Two-stage mesophilic anaerobic–thermophilic digestion for sludge sanitation to obtain advanced treated sludge

Lloret, Eva; Salar-García, M.J.; Blaya, Josefa; Pascual, José Antonio

doi:10.1016/j.cej.2013.06.066

Cited by 20 publications

(7 citation statements)

References 21 publications

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“…The capillary tubes containing the bacterial suspension were subjected to different temperatures (55,60,65, and 70 • C) for different treatment times. They were simultaneously immersed in a water bath maintained at the desired temperature by a hot plate (Stuart Co., Stone, UK) (see Figure S1 in Supplementary Materials).…”

Section: Thermal Pasteurization 221 Thermal Treatment Protocolmentioning

confidence: 99%

Conventional and Innovative Hygienization of Feedstock for Biogas Production: Resistance of Indicator Bacteria to Thermal Pasteurization, Pulsed Electric Field Treatment, and Anaerobic Digestion

2021

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Animal by-products (ABP) can be valorized via anaerobic digestion (AD) for biogas energy generation. The digestate issued from AD process is usually used to fertilize farming land for agricultural activities, which may cause potential sanitary risk to the environment. The European Union (EU) requires that certain ABP be thermally pasteurized in order to minimize this sanitary risk. This process is called hygienization, which can be replaced by alternative nonthermal technologies like pulsed electric field (PEF). In the present study, Enterococcus faecalis ATCC 19433 and Escherichia coli ATCC 25922 were used as indicator bacteria. Their resistance to thermal pasteurization and PEF treatment were characterized. Results show that Ent. faecalis and E. coli are reduced by 5 log10 in less than 1 min during thermal pasteurization at 70 °C. The critical electric field strength was estimated at 18 kV∙cm−1 for Ent. faecalis and 1 kV∙cm−1 for E. coli. “G+” bacteria Ent. faecalis are generally more resistant than “G-” bacteria E. coli. AD process also plays an important role in pathogens inactivation, whose performance depends on the microorganisms considered, digestion temperature, residence time, and type of feedstock. Thermophilic digestion is usually more efficient in pathogens removal than mesophilic digestion.

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Section: Thermal Pasteurization 221 Thermal Treatment Protocolmentioning

confidence: 99%

Conventional and Innovative Hygienization of Feedstock for Biogas Production: Resistance of Indicator Bacteria to Thermal Pasteurization, Pulsed Electric Field Treatment, and Anaerobic Digestion

2021

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“…The TS and volatile solid (VS) values of sludge samples were tested according to the standard methods (2540 B for TS and 2540 E for VS). 23 Capillary suction time was determined using a 304 M CST device (Triton, UK). A self-developed measuring device was used to measure the SRF according to methods described in Liu et al 26 The reported CST value was normalized against TS, with the unit expressed as s L g −1 TS.…”

Section: Acs Sustainable Chemistry and Engineeringmentioning

confidence: 99%

“…Total coliforms and E. coli have been used as indicators for the presence of pathogens in sludge, and E. coli represents about 90% of fecal coliforms. 23 Therefore, the inactivation of pathogens was evaluated with the contents of total coliforms and E. coli before and after different treatments to find out the reduction values of pathogens according to the US EPA standard. This study helps to optimize the sludge reduction process to achieve a high efficiency in both sludge dewaterability and pathogen inactivation.…”

Section: ■ Introductionmentioning

confidence: 99%

Enhanced Sludge Dewaterability and Pathogen Inactivation by Synergistic Effects of Zero-Valent Iron and Ozonation

Xiao

Yang

et al. 2018

ACS Sustainable Chem. Eng.

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In this study, the efficiency of the combined zerovalent iron (ZVI) and ozone (O 3 ) treatment at a pH of 2 (acid-ZVI-O 3 ) for simultaneous improvement of sludge dewaterability and pathogen inactivation was investigated. The results showed that the ozone treatment alone deteriorated sludge dewaterability, while the introduction of acid-ZVI into the ozone treatment could significantly enhance the sludge dewaterability. At the optimal conditions with 30 mg O 3 g −1 of total solid (TS) and 63 mg ZVI g −1 of TS at a pH of 2, the capillary suction time of conditioned sludge was 1.63 s L g −1 TS, which was much smaller than those of raw sludge (10.45 s L g −1 TS), the single ozonation treated sludge (16.07 s L g −1 TS), and the acid-ZVItreated sludge (6.98 s L g −1 TS). The acid-ZVI-O 3 treatment promoted the generation of hydroxyl radicals and showed synergistic effects in removing key hydrophilic substances which would deteriorate sludge dewaterability, i.e., humic acid-like compounds and soluble microbial byproduct-like substances in the tightly bound extracellular polymeric substances (TB-EPSs). Ferric iron was generated therein and worked as a coagulant to agglomerate sludge particles. The enhanced sludge dewaterability was further confirmed by a laboratory-scale diaphragm filter press. Moreover, the acid-ZVI-O 3 treatment showed an effective inactivation of pathogens, which was below the limit specified for class A biosolids, according to the US EPA standard. As such, enhanced sludge dewaterability and pathogen inactivation can be simultaneously achieved with the acid-ZVI-O 3 treatment.

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“…Al-rich water treatment residuals) did not cause significant changes in speciation or lability of the metals though they may present advantages when biosolids are used for site remediation. Two-stage digestion (mesophilic and thermophilic) was assessed for pathogen inactivation potential (Lloret et al 2013). The traditional Class A thermophilic anaerobic digestion was not able to inactivate the Clostridium perfringens (9.6 x 10 4 CFU/mL remaining) but the two-stage approach was successful.…”

Section: Digestionmentioning

confidence: 99%

Biosolids and Sludge Management

Brisolara

Sandberg

2014

Water Environment Research

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This review section covers journal articles and conference papers related to biosolids and sludge management that were published in 2013. The literature review has been divided into the following sections:  • Biosolids regulations and management issues,  • Biosolids characteristics and measurement  including microconstituents, pathogens, and nanoparticles,  •Sludge treatment technologies including pretreatment and sludge minimization, conditioning and dewatering, innovative technologies, and digestion,  • Disposal and reuse including land application and innovative alternatives,  • Odor and air emissions,  • Energy issues, and  • Risk analysis

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Two-stage mesophilic anaerobic–thermophilic digestion for sludge sanitation to obtain advanced treated sludge

Cited by 20 publications

References 21 publications

Conventional and Innovative Hygienization of Feedstock for Biogas Production: Resistance of Indicator Bacteria to Thermal Pasteurization, Pulsed Electric Field Treatment, and Anaerobic Digestion

Conventional and Innovative Hygienization of Feedstock for Biogas Production: Resistance of Indicator Bacteria to Thermal Pasteurization, Pulsed Electric Field Treatment, and Anaerobic Digestion

Enhanced Sludge Dewaterability and Pathogen Inactivation by Synergistic Effects of Zero-Valent Iron and Ozonation

Biosolids and Sludge Management

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