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- Liang, Jiawei, et al.
(author)
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Performance and microbial communities of a novel integrated industrial-scale pulp and paper wastewater treatment plant
- 2021
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In: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526. ; 278
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Journal article (peer-reviewed)abstract
- Ltd Paper production generates pulp and paper wastewater (PPW), and it is difficult to remove the high-level pollutants in PPW efficiently. Herein, an efficient industrial-scale pulp and paper wastewater treatment plant (PP-WWTP) that integrated physicochemical and biological processes is investigated and reported. This PP-WWTP treated 2.3 Mt of wastewater with 17,388 ± 1436 mg/L chemical oxygen demand (COD) annually. The PP-WWTP can effectively remove over 99.81% of the COD. In detail, the physical, anaerobic, aerobic and chemical steps accounted for 41.6%, 40.0%, 11.9%, and 6.5% of COD removal, respectively. The microbial communities of the bioreactors removed the pollutants efficiently and contained diverse microbes. Further metagenomic analyses of the bioreactors identified more than 90,000 genes/gene fragments encoding for carbohydrate-active enzymes (CAZys), demonstrating high lignocellulose degradation ability of the bioreactors at molecular level. The xylanase activity assay showed some lignocellulase in the bioreactors were functional. Recycling the residual heat from the PPW along with energy recovered from biological treatment of the PPW, in the form of biogas (20,000 m³/d), could generate more than 1.5 M USD benefits/y. The results of this study demonstrated that the integrated physicochemical and biological process for PPWW treatment could effectively remove pollutants while generating revenue.
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| 2. |
- Tang, Jinfeng, 1984, et al.
(author)
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Highly efficient recovery and clean-up of four heavy metals from MSWI fly ash by integrating leaching, selective extraction and adsorption
- 2019
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In: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526. ; 234, s. 139-149
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Journal article (peer-reviewed)abstract
- Municipal solid waste incineration (MSWI) fly ash contains significant amounts of heavy metals (e.g., Cd, Cu, Pb and Zn) and is therefore considered to be a hazardous waste requiring proper treatment prior to its disposal. In this work, an integrated hydrometallurgical process for treatment of MSWI fly ash was evaluated. Valuable metals, e.g. Cu and Zn, were first recovered by combining leaching and extraction sequentially. In the next step, the t removal of Cd and Pb from the remaining leachate using four types of iron-based adsorbents was evaluated. The leaching was optimized with respect to pH, leaching time and liquid to solid ratio. A test done under optimal conditions gave metal releases of 100% and 80% for Cu and Zn as well as 100% and 85% for Cd and Pb, respectively. The resulting leachate was contacted with organic phases based on kerosene containing the extractants LIX860N–I for Cu extraction and Cyanex 572 for Zn extraction in two consecutive steps. Efficient extractions were achieved, thus demonstrating that the combination of leaching and extraction can be successfully used for the recovery of Cu and Zn. Adsorption of heavy metal ions on various iron based sorbents to detoxify the aqueous effluent from the extraction showed good removal efficiency (more than 95%) for both Cd and Pb. The results of this study show that the proposed integrated process is a promising tool that can be used in the strategy for metal recovery and detoxification of MSWI fly ash.
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| 3. |
- Tang, Jinfeng, 1984, et al.
(author)
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Optimizing critical metals recovery and correlative decontamination from MSWI fly ash: Evaluation of an integrating two-step leaching hydrometallurgical process
- 2022
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In: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526. ; 368
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Journal article (peer-reviewed)abstract
- While municipal solid waste incineration (MSWI) fly ash is classified as hazardous waste, it can also serve as an urban mining source for numerous precious metals. Of particular interest are antimony (Sb) and zinc (Zn); the former of which is a strategic and critical metal that is being rapidly depleted, putting society at high risk for supply shortages. In this work, a two-step leaching method for recovering Sb and Zn from MSWI fly ash is proposed. Furthermore, the leaching behavior and adsorption mechanism of Sb in the MSWI fly ash waste stream were also investigated. Results from the first constant pH leaching tests (CPLT) showed that under diluted acidic condition, the maximum amount of Sb released from fly ash was ∼20%. In addition, at pH 4.0, 67% of the fly ash was dissolved, while 79.3% and 12.1% of the Zn and Sb, respectively, were recovered. After optimizing and executing a second Sb leaching procedure (6 M HCl solution at 60 °C), >80% of the Sb was recovered. Thus, the proposed two-step leaching process, consisting of extraction followed by decontamination using a magnetic HAP@CoFe2O4 adsorbent, can eliminate the Sb in fly ash effluent with a removal efficiency >95%. Moreover, this process produces less toxic products and lowers the effluent residue concentration. As such, the two-step process described herein is suggested for Sb and Zn recovery from fly ash; as it not only enables precious metal recovery, but also aids in treating secondary waste streams produced from urban mining.
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