Retention of titanium dioxide nanoparticles in biological activated carbon filters for drinking water and the impact on ammonia reduction

Most of the infections caused by multi-drug resistant (MDR) P. aeruginosa strains are extremely difficult to be treated with conventional antibiotics. Biofilm formation and efflux pumps are recognized as the major antibiotic resistance mechanisms in MDR P. aeruginosa. Biofilm formation by P. aeruginosa depends mainly on the cell-to-cell communication quorum-sensing (QS) systems. Titanium dioxide nanoparticles (TDN) have been used as antimicrobial agents against several microorganisms but have not been reported as an anti-QS agent. This study aims to evaluate the impact of titanium dioxide nanoparticles (TDN) on QS and efflux pump genes expression in MDR P. aeruginosa isolates. The antimicrobial susceptibility of 25 P. aeruginosa isolates were performed by Kirby–Bauer disc diffusion. Titanium dioxide nanoparticles (TDN) were prepared by the sol gel method and characterized by different techniques (DLS, HR-TEM, XRD, and FTIR). The expression of efflux pumps in the MDR isolates was detected by the determination of MICs of different antibiotics in the presence and absence of carbonyl cyanide m-chlorophenylhydrazone (CCCP). Biofilm formation and the antibiofilm activity of TDN were determined using the tissue culture plate method. The effects of TDN on the expression of QS genes and efflux pump genes were tested using real-time polymerase chain reaction (RT-PCR). The average size of the TDNs was 64.77 nm. It was found that TDN showed a significant reduction in biofilm formation (96%) and represented superior antibacterial activity against P. aeruginosa strains in comparison to titanium dioxide powder. In addition, the use of TDN alone or in combination with antibiotics resulted in significant downregulation of the efflux pump genes (MexY, MexB, MexA) and QS-regulated genes (lasR, lasI, rhll, rhlR, pqsA, pqsR) in comparison to the untreated isolate. TDN can increase the therapeutic efficacy of traditional antibiotics by affecting efflux pump expression and quorum-sensing genes controlling biofilm production.

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From micro to macro-contaminants: The impact of low-energy titanium dioxide photocatalysis followed by filtration on the mitigation of drinking water organics

Chemosphere ◽

10.1016/j.chemosphere.2018.10.213 ◽

2019 ◽

Vol 217 ◽

pp. 111-121 ◽

Cited By ~ 4

Author(s):

Brooke K. Mayer ◽

Carlan Johnson ◽

Yu Yang ◽

Nicole Wellenstein ◽

Emily Maher ◽

...

Keyword(s):

Drinking Water ◽

Titanium Dioxide ◽

Low Energy ◽

Titanium Dioxide Photocatalysis ◽

The Impact

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Pesticide removals in the nitrifying expanded-bed filter at drinking water treatment plant

Journal of Science and Technology in Civil Engineering (STCE) - NUCE ◽

10.31814/stce.nuce2021-15(1)-01 ◽

2020 ◽

Vol 15 (1) ◽

pp. 1-13

Author(s):

Nguyet Thi-Minh Dao ◽

The-Anh Nguyen ◽

Viet-Anh Nguyen ◽

Mitsuharu Terashima ◽

Hidenari Yasui

Keyword(s):

Drinking Water ◽

Activated Carbon ◽

Water Treatment ◽

Treatment Plant ◽

Drinking Water Treatment ◽

Cost Effective ◽

Water Treatment Plant ◽

Field Analysis ◽

Expanded Bed ◽

Biological Activated Carbon

The occurrence of pesticides even at low concentrations in drinking water sources might induce potential risks to public health. This study aimed to investigate the removal mechanisms of eight pesticides by the nitrifying expanded-bed filter using biological activated carbon media at the pretreatment of a drinking water plant. The field analysis demonstrated that four pesticides Flutolanil, Buprofezin, Chlorpyrifos, and Fenobucard, were removed at 82%, 55%, 54%, and 52% respectively, while others were not significantly removed. Under controlled laboratory conditions with continuous and batch experiments, the adsorption onto the biological activated carbon media was demonstrated to be the main removal pathway of the pesticides. The contribution of microorganisms to the pesticide removals was rather limited. The pesticide removals observed in the field reactor was speculated to be the adsorption on the suspended solids presented in the influent water. The obtained results highlighted the need to apply a more efficient and cost-effective technology to remove the pesticide in the drinking water treatment process. Keywords: biological activated carbon; drinking water treatment; nitrifying expanded-bed filter; pesticide removal.

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Colonization of Biological Activated Carbon in Drinking Water Purification

2010 International Conference on Challenges in Environmental Science and Computer Engineering ◽

10.1109/cesce.2010.53 ◽

2010 ◽

Author(s):

He Wang ◽

Zhonglin Chen ◽

Jimin Shen ◽

Feifei Xiang ◽

Yu Liu ◽

...

Keyword(s):

Drinking Water ◽

Activated Carbon ◽

Water Purification ◽

Biological Activated Carbon ◽

Drinking Water Purification

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Impact of temperature and dissolved oxygen level on the population dynamics of naidids and their reproduction in biological activated carbon filters: a life table demographic study

Water Science & Technology Water Supply ◽

10.2166/ws.2019.002 ◽

2019 ◽

Vol 19 (5) ◽

pp. 1363-1370

Author(s):

Xiao-Bao Nie ◽

Yu-Qing Wu ◽

Yuan-Nan Long ◽

Chang-Bo Jiang ◽

Li Kong

Keyword(s):

Population Dynamics ◽

Drinking Water ◽

Activated Carbon ◽

Life Table ◽

Doubling Time ◽

Population Doubling ◽

Population Doubling Time ◽

Biological Activated Carbon ◽

Water Plant ◽

Water Plants

Abstract Aquatic macro-organisms, such as naidids, propagate excessively in biological activated carbon (BAC) filters. This has become a troublesome problem for drinking water plants. For successful control of naidid contamination risk, it is necessary to determine the population dynamics under different environmental conditions within drinking water plants, with special emphasis on BAC filters. In this study, field studies of naidid distribution in a drinking water plant were conducted, and the effects of temperature and dissolved oxygen (DO) on naidid population dynamics were investigated using the life table method. The results indicated that naidid pollution in the water plant occurred seasonally and was induced by the excessive propagation of naidids in the BAC filters. Increased temperature and DO increased the naidid intrinsic rate of natural increase and decreased the naidid population doubling time. The life table method was also used to acquire the reproductive parameters of naidids in BAC filters based on simulative experiments. These results indicated that naidids can reproduce asexually in BAC filters, and the population doubling time was 12.60 days.

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Impact of Titanium Dioxide Nanoparticles on Cd Phytotoxicity and Bioaccumulation in Rice (Oryza sativa L.)

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17092979 ◽

2020 ◽

Vol 17 (9) ◽

pp. 2979 ◽

Cited By ~ 2

Author(s):

Wei Zhang ◽

Jinghua Long ◽

Jianmin Geng ◽

Jie Li ◽

Zhongyi Wei

Keyword(s):

Titanium Dioxide ◽

Oryza Sativa ◽

Plant Height ◽

Oryza Sativa L ◽

Titanium Dioxide Nanoparticles ◽

Engineered Nanoparticles ◽

Control Treatment ◽

Booting Stage ◽

Tio2 Nps ◽

The Impact

The impact of engineered nanoparticles (ENPs) on the migration and toxicity of coexisting pollutants is still unclear, especially in soil media. This study aims to evaluate the impact of titanium dioxide nanoparticles (TiO2 NPs) on the phytotoxicity of cadmium (Cd) to Oryza sativa L., and the migration of cadmium (Cd) in the soil-rice system. Three different Cd stress groups (C1 group: 1.0 mg kg−1, C2 group: 2.5 mg kg−1 and C3 group: 5.0 mg kg−1) were set in the pot experiment, and the target concentration of TiO2 NPs in each group were 0 mg kg−1 (T0), 50 mg kg−1 (T1), 100 mg kg−1 (T2) and 500 mg kg−1 (T3). Plant height and biomass decreased with the increasing of Cd content in paddy soil. TiO2 NPs could lower the phytotoxicity of Cd in terms of the changes in the morphological and biochemical characteristics, especially in the tillering and booting stage. In the tillering stage, TiO2 NPs addition caused a significant increase in plant height, biomass and the total chlorophyll content in the leaves of Oryza saliva L. In the booting stage, TiO2 NPs addition caused a 15% to 32% and 24% to 48% reduction of malondialdehyde (MDA) content for the C2 and C3 group, respectively, compared to that of the respective control treatment (T0). TiO2-NPs addition reduced the activity of peroxidase (POD) in the leaves in the booting and heading stage, and the activity of catalase (CAT) in the tillering stage. In the C1 and C2 group, the grain Cd content in the 100 and 500 mg kg−1 TiO2 NPs treatments reached 0.47–0.84 mg kg−1, obviously higher than that of the treatment without TiO2 NPs (0.27–0.32 mg kg−1), suggesting that TiO2-NPs could promote Cd migration in the soil-rice system.

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A pilot study of hybrid biological activated carbon (BAC) filtration-ultrafiltration process for water supply in rural areas: role of BAC pretreatment in alleviating membrane fouling

Environmental Science Water Research & Technology ◽

10.1039/c7ew00381a ◽

2018 ◽

Vol 4 (2) ◽

pp. 315-324 ◽

Cited By ~ 5

Author(s):

Fangshu Qu ◽

Zhongsen Yan ◽

Hao Wang ◽

Xiaobo Wang ◽

Heng Liang ◽

...

Keyword(s):

Drinking Water ◽

Activated Carbon ◽

Pilot Study ◽

Membrane Fouling ◽

Rural Areas ◽

Potable Water ◽

Drinking Water Treatment ◽

Biological Activated Carbon ◽

Ultrafiltration Process

For decentralized drinking water treatment in rural areas, a hybrid process of biological activated carbon (BAC) filtration and ultrafiltration (UF) was applied to obtain potable water.

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