Journal of Water Process Engineering
·
2024
·
IF 6.3
Miao Yu,Xinyuan Lv,Ziqi Wang,Minghao Sui
Virus-induced risks to water quality persist, with the viability of viruses in complex aquatic environments impacted by various factors, including coexisting bacteria and exposure to light. This study investigated the disinfection efficacy of UV 254 irradiation and free chlorine (FC) on Bacteriophage phiX174 in the presence of coexisting bacteria, specifically Escherichia coli ( E. coli ) and Bacillus subtilis ( B. subtilis ). To elucidate the underlying mechanisms, this study examined the effects of bacterial compounds (i.e., E. coli lipopolysaccharide (LPS) and B. subtilis peptidoglycan (PGN)) on viral inactivation, thermal stability, and environmental persistence. The research results demonstrated that bacterial presence and their associated compounds significantly impaired viral inactivation, with greater concentrations of coexisting bacteria and their compounds exacerbating this effect. Additionally, the photoreactivation of phiX174 was explored following UV 254 irradiation, indicating that high-dose UV 254 , coupled with low nutrient availability and minimal host bacteria levels, effectively suppressed viral photoreactivation. This study is the first to investigate the multifactorial effects on viral photoreactivation. The results offer novel insights into the challenges associated with virus-related pressures in water treatment, with potential implications for optimizing disinfection processes.
研究领域:
环境科学
·
微生物学
✓ 已验证
DOI
高影响因子
WATER RESEARCH
·
2024
·
IF 11.4
Zi-Bo Jing,Wen-Long Wang,Yu-Jia Nong,Lu Peng,Zi-Chen Yang,Bei Ye,Min-Yong Lee,Qian-Yuan Wu
Low-pressure mercury lamps emitting at 254 nm (UV254) are used widely for disinfection. However, subsequent exposure to visible light results in photoreactivation of treated bacteria. This study employed a krypton chloride excimer lamp emitting at 222 nm (UV222) to inactivate E. coli . UV222 and UV254 treatment had similar E. coli -inactivation kinetics. Upon subsequent irradiation with visible light, E. coli inactivated by UV254 was reactivated from 2.71-log to 4.75-log, whereas E. coli inactivated by UV222 showed negligible photoreactivation. UV222 treatment irreversibly broke DNA strands in the bacterium, whereas UV254 treatment primarily formed nucleobase dimers. Additionally, UV222 treatment caused cell membrane damage, resulting in wizened, pitted cells and permeability changes. The damage to the cell membrane was mainly due to the photolysis of proteins and lipids by UV222. Furthermore, the photolysis of proteins by UV222 destroyed enzymes, which blocked photoreactivation and dark repair. The multiple damages can be further evidenced by 4.0–61.1 times higher quantum yield in the photolysis of nucleobases and amino acids for UV222 than UV254. This study demonstrates that UV222 treatment damages multiple sites in bacteria, leading to their inactivation. Employing UV222 treatment as an alternative to UV254 could be viable for inhibiting microorganism photoreactivation in water and wastewater.
研究领域:
微生物学
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环境科学
·
光生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2023
·
IF 13.6
Hu Li,Ruoyu Zhang,Jiawei Zhang,Qi Wang,Yanjie Wang,Jian Zhou,Tiecheng Wang
Dissemination of antibiotic resistance genes (ARGs) is a huge challenge worldwide. Information regarding underlying mechanisms of conjugation transfer of sublethal ARGs under photoreactivation is still lacking. In this study, experimental exploration and model prediction were conducted to evaluate the effects of photoreactivation on conjugation transfer of plasma-induced sublethal ARGs. The experimental results showed that reactive species (O 2 - •, 1 O 2 , and •OH) generated in the plasma process led to 0.32, 1.45, 3.21, 4.10, and 3.96-log removal for tetC , tetW , bla TEM -1 , aac(3)-II , and intI1 after 8 min treatment at 18 kV, respectively. Their attacks led to breakage and mineralization of ARGs-containing DNA and disturbance of bacterial metabolism. The conjugation transfer frequency increased by 0.58-fold after 48 h of photoreactivation compared with the plasma treatment, as well as the abundances of ARGs and reactive oxygen species levels. The alleviation effects of photoreactivation were independent of cell membrane permeability, but related to promotion of intercellular contact. Ordinary differential equation model predicted that the stabilization time of long-term transfer of ARGs significantly increased by 50 % after photoreactivation compared with the plasma treatment, and the conjugation transfer frequency also increased. This study firstly revealed the mechanisms of conjugation transfer of sublethal ARGs under photoreactivation.
研究领域:
微生物学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Processes
·
2022
·Vol. 10
·期 8
·1622
·
IF 3.352
Hai Lu,Xiaoyan Wang,Xueqi Li,Xiaoyu Zhang
The combined disinfection process of ultraviolet and sodium hypochlorite has more advantages than the single disinfection method in reducing the disinfectant dosage, shortening the reaction time, and resisting the impact of water quality changes and inhibiting the light reactivation of microorganisms. Given this, using the secondary effluent of a sewage plant as the research object, the disinfection efficiency of the combined process of ultraviolet and sodium hypochlorite was investigated. The experimental results showed that the inactivation effect of UV followed by sodium hypochlorite on fecal coliform and the inhibition of microbial photoreactivation was more significant than that of simultaneous disinfection of UV and sodium hypochlorite disinfection. When the UV dose was 24 mJ/cm2, after disinfection with UV followed by sodium hypochlorite, only 1 mg/L of sodium hypochlorite was required to be added, and a contact reaction time of 1 min for the fecal coliform index to meet the first-Class A emission standard. After disinfection, the effluent’s maximum reactivation rate of fecal coliform was 26.96%. However, the simultaneous disinfection of ultraviolet and sodium hypochlorite required the addition of 3 mg/L of sodium hypochlorite. After disinfection, the maximum reactivation rate of the fecal coliform group reached 30.81%.
研究领域:
环境科学
·
微生物学
✓ 已验证
DOI
高影响因子
WATER AIR AND SOIL POLLUTION
·
2022
·Vol. 233
·期 10
·1-13
·
IF 2.984
Wu Zuwei,Ye Yuanyao,Cai Tingting,Jiang Wei,Ren Yongzheng,Liu Dongqi,Zhang Tiancheng,Zhang YanRong
Rainwater has been used in areas that have limited water resources. In this scenario, ultraviolet (UV) disinfection is often used to improve the quality of rainwater before its reuse. However, the technology is weakened by photoreactivation and dark repair for promoting the regrowth of microbes in treated rainwater. In this work, a system integrating UV and self-doped TiO 2 nanotube arrays (the UV-TiO 2 system) was used to solve the issue. The effects of the power of UV lamps, pH value, the area of TiO 2 nanotube arrays, biomass concentration, humic acid, sulfate, and nitrate concentration on the disinfection effect of the two systems were also studied. To achieve the standard of drinking water quality, the single UV system and UV-TiO 2 system needed 17 s and 12 s respectively for the rainwater treatment at medium biomass concentration. Increasing the area of TiO 2 nanotube arrays would improve UV-TiO 2 disinfection efficiency. Furthermore, the UV-TiO 2 system could better adapt to the changes in biomass concentration and low pH conditions than the UV system. The total colony count disinfected by the UV system was approximately 3.2 times higher than that by the UV-TiO 2 system after 8-h exposure to fluorescence light. The experimental results showed that the UV-TiO 2 system was better than the UV system in terms of disinfection, faster and more efficient inactivation, and inhibition of photoreactivation and dark repair.
研究领域:
环境科学
·
微生物学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）