method that combines physical and chemical treatment to solubilize AGS and extract structural EPS.

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Section: Stability Test Of the Ionic Hydrogelsupporting

confidence: 88%

Extraction of Structural Extracellular Polymeric Substances from Aerobic Granular Sludge

Felz

Al-Zuhairy

Aarstad

et al. 2016

JoVE

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“…The supernatant was freeze‐dried, then dissolved in tetrahydrofuran, passed through a 0.45‐μm filter, and analyzed by gel permeation chromatography (VE 2001 GPC‐TDA 302; Viscotek, USA) (Zhang, Xian, Zhu, Li, & Gong, ). Polystyrene was used as a standard substance, and the number average molecular weight (Mn), weight average molecular weight (Mw), and distribution width index ( d ) were calculated after using the aid of the response constant of the crack solution (α and log K ) to universal calibration the Mark–Houwink equation (Hernando, Cabanillas, Labanda, & Llorens, ).…”

Section: Methodsmentioning

confidence: 99%

Effect on sludge disintegration by EDTA‐enhanced thermal‐alkaline treatment

Liu

Jin

Liu

et al. 2019

Water Environment Research

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Sludge disintegration is an effective pretreatment to enhance the biodegradability of sludge. At present, the thermal-alkaline is one of the most commonly used methods, but it has a massive consumption of energy and chemical reagents. EDTA-enhanced thermal-alkaline treatment was used to strengthen the dewatered sludge disintegration at mid-low temperature in this study. Results showed that the dissolving-out quantity of soluble chemical oxygen demand and the volatile solid (VS) in residual sludge in the EDTA-added group were 14.7% higher and 7% lower than those in control system without EDTA, respectively, indicating that EDTA addition improved the performance of sludge disintegration. The addition of EDTA loosened the floc structure and enhanced the hydrolyzability of dissolved organic matters (DOM) with a narrower distribution of the relative molecular weight. The membrane damage of microbial cells in EDTA-added group reached 73.3% after 120 min, which was much higher than that in the control group (31.9%). EDTA contains a large number of hydrogen bond acceptors and could form hydrogen bonds with alcohols and phenols in solubilization products and DOM. It was speculated that the mechanism of EDTA-enhanced sludge disintegration was related to the formation of hydrogen bonds between EDTA and organic matter inside and outside the cell. © 2019 Water Environment Federation • Practitioner points• The addition of EDTA facilitated the thermal-alkali cracking of dewatered sludge. • EDTA increased the particle size of sludge and enhanced the hydrolysis of DOM. • The strengthening effect mainly occurred at the beginning of TB-EPS dissolving slowly. • Hydrogen bond played important roles in the enhanced disintegration of sludge by EDTA.

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“…A mixture of primary sludge and waste activated sludge (WAS) is typically fed to WWTP anaerobic digesters. However, WAS has a relatively low biodegradability due to its microbial biomass and extracellular polymeric substances (EPSs) composition (Carrere et al, 2016;Ruiz-Hernando et al, 2015). The introduction of pre-treatments before AD can be used to improve WAS biodegradability.…”

Section: Introductionmentioning

confidence: 99%

Assessing the usefulness of clostridia spores for evaluating sewage sludge hygienization

Martín-Díaz

Ruiz-Hernando

Astals

et al. 2017

Bioresource Technology

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The capability of clostridia spores to act as pathogen indicators in sewage sludge treatment was investigated. Sulfite-reducing clostridia and E. coli levels were monitored during waste activated sludge pre-treatments (alkali and ultrasound) and its subsequent mesophilic anaerobic digestion. E. coli was maintained or reduced depending on treatment type and intensity. However, alkali pre-treatment (35.3 gNaOH/kg TS) by itself and alkali (157 gNaOH/kg TS) and ultrasound (27,000 kJ/kg TS) pre-treatments followed by anaerobic digestion provoked reproducible clostridia increases.Specifically, up to 2.7 log 10 after 35.3 gNaOH/kg TS pre-treatment and up to 1.9 and 1.1 log 10 after digesting the 157 gNaOH/kg TS and 27,000 kJ/kg TS pre-treated sludge, respectively. Having rejected the hypotheses of sporulation and floc dissipation, the most plausible explanation for these clostridia increases is re-growth. These results question the suitability of clostridia spores as indicators of sludge treatment and other biological treatments where clostridia may have a role.

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Ultrasound, thermal and alkali treatments affect extracellular polymeric substances (EPSs) and improve waste activated sludge dewatering

Cited by 79 publications

References 30 publications

Extraction of Structural Extracellular Polymeric Substances from Aerobic Granular Sludge

Extraction of Structural Extracellular Polymeric Substances from Aerobic Granular Sludge

Effect on sludge disintegration by EDTA‐enhanced thermal‐alkaline treatment

Assessing the usefulness of clostridia spores for evaluating sewage sludge hygienization

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