2,414 research outputs found
Pharmaceuticals and environmental risk assessment in municipal wastewater treatment plants and rivers from Peru
This is the first study dealing with removal of the pharmaceutical substances in municipal wastewater treatment plants (MWWTPs) from Peru and the impact of these compounds in surface waters receiving treated wastewater. To this aim, samples from MWWTP of Lima (Peruvian Coast), MWWTP of Cusco, Puno and Juliaca (Peruvian Highlands), as well surface water (confluence of Torococha and Coata rivers in Juliaca) were analyzed. A total of 38 target pharmaceuticals were included in this study and were determined by Liquid Chromatography coupled to tandem Mass Spectrometry (LC-MS/MS). Around 60% and 75% of the target pharmaceuticals could be quantified in surface water and MWWTPs, respectively. Acetaminophen was the drug found at the highest concentration, and it was present in all the treated wastewater samples reaching average values above 100 ÎŒg/L in the department of Puno. The gabapentin anti-epileptic drug (up to 11.85 ÎŒg/L in MWWTP Lima) and the antibiotics clarithromycin, trimethoprim, ciprofloxacin, sulfamethoxazole and azithromycin (1.86 to 4.47 ÎŒg/L in MWWTP Lima) were also found at moderate concentrations in the treated wastewater. In surface water, the highest concentration corresponded also to acetaminophen (28.70 ÎŒg/L) followed by sulfamethoxazole (4.36 ÎŒg/L). As regards the pharmaceuticals removal, data of this work showed that the MWWTP Cusco (aerobic biologic process by synthetic trickling filters as secondary treatment) was more efficient than the MWWTP Lima (a preliminary treatment that combines grilles, sand trap, degreaser-aerated and sieved of 1.0 mm). However, many pharmaceuticals (around 50% of the compounds investigated) presented concentrations in treated wastewater similar or even higher than in influent wastewater. The environmental ecological risk of pharmaceuticals was assessed based on calculated Risk Quotient (RQ) in the treated wastewater and surface water from the concentration data found in the samples. According to our data, three antibiotics (clarithromycin, ciprofloxacin, clindamycin) and the analgesic acetaminophen posed high environmental risk (RQ â„ 1) on the aquatic environment. In the river, all antibiotics (except norfloxacin) as well as the analgesic-anti-inflammatory compounds acetaminophen, diclofenac posed a high environmental risk (RQ â„ 1). Based on data reported in this work for the first time in water samples from Peru, it can be deduced that the treatment processes applied in important cities from Peru are not enough efficient to remove pharmaceuticals in wastewater. As a consequence, severe environmental risks associated to the presence of pharmaceuticals in treated wastewater and surface water are expected; so complementary treatment processes should be implemented in the MWWTPs for a more efficient elimination of these compounds
Improvement of the carbocatalytic degradation of pharmaceuticals in water by the use of ultrasound waves
A carbonaceous material obtained from wood wastes (SW-Mn) was initially used for the removal of pharmaceuticals in water by a carbocatalytic system. The SW-Mn material adsorbed only 41% of the diclofenac (DCF) and 3% of the valsartan (VAL). Interestingly, SW-Mn activated peroxymonosulfate (PMS) and presented a significant increase in the removal rate of DCF, surpassing 90%, while VAL achieved a 24% removal rate at 20 min of treatment. The carbonaceous material was not effective in activating peroxydisulfate or hydrogen peroxide. Nevertheless, the addition of ultrasound waves at 40 kHz to the carbocatalytic system (SW-Mn +PMS) significantly enhanced VAL degradation, exhibiting a high synergy index (4.98). The routes of the degradation were determined using scavengers, and XPS and EPR analyses, evidencing the main action of singlet oxygen in both carbocatalytic and sonocarbocatalytic systems. It is important to note that radicals also participated in the sonocarbocatalytic process, albeit with a minor contribution. The reuse of SW-Mn was tested during various cycles, showing up to a 39.2% VAL degradation rate after the third consecutive reuse. Moreover, the sonocarbocatalytic system was applied to a sample of irrigation crop water spiked with VAL. The treatment induced a partial elimination of the pollutant due to some interfering effects of the matrix components
Comparative Assessment of Shrimp Hydrolyzates as Alternative Organic Fertilizers for Legumes
The global annual production of shrimp is nearly 4Â million metric tons generating almost half of this weight in waste. This study assessed the crop production of legumes fertilized with shrimp exoskeletons obtained by microwaves under greenhouse conditions. Plants were grown under the following fertilization regimes: (i) untreated shrimp waste, (ii) shrimp waste pellets, (iii) shrimp-based pellets having a hydrolysis degree of 42%, (iv) untreated cellulose pellets, (v) untreated soil, (vi) untreated cotton substrate, and (vii) two commercial fertilizers (CF1 and CF2). CF1 and CF2 showed the largest electric conductivity and ionic exchange capability, whereas the fertilizing pellets showed the lowest values. However, pH, densification and conductivity of soil were not affected by fertilization. Shrimp waste showed a high content of C, N, O, Ca and P mainly derived from chitin, proteins and minerals. All fertilizers showed typical type II isotherms, but the untreated soil and CF2 per se exhibited the largest water uptake. The soil microbiota increased during the growing cycle and then decreased as the reproductive phase started. Further, soil planted with Phaseolus vulgaris showed a larger microbial population than Pisum sativum. The best plant growth was achieved when treated with CF2, whereas the raw shrimp waste caused a beneficial plant growth and crop yield mainly in Phaseolus vulgaris
Methods involved in the treatment of four representative pharmaceuticals in hospital wastewater using sonochemical and biological processes
A primary pollution source by pharmaceuticals is hospital wastewater (HWW). Herein, the methods involved in the action of a biological system (BS, aerobic activated sludge) or a sonochemical
treatment (US, 375 kHz and 30.8 W), for degrading four relevant pharmaceuticals (azithromycin,
ciprofloxacin, paracetamol, and valsartan) in HWW, are shown. Before treatment of HWW, the
correct performance of BS was assessed using glucose as a reference substance, monitoring oxygen consumption, and organic carbon removal. Meanwhile, for US, a preliminary test using
ciprofloxacin in distilled water was carried out. The determination of risk quotients (RQ) and
theoretical analyses about reactive moieties on these target substances are also presented. For
both, the degradation of the pharmaceuticals and the calculation of RQ, analyses were performed
by LC-MS/MS. The BS action decreased the concentration of paracetamol and valsartan by âŒ96
and 86%, respectively. However, a poor action on azithromycin (2% removal) was found, whereas
ciprofloxacin concentration increased âŒ20%; leading to an RQ value of 1.61 (high risk) for the
pharmaceuticals mixture. The analyses using a biodegradation pathway predictor (EAWAG-BDD
methodology) revealed that the amide group on paracetamol and alkyl moieties on valsartan
could experience aerobic biotransformations. In turn, US action decreased the concentration of
the four pharmaceuticals (removals > 60% for azithromycin, ciprofloxacin, and paracetamol),
diminishing the environmental risk (RQ: 0.51 for the target pharmaceuticals mixture). Atomic
charge analyses (based on the electronegativity equalization method) were performed, showing
that the amino-sugar on azithromycin; piperazyl ring, and double bond close to the two carbonyls
on ciprofloxacin, acetamide group on paracetamol, and the alkyl moieties bonded to the amide
group of valsartan are the most susceptible moieties to attacks by sonogenerated radicals. The
LC-MS/MS analytical methodology, RQ calculations, and theoretical analyses allowed for determining the degrading performance of BS and US toward the target pollutants in HWW
Sonochemical degradation of antibiotics from representative classes-Considerations on structural effects, initial transformation products, antimicrobial activity and matrix
In this work, the sonochemical treatment (at 354 kHz and 88 W L-120 ) of six relevant antibiotics belonging to fluoroquinolones (ciprofloxacin and norfloxacin), penicillins (oxacillin and cloxacillin) and cephalosporins (cephalexin and cephadroxyl) classes
was evaluated. Firstly, the ability of the process to eliminate them was tested,
showing that sonodegradation of these antibiotics is strongly chemical structure25
dependent. Thus, correlations among initial degradation rate of pollutants (Rd),
solubility in water (Sw), water-octanol partition coefficient (Log P) and topological
polar surface area (TPSA) were tested. Rd exhibited a good correlation with Log P
(i.e., the hydrophobicity degree of antibiotics). The considered penicillins had the
fastest elimination and from the constitutional analysis using Lemke method was
clear that the functional groups arrangement on these antibiotics made them highly
hydrophobics. The penicillins were degraded closer at cavitation bubble than the
fluoroquinolones or cephalosporins. The investigation of degradation products
showed that sonogenerated hydroxyl radical primary attacked the ÎČ-lactam ring of
cloxacillin and cephalexin, whereas on norfloxacin induced a decarboxylation. On
the other hand, the evolution of antimicrobial activity was also followed. It was
evidenced the process capacity to remove antimicrobial activity from treated
solutions, which was associated to the transformations of functional groups on
antibiotics with important role for interaction with bacteria. Additionally, degradation
of antibiotics having the highest (the most hydrophobic, i.e., cloxacillin) and lowest
(the most hydrophilic, i.e., cephadroxyl) Rd, was performed in synthetic matrices
(hospital wastewater and seawater). Ultrasound degraded both antibiotics; for cloxacillin in such waters higher eliminations than in distilled water were observed
(probably due to a salting-out effect exerted by matrix components). Meanwhile, for
cephadroxyl a moderate inhibition of degradation in hospital wastewater and
seawater respect to distilled water was found, this was related to competition by
hydroxyl radical of the other substances in the matrices. These results show the
quite selectivity of high frequency ultrasound to eliminate antibiotics form different
classes even in complex matrices
Degradation of seventeen contaminants of emerging concern in municipal wastewater effluents by sonochemical advanced oxidation processes
The simultaneous degradation of seventeen emerging concern pollutants in effluent
from the municipal wastewater treatment plant (MWTP) of BogotĂĄ-Colombia was
studied using high frequency ultrasound (375 kHz). The considered compounds in the
effluent corresponded to pharmaceuticals (diclofenac, carbamazepine, venlafaxine,
ciprofloxacin, norfloxacin, valsartan, losartan, irbesartan, sulfamethoxazole,
clarithromycin, azithromycin, erythromycin, metronidazole, trimethoprim and the high potentiality of the sono-photo-Fenton/oxalic acid system for the pollutants
elimination in real-world wastewater matrices.
clindamycin); cocaine and its major metabolite benzoylecgonine. Due to limitation of the
MWTP for the pollutants elimination, ultrasound was applied to remove these
compounds. Interestingly, ultrasonic physical action led to releasing of ciprofloxacin,
norfloxacin, diclofenac and sulfamethoxazole from suspended solids, whereas the
chemical effects induced degradation of the rest of compounds. For the latter ones, an
interesting correlation between the sonodegradation and arithmetic multiplication
between hydrophobicity and concentration of pollutants was established. Afterwards,
the sonochemical process was complemented with ferrous ions (sono-Fenton), ferrous
ions plus light (sono-photo-Fenton) or ferrous ions plus light in presence of oxalic acid
(sono-photo-Fenton/oxalic acid). Additionally, to clarify fundamental aspects of the
different systems, individual treatments in distilled water of a model pollutant (valsartan)
were performed. The complemented processes significantly enhanced all compounds
degradation, following the order: sono-photo-Fenton/oxalic acid > sono-photo-Fenton ~
sono-Fenton > sonochemistry. The Fe2+ addition improved the pollutants elimination by
generation of more hydroxyl radicals in the solution bulk. Meanwhile, oxalic acid
avoided Fe3+ precipitation favoring the iron catalytic cycle. Thus, the work demonstrate
Degradation of hexacyanoferrate (III) ion by the coupling of the ultraviolet light and the activation of persulfate at basic pH
The ultraviolet light activation of persulfate (PS) under alkaline conditions was evaluated for treating hexacyanoferrate (III) ion ([Fe(CN)6]3-). The effect of the wavelength type (i.e., UVA and UVC), initial PS concentration (0.3, 0.6, and 0.9 g Lâ1), and pH value (11 and 13) on the degradation of 50 mg Lâ1 of [Fe(CN)6]3- were studied. Finally, the role of the main degrading agents (SO4âą-, O2âą-, or HOâą) involved in the degradation process was determined using scavengers and a degradation pathway for [Fe(CN)6]3- was proposed. Results show that [Fe(CN)6]3- can be decomposed by UVC light, while UVA is not effective neither in [Fe(CN)6]3- photolysis nor in the activation of PS. Alkaline activation alone at pH 13 can also not degrade the cyanocomplex. However, the combination of UVC with PS (0.3 g Lâ1) at pH 13 showed high efficiency in the elimination of [Fe(CN)6]3-, achieving 93.3% of removal after 125 min of treatment. The highest CN- release and Fe dissolved removal also occurs at pH 13 and 0.3 g Lâ1 PS. Further increases in initial PS concentrations may lead to an excess of radicals in solution, resulting in detrimental recombination reactions that affect the efficiency of the process. Quenching tests showed that the importance of radicals involved in the degradation of [Fe(CN)6]3- follows the order: HOâą > O2âą- >>> 1O2 or SO4âą-, and allowed to demonstrate that singlet oxygen could participate in the UVC photolysis of [Fe(CN)6]3-. All these results suggest the feasibility of this technology to treat this type of industrial wastewater efficiently
Effect of the presence of inorganic ions and operational parameters on free cyanide degradation by ultraviolet C activation of persulfate in synthetic mining wastewater
This work studied the influence of several parameters on free cyanide (CNâ) degradation (50 mg Lâ1) by the UVC-activated persulfate (PS) at alkaline conditions (UVC/PS). Firstly, photolysis and alkaline activation of PS were evaluated. Then, the effect of initial PS concentration (0.2, 0.4, and 0.6 g Lâ1) and dissolved oxygen in solution (absence/presence) were studied. Lastly, the influence of phosphate, carbonate, and nitrate presence at different concentrations (50, 150, 350, and 500 mg Lâ1) on CNâ elimination was tested. Additionally, the electric energy per order (EEO), a measure of the energy consumption in the process was determined, and a mechanistic view of CNâ degradation was proposed. The results show that photolysis and alkaline activation of PS degraded 8 and 11% of CNâ, respectively, whereas their combination presented a synergistic effect on CNâ pollutant elimination. While oxygen had a vital role in photolysis due to the formation of 1O2 to oxidize CNâ to CNOâ, HOâą and SO4âąâ were primarily responsible for CNâ degradation by UVC/PS. It was also found that cyanide removal followed a pseudo-first-order kinetics whose apparent reaction rate constant (k) increased from 0.0104 to 0.0297 minâ1 as the initial concentration of PS increased from 0.2 to 0.6 g Lâ1, indicating a strong dependency of the removal efficiency on the PS amount. Remarkably, cyanide degradation by the combined UVC/PS showed a high CNâ conversion and selectivity even in the presence of high concentrations of phosphate, carbonate, and nitrate ions (500 mg Lâ1), which resulted in CNâ removals higher than 80% after 60 min of degradation treatment. Furthermore, the EEO values were similar in the presence and absence of phosphate or carbonate; however, they decreased slightly with nitrate presence. All these results suggest the feasibility of the combined UVC/PS process for the elimination of cyanide such as that found in mining wastewater
Selecting the best AOP for isoxazolyl penicillins degradation as a function of water characteristics: Effects of pH, chemical nature of additives and pollutant concentration
To provide new insights toward the selection of the most suitable AOP for isoxazolyl penicillins elimination, the degradation of dicloxacillin, a isoxazolyl penicillin model, was studied using different advanced oxidation processes (AOPs): ultrasound (US), photo-Fenton (UV/H2O2/Fe2+) and TiO2 photo catalysis (UV/TiO2). Although all processes achieved total removal of the antibiotic and antimicrobial activity, and increased the biodegradability level of the solutions, significant differences concerning the mineralization extend, the pH of the solution, the pollutant concentration and the chemical nature of additives were found. UV/TiO2 reached almost complete mineralization; while 10% mineralization was obtained for UV/H2O2/Fe2+ and practically zero for US. Effect of initial pH, mineral natural water and the presence of organic (glucose, 2-propanol and oxalic acid) were then investigated. UV/H2O2/Fe2+ and US processes were improved in acidic media, while natural pH favored UV/TiO2 system. According to both the nature of the added organic compound and the process, inhibition, no effect or enhancement of the degradation rate was observed. The degradation in natural mineral water showed contrasting results according to the antibiotic concentration: US process was enhanced at low concentration of dicloxacillin followed by detrimental effects at high substrate concentrations. A contrary effect was observed during photo-Fenton, while UV/TiO2 was inhibited in all of cases. Finally, a schema illustrating the enhancement or inhibiting effects of water matrix is proposed as a tool for selecting the best process for isoxazolyl penicillins degradation. (C) 2016 Elsevier Ltd. All rights reserved
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