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Wang JJ, Zhou YY, Xiang JL, Du HS, Zhang J, Zheng TG, Liu M, Ye MQ, Chen Z, Du Y. Disinfection of wastewater by a complete equipment based on a novel ultraviolet light source of microwave discharge electrodeless lamp: Characteristics of bacteria inactivation, reactivation and full-scale studies. Sci Total Environ 2024; 917:170200. [PMID: 38296065 DOI: 10.1016/j.scitotenv.2024.170200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 01/14/2024] [Accepted: 01/14/2024] [Indexed: 02/06/2024]
Abstract
Ultraviolet (UV) light is widely used for wastewater disinfection. Traditional electrode-excited UV lamps, such as low-pressure mercy lamps (LPUV), encounter drawbacks like electrode aging and rapid light attenuation. A novel UV source of microwave discharge electrodeless lamp (MDEL) has aroused attention, yet its disinfection performance is unclear and still far from practical application. Here, we successfully developed a complete piece of equipment based on MDELs and achieved the application for disinfection in wastewater treatment plants (WWTPs). The light emitted by an MDEL (MWUV) shared a spectrum similar to that of LPUV, with the main emission wavelength at 254 nm. The inactivation rate of Gram-negative E. coli by MWUV reached 4.5 log at an intensity of 1.6 mW/cm2 and a dose of 20 mJ/cm2. For Gram-positive B. subtilis, an MWUV dose of 50 mJ/cm2 and a light intensity of 1.2 mW/cm2 reached an inactivation rate of 3.4 log. A higher MWUV intensity led to a better disinfection effect and a lower photoreactivation rate of E. coli. When inactivated by MWUV with an intensity of 1.2 mW/cm2 and a dose of 16 mJ/cm2, the maximum photoreactivation rate and reactivation rate constant Kmax of E. coli were 0.63 % and 0.11 % h-1 respectively. Compared with the photoreactivation, the dark repair of E. coli was insignificant. The full-scale application of the MDEL equipment was conducted in two WWTPs (10,000 m3/d and 15,000 m3/d). Generally 2-3 log inactivation rates of fecal coliforms in secondary effluent were achieved within 5-6 s contact time, and the disinfected effluent met the emission standard (1000 CFU/L). This study successfully applied MDEL for disinfection in WWTPs for the first time and demonstrated that MDEL has broad application prospects.
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Affiliation(s)
- Jun-Jie Wang
- College of Architecture and Environment, Sichuan University, Chengdu 610000, China
| | - Yun-Yi Zhou
- College of Architecture and Environment, Sichuan University, Chengdu 610000, China
| | - Jue-Lin Xiang
- College of Architecture and Environment, Sichuan University, Chengdu 610000, China
| | - Hai-Sheng Du
- Sichuan Macyouwei Environmental Protection Technology Co., Ltd, Chengdu 610000, China
| | - Jin Zhang
- Sichuan Science City Tianren Environmental Protection Co., Ltd, Mianyang 621022, China
| | - Ti-Gang Zheng
- Sichuan Science City Tianren Environmental Protection Co., Ltd, Mianyang 621022, China
| | - Min Liu
- College of Architecture and Environment, Sichuan University, Chengdu 610000, China
| | - Ming-Qi Ye
- Everbright Water (Shenzhen) Limited, Shenzhen 518000, China
| | - Zhuo Chen
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Ye Du
- College of Architecture and Environment, Sichuan University, Chengdu 610000, China.
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Xiang JL, Wang JJ, Wu ZJ, Xu BJ, Du HS, Chen Y, Liu M, Lee MY, Wang WL, Du Y. Efficient wastewater disinfection using a novel microwave discharge electrodeless ultraviolet system with ozone at an ultra-low dose. J Hazard Mater 2024; 464:133011. [PMID: 37988868 DOI: 10.1016/j.jhazmat.2023.133011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 11/05/2023] [Accepted: 11/12/2023] [Indexed: 11/23/2023]
Abstract
Microwave discharge electrodeless lamp (MDEL) is a novel ultraviolet (UV) light source. Synergistic disinfection using UV light emitted by MDEL (MWUV) coupled with ozone (O3) at an ultra-low dose was investigated. Escherichia coli and Bacillus subtilis were deactivated more effectively by MWUV/O3 than by either MWUV or O3 alone. MWUV/O3 treatment using an O3 concentration of 0.4 mg/L gave an E. coli inactivation rate of 5.52 log. The photoreactivation degree and rate of E. coli were lower after inactivation by MWUV/O3 treatment than after MWUV treatment alone. The maximum photoreactivation rates after the MWUV/O3 and MWUV treatments were 2.90% and 16.08%, respectively. MWUV/O3 disinfection also inhibited dark resurrection of E. coli and gave a maximum dark resurrection rate of 0.0036%. Electron paramagnetic resonance spectroscopy indicated that more hydroxyl radicals were generated during MWUV/O3 treatment. Scanning electron microscopy and laser confocal scanning microscopy observations indicated that O3 played a key role in breaking down the cell structure. MWUV/O3 treatment gave a good disinfection effect on fecal coliform bacteria in actual domestic wastewater. The results indicated that inactivation of bacteria can be more effectively achieved by MWUV treatment with O3.
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Affiliation(s)
- Jue-Lin Xiang
- College of Architecture and Environment, Sichuan University, Chengdu 610000, China
| | - Jun-Jie Wang
- College of Architecture and Environment, Sichuan University, Chengdu 610000, China
| | - Zhi-Jing Wu
- College of Architecture and Environment, Sichuan University, Chengdu 610000, China
| | - Bao-Jun Xu
- College of Architecture and Environment, Sichuan University, Chengdu 610000, China
| | - Hai-Sheng Du
- Sichuan Macyouwei Environmental Protection Technology Co., Ltd, Chengdu 610000, China
| | - Ying Chen
- College of Architecture and Environment, Sichuan University, Chengdu 610000, China
| | - Min Liu
- College of Architecture and Environment, Sichuan University, Chengdu 610000, China
| | - Min-Yong Lee
- Division of Chemical Research, National Institute of Environmental Research, Seogu, Incheon 22689, Republic of Korea
| | - Wen-Long Wang
- Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Institute of Environment and Ecology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Ye Du
- College of Architecture and Environment, Sichuan University, Chengdu 610000, China.
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Zhang YX, Xiang JL, Wang JJ, Du HS, Wang TT, Huo ZY, Wang WL, Liu M, Du Y. Ultraviolet-based synergistic processes for wastewater disinfection: A review. J Hazard Mater 2023; 453:131393. [PMID: 37062094 DOI: 10.1016/j.jhazmat.2023.131393] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 04/07/2023] [Accepted: 04/08/2023] [Indexed: 05/03/2023]
Abstract
Ultraviolet (UV) irradiation is widely used for wastewater disinfection but suffers from low inactivation rates and can cause photoreactivation of microorganisms. Synergistic disinfection with UV and oxidants is promising for enhancing the inactivation performance. This review summarizes the inactivation effects on representative microorganisms by UV/hydrogen peroxide (H2O2), UV/ozone (O3), UV/persulfate (PS), UV/chlorine, and UV/chlorine dioxide (ClO2). UV synergistic processes perform better than UV or an oxidant alone. UV mainly attacks the DNA or RNA in microorganisms; the oxidants H2O2 and O3 mainly attack the cell walls, cell membranes, and other external structures; and HOCl and ClO2 enter cells and oxidize proteins and enzymes. Free radicals can have strong oxidation effects on cell walls, cell membranes, proteins, enzymes, and even DNA. At similar UV doses, the inactivation rates of Escherichia coli with UV alone, UV/H2O2, UV/O3, UV/PS (peroxydisulfate or peroxymonosulfate), and UV/chlorinated oxidant (chlorine, ClO2, and NH2Cl) range from 2.03 to 3.84 log, 2.62-4.30 log, 4.02-6.08 log, 2.93-5.07 log, and 3.78-6.55 log, respectively. The E. coli inactivation rates are in the order of UV/O3 ≈ UV/Cl2 > UV/PS > UV/H2O2. This order is closely related to the redox potentials of the oxidants and quantum yields of the radicals. UV synergistic disinfection processes inhibit photoreactivation of E. coli in the order of UV/O3 > UV/PS > UV/H2O2. The activation mechanisms and formation pathways of free radicals with different UV-based synergistic processes are presented. In addition to generating HO·, O3 can reduce the turbidity and chroma of wastewater to increase UV penetration, which improves the disinfection performance of UV/O3. This knowledge will be useful for further development of the UV-based synergistic disinfection processes.
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Affiliation(s)
- Yi-Xuan Zhang
- College of Architecture and Environment, Sichuan University, Chengdu 610000, China
| | - Jue-Lin Xiang
- College of Architecture and Environment, Sichuan University, Chengdu 610000, China
| | - Jun-Jie Wang
- College of Architecture and Environment, Sichuan University, Chengdu 610000, China
| | - Hai-Sheng Du
- Sichuan Macyouwei Environmental Protection Technology Co., Ltd, Chengdu 610000, China
| | - Ting-Ting Wang
- College of Architecture and Environment, Sichuan University, Chengdu 610000, China
| | - Zheng-Yang Huo
- School of Environment and Natural Resources, Renmin University of China, Beijing 100872, China
| | - Wen-Long Wang
- Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Institute of Environment and Ecology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.
| | - Min Liu
- College of Architecture and Environment, Sichuan University, Chengdu 610000, China
| | - Ye Du
- College of Architecture and Environment, Sichuan University, Chengdu 610000, China.
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Zhang ZD, Wang C, Du HS, Liu Q, Guo G, Huo WJ, Zhang J, Zhang YL, Pei CX, Zhang SL. Effects of sodium selenite and coated sodium selenite on lactation performance, total tract nutrient digestion and rumen fermentation in Holstein dairy cows. Animal 2020; 14:2091-2099. [PMID: 32340650 DOI: 10.1017/s1751731120000804] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Se can enhance lactation performance by improving nutrient utilization and antioxidant status. However, sodium selenite (SS) can be reduced to non-absorbable elemental Se in the rumen, thereby reducing the intestinal availability of Se. The study investigated the impacts of SS and coated SS (CSS) supplementation on lactation performance, nutrient digestibility, ruminal fermentation and microbiota in dairy cows. Sixty multiparous Holstein dairy cows were blocked by parity, daily milk yield and days in milk and randomly assigned to five treatments: control, SS addition (0.3 mg Se/kg DM as SS addition) or CSS addition (0.1, 0.2 and 0.3 mg Se/kg DM as CSS addition for low CSS (LCSS), medium CSS (MCSS) and high CSS (HCSS), respectively). Experiment period was 110 days with 20 days of adaptation and 90 days of sample collection. Dry matter intake was higher for MCSS and HCSS compared with control. Yields of milk, milk fat and milk protein and feed efficiency were higher for MCSS and HCSS than for control, SS and LCSS. Digestibility of DM and organic matter was highest for CSS addition, followed by SS addition and then control. Digestibility of CP was higher for MCSS and HCSS than for control, SS and LCSS. Higher digestibility of ether extract, NDF and ADF was observed for SS or CSS addition. Ruminal pH decreased with dietary Se addition. Acetate to propionate ratio and ammonia N were lower, and total volatile fatty acids (VFAs) concentration was greater for SS, MCSS and HCSS than control. Ruminal H ion concentration was highest for MCSS and HCSS and lowest for control. Activities of cellobiase, carboxymethyl-cellulase, xylanase and protease and copies of total bacteria, fungi, Ruminococcus flavefaciens, Fibrobacter succinogenes and Ruminococcus amylophilus increased with SS or CSS addition. Activity of α-amylase, copies of protozoa, Ruminococcus albus and Butyrivibrio fibrisolvens and serum glucose, total protein, albumin and glutathione peroxidase were higher for SS, MCSS and HCSS than for control and LCSS. Dietary SS or CSS supplementation elevated blood Se concentration and total antioxidant capacity activity. The data implied that milk yield was elevated due to the increase in total tract nutrient digestibility, total VFA concentration and microorganism population with 0.2 or 0.3 mg Se/kg DM from CSS supplementation in dairy cows. Compared with SS, HCSS addition was more efficient in promoting lactation performance of dairy cows.
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Affiliation(s)
- Z D Zhang
- College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province030801, P. R. China
| | - C Wang
- College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province030801, P. R. China
| | - H S Du
- College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province030801, P. R. China
| | - Q Liu
- College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province030801, P. R. China
| | - G Guo
- College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province030801, P. R. China
| | - W J Huo
- College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province030801, P. R. China
| | - J Zhang
- College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province030801, P. R. China
| | - Y L Zhang
- College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province030801, P. R. China
| | - C X Pei
- College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province030801, P. R. China
| | - S L Zhang
- College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province030801, P. R. China
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Zhang J, Ji CN, Du HS, Zheng ZH, Mao YM. [A study of a derivative of Taq DNA polymerase]. Yi Chuan Xue Bao 1999; 26:179-85. [PMID: 10375865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Using the method of double primer oligonucleotide-mediated mutagenesis, the high expression plasmid of TaqND236, a derivative of Taq DNA polymerase, was constructed. To determine the frameshift mutation frequency of the in vitro DNA synthesis, we constructed a Gapped-DNA system using the pFDPM118 (a mutant of pUC118 with a -1 frameshift mutation on the lacZ gene) as template. By calculating the ratio of blue and white colonies on the X-gal plate after transforming E. coli TG1, the frameshift mutation frequency of Taq and TaqND236 was measured. It was found that the replication fidelity of the deleted Taq-TaqND236 increased more than 10 folds.
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Affiliation(s)
- J Zhang
- Institute of Genetics, Fudan University, Shanghai
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