scholarly journals Removal of crotamiton and its degradation intermediates from secondary effluent using TiO2–zeolite composites

2017 ◽  
Vol 77 (3) ◽  
pp. 788-799 ◽  
Author(s):  
Qun Xiang ◽  
Shuji Fukahori ◽  
Youhei Nomura ◽  
Taku Fujiwara
Keyword(s):  
Biological Treatment ◽  
Photocatalytic Decomposition ◽  
Secondary Effluent ◽  
Ultrapure Water ◽  
Water Matrix ◽  
Treatment Processes ◽  
Adsorption Capacities ◽  
High Silica ◽  
Adsorption Rates ◽  
Degradation Intermediates

Abstract Crotamiton, a scabicide and antipruritic agent persistent during biological treatment processes, is frequently detected in secondary effluent. In this study, titanium dioxide (TiO2) and high-silica zeolite (HSZ-385) composites were synthesized and applied for the treatment of crotamiton in secondary effluent. Crotamiton was rapidly adsorbed by HSZ-385, and the adsorption performance of crotamiton in the secondary effluent was quite close to that in the test using ultrapure water. Even though the TiO2–zeolite composites showed lower adsorption rates than that of HSZ-385, similar crotamiton adsorption capacities were revealed using both test materials. The photocatalytic decomposition of crotamiton was significantly inhibited by the water matrix at low initial concentrations. The TiO2–zeolite composites rapidly adsorbed crotamiton from secondary effluent, and then the crotamiton was gradually decomposed under ultraviolet irradiation. Importantly, when using TiO2–zeolite composites, coexisting material in the secondary effluent did not markedly inhibit crotamiton removal at low initial crotamiton concentration. The behaviors of the main intermediates during treatment demonstrated that the main degradation intermediates of crotamiton were also captured by the composites.

Effectiveness of high-silica zeolites for the adsorption of methyl tertiary-butyl ether from natural water

2005 ◽  
Vol 5 (5) ◽  
pp. 83-91 ◽  
Author(s):  
D.R.U. Knappe ◽  
A.A. Rossner Campos
Keyword(s):  
Natural Organic Matter ◽  
Activated Carbons ◽  
Methyl Tertiary Butyl Ether ◽  
Ultrapure Water ◽  
Butyl Ether ◽  
Tertiary Butyl ◽  
Adsorption Capacities ◽  
High Silica ◽  
High Silica Zeolites ◽  
Adsorption Systems

MTBE adsorption isotherm data were collected for a matrix of high-silica zeolites with different pore sizes (ZSM-5/silicalite, mordenite, beta, Y), exchangeable cations (H+, Na+, NH4+), and hydrophobicities (SiO2/Al2O3 ratios). MTBE adsorption capacities of high-silica zeolites were compared with those of one coconut-shell-based and two coal-based granular activated carbons (GACs) as well as a carbonaceous resin. Isotherm experiments were conducted in ultrapure water buffered at pH 7.2 and in Tar River water (Greenville, NC) to determine the effects of co-adsorbing and preloaded natural organic matter (NOM) on MTBE adsorption. The results of this study showed that (1) high-silica zeolites with small pores (ZSM-5/silicalite, mordenite) exhibit higher MTBE adsorption capacities than GACs, (2) NOM has little or no effect on MTBE adsorption capacities of ZSM-5/silicalite zeolites, and (3) equilibrium model results suggest that silicalite-based adsorption systems are cost-competitive with activated-carbon-based adsorption systems while offering operational advantages such as longer adsorber life and possibly greater ease of regeneration.

scholarly journals Ozone-Based Advanced Oxidation Processes for Primidone Removal in Water using Simulated Solar Radiation and TiO2 or WO3 as Photocatalyst

Molecules ◽  
2019 ◽  
Vol 24 (9) ◽  
pp. 1728 ◽  
Author(s):  
Manuel A. Figueredo ◽  
Eva M. Rodríguez ◽  
Manuel Checa ◽  
Fernando J. Beltran
Keyword(s):  
Transformation Products ◽  
Degradation Pathway ◽  
Secondary Effluent ◽  
Ultrapure Water ◽  
Visible Radiation ◽  
Beneficial Effects ◽  
Photocatalytic Ozonation ◽  
Toc Removal ◽  
Water Matrix ◽  
Environmentally Safe

In this work, primidone, a high persistent pharmacological drug typically found in urban wastewaters, was degraded by different ozone combined AOPs using TiO2 P25 and commercial WO3 as photocatalyst. The comparison of processes, kinetics, nature of transformation products, and ecotoxicity of treated water samples, as well as the influence of the water matrix (ultrapure water or a secondary effluent), is presented and discussed. In presence of ozone, primidone is rapidly eliminated, with hydroxyl radicals being the main species involved. TiO2 was the most active catalyst regardless of the water matrix and the type of solar (global or visible) radiation applied. The synergy between ozone and photocatalysis (photocatalytic ozonation) for TOC removal was more evident at low O3 doses. In spite of having a lower band gap than TiO2 P25, WO3 did not bring any beneficial effects compared to TiO2 P25 regarding PRM and TOC removal. Based on the transformation products identified during ozonation and photocatalytic ozonation of primidone (hydroxyprimidone, phenyl-ethyl-malonamide, and 5-ethyldihydropirimidine-4,6(1H,5H)-dione), a degradation pathway is proposed. The application of the different processes resulted in an environmentally safe effluent for Daphnia magna.

Изучение отклика дегидрогеназной активности ила на изменение технологических параметров работы аэротенка

2020 ◽  
Author(s):  
N. Zaletova ◽  
S. Zaletov
Keyword(s):  
Wastewater Treatment ◽  
Dehydrogenase Activity ◽  
Biological Treatment ◽  
Biological Process ◽  
Organic Load ◽  
Treatment Processes ◽  
Mode Of Operation ◽  
Concentrated Solution ◽  
Available Information ◽  
Complicated Mechanism

Биологический метод очистки сточных вод представляет собой сложный многокомпонентный процесс, ключевой составляющей которого является работа ферментной системы. Известно, что одним из важнейших ферментов, обеспечивающих биологический процесс, являются дегидрогеназы. Полностью сложнейший механизм действия ферментов до конца пока не раскрыт, однако в практике контроля процессов биологической очистки используется показатель дегидрогеназной активности ила. Результаты исследований позволили дополнить имеющуюся информацию фактическими данными о взаимообусловленности уровня дегидрогеназной активности ила и показателей отдельных технологических параметров биологической очистки. Показано, что режим работы аэротенков (нагрузка на ил, доза активного ила и др.) и величина показателей исходной дегидрогеназной активности и дегидрогеназной активности этого же образца ила со слабо концентрированным раствором (ДАИН2О) связаны между собой и зависят от нагрузки на ил по органическим веществам. Полученные результаты исследования могут быть использованы для контроля биологического процесса очистки сточных вод.The biological method of wastewater treatment is a comprehensive multicomponent process the activities of the enzyme system being the key component of it. It is known that dehydrogenases have been one of the most important enzymes the ensure the biological process. The complicated mechanism of the action of enzymes has not been fully described so far however, in the practice of monitoring biological treatment processes, an indicator of the dehydrogenase activity of sludge is used. The research results provided for supplementing the available information with actual data on the interdependence of the level of dehydrogenase activity of sludge and indicators of individual process parameters of biological treatment. It was shown that the mode of operation of aeration tanks (organic matter load on sludge, dose of activated sludge, etc.) and the values of the initial dehydrogenase activity and dehydrogenase activity of the same sludge sample with weakly concentrated solution (DASН2О) are interconnected and depend on the organic load on sludge. The results of the study can be used to control the biological process of wastewater treatment.The biological method of wastewater treatment is a comprehensive multicomponent process the activities of the enzyme system being the key component of it. It is known that dehydrogenases have been one of the most important enzymes the ensure the biological process. The complicated mechanism of the action of enzymes has not been fully described so far however, in the practice of monitoring biological treatment processes, an indicator of the dehydrogenase activity of sludge is used. The research results provided for supplementing the available information with actual data on the interdependence of the level of dehydrogenase activity of sludge and indicators of individual process parameters of biological treatment. It was shown that the mode of operation of aeration tanks (organic matter load on sludge, dose of activated sludge, etc.) and the values of the initial dehydrogenase activity and dehydrogenase activity of the same sludge sample with weakly concentrated solution (DASН2О) are interconnected and depend on the organic load on sludge. The results of the study can be used to control the biological process of wastewater treatment.

Advanced Biological Treatment Processes for Industrial Wastewaters - Principles & Applications

2015 ◽  
Vol 5 (0) ◽  
pp. 9781780402345-9781780402345 ◽  
Author(s):  
F. Cervantes ◽  
S. Pavlostathis ◽  
A. van Haandel
Keyword(s):  
Biological Treatment ◽  
Industrial Wastewaters ◽  
Treatment Processes

The Characteristics of Community Wastewater Biological Treatment Processes in Taiwan

1986 ◽  
Vol 18 (7-8) ◽  
pp. 289-296
Author(s):  
C. F. Ouyang ◽  
T. J. Wan
Keyword(s):  
Biological Treatment ◽  
Wastewater Treatment Plants ◽  
Oxygen Demand ◽  
Field Investigation ◽  
Oxidation Ditch ◽  
Trickling Filter ◽  
Rotating Biological Contactor ◽  
Treatment Processes ◽  
Treatment Characteristics ◽  
Sludge Thickening

This study investigated and compared the treatment characteristics of three different kinds of biological wastewater treatment plants (including rotating biological contactor, trickling filter and oxidation ditch) which are currently operated in Taiwan. The field investigation of this study concentrated on the following items: the performance of biological oxygen demand (BOD) and suspended solids (SS) removal; the sludge yield rate of BOD removal; the settleability of sludge solids; the properties of sludge thickening; the power consumption and land area requirement per unit volume of wastewater. Finally, based on the results of the field investigation, a comparison of the treatment characteristics of the three different biological treatment processes was evaluated.

scholarly journals Oxidation of Citalopram with Sodium Hypochlorite and Chlorine Dioxide: Influencing Factors and NDMA Formation Kinetics

Molecules ◽  
2019 ◽  
Vol 24 (17) ◽  
pp. 3065
Author(s):  
Juan Lv ◽  
Yan Wang ◽  
Na Li
Keyword(s):  
Sodium Hypochlorite ◽  
Chlorine Dioxide ◽  
Wastewater Treatment Plants ◽  
Ph Value ◽  
High Reactivity ◽  
Secondary Effluent ◽  
Water Matrix ◽  
Formation Kinetics ◽  
Operational Variables ◽  
Two Stages

The highly prescribed antidepressant, citalopram, as one of newly emerging pollutants, has been frequently detected in the aquatic environment. Citalopram oxidation was examined during sodium hypochlorite (NaOCl) and chlorine dioxide (ClO2) chlorination processes since conventional wastewater treatment plants cannot remove citalopram effectively. Citalopram has been demonstrated to form N-nitrosodimethylamine (NDMA) during chlorination in our previous study. Further investigation on NDMA formation kinetics was conducted in the present study. Influences of operational variables (disinfectant dose, pH value) and water matrix on citalopram degradation, as well as NDMA generation, were evaluated. The results indicated high reactivity of citalopram with NaOCl and ClO2. NDMA formation included two stages during CIT oxidation, which were linear related with reaction time. NaOCl was more beneficial to remove CIT, but it caused more NDMA formation. Increasing disinfectant dosage promoted citalopram removal and NDMA formation. However, no consistent correlation was found between citalopram removal and pH. Contrary to the situation of citalopram removal, NDMA generation was enhanced when citalopram was present in actual water matrices, especially in secondary effluent. DMA, as an intermediate of citalopram chlorination, contributed to NDMA formation, but not the only way.

scholarly journals Occurrence of SARS-CoV-2 RNA in Six Municipal Wastewater Treatment Plants at the Early Stage of COVID-19 Pandemic in The United States

Pathogens ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 798
Author(s):  
Samendra P. Sherchan ◽  
Shalina Shahin ◽  
Jeenal Patel ◽  
Lauren M. Ward ◽  
Sarmila Tandukar ◽  
...  
Keyword(s):  
United States ◽  
Wastewater Treatment ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Quantitative Polymerase Chain Reaction ◽  
The United States ◽  
Secondary Effluent ◽  
Untreated Wastewater ◽  
Treatment Processes ◽  
Wastewater Samples

In this study, we investigated the occurrence of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) RNA in primary influent (n = 42), secondary effluent (n = 24) and tertiary treated effluent (n = 34) collected from six wastewater treatment plants (WWTPs A–F) in Virginia (WWTP A), Florida (WWTPs B, C, and D), and Georgia (WWTPs E and F) in the United States during April–July 2020. Of the 100 wastewater samples analyzed, eight (19%) untreated wastewater samples collected from the primary influents contained SARS-CoV-2 RNA as measured by reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) assays. SARS-CoV-2 RNA were detected in influent wastewater samples collected from WWTP A (Virginia), WWTPs E and F (Georgia) and WWTP D (Florida). Secondary and tertiary effluent samples were not positive for SARS-CoV-2 RNA indicating the treatment processes in these WWTPs potentially removed SARS-CoV-2 RNA during the secondary and tertiary treatment processes. However, further studies are needed to understand the log removal values (LRVs) and transmission risks of SARS-CoV-2 RNA through analyzing wastewater samples from a wider range of WWTPs.

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