Heterogeneous photocatalysis and photo-Fenton of estradiol in wastewater

The European Directive 2000/60/CE stresses the need of adopting measures against water pollution in order to achieve a progressive reduction of pollutants and water reuse. Advanced Oxidation Processes (AOPs) are promising ways to perform the mineralization of pollutants. AOPs are characterized by the in situ production of hydroxyl radicals, which are highly reactive species capable of oxidizing organic materials in a non-selective way. The main objective of this to study was to compare the 17-β Estradiol (E2) degradation in wastewater by different AOPs including UV, UV+oxidant, UV-TiO2, photo-Fenton, UV-photosphere, UV-graphenesphere, UV-oxone (a photo-Fenton like process based on peroxymonopersulfate as oxidant). Homogeneous photo–Fenton like process using peroxymonopersulfate as oxidant and heterogeneous photocatalysis using TiO2 were the most effective technologies for the fast removal of estrogenic hormone. Both processes were very fast considering that 95% of E2 was removed in few minutes. Moreover, UV-oxone was more efficient than UV-TiO2 since with the first technology the complete mineralization of E2 was achieved within 2 minutes without the production of dangerous by-products

idoum

Innovative Decentralized and low cost treatment systems for Optimal Urban wastewater Management. Reuse of treated wastewater is increasingly seen as one of the solutions to tackle the water scarcity problem and to limit the pollution load to surface water. Yet, using reclaimed water for non-potable purposes and particularly to irrigate food crops presents an exposure pathway for antibiotics and antibiotic resistant bacteria and genes (ARB&G) to enter the human food chain. Wastewater reuse is currently of particular concern as potential source of selective pressure that elevates the levels of antibiotic resistance in native bacteria. [More](http://www.waterjpi.eu/joint-calls/joint-call-2017-ic4water/booklet/idoum-1

Evidence for the impact of sulfamethoxazole residues on denitrification rates in soil and formation of transformation products of concern

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Enantiomeric fractionation for quantitative assessment of anaerobic biodegradation rates: The case of climbazole.

International audienceAn efficient chiral liquid chromatography -high resolution - mas spectrometry method has been developed for thedetermination of climbazole (CBZ) enantiomers in wastewater / sludge.The obtimized analytical method has been validated with good qualityparameters including resolution > 1.1 and method quantification limitsdown to the ng/L range. On the basis of this newly developed analyticalmethod, the stereochemisttry of CBZ was investigated over time ineffluent / sludge biotic and steril microcosms under anaerobic dark andlight conditions and in influents and effluents of five differentsubsurface constructed wetlands (CWs). CBZ stereoselectivedegradation was exclusively observed under biotic conditions,confirming the specificity of enantiomeric fraction variations tobiodegradation processes. CBZ was always biotransformed into CBZalcohol due to the specific and enantioselective reduction of the ketonefunction into a secondary alcohol function. This transformation wasalmost quantitative and biodegradation gave a good first order kineticfit. We investigated the possibility to apply the Rayleigh equation toenantioselective processes by replacing the isotope ratio by theenantiomer ratio for quantitative biodegradation assessment of CBZ inbiological treatment processes and in receiving surface water or soil.The results of enantiomeric enrichment pointed the way for aquantitative assessment of in situ biodegradation processes due to agood fit (R2 > 0.98) of the anaerobic CBZ biodegradation to theRayleigh dependency in all the biotic microcosms and in CWs. Theseresults demonstrate that enantiomeric fractionation constitutes a veryinteresting quantitative indicator of CBZ biodegradation under anaerobicconditions. The enantiomeric fractionation tool does not imply toachieve a mass balance of the contaminant, which constitutes a relevantadvantage over the conservative tracer approaches. A prediction of theextent of biodegradation is also allowed as fars as the enantiomericenrichment factor is known

Oxidative degradation of pentachlorophenol by permanganate for ISCO application

International audiencePotassium permanganate (KMnO4) has been an effective technology for the in situ chemical oxidation (ISCO) of many organic compounds including chlorinated alkanes and alkenes, but it has rarely been applied for oxidizing aromatic organochlorines. This study confirms the ability of permanganate to oxidize an aromatic chlorinated compound, pentachlorophenol (PCP), in an efficient manner at neutral pH. The rate of the reaction between KMnO4 and PCP was calculated and the results indicated that the reaction between PCP and permanganate is relatively fast with a second-order rate constant k″ ∼ 30 M−1 s−1. Besides the kinetic aspect, the authors identified the main reaction by-products, and proposed a possible reaction mechanism scheme. The general pathway shows the formation of chlorinated intermediates, and ultimately, the complete mineralization to chloride, water, and CO2 confirmed by total organic carbon and chloride measurement in solution. Flow-through column experiments, consisting of flushing a PCP-contaminated sandy or natural soil with oxidant, showed the good ability of permanganate to eliminate the pollutant. After 24 h of treatment, 77% and 56% of PCP abatement were obtained for sandy and natural soil, respectively. These findings show the high potential of permanganate for the in situ remediation of aromatic organochlorine contaminated soils

Enantioselective reductive transformation of climbazole: A concept towards quantitative biodegradation assessment in anaerobic biological treatment processes

International audienceAn efficient chiral method-based using liquid chromatography-high resolution-mass spectrometry analytical method has been validated for the determination of climbazole (CBZ) enantiomers in waste-water and sludge with quantification limits below the 1 ng/L and 2 ng/g range, respectively. On the basis of this newly developed analytical method, the stereochemistry of CBZ was investigated over time in sludge biotic and sterile batch experiments under anoxic dark and light conditions and during waste-water biological treatment by subsurface flow constructed wetlands. CBZ stereoselective degradation was exclusively observed under biotic conditions, confirming the specificity of enantiomeric fraction variations to biodegradation processes. Abiotic CBZ enantiomerization was insignificant at circumneutral pH and CBZ was always biotransformed into CBZ-alcohol due to the specific and enantioselective reduction of the ketone function of CBZ into a secondary alcohol function. This transformation was almost quantitative and biodegradation gave good first order kinetic fit for both enantiomers. The possibility to apply the Rayleigh equation to enantioselective CBZ biodegradation processes was investigated. The results of enantiomeric enrichment allowed for a quantitative assessment of in situ biodegradation processes due to a good fit (R-2 > 0.96) of the anoxic/anaerobic CBZ biodegradation to the Rayleigh dependency in all the biotic microcosms and was also applied in subsurface flow constructed wetlands. This work extended the concept of applying the Rayleigh equation towards quantitative biodegradation assessment of organic contaminants to enantioselective processes operating under anoxic/anaerobic conditions

Biotic nitrosation of diclofenac in a soil aquifer system (Katari watershed, Bolivia)

Up till now, the diclofenac (DCF) transformation into its nitrogen-derivatives, N-nitroso-DCF (NO-DCF) and 5-nitro-DCF (NO2-DCF), has been mainly investigated in waste water treatment plant under nitrification or denitrification processes. This work reports, for the first time, an additional DCF microbial mediated nitrosation pathway of DCF in soil under strictly anoxic conditions probably involving codenitrification processes and fungal activities. This transformation pathway was investigated by using field observations data at a soil aquifer system (Katari watershed, Bolivia) and by carrying out soil slurry batch experiments. It was also observed for diphenylamine (DPA). Field measurements revealed the occurrence of NO-DCF, NO2-DCF and NO-DPA in groundwater samples at concentration levels in the 6-68 s/L range. These concentration levels are more significant than those previously reported in waste water treatment plant effluents taking into account dilution processes in soil. Interestingly, the p-benzoquinone imine of 5-OH-DCF was also found to be rather stable in surface water. In laboratory batch experiments under strictly anoxic conditions, the transformation of DCF and DPA into their corresponding N-nitroso derivatives was well correlated to denitrification processes. It was also observed that NO-DCF evolved into NO2-DCF while NO-DPA was stable. In vitro experiments showed that the Fisher-Hepp rearrangement could not account for NO2-DCF formation. One possible mechanism might be that NO-DCF underwent spontaneous NO loss to give the resulting intermediates diphenylaminyl radical or nitrenium cation which might evolve into NO2-DCF in presence of NO2 radical or nitrite ion, respectively