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Shen S, Xie L, Wan R, Li X, Lu X, Dai H. Sediment microbial fuel cell coupled floating treatment wetland for enhancing non-reactive phosphorus removal. CHEMOSPHERE 2024; 358:142142. [PMID: 38677619 DOI: 10.1016/j.chemosphere.2024.142142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Revised: 04/07/2024] [Accepted: 04/24/2024] [Indexed: 04/29/2024]
Abstract
The presence of non-reactive phosphorus (NRP) in environmental waters presents a potential risk of eutrophication and poses challenges for the removal of all phosphorus (P) fractions. This study presents the first investigation on the removal performance and mechanism of three model NRP compounds, sodium tripolyphosphate (STPP), adenosine 5'-monophosphate (AMP) and 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC), in the sediment microbial fuel cell-floating treatment wetland (SMFC-FTW). Coupling SMFC with plants proved to be effective at removing NRP via electrochemical oxidation and plant uptake, particularly the challenging-to-degrade phosphonates that contain C-P bonds. Compared with the control group, the removal efficiencies of the model NRP in SMFC were observed to increase by 11.9%-20.8%. SMFC promoted the conversion of NRP to soluble reactive phosphorus (sRP) and the transfer of P to sediment. Furthermore, the electrochemical process enhanced both plant growth and P uptake, and increased P assimilation by 72.6%. The presence of plants in the bioelectrochemical system influenced the occurrence and fate of P by efficiently assimilating sRP and supporting microbial transformation of NRP. Consequently, plants enhanced the removal efficiencies of all P fractions in the overlying water. This study demonstrated that SMFC-FTW is a promising technology to remove various NRP species in environmental waters.
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Affiliation(s)
- Shuting Shen
- School of Ecology and Environment, Anhui Normal University, 189 South of Jiuhua Road, Wuhu, Anhui 241002, China; Southeast Univ, Sch Energy & Environment, 2 Sipailou Rd, Nanjing 210096, Jiangsu, China.
| | - Longxiao Xie
- School of Ecology and Environment, Anhui Normal University, 189 South of Jiuhua Road, Wuhu, Anhui 241002, China.
| | - Rui Wan
- School of Ecology and Environment, Anhui Normal University, 189 South of Jiuhua Road, Wuhu, Anhui 241002, China.
| | - Xiang Li
- School of Ecology and Environment, Anhui Normal University, 189 South of Jiuhua Road, Wuhu, Anhui 241002, China.
| | - Xiwu Lu
- Southeast Univ, Sch Energy & Environment, 2 Sipailou Rd, Nanjing 210096, Jiangsu, China.
| | - Hongliang Dai
- Southeast Univ, Sch Energy & Environment, 2 Sipailou Rd, Nanjing 210096, Jiangsu, China; School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, No. 2 Mengxi Road, Zhenjiang 212018, China.
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Jafari M, Botte GG. Electrochemical valorization of waste activated sludge for short-chain fatty acids production. Front Chem 2022; 10:974223. [PMID: 36110143 PMCID: PMC9469876 DOI: 10.3389/fchem.2022.974223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 08/02/2022] [Indexed: 11/13/2022] Open
Abstract
A tremendous amount of waste activated sludge (WAS) ends up in landfilling even after a substantial retention time during anaerobic digestion. This leftover activated sludge is an organic-rich material with the high potential to produce value-added chemicals such as short chain fatty acids (SCFAs). In the present study, a novel electrochemical conversion of activated sludge (E-WAS) was carried out on the surface of non-precious electrodes (nickel, stainless-steel and copper) in alkaline media at low applied potential and temperature. Cyclic voltammetry showed that Cu (II)/Cu (III) and Ni (II)/Ni(III) redox couple catalyzed the WAS oxidation reaction to produce SCFAs and hydrogen. The results revealed that Cu(II)/Cu(III) has higher catalytic oxidation capability towards SCFAs. Yields of 48.7, 21.4, and 14.6 mg SCFAs per g of volatile solids were achieved by using copper, nickel and stainless-steel as working electrodes, respectively. Post analysis characterization techniques indicate that copper oxide films lead to WAS oxidation. Total volatile solid removal of 30% was obtained at 35°C and 1.65 V in 0.2 M NaOH after 2 h of operation in an electrochemical digestor with copper electrodes which is more efficient than a conventional alkaline treatment (24 h, 55%, 1M NaOH). Ammonia was produced as the by-product of E-WAS oxidation. The highest amount of ammonia (250 mg L−1) was obtained by using nickel as the working electrode after 2 h operation at 35°C and 1.35 V applied potential. The change in WAS morphology revealed that the copper oxide film is an effective electrocatalyst for WAS disinfection.
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