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RESEARCH PRODUCT
Unveiling the distinctive role of titanium dioxide nanoparticles in aerobic sludge digestion.
Chen WangGiorgio ManninaXiaohu DaiWei WeiBing-jie Nisubject
Environmental Engineering0207 environmental engineering02 engineering and technology010501 environmental sciences01 natural sciencesWaste Disposal Fluidchemistry.chemical_compoundDigestion (alchemy)Environmental ChemistryHumic acidAerobic digestionAnaerobiosisCellulose020701 environmental engineeringWaste Management and Disposal0105 earth and related environmental scienceschemistry.chemical_classificationTitaniumSettore ICAR/03 - Ingegneria Sanitaria-AmbientaleSewageAerobic digestion Recalcitrant organics Sludge degradation Solubilization Titanium dioxide nanoparticles Anaerobiosis Digestion Titanium Waste Disposal Fluid Nanoparticles Sewagetechnology industry and agricultureBiodegradationPollution6. Clean waterAnaerobic digestionActivated sludgechemistryEnvironmental chemistryNanoparticlesSewage treatmentDigestionEnvironmental Sciencesdescription
Abstract Aerobic digestion is considered to be a common process for the stabilization of waste activated sludge (WAS) in the small-sized wastewater treatment systems, while the broad application of titanium dioxide nanoparticles (TiO2 NPs) results in their unavoidable existence in WAS aerobic digestion, with its role in aerobic sludge digestion being never documented. This study set up a series of aerobic sludge digesters to evaluate the previously unknown role of TiO2 NPs on the performance of the digesters. The volatile solids (VS) degradation percentage increased from 21.9 ± 0.6% to 26.9 ± 0.1% − 30.0 ± 0.3% with the different contents of TiO2 NPs (0, 1, 20 and 50 mg/L). Similarly, the total inorganic nitrogen production increased from 23.1 ± 0.3 to 31.0 ± 0.1 mg N/g VS with the rising TiO2 NPs concentrations from 0 to 50 mg/L. The microbial analysis suggested that TiO2 NPs contributed to the accumulation of specific microbes correlated with the degradation of organic substances and the conversion of nitrogen compounds. Model-based analysis showed the higher biodegradability and hydrolysis rate of sludge with TiO2 NPs. Further mechanistic studies indicated that the enhancement of WAS solubilization and the degradation of recalcitrant substances (e.g., humic acid and cellulose) contributed to the better performance of experimental aerobic digesters, which was confirmed by the fourier transformation infrared spectroscopy (FTIR) indicating the converting of these materials into biodegradable substrates for digestion with TiO2 NPs. It could be inferred from this investigation that aerobic digestion rather than anaerobic digestion would be a more suitable treatment method for sludge containing TiO2 NPs.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2022-03-01 | The Science of the total environment |