Phase separated pretreatment strategies for enhanced waste activated sludge disintegration in anaerobic digestion: An outlook and recent trends

Sharmila, V. Godvin; Kumar, Gopalakrishnan; Sivashanmugham, P.; Piechota, Grzegorz; Park, Jeong Hoon; Kumar, S. Adish; Banu, J. Rajesh

doi:10.1016/j.biortech.2022.127985

Cited by 17 publications

(9 citation statements)

References 83 publications

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“…And the type of pretreatment presented lower importance in affecting methane production compared with substrate concentrations. The interactions between EPS surrounding the microbial cells and pretreatment rely on the inherent mechanisms (i.e., hydrolysis, oxidation, and reduction). , And the toxic effects of the chemical agent were found to be highly related to the final methane yield. Different concentrations of chemicals may have different effects on the microorganisms associated with methane production.…”

Section: Resultsmentioning

confidence: 99%

Predicting and Evaluating Different Pretreatment Methods on Methane Production from Sludge Anaerobic Digestion via Automated Machine Learning with Ensembled Semisupervised Learning

Cheng,

Xu,

et al. 2023

ACS EST Eng.

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Accurate prediction of methane production in anaerobic digestion with various pretreatment strategies is of the utmost importance for efficient sludge treatment and resource recovery. Traditional machine learning (ML) algorithms have shown limited prediction accuracy due to challenges in optimizing complex parameters and the scarcity of data. This work proposed a novel integrated system that employed an ensemble semisupervised learning (SSL)-automated ML (AutoML) model with limited variable inputs to reveal the effects of different pretreatments on methane production during sludge digestion with explainable analysis. Considering the direct correlations of the pretreatment type and digestion substrates, the pretreatment type is considered as a hidden variable. Results demonstrated that the AutoML model outperformed the conventional ML models (i.e., support vector regression (SVR), extreme gradient boosting (XGB), etc.), as evidenced by its higher R 2 value. Moreover, the integration of SSL further enhanced the prediction accuracy by effectively leveraging unlabeled data, leading to a reduction in the mean squared error from 11.3 to 9.7. Explainable analysis results revealed the significance of different variables and the utmost importance of operating time, followed by proteins, carbohydrates, chemical oxygen demand, and volatile fatty acids. Furthermore, principal component and correlation analysis unveiled the interconnected relationships among substrate concentration, microbial communities, and metabolic functions for methane production and found that the increasing substrate concentration promoted the enrichment of functional microbial and metabolic functions. These insights shed light on the advantages of SSL-AutoML in predicting methane production in anaerobic digestion systems and elucidate the dependence relationships with key variables, offering valuable guidance for effective sludge pretreatment with enhanced resource recovery capabilities.

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Section: Resultsmentioning

confidence: 99%

Predicting and Evaluating Different Pretreatment Methods on Methane Production from Sludge Anaerobic Digestion via Automated Machine Learning with Ensembled Semisupervised Learning

Cheng,

Xu,

et al. 2023

ACS EST Eng.

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“…UDs cause twisting, rotation or spinning of macromolecules with asymmetric shapes [ 64 ]. These phenomena cause a change in the charge of the cell surface, a change in the permeability of the cell membrane, rupture, disintegration and fragmentation of the cell membrane [ 65 ]. This allows organic compounds to transfer to the dissolved phase and thus be more available to anaerobic bacteria in the AD process [ 66 ].…”

Section: Resultsmentioning

confidence: 99%

Ultrasonic Disintegration to Improve Anaerobic Digestion of Microalgae with Hard Cell Walls—Scenedesmus sp. and Pinnularia sp.

Dębowski

Kazimierowicz

Świca

et al. 2022

Plants

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Microalgae are considered to be very promising feedstocks for biomethane production. It has been shown that the structure of microalgal cell walls can be highly detrimental to the anaerobic digestibility of biomass. Therefore, there is a real need to seek ways to eliminate this problem. The aim of the present study was to assess the effect of ultrasonic disintegration of Scenedesmus sp. and Pinnularia sp. microalgal biomass on the performance and energy efficiency of anaerobic digestion. The pretreatment was successful in significantly increasing dissolved COD and TOC in the system. The highest CH4 yields were noted for Scenedesmus sp. sonicated for 150 s and 200 s, which produced 309 ± 13 cm3/gVS and 313 ± 15 cm3/gVS, respectively. The 50 s group performed the best in terms of net energy efficiency at 1.909 ± 0.20 Wh/gVS. Considerably poorer performance was noted for Pinnularia sp., with biomass yields and net energy gains peaking at CH4 250 ± 21 cm3/gVS and 0.943 ± 0.22 Wh/gVS, respectively. Notably, the latter value was inferior to even the non-pretreated biomass (which generated 1.394 ± 0.19 Wh/gVS).

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“…Conventional methods of biosolids disposal are landfilling, incineration, and dumping at sea. This leads to the accumulation of pollutants in environmental matrices, decreased land availability, and increased regulatory control [ 3 ]. In addition, some value-added products can be obtained from biosolids treatments, considering the chemical composition of biosolids (biomass).…”

Section: Introductionmentioning

confidence: 99%

Enzymatic Treatments for Biosolids: An Outlook and Recent Trends

Quintero-García

Pérez-Soler

Amezcua‐Allieri

2023

IJERPH

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Wastewaters are nutrient-rich organic materials containing significant concentrations of different nutrients, dissolved and particulate matter, microorganisms, solids, heavy metals, and organic pollutants, including aromatic xenobiotics. This variety makes wastewater treatment a technological challenge. As a result of wastewater treatment, biosolids are generated. Biosolids, commonly called sewage sludge, result from treating and processing wastewater residuals. Increased biosolids, or activated sludge, from wastewater treatment is a major environmental and social problem. Therefore, sustainable and energy-efficient wastewater treatment systems must address the water crisis and environmental deterioration. Although research on wastewater has received increasing attention worldwide, the significance of biosolids treatments and valorization is still poorly understood in terms of obtaining value-added products. Hence, in this review, we established some leading technologies (physical, chemical, and biological) for biosolids pretreatment. Later, the research focuses on natural treatment by fungal enzymes to end with lignocellulosic materials and xenobiotic compounds (polyaromatic hydrocarbons) as a carbon source to obtain biobased chemicals. Finally, this review discussed some recent trends and promising renewable resources within the biorefinery approach for bio-waste conversion to value-added by-products.

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Phase separated pretreatment strategies for enhanced waste activated sludge disintegration in anaerobic digestion: An outlook and recent trends

Cited by 17 publications

References 83 publications

Predicting and Evaluating Different Pretreatment Methods on Methane Production from Sludge Anaerobic Digestion via Automated Machine Learning with Ensembled Semisupervised Learning

Predicting and Evaluating Different Pretreatment Methods on Methane Production from Sludge Anaerobic Digestion via Automated Machine Learning with Ensembled Semisupervised Learning

Ultrasonic Disintegration to Improve Anaerobic Digestion of Microalgae with Hard Cell Walls—Scenedesmus sp. and Pinnularia sp.

Enzymatic Treatments for Biosolids: An Outlook and Recent Trends

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