Evaluating Microtox© as a tool for biodegradability assessment of partially treated solutions of pesticides using Fe3+ and TiO2 solar photo-assisted processes

Lapertot, Miléna; Ebrahimi, Sirous; Oller, Isabel; Maldonado, Manuel I.; Gernjak, Wolfgang; Malato, Sixto; Pulgarín, C.

doi:10.1016/j.ecoenv.2007.01.007

Cited by 44 publications

(11 citation statements)

References 61 publications

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“…1, 2, 3 and 5 in Table , which were all identified in the Fenton‐like oxidation effluents obtained with the 25% dose). This result is consistent with previous findings in the Fenton oxidation of pesticides including increased formation of carboxylic acids with increase in the H 2 O 2 dose and a gradual reduction of ecotoxicity to nonecotoxic levels in the effluent treated with the stoichiometric dose. Based on these results, the Fenton‐like effluents obtained with the 50% and 75% doses were subjected to further biological treatment in order to completely remove TMX, reduce ecotoxicity and increase biodegradability to an acceptable level.…”

Section: Resultssupporting

confidence: 93%

Thiamethoxam removal by Fenton and biological oxidation

Gomez‐Herrero

Lebik-Elhadi

Aït-Amar

et al. 2019

J of Chemical Tech & Biotech

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BACKGROUND Thiamethoxam (TMX) is a potential insecticide pollutant of hydric resources that must be removed. Advanced oxidation processes (AOPs) are usually effective, but expensive to implement. Combining Fenton's reagent with biological oxidation circumvents the shortcomings of Fenton technology, facilitating the biodegradation of the resulting effluents in a sequencing batch reactor (SBR). RESULTS Fenton‐like oxidation of TMX with variable hydrogen peroxide (H2O2) doses afforded total organic carbon (TOC) conversion and chemical oxygen demand (COD) removal by (respectively) 40% and 80% from pure TMX, and 40% and 60% from commercial TMX. The effluents from Fenton oxidation using substoichiometric H2O2 doses were less ecotoxic and more biodegradable than the initial solution and, therefore, susceptible to a biological treatment. Biological oxidation of effluents obtained from 50% and 75% H2O2 doses was accomplished for different organic loads in 6‐h cycles. Coupling Fenton and biological oxidation of TMX afforded TOC conversion and COD removal of 80% for the effluent obtained with a 75% H2O2 dose. CONCLUSIONS Coupling Fenton–biological oxidation efficiently reduces the amounts of H2O2 needed and produces biodegradable effluents. In addition, the biological treatment increases COD and TOC removal by ≤80% for the overall treatment. © 2019 Society of Chemical Industry

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Section: Resultssupporting

confidence: 93%

Thiamethoxam removal by Fenton and biological oxidation

Gomez‐Herrero

Lebik-Elhadi

Aït-Amar

et al. 2019

J of Chemical Tech & Biotech

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“…Ready biodegradability tests are fairly restrictive because of the low inoculum concentration employed (Reuschenbach et al 2003) and are normally used to predict the potential risk of a pure chemical compound in a natural environment. Inherent biodegradability test (Zahn-Wellens test) has less restrictions but is not useful in practice for predicting the behavior in a treatment plant, since it is quite time-consuming (Lapertot et al 2008). Simulation tests are carried out in continuous regime commonly upon a testing time of 12 weeks, in order to study the biodegradation capacity of acclimated biomass.…”

Section: Introductionmentioning

confidence: 99%

“…Assessing the potential impact of a chemical in a bioreactor should include not only studying the inhibition of the activity of the sludge but also evaluation of the biodegradability, since low toxicity and high biodegradability are not necessarily linked (Oller et al 2007;Lapertot et al 2008) and the accumulation of non-biodegradable compounds can lead to destabilization of the biological reactor. However, toxicity, biodegradability and inhibition, are terms sometimes interchangeably considered in the literature.…”

Section: Introductionmentioning

confidence: 99%

Comparison of experimental methods for determination of toxicity and biodegradability of xenobiotic compounds

et al. 2011

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Different methods for determining the toxicity and biodegradability of hazardous compounds evaluating their susceptibility to biological treatment were studied. Several compounds including chlorophenols and herbicides have been evaluated. Toxicity was analyzed in terms of EC50 and by a simple respirometric procedure based on the OECD Method 209 and by the Microtox® bioassay. The values of EC50 obtained from respirometry were in all the cases higher than those from the Microtox® test. The respirometric inhibition values of chlorophenols were related well with the number of chlorine atoms and their position in the aromatic ring. In general, herbicides showed lower inhibition, being alachlor the less toxic from this criterion. For determination of biodegradability an easier and faster alternative to the OECD Method 301, with a higher biomass to substrate ratio is proposed. When this test was negative, the Zahn-Wellens one was performed in order to evaluate the inherent biodegradability. In the fast test of biodegradability, 4-chlorocatechol and 4-chlorophenol showed a complete biodegradation by an unacclimated sludge upon 48 h. These results together with their low respirometric inhibition, allow concluding that these compounds could be conveniently removed in a WWTP. Alachlor, 2,4-dichlorophenol, 2,4,6-trichlorophenol and MCPA showed a partial biodegradation upon 28 days by the Zahn-Wellens inherent biodegradability test.

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“…The light emitted by the bacteria was measured after 5 min of contact time. Toxicity was expressed as toxicity units, TU = 100/ EC 50 , where EC 50 is defined as the effective concentration of the toxicant, expressed as a percentage relative to the original sample strength, that causes a 50% reduction in the light output of the test organisms during the designated time interval [49,50].…”

Section: Toxicity Measurementsmentioning

confidence: 99%

Toxic effect of H₂O₂in H₂O₂/UV, photo-Fenton and heterogeneous photocatalysis (TiO₂/H₂O₂/UV) systems to treat textile wastewater

López-López

Purswani

Martín-Pascual

et al. 2014

Desalination and Water Treatment

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UV) processes for the treatment of a highly polluted coloured wastewater was analysed. The experiments were carried out with different H 2 O 2 concentrations (0.25, 0.5, 1, 2 and 5 g/L). The toxic properties of different H 2 O 2 concentrations in textile wastewater were tested by the use of a Microtox bioassay with Vibrio fischeri. The efficiency of the process was checked by assessing the physicochemical parameters, total organic carbon (TOC) and colour. The use of TiO 2 as a catalyst with UV photolysis was the most effective method to remove toxins, organic material and colour using the five concentrations of H 2 O 2 tested. By using 5 g/L of H 2 O 2 , 94% TOC removal was achieved. In relation to colour removal, this was greater than 99% with 5 g/L of H 2 O 2 in all three processes. The use of a catalyst allowed us to reduce the hydraulic retention time of the process to 30 min with Fe 2+ and 45 min with TiO 2. Controlling the amount of H 2 O 2 used as the oxidant in an advanced oxidation process (AOP) is important since it was found to increase the toxicity of the influent with the addition of H 2 O 2 by 4.99 ± 1.48%, 27.4 ± 3.24%, 39.16 ± 5.64%, 53.40 ± 4.15% and 59.39 ± 4.67% with 0.25, 0.5, 1, 2 and 5 g/L H 2 O 2 , respectively. Therefore, under the studied conditions, an H 2 O 2 concentration greater than 1 g/L is not recommended for an AOP in order to avoid an excess of H 2 O 2 in the effluent.

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Evaluating Microtox© as a tool for biodegradability assessment of partially treated solutions of pesticides using Fe3+ and TiO2 solar photo-assisted processes

Cited by 44 publications

References 61 publications

Thiamethoxam removal by Fenton and biological oxidation

Thiamethoxam removal by Fenton and biological oxidation

Comparison of experimental methods for determination of toxicity and biodegradability of xenobiotic compounds

Toxic effect of H₂O₂in H₂O₂/UV, photo-Fenton and heterogeneous photocatalysis (TiO₂/H₂O₂/UV) systems to treat textile wastewater

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Evaluating Microtox© as a tool for biodegradability assessment of partially treated solutions of pesticides using Fe3+ and TiO2 solar photo-assisted processes

Cited by 44 publications

References 61 publications

Thiamethoxam removal by Fenton and biological oxidation

Thiamethoxam removal by Fenton and biological oxidation

Comparison of experimental methods for determination of toxicity and biodegradability of xenobiotic compounds

Toxic effect of H2O2in H2O2/UV, photo-Fenton and heterogeneous photocatalysis (TiO2/H2O2/UV) systems to treat textile wastewater

Contact Info

Product

Resources

About

Toxic effect of H₂O₂in H₂O₂/UV, photo-Fenton and heterogeneous photocatalysis (TiO₂/H₂O₂/UV) systems to treat textile wastewater