Ozonation and advanced oxidation technologies to remove endocrine disrupting chemicals (EDCs) and pharmaceuticals and personal care products (PPCPs) in water effluents

Removal of pharmaceuticals in microcosm constructed wetlands using Typha spp. and LECA

Microcosm constructed wetlands systems established with a matrix of light expanded clay aggregates (LECA) and planted with Typha spp. were used to evaluate their ability to remove pharmaceuticals ibuprofen, carbamazepine and clofibric acid from wastewaters. Seasonal variability of these systems' performances was also evaluated. Overall, removal efficiencies of 96%, 97% and 75% for ibuprofen, carbamazepine and clofibric acid, respectively, were achieved under summer conditions after a retention time of 7 days. In winter, a maximum loss of 26% in removal efficiency was observed for clofibric acid. Removal kinetics was characterized by a fast initial step (>50% removal within 6h) mainly due to adsorption on LECA but, on a larger timescale, plants also contributed significantly to the system's performance. Despite the fact that further tests using larger-scale systems are required, this study points to the possible application of these low-cost wastewater treatment systems for dealing with pharmaceuticals contaminated wastewater.

Ciprofloxacin in hospital effluent: degradation by ozone and photoprocesses

There are several papers in the literature that have recorded satisfactory results for the degradation of different pharmaceuticals in aqueous solutions by means of oxidation processes; however, only a few of them relied on real samples in carrying out their investigations. This study examines the results of the performance of photo-induced oxidation, heterogeneous photocatalysis, ozonation and peroxone in degrading the fluoroquinolone antimicrobial ciprofloxacin (CIP) in a hospital effluent. The real samples were collected from the treatment system of the University Hospital of Santa Maria (HUSM). Liquid chromatography with fluorescence detection (LC-FLD) was used to monitor the decrease of the CIP concentration. As expected, photo-induced oxidation was much slower than the other processes in bringing about total CIP degradation. Both heterogeneous photocatalysis and peroxone led to almost complete CIP degradation after 60 min treatment. Ozonation showed the best performance: total degradation after 30 min treatment. This was an unexpected result in view of the greater capacity of the other two processes to generate hydroxyl radicals. However, this finding supports a result in the literature that has tended to be overlooked. The by-products formed during the application of the processes were found to be very similar. Moreover, on the basis of the data obtained from the literature, there is some evidence to suggest that the by-products are derived from the oxidation of the piperazine group.

Comparison of six different sewage treatment processes--reduction of estrogenic substances and effects on gene expression in exposed male fish

Treated sewage effluents often contain a mixture of estrogenic compounds in low concentrations. The total combined activity of these, however, may be sufficiently high to affect the reproduction of aquatic vertebrates. The introduction of advanced treatment technologies has been suggested as a way to remove micro-contaminants, including estrogenic substances. In this study, one municipal influent was treated with six different processes in parallel on a semi-large scale in order to assess their potential to reduce substances that could contribute to estrogenic effects in male fish. The effluent from a conventional, activated sludge treatment line was compared to a similarly treated effluent with a final sand-filtering step. The addition of ozonation (15 g O(3)/m(3)), a moving bed biofilm reactor (MBBR) or both in combination was also evaluated. There was also a separate treatment line that was based on a membrane bioreactor. A small battery of hepatic estrogen-responsive genes was measured in the exposed fish using quantitative PCR. Concentrations of steroid estrogens and estrogenic phenols in the effluents were measured by GC-ECNI-MS. The ozonated effluents were the only tested effluents for which all measured biological effects in exposed fish were removed. Chemical data suggested that the MBBR technology was equally effective in removing the analyzed estrogens; however, elevated expression of estrogen-responsive genes suggested that some estrogenic substances were still present in the effluent. The membrane bioreactor removed most of the measured estrogens and it reduced the induction of the estrogen-responsive genes. However, fish exposed to this effluent had significantly enlarged livers. Given that the same influent was treated in parallel with a broad set of technologies and that the chemical analyses were combined with an in vivo assessment of estrogenic responses, this study provides valuable input into the assessment of advanced treatment processes for removing estrogenic substances.

Ozonation of pharmaceutical compounds: Rate constants and elimination in various water matrices

The ozonation of four pharmaceuticals (metoprolol, naproxen, amoxicillin, and phenacetin) in ultra-pure (UP) water was studied in the pH range between 2.5 and 9. The experiments allowed the determination of the apparent rate constants for the reactions between ozone and the selected compounds. The values obtained varied depending on the pH, and ranged between 239 and 1.27x10(4)M(-1) s(-1) for metoprolol; 2.62x10(4) and 2.97x10(5)M(-1)s(-1) for naproxen; 2.31x10(3) and 1.21x10(7)M(-1)s(-1) for amoxicillin; and 215 and 1.57x10(3)M(-1)s(-1) for phenacetin. Due to the acidic nature of these substances, the degree of dissociation of each pharmaceutical was determined at every pH of work, and the specific rate constants of the neutral and ionic species formed were evaluated. Additionally, the simultaneous ozonation of the pharmaceuticals in different water matrices was carried out by considering a groundwater, a surface water from a public reservoir, and three secondary effluents from municipal wastewater treatment plants. The influence of the operating conditions (initial ozone dose, nature of pharmaceuticals and type of water) on the pharmaceuticals elimination efficiency was established, and a kinetic model was proposed for the evaluation of the partial contribution to the global oxidation of both, the direct ozonation reaction and the radical pathway.

Degradation of sulfamethoxazole in water by solar photo-Fenton. Chemical and toxicological evaluation

In this work, the photocatalytic degradation of the antibiotic sulfamethoxazole (SMX) by solar photo-Fenton at pilot plant scale was evaluated in distilled water (DW) and in seawater (SW). Degradation and mineralization of SMX were strongly hindered in SW compared to DW. The influence of H(2)O(2) and iron concentration on the efficiency of the photocatalytic process was evaluated. An increase in iron concentration from 2.6 to 10.4 mg L(-1) showed only a slight improvement in SMX degradation and mineralization. However, an increase in H(2)O(2) concentration up to 120 mg L(-1) during photo-Fenton in DW decreased SMX solution toxicity from 85% to 20%, according to results of Daphnia magna bioassays. The same behaviour was not observed after photo-Fenton treatment in SW. Despite 45% mineralization in SW, toxicity increased from 16% to 86% as shown by Vibrio fischeri bioassays, which suggests that the intermediates generated in SW are different from those in DW. A SMX degradation pathway during the photo-Fenton treatment in DW is proposed.

Effects of ozone pre-treatment on diclofenac: intermediates, biodegradability and toxicity assessment

Diclofenac (DCF), a common analgesic, anti-arthritic and anti-rheumatic drug, is one of the most frequently detected compounds in water. This study deals with the degradation of diclofenac in aqueous solution by ozonation. Biodegradability (BOD(5)/COD ratio and Zahn-Wellens test), acute ecotoxicity and inhibition of activated sludge activity were determined in ozonated and non-ozonated samples. Liquid chromatography coupled with time-of-flight mass spectrometry (LC/TOF-MS) was used to identify the intermediates formed in 1 h of ozonation. Eighteen intermediates were identified by these techniques and a tentative degradation pathway for DCF ozonation is proposed. Experimental results show that ozone is efficient at removing DCF: >99% removal (starting from an initial concentration of 0.68 mmol L(-1)) was achieved after 30 min of ozonation (corresponding to an absorbed ozone dose of 0.22 g L(-1), which is 4.58 mmol L(-1)). However, only 24% of the substrate was mineralized after 1 h of ozonation. The biodegradability, respiration inhibition in activated sludge and acute toxicity tests demonstrate that ozonation promotes a more biocompatible effluent of waters containing DCF.

Antibiotic removal from water: elimination of amoxicillin and ampicillin by microscale and nanoscale iron particles

Zerovalent iron powder (ZVI or Fe(0)) and nanoparticulate ZVI (nZVI or nFe(0)) are proposed as cost-effective materials for the removal of aqueous antibiotics. Results showed complete removal of Amoxicillin (AMX) and Ampicillin (AMP) upon contact with Fe(0) and nFe(0). Antibiotics removal was attributed to three different mechanisms: (i) a rapid rupture of the beta-lactam ring (reduction), (ii) an adsorption of AMX and AMP onto iron corrosion products and (iii) sequestration of AMX and AMP in the matrix of precipitating iron hydroxides (co-precipitation with iron corrosion products). Kinetic studies demonstrated that AMP and AMX (20 mg L(-1)) undergo first-order decay with half-lives of about 60.3+/-3.1 and 43.5+/-2.1 min respectively after contact with ZVI under oxic conditions. In contrast, reactions under anoxic conditions demonstrated better degradation with t(1/2) of about 11.5+/-0.6 and 11.2+/-0.6 min for AMP and AMX respectively. NaCl additions accelerated Fe(0) consumption, shortening the service life of Fe(0) treatment systems.

Nonylphenol, octylphenol, and bisphenol-A in the aquatic environment: a review on occurrence, fate, and treatment

This paper reviews the current knowledge on the occurrence, biodegradation, and photooxidation of nonylphenol (NP), octylphenol (OP), and bisphenol-A (BPA) in aquatic environment. Generally, the concentrations determined were 0.006-32.8, < 0.001-1.44, and 0.0005-4.0 mu g L(-1) for NP, OP, and BPA respectively in river waters worldwide. Anthropogenic activities that can lead to run-off and storm water discharge may contribute to such concentrations in rivers. Pathways for biodegradation of NP and BPA appear to be similar. The influence of ferric ions, oxalate, hydrogen peroxide, and dissolved organic matter (DOM) on the photooxidation of NP and BPA in natural water is presented. Several techniques including nanofiltration, adsorption, sonochemical, photocatalytic, chlorination, ozonation, and ferrate(VI) oxidation for removals of NP, OP, and BPA are also reviewed.

Degradation of the endocrine disrupting chemicals (EDCs) carbamazepine, clofibric acid, and iopromide by corona discharge over water

Common wastewater treatment plants often do not eliminate endocrine disrupting chemicals (EDCs). Aqueous solutions of three EDCs were treated with an enhanced corona discharge technology. The three EDCs were clofibric acid, a blood lipid regulator, carbamazepine, an antiepileptic drug, and iopromide, a contrast media. To simulate real conditions, EDC solutions containing landfill leachate were also used. In our setup, two barrier electrodes provided an atmospheric pressure corona discharge over a thin water film, in which the counter-electrode was submerged. Clofibric acid, carbamazepine, and iopromide were effectively removed from a single solution. After a treatment of 15min, there were no traces of iopromide estrogen activity either as a single substance or as degradation products when using an E-Screen Assay. Continuous treatment was compared with pulsed treatment using carbamazepine solutions mixed with pretreated landfill leachate. Best degradation results were achieved with a 500 W continuous duty cycle treatment. Counter-electrodes from materials such as boron doped diamond (BDD), titanium iridium oxide, and iron were investigated for their influences on the process effectivity. Significant improvements were achieved by using an enclosed reactor, BDD electrodes, and circulating only a fresh air or argon/air mixture as cooling gas through the barrier electrodes.

Oxidative transformations of environmental pharmaceuticals by Cl₂, ClO₂, O₃, and Fe(VI): kinetics assessment

Several pharmaceuticals have been detected globally in surface water and drinking water, which indicate their insufficient removal from water and wastewater using conventional treatment methods. This paper reviews the kinetics of oxidative transformations of pharmaceuticals (antibiotics, lipid regulators, antipyretics, anticonvulsants, and beta-blockers) by Cl(2), ClO(2), O(3), and ferrate(VI) (Fe(VI)O(4)(2-),Fe(VI)) under treatment conditions. In the chlorination of sulfonamide antibiotics, HOCl is the major reactive Cl(2) species whereas in the oxidation by Fe(VI), HFeO(4)(-) is the dominant reactive species. Both oxidation processes can oxidize sulfonamides in seconds at a neutral pH (t(1/2)≤ 220 s; 1 mg L(-1) HOCl or K(2)FeO(4)). The reactivity of O(3) with pharmaceuticals is generally higher than that of HOCl (k(app,pH 7) (O(3))=1-10(7)M(-1)s(-1); k(app,pH 7) (HOCl)=10(-2)-10(5)M(-1)s(-1)). Ozone selectively oxidizes pharmaceuticals and reacts mainly with activated aromatic systems and non-protonated amines. Oxidative transformation of most pharmaceuticals by O(3) occurs in seconds (t(1/2)≤ 100 s; 1 mg L(-1) O(3)) while half-lives for oxidations by HOCl differ by at least two orders of magnitude. Ozone appears to be efficient in oxidizing pharmaceuticals in aquatic environments. The limited work on Fe(VI) shows that it can also potentially transform pharmaceuticals in treatment processes.

Ultrasonic treatment of water contaminated with ibuprofen

The application of ultrasound (US) waves for remediation of wastewater is an area of increasing interest and promising results. The aim of this paper is to evaluate the influence of several parameters of the US process on the degradation of ibuprofen (IBP), a widely used non-steroidal anti-inflammatory recalcitrant drug found in water. Applied US power, dissolved gas, pH and initial concentration of IBP were the parameters investigated under sonication (300 kHz). Ultrasound increased the degradation of IBP from 30 to 98% in 30 min. Initial rate of IBP degradation was evaluated in the range of 1.35 and 6.1 micromolL(-1)min(-1) for initial concentrations of 2 to 21 mgL(-1) or 9.7 micromolL(-1) to 101 micromolL(-1), respectively. Under air and oxygen the degradation rate of IBP was 4 micromolL(-1)min(-1) being higher than that when argon was used. The most favorable degradation pH was acidic media. Complete removal of IBP was achieved but some dissolved organic carbon (DOC) remained in solution showing that long-lived intermediates were recalcitrant to the US irradiation. However, chemical and biological oxygen demands (COD and BOD(5)) indicated that the process oxidize the ibuprofen compound to biodegradable substances removable in a subsequent biological step.