This work proposes an efficient combined treatment for the decontamination of a pesticide-containing wastewater resulting from phytopharmaceutical plastic containers washing, presenting a moderate ...organic load (COD=1662–1960mgO2L−1; DOC=513–696mgCL−1), with a high biodegradable organic carbon fraction (81%; BOD5=1350–1600mgO2L−1) and a remaining recalcitrant organic carbon mainly due to pesticides. Nineteen pesticides were quantified by LC–MS/MS at concentrations between 0.02 and 45mgL−1 (14–19% of DOC). The decontamination strategy involved a sequential three-step treatment: (a) biological oxidation process, leading to almost complete removal of the biodegradable organic carbon fraction; (b) solar photo-Fenton process using CPCs, enhancing the bio-treated wastewater biodegradability, mainly due to pesticides degradation into low-molecular-weight carboxylate anions; (c) and a final polishing step to remove the residual biodegradable organic carbon, using a biological oxidation process. Treatment performance was evaluated in terms of mineralization degree (DOC), pesticides content (LC–MS/MS), inorganic ions and low-molecular-weight carboxylate anions (IC) concentrations. The estimated phototreatment energy necessary to reach a biodegradable wastewater, considering pesticides and low-molecular-weight carboxylate anions concentrations, Zahn-Wellens test and BOD5/COD ratio, was only 2.3kJUVL−1 (45min of photo-Fenton at a constant solar UV power of 30Wm−2), consuming 16mM of H2O2, which pointed to 52% mineralization and an abatement higher than 86% for 18 pesticides. The biological oxidation/solar photo-Fenton/biological oxidation treatment system achieved pesticide removals below the respective detection limits and 79% mineralization, leading to a COD value lower than 150mgO2L−1, which is in agreement with Portuguese discharge limits regarding water bodies.
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► Phytopharmaceutical containers washing wastewater presents a mixture of pesticides. ► Photo-Fenton reaction enhances the pesticide-containing wastewater biodegradability. ► Pesticides degradation into low-molecular-weight carboxylate anions was very fast
A multistage treatment system, at a scale close to the industrial, was designed for the treatment of a mature raw landfill leachate, including: a) an activated sludge biological oxidation (ASBO), ...under aerobic and anoxic conditions; b) a solar photo-Fenton process, enhancing the bio-treated leachate biodegradability, with and without sludge removal after acidification; and c) a final polishing step, with further ASBO.
The raw leachate was characterized by a high concentration of humic substances (HS) (1211 mg CHS/L), representing 39% of the dissolved organic carbon (DOC) content, and a high nitrogen content, mainly in the form of ammonium nitrogen (>3.8 g NH4+–N/L).
In the first biological oxidation step, a 95% removal of total nitrogen and a 39% mineralization in terms of DOC were achieved, remaining only the recalcitrant fraction, mainly attributed to HS (57% of DOC). Under aerobic conditions, the highest nitrification rate obtained was 8.2 mg NH4+–N/h/g of volatile suspended solids (VSS), and under anoxic conditions, the maximum denitrification rate obtained was 5.8 mg (NO2−–N + NO3−–N)/h/g VSS, with a C/N consumption ratio of 2.4 mg CH3OH/mg (NO2−–N + NO3−–N).
The precipitation of humic acids (37% of HS) after acidification of the bio-treated leachate corresponds to a 96% DOC abatement. The amount of UV energy and H2O2 consumption during the photo-Fenton reaction was 30% higher in the experiment without sludge removal and, consequently, the reaction velocity was 30% lower. The phototreatment process led to the depletion of HS >80%, of low-molecular-weight carboxylate anions >70% and other organic micropollutants, thus resulting in a total biodegradability increase of >70%.
The second biological oxidation allowed to obtain a final treated leachate in compliance with legal discharge limits regarding water bodies (with the exception of sulfate ions), considering the experiment without sludge.
Finally, the high efficiency of the overall treatment process was further reinforced by the total removal percentages attained for the identified organic trace contaminants (>90%).
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•Multistage treatment system for stabilized raw leachate from sanitary landfill.•Integration of biological/chemical/biological oxidations processes.•Nitrogen removal using biological nitrification and denitrification reactions.•The photo-oxidation led to the depletion of HS and other organic micropollutants.•Organic trace contaminants identification and evolution profile follow-up.
In this work the photodegradation pathways and rates of oseltamivir ester (OE) and oseltamivir carboxylate (OC) were studied under artificial and natural solar irradiation with the goal of assessing ...the potential of photolysis as a removal mechanism in aquatic environments. The structures of the photoproducts of OE, elucidated by ultra performance liquid chromatography-quadrupole-time-of-flight-mass spectrometry (UPLC-QToF-MS), were proposed to originate from hydration of the cyclohexene ring (TP330), ester hydrolysis (TP284), a combination thereof (TP302), intramolecular cyclization involving the ester (TP312), and cleavage of the ethylpropoxy side chain (TP226). The only photoproduct detected in case of OC was postulated to correspond to the hydration of the α,β-unsaturated acid (TP302). Under simulated solar irradiation the degradation rate of OC was approximately 10 times slower than that of OE, with half-lives ranging from 48 h in ultrapure water to 12 h in surface water from Sant Joan Despi, Llobregat river. The photodegradation under natural solar irradiation during the season of pandemic Influenza peak incidence was about 150 days for OC and 15 days for OE. In general, the photoproducts proved to be more resistant toward further photodegradation than the parent antivirals. In a monitoring survey of surface waters from the Ebro river (NE Spain), OC and OE were detected along with the photoproducts TP330 and 312.
In order to reduce the amount of sample to be collected and the time consumed in the analytical process, a broad range of analytes should be preferably considered in the same analytical procedure. A ...suitable methodology for pesticide residue analysis in soil samples was developed based on ultrasonic extraction (USE) and gas chromatography–mass spectrometry (GC–MS). For this study, different classes of pesticides were selected, both recent and old persistent molecules: parent compounds and degradation products, namely organochlorine, organophosphorous and pyrethroid insecticides, triazine and acetanilide herbicides and other miscellaneous pesticides. Pesticide residues could be detected in the low- to sub-ppb range (0.05–7.0
μg
kg
−1) with good precision (7.5–20.5%, average 13.7% R.S.D.) and extraction efficiency (69–118%, average 88%) for the great majority of analytes. This methodology has been applied in a monitoring program of soil samples from an intensive horticulture area in Póvoa de Varzim, North of Portugal. The pesticides detected in four sampling programs (2001/2002) were the following: lindane, dieldrin, endosulfan, endosulfan sulfate, 4,4′-DDE, 4,4′-DDD, atrazine, desethylatrazine, alachlor, dimethoate, chlorpyrifos, pendimethalin, procymidone and chlorfenvinphos. Pesticide contamination was investigated at three depths and in different soil and crop types to assess the influence of soil characteristics and trends over time.
► Municipal WWTP effluent contaminated with pharmaceuticals and earthy-musty compounds. ► CPC pilot plant for TiO2-solar photocatalysis as a complementary tertiary treatment. ► Complete removal of 19 ...out of 22 pharmaceuticals with ca. 32kJL−1 solar UV energy. ► Zahn–Wellens test indicates many pharmaceuticals are refractory to biotreatment. ► V. fischeri bioassay revealed no toxicity increase during photocatalytic treatment.
Emerging pollutants, such as pharmaceuticals, are widely disseminated in the aquatic media. Though in low concentrations in the environment, they still pose concerns mainly over potential chronic toxicity effects. Consequently, this work reports on the successful attempt to develop a photocatalytic treatment method, using suspended TiO2 in a concentration of 200mgL−1 and solar UV radiation as the photon source, firstly designed for lorazepam (Lorenin® pills) degradation and further applied to the treatment of a real municipal WWTP effluent, containing several other emerging contaminants (ECs).
Initial effluent physicochemical characterization revealed the presence of 22 pharmaceutical compounds in moderate concentrations (maximum of 680ngL−1, except for diclofenac ∼24μgL−1 and hydrochlorothiazide ∼3μgL−1) and a low dissolved organic carbon (DOC) content. Therefore, the main purpose of the work was not to increase the effluent’s biodegradability, but to improve the removal rates of the several present ECs.
Pharmaceuticals’ degradation kinetics, using a solar pilot plant with CPCs, were thoroughly studied. A pseudo-first order kinetic model was able to successfully predict the experimental data. The overall treatment was considered efficient, with a complete removal of the majority of these micropollutants, except for ciprofloxacin (35%), ketoprofen (61%) and bisoprolol (77%). Nevertheless, a small increase in the reaction time could easily accomplish their total degradation.
Zahn–Wellens biodegradability assay allowed withdrawing some conclusions about which pharmaceuticals could be degraded by means of biotreatment, thus avoiding the need to apply a photocatalytic treatment.
Finally, Vibrio fischeri acute toxicity test showed that the effluent itself presented no significant toxicity and that the intermediate oxidation compounds, possibly formed during phototreatment, did not reflect any significant increase of toxicity.
This study focuses on the degradation of pharmaceuticals from a municipal wastewater after secondary treatment by applying various advanced oxidation processes (AOPs) and electrochemical AOPs (EAOPs) ...like UVC, H2O2/UVC, anodic oxidation (AO), AO with electrogenerated H2O2 (AO-H2O2), AO-H2O2/UVC and photoelectro-Fenton (PEF) using either UVC radiation (PEF-UVC) or UVA radiation (PEF-UVA). The municipal wastewater after secondary treatment was spiked with 5.0 mg L−1 of trimethoprim (TMP) antibiotic. The efficiency of processes to remove TMP followed the order UVC < AO-H2O2 < PEF-UVA << AO ≈ PEF-UVC < AO-H2O2/UVC < PEF-UVA (pH = 2.8) < H2O2/UVC ≈ PEF-UVC (pH = 2.8), using neutral pH, except when identified. While the UVC radiation alone led to a very low TMP removal, the H2O2/UVC process promoted a very high TMP degradation due to the production of hydroxyl radicals (OH) by H2O2 cleavage. In the AO-H2O2/UVC process, the electrogeneration of H2O2 can avoid the risks associated with the transportation, storage and manipulation of this oxidant and, furthermore, OH at the anode surface are also formed. Nevertheless, low contents of H2O2 were detected mainly at the beginning of the reaction, leading to a lower initial reaction rate when compared with the H2O2/UVC system. In the PEF-UVC, the addition of iron at neutral pH led to the visible formation of insoluble iron oxides that can filter the light. At pH 2.8, the iron remained dissolved, thereby promoting the Fenton's reaction and increasing the organics removal. The UVA-driven processes showed limited efficiency when compared with those using UVC light. For all processes with H2O2 electrogeneration, the active chlorine species can be scavenged by the H2O2, diminishing the efficiency of the processes. This can explain the lower efficiency of AO-H2O2 when compared with AO. Moreover, the degradation of the MWWTP effluent spiked with 18 pharmaceuticals in μg L−1 during AO process was assessed as well as the influence of the following operational variables on the process efficiency: (i) H2O2 concentration on H2O2/UVC, (ii) current density on AO, AO-H2O2, AO-H2O2/UVC, PEF-UVC and PEF-UVA, and (iii) pH on PEF-UVA.
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•First study on AO-H2O2, AO-H2O2/UVC, PEF-UVC and PEF-UVA to degrade a MWWTP effluent.•Unprecedented comparison of chemical and electrochemical advanced oxidation processes.•Trimethoprim removal: PEF-UVC ≈ H2O2/UVC > PEF-UVA > AO-H2O2/UVC > AO > AO-H2O2 > UVC.•Assessment of pharmaceuticals removal at mg L−1 and μg L−1 levels.•Assessment of the effect of H2O2 content, current density and pH on various processes.
We present the latest advances in green analytical chemistry for application to organic-pollution analysis in aquatic environments. We review the main strategies to reduce toxic reagents, solvent ...wastes and energy consumption. We pay special attention to new approaches to environmental analysis, allowing automation, miniaturization, and on-site, on-line and direct analysis (e.g., biosensors).
Solid-phase microextraction (SPME) is a simple and effective adsorption and desorption technique, which eliminates the need for solvents or complicated apparatus, for concentrating volatile or ...nonvolatile compounds in liquid samples or headspace. SPME is compatible with analyte separation and detection by gas chromatography and high-performance liquid chromatography, and provides linear results for wide concentrations of analytes. By controlling the polarity and thickness of the coating on the fibre, maintaining consistent sampling time, and adjusting other extraction parameters, an analyst can ensure highly consistent, quantifiable results for low concentration analytes. To date, about 400 articles on SPME have been published in different fields, including environment (water, soil, air), food, natural products, pharmaceuticals, biology, toxicology, forensics and theory. As the scope of SPME grew, new improvements were made with the appearance of new coatings that allowed an increase in the specificity of this extraction technique. The key part of the SPME fibre is of course the fibre coating. At the moment, 27 variations of fibre coating and size are available. Among the newest are a fibre assembly with a dual coating of divinylbenzene and Carboxen suspended in poly(dimethylsiloxane), and a series of 23 gauge fibres intended for specific septumless injection system. The growth of SPME is also reflected in the expanding number of the accessories that make the technology even easier to use Also available is a portable field sampler which is a self-contained unit that stores the SPME fibre after sampling and during the shipment to the laboratory. Several scientific publications show the results obtained in inter-laboratory validation studies in which SPME was applied to determine the presence of different organic compounds at ppt levels, which demonstrates the reliability of this extraction technique for quantitative analysis.
•Determination of nine triazine herbicides and eight degradation products in seawater.•A method using on-line SPE coupled with UPLC-tandem mass spectrometry was developed.•Limits of quantification ...(LOQ) ranged from 0.023 to 0.657μgL−1.•Analytical recoveries and precision were satisfactory for all compounds.
A fast, simple, selective and sensitive method has been developed for the determination of nine triazine herbicides (ametryn, atrazine, cyanazine, prometryn, propazine, simazine, simetryn, terbuthylazine and terbutryn) and eight degradation products (desethyl atrazine, desethyl-desisopropyl atrazine, desethyl 2-hydroxyatrazine, desethyl terbuthylazine, desisopropyl atrazine, desisopropyl 2-hydroxyatrazine, 2-hydroxyatrazine and 2-hidroxyterbuthylazine) in seawater samples. On-line solid-phase extraction coupled with ultra-pressure liquid chromatography-tandem mass spectrometry was employed for simultaneous analysis of all compounds in 11min. Validation parameters were studied through the estimation of the limits of detection and quantification, calibration curves and precision. Limits of quantification ranged from 0.023 to 0.657μgL−1. Good linearity was obtained for all compounds with R2>0.99 in all cases. Furthermore, inter-day precision (0–2.1%) and intra-day precision (0–3.9%) were shown to be satisfactory. On-line solid-phase extraction recoveries in spiked unpolluted seawater sample were evaluated and acceptable values (80.3–99.8%) with adequate RSD (0.1–3.1%) were found.
Finally, the proposed method was applied to the analysis of the target compounds in seawater samples collected from seawater nearby a zone of intensive horticulture of Matosinhos (Portugal). The concentrations of the herbicides were below the limit of detection in all cases.
An environmentally friendly methodology is proposed for the analysis of pesticides in soil samples based on supercritical fluid extraction (SFE) and analysis at high selectivity and sensitivity, by ...gas chromatography–tandem mass spectrometry (GC–MS–MS). The pesticides investigated are among the most commonly used in intensive horticulture activities comprising organochlorine and organophosphorous insecticides, triazine and acetanilide herbicides, amongst others. An experimental design approach was used for modelling SFE and optimised extraction conditions were derived for the total pesticides extraction or for specific sub-groups of interest. Pesticide residues could be detected in soils in the sub-ppb range (0.1–3.7
μg
kg
−1), with quite good precision (4.2–15.7%) and extraction efficiency (80.4–106.5%). The analysis of soil samples from an intensive horticulture area in Póvoa de Varzim, north of Portugal, revealed the presence of persistent pesticides, parent compounds and degradation products among the following: endosulfan, endosulfan sulfate, dieldrin, 4,4′-DDE, 4,4′-DDD, atrazine, alachlor, metolachlor, chlorpyrifos, pendimethalin and lindane. The important features to point out are the easy interpretation of chromatograms and straightforward confirmation of analytes that greatly facilitates the analyst judgement on the contamination of the sample.
