1
|
Liu B, Zhu T, Liu W, Zhou R, Zhou S, Wu R, Deng L, Wang J, Van der Bruggen B. Ultrafiltration pre-oxidation by boron-doped diamond anode for algae-laden water treatment: membrane fouling mitigation, interface characteristics and cake layer organic release. WATER RESEARCH 2020; 187:116435. [PMID: 32977188 DOI: 10.1016/j.watres.2020.116435] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/21/2020] [Accepted: 09/17/2020] [Indexed: 06/11/2023]
Abstract
In this study, ultrafiltration (UF) pre-oxidation with a boron-doped diamond (BDD) electrode was employed aiming to mitigate membrane fouling during algae-laden water treatment. It was found that BDD anodizing can efficiently alleviate membrane fouling regardless of the filtration membrane material when the oxidation time was over 30 min. This was because that the cake layer fouling resistance was highly mitigated by the pre-oxidation process. The generated small molecular organics after anodic oxidation might increase the potential of pore blockage. The anodizing preferentially oxidized hydrophobic organic and fluorescent substances, which is conducive to reducing membrane fouling and improving production efficiency. Besides, disinfection byproduct precursors and harmful algae derived substances of UF filtrated solution were contained. The algae bodies tend to agglomeration and the zeta potential obviously declined after the pretreatment, which is instrumental in forming a loose cake layer structure. In addition, the interaction force between membrane and foulants also converted to a repulsion force after pre-oxidation, which implies that BDD pre-oxidation was an effective way to mitigate cake layer fouling by reducing foulant-membrane interactions. At last, the secondary organic release of a dynamic formed cake layer was proved to be limited especially for living algae cells.
Collapse
Affiliation(s)
- Bin Liu
- Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, 410082, Changsha, China; Department of Chemical Engineering, Process Engineering for Sustainable Systems (ProcESS), KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Tingting Zhu
- Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, 410082, Changsha, China
| | - Wenkai Liu
- Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, 410082, Changsha, China
| | - Rui Zhou
- Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, 410082, Changsha, China
| | - Shiqing Zhou
- Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, 410082, Changsha, China
| | - Ruoxi Wu
- Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, 410082, Changsha, China.
| | - Lin Deng
- Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, 410082, Changsha, China
| | - Jing Wang
- School of Chemical Engineering and Energy, Zhengzhou University, Zhengzhou 450001, China
| | - Bart Van der Bruggen
- Department of Chemical Engineering, Process Engineering for Sustainable Systems (ProcESS), KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| |
Collapse
|
2
|
Tang Y, Hu X, Cai J, Xi Z, Yang H. An enhanced coagulation using a starch-based coagulant assisted by polysilicic acid in treating simulated and real surface water. CHEMOSPHERE 2020; 259:127464. [PMID: 32593001 DOI: 10.1016/j.chemosphere.2020.127464] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 06/15/2020] [Accepted: 06/16/2020] [Indexed: 06/11/2023]
Abstract
In this work, a simple and environmentally-friendly enhanced coagulation, by using a cationic starch-based coagulant (starch-3-chloro-2-hydroxypropyl trimethyl ammonium chloride, St-CTA) coupled with an optimized polysilicic acid (PSA), has been tried to coagulate the kaolin suspensions and humic acid (HA) aqueous solutions, which are used as the simulated sources of inorganic colloidal particles and organic pollutant, respectively, in micro-polluted turbid surface water. Dosing of St-CTA and PSA at the same time is more efficient and more convenient than other two separated feeding methods in this enhanced coagulation process. The synergic coagulation process and mechanism were studied and discussed in detail based on the apparent coagulation performance, floc properties, and zeta potentials of supernatants. St-CTA caused an efficient charge neutralization, i.e. compression of electric double layer of kaolin particles and electrostatic adsorption of HA, followed by an effective netting-bridging effect of PSA, resulting in an improved purification performance. St-CTA with a higher charge density showed better purification performance due to enhanced charge neutralization effect. In addition to simulated water, the validation of this enhanced coagulation process was further confirmed by comparison with a conventional coagulant, polyaluminium chloride, in treating a real surface water. This work thus provides a simple and environmentally-friendly strategy to efficiently purify micro-polluted turbid surface water and further improve the water safety.
Collapse
Affiliation(s)
- Yunong Tang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, PR China
| | - Xinyu Hu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, PR China
| | - Jun Cai
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, PR China
| | - Zhonghua Xi
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, PR China
| | - Hu Yang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, PR China.
| |
Collapse
|
3
|
Development of an Environmental Decision Support System for Enhanced Coagulation in Drinking Water Production. WATER 2020. [DOI: 10.3390/w12082115] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Drinking water production is subject to multiple water quality requirements such as minimizing disinfection byproducts (DBPs) formation, which are highly related to natural organic matter (NOM) content. For water treatment, coagulation is a key process for removing water pollutants and, as such, is widely implemented in drinking water treatment plants (DWTPs) facilities worldwide. In this context, artificial intelligence (AI) tools can be used to aid decision making. This study presents an environmental decision support system (EDSS) for coagulation in a Mediterranean DWTP. The EDSS is structured hierarchically into the following three levels: data acquisition, control, and supervision. The EDSS relies on influent water characterization, suggesting an optimal pH and coagulant dose. The model designed for the control level is based on response surface methodology (RSM), targeted to optimize removal for the response variables (turbidity, total organic carbon (TOC), and UV254). Results from the RSM model provided removal percentages for turbidity (64.6%), TOC (21.9%), and UV254 (30%), which represented an increase of 4%, 33%, and 28% as compared with the DWTP water sample. Regarding the entire EDSS, 62%, 21%, and 25% of turbidity, TOC, and UV254 removal were fixed as the optimization criteria. Supervision rules (SRs) were included at the top of the architecture to intensify process performance under specific circumstances.
Collapse
|
4
|
Improving the performance of loose nanofiltration membranes by poly-dopamine/zwitterionic polymer coating with hydroxyl radical activation. Sep Purif Technol 2020. [DOI: 10.1016/j.seppur.2019.116412] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
|
5
|
Du P, Li X, Yang Y, Su Z, Li H, Wang N, Guo T, Zhang T, Zhou Z. Optimized coagulation pretreatment alleviates ultrafiltration membrane fouling: The role of floc properties and slow-mixing speed on mechanisms of chitosan-assisted coagulation. J Environ Sci (China) 2019; 82:82-92. [PMID: 31133272 DOI: 10.1016/j.jes.2019.02.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 02/26/2019] [Accepted: 02/27/2019] [Indexed: 06/09/2023]
Abstract
To alleviate ultrafiltration (UF) membrane fouling, the pre-coagulation of poly-aluminum chloride (PACl) with the aid of chitosan (CTS) was conducted for synthetic humic acid-kaolin water treatment. Pre-coagulation of three molecular weights (MW) CTSs (50-190 kDa (CTSL), 190-310 kDa (CTSM) and 310-375 kDa (CTSH)) was optimized with slow-mixing speeds of 30, 60 and 90 r/min, respectively. The removal efficiency and floc properties as well as membrane fouling were analyzed, and were compared to results obtained by conventional coagulation with PACl. Results showed that variations in floc properties could be ascribed to the coagulation mechanisms of CTSL/CTSM/CTSH at different slow-mixing speeds, resulting in reduced UF membrane fouling. Specifically, at the low speed of 30 r/min, all three CTS types produced flocs with similar properties, while CTSL resulted in the lowest removal efficiency and aggravated irreversible fouling. At the appropriate speed of 60 r/min, CTSM generated the most compact flocs with the combined effects of bridging and path mechanisms. The compact cake layer formed could alleviate irreversible fouling, which was beneficial for prolonging the operation of the UF membrane. At the high speed of 90 r/min, CTSH formed fragile flocs and aggravated irreversible membrane fouling. We considered membrane fouling to be affected by floc properties and the resultant removal efficiency, which was governed by the MW of the CTS used and the slow-mixing speed applied as well.
Collapse
Affiliation(s)
- Peng Du
- College of Architecture and Civil engineering, Beijing University of Technology, Beijing 100124, China
| | - Xing Li
- College of Architecture and Civil engineering, Beijing University of Technology, Beijing 100124, China
| | - Yanling Yang
- College of Architecture and Civil engineering, Beijing University of Technology, Beijing 100124, China
| | - Zhaoyang Su
- College of Architecture and Civil engineering, Beijing University of Technology, Beijing 100124, China
| | - Hang Li
- College of Architecture and Civil engineering, Beijing University of Technology, Beijing 100124, China
| | - Nan Wang
- College of Architecture and Civil engineering, Beijing University of Technology, Beijing 100124, China
| | - Tingting Guo
- College of Architecture and Civil engineering, Beijing University of Technology, Beijing 100124, China
| | - Tingting Zhang
- College of Architecture and Civil engineering, Beijing University of Technology, Beijing 100124, China
| | - Zhiwei Zhou
- College of Architecture and Civil engineering, Beijing University of Technology, Beijing 100124, China.
| |
Collapse
|
6
|
Liu Z, Wei H, Li A, Yang H. Enhanced coagulation of low-turbidity micro-polluted surface water: Properties and optimization. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2019; 233:739-747. [PMID: 30396682 DOI: 10.1016/j.jenvman.2018.08.101] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 08/21/2018] [Accepted: 08/27/2018] [Indexed: 06/08/2023]
Abstract
Micro-polluted surface water with low turbidity and low content of dissolved organic matter (DOM) is usually inefficiently purified. In this work, a combined technique for the enhanced coagulation of this surface water was proposed and investigated using cationic grafted starch (St-G) and polyaluminum chloride (PACl) as co-coagulants, followed by a magnetic ion-exchange resin (MIER). St-G was fed before PACl, and this procedure not only efficiently removes turbidity but also largely reduces the doses of the two coagulants. MIER remarkably removed DOM, and raw water was effectively purified. The entire coagulation process was further optimized through response surface methodology based on a central composite design by using the doses of St-G, PACl, and MIER as input variables. The dose effects of the three chemicals on the coagulation performance for turbidity and DOM removal were examined, and the coagulation mechanisms, including the interactive effect among various chemicals, were discussed in detail. This work provided a new strategy for the efficient treatment of low-turbidity micro-polluted surface water by utilizing organic and inorganic co-coagulants with magnetic ion-exchange resin in practical applications.
Collapse
Affiliation(s)
- Zhouzhou Liu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, PR China
| | - Hua Wei
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, PR China
| | - Aimin Li
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, PR China
| | - Hu Yang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, PR China.
| |
Collapse
|