Ozonation as an advanced oxidant in treatment of bamboo industry wastewater

The present study employed ozonation process to treat the bamboo industry wastewater (BIWW). The impact of ozone dosage and initial organic concentration on color, COD and TOC removal rates were studied along with characterization of the major organics in raw and treated wastewater. The results suggested the ozone dosage of 3.15 g h⁻¹ (concentration 52.5 mg L⁻¹) was suitable for the treatment. After 25 min ozonation of 1 L raw wastewater, the color, COD and TOC removal efficiencies were 95%, 56% and 40%, respectively, with an influent COD concentration of 835 mg L⁻¹. The ratio of kg O₃ kg⁻¹ COD at 3.15 g h⁻¹ was 2.8 (<3), revealing that ozonation was a cost effective process for tertiary treatment of BIWW. Longer oxidization time was required to achieve similar results for raw wastewater with higher COD concentration. The chromatogram from gel permeation chromatography revealed that ozonation resulted in the breakdown of high molecular weight compounds into lower molecular weight components but could not completely mineralize the organic matter. The majority of these compounds were identified in both raw and ozonated samples via GC-MS analysis. In addition to ester derivatives as the main intermediates of ozonation, 1-chloroctadecane, methyl stearate, benzophenone and α-cyperone were identified as the by-products of ozonation.     

Removal of tetrabromobisphenol A by conventional activated sludge, submerged membrane and membrane aerated biofilm reactors

The goal of this study was to compare removal efficiencies of tetrabromobisphenol A (TBBPA) using typical wastewater treatment technologies, and to identify the most significant mechanisms of removal. Two types of municipal wastewater reactors were studied: a full-scale conventional activated sludge (CAS) reactor with tertiary treatment; and three pilot-scale membrane bioreactors (MBRs) having different sludge retention times (SRTs). All four reactors were fed the same influent. A third reactor type, a membrane aerated biofilm reactor (MABR) was fed tap water, ammonia, and TBBPA. TBBPA in municipal influent ranged from 1 to 41 ng L⁻¹ (n = 10). The CAS effluent had an average TBBPA concentration of 0.7 ± 1.3 ng L⁻¹ (n = 3). Effluent concentrations from the MBRs were an average of 6 ± 6 ng L⁻¹ TBBPA (n = 26). Significant TBBPA removal was observed in the MABR throughout the 5 week of study (p ? 0.05). Removal of TBBPA from wastewater treatment was found to be due to a combination of adsorption and biological degradation. Based on experimental results, nitrification is likely a key process therein. No significant relationship between removal of TBBPA and SRT was identified (p ? 0.05).     

SMX degradation by ozonation and UV radiation: a kinetic study

The rate constants of sulfamethoxazole (SMX) degradation by ozonation and UV₂₅₄ radiation were investigated under various parameters including influent ozone gas concentration, initial SMX concentration, UV light intensity, ionic strength, water quality in terms of varying anions (bicarbonate, sulfate and nitrate), humic acid (HA) and pH. The results indicated that the removal of SMX by ozonation and UV₂₅₄ radiation fitted well to a pseudo first-order kinetic model and the rate constants were in the range of (0.9-9.8) × 10⁻³ and (1.7-18.9) × 10⁻³ s⁻¹, respectively. The second-order rate constants of SMX with ozone (k_O3), under varying operational parameters, were also determined and varied in the range of (0.60-3.38) ± 0.13 × 10⁵ M⁻¹ s⁻¹. In addition, SMX degradation through UV pretreatment followed by ozonation in the presence of HA was proved to be an effective method which can remove SMX with a low ozone dose. The results suggested that ozonation of SMX was more affected by concentration of influent ozone gas, alkalinity, and HA, while incident UV light intensity, pH, and HA were the dominant factors influencing UV degradation of SMX.     

Ozonation effects on emerging micropollutants and effluent organic matter in wastewater: characterization using changes of three-dimensional HP-SEC and EEM fluorescence data

The degradation of effluent organic matter (EfOM) in a municipal wastewater treated by ozonation was characterized using the methods of high-performance size-exclusion chromatography (HP-SEC) and excitation/emission matrix (EEM) fluorescence combined with parallel factor analysis (PARAFAC). The removal of 40 diverse trace-level contaminants of emerging concern (CEC) present in the wastewater was determined as well. Ozonation caused a rapid decrease of the absorbance and fluorescence of the wastewater, which was associated primarily with the oxidation of high and low apparent molecular weight (AMW) EfOM fractions. PARAFAC analysis also showed that components C1 and C2 decreased prominently in these conditions. The EfOM fraction of intermediate molecular weight ascribable to a terrestrial humic-like component (C3) tended to be less reactive toward ozone. Relative changes of EEM fluorescence were quantified using F _max values of PARAFAC-identified components (∆F/F ⁰ _max). Unambiguous relationships between ∆F/F ⁰ _max values and the extent of the degradation of the examined CECs (∆C/C₀) were established. This allowed correlating main parameters of the ∆C/C₀ vs. ∆F/F ⁰ _max relationships with the rates of oxidation of these CECs. The results demonstrate the potential of online measurements of EEM fluorescence for quantitating effects of ozonation on EfOM and micropollutants in wastewater effluents.

     

Spectroscopic study of the degradation of antibiotics and the generation of representative EfOM oxidation products in ozonated wastewater

This study examined effects of ozonation on thirteen fluoroquinolone, macrolide and lincosamide antibiotics present in municipal wastewater. Transformations of effluent organic matter (EfOM) caused by ozonation were characterized using absorbance/fluorescence spectroscopy and high performance size exclusion chromatography (HPSEC). Concentrations of aldehydes and carboxylic acids generated via the oxidation of EfOM were also determined. The absorbance and fluorescence of ozonated wastewater decreased with increasing ozone dose or treatment time. HPSEC data showed that these phenomena corresponded to the oxidation of all EfOM fractions, with some preference towards the degradation of the EfOM molecules with high apparent molecular weight. The removal of antibiotics and production of aldehydes and carboxylic acids were strongly correlated with the changes in both EfOM absorbance and fluorescence. Applications of a model describing the concurrent degradation of trace level contaminants and relative changes of EfOM emission allowed achieving a good fitting between the experimental and modeled ΔC/C₀ vs. ΔA/A₀ and ΔC/C₀ vs. ΔF/F₀ data.     

The functional and physiological status of Gammarus fossarum (Crustacea; Amphipoda) exposed to secondary treated wastewater

Climate change scenarios predict lower flow rates during summer that may lead to higher proportions of wastewater in small and medium sized streams. Moreover, micropollutants (e.g. pharmaceuticals and other contaminants) continuously enter aquatic environments via treated wastewater. However, there is a paucity of knowledge, whether extended exposure to secondary treated wastewater disrupts important ecosystem functions, e.g. leaf breakdown. Therefore, the amphipod shredder Gammarus fossarum was exposed to natural stream water (n = 34) and secondary treated wastewater (n = 32) for four weeks in a semi-static test system under laboratory conditions. G. fossarum exposed to wastewater showed significant reductions in feeding rate (25%), absolute consumption (35%), food assimilation (50%), dry weight (18%) and lipid content (22%). Thus, high proportions of wastewater in the stream flow may affect both the breakdown rates of leaf material and thus the availability of energy for the aquatic food web as well as the energy budget of G. fossarum.     

Bioaccumulation of the pharmaceutical 17α-ethinylestradiol in shorthead redhorse suckers (Moxostoma macrolepidotum) from the St. Clair River, Canada

17α-ethynylestradiol (EE2), a synthetic estrogen prescribed as a contraceptive, was measured in Shorthead Redhorse Suckers (ShRHSs) (Moxostoma macrolepidotum) collected near a wastewater treatment plant (WWTP) in the St. Clair River (Ontario, Canada). We detected EE2 in 50% of the fish samples caught near the WWTP (Stag Island), which averaged 1.6 ± 0.6 ng/g (wet weight) in males and 1.43 ± 0.96 ng/g in females. No EE2 was detected in the samples from the reference site (Port Lambton) which was 26 km further downstream of the Stag Island site. Only males from Stag Island had VTG induction, suggesting the Corunna WWTP effluent as a likely source of environmental estrogen. EE2 concentrations were correlated with total body lipid content (R² = 0.512, p < 0.01, n = 10). Lipid normalized EE2 concentrations were correlated with δ¹⁵N (R² = 0.436, p < 0.05, n = 10), suggesting higher EE2 exposures in carnivores. Our data support the hypothesis of EE2 bioaccumulation in wild fish.     

Whole effluent toxicity assessment at a wastewater treatment plant upgraded with a full-scale post-ozonation using aquatic key species

Ozonation as final wastewater (WW) polishing step, following conventional activated sludge treatment is increasingly implemented in sewage treatment for contaminant degradation to prevent surface water pollution. While the oxidative degradation of chemicals has been extensively investigated, the in vivo toxicological characteristics of ozonated whole effluents are rarely a matter of research.In the present study, whole effluents were toxicologically evaluated with an in vivo test battery before and after full-scale ozonation and subsequent sand filtration on site at a treatment plant. One aquatic plant (duckweed, Lemna minor) and five invertebrate species of different systematic groups (Lumbriculus variegatus, Chironomus riparius, Potamopyrgus antipodarum, Daphnia magna) were exposed to the effluents in a flow-through-designed test system with a test duration of 7-28 d.None of the considered toxicity endpoints correlated with the pollutant elimination. A tendency towards an increased toxicity after ozonation was apparent in three of the test systems showing [statistically] significant adverse effects in the L. variegatus toxicity test (decrease in reproduction and biomass). After sand filtration, adverse effects were reduced to a similar level like after conventional treatment. Solely the Daphnia reproduction test revealed beneficial effects after ozonation in combination with sand filtration.Results of the test battery indicate the formation of adverse oxidation products during WW ozonation. L. variegatus appeared to be the most sensitive of the five test species. Sand filtration effectively removes or detoxifies toxic oxidation products, as toxic effects were subsequently reduced to the level after conventional treatment.     

Ecotoxicity evaluation of selected sulfonamides

Sulfonamides (SAs) are a group of antibiotic drugs widely used in veterinary medicine. The contamination of the environment by these pharmaceuticals has raised concern in recent years. However, knowledge of their (eco)toxicity is still very basic and is restricted to just a few of these substances. Even though their toxicological analysis has been thoroughly performed and ecotoxicological data are available in the literature, a systematic analysis of their ecotoxicological potential has yet to be carried out. To fill this gap, 12 different SAs were chosen for detailed analysis with the focus on different bacteria as well as non-target organisms (algae and plants). A flexible (eco)toxicological test battery was used, including enzymes (acetylcholinesterase and glutathione reductase), luminescent marine bacteria (Vibrio fischeri), soil bacteria (Arthrobacter globiformis), limnic unicellular green algae (Scenedesmus vacuolatus) and duckweed (Lemna minor), in order to take into account both the aquatic and terrestrial compartments of the environment, as well as different trophic levels. It was found that SAs are not only toxic towards green algae (EC₅₀ = 1.54-32.25 mg L⁻¹) but have even stronger adverse effect on duckweed (EC₅₀ = 0.02-4.89 mg L⁻¹) than atrazine - herbicide (EC₅₀ = 2.59 mg L⁻¹).     

Fate of bulk and trace organics during a simulated aquifer recharge and recovery (ARR)-ozone hybrid process

The attenuation of bulk organic matter and trace organic contaminants (TOrCs) was evaluated for various aquifer recharge and recovery (ARR)-ozone (O₃) hybrid treatment process combinations using soil-batch reactor and bench-scale ozonation experiments as a proof of concept prior to pilot and/or field studies. In water reclamation and especially potable reuse, refractory bulk organic matter and TOrCs are of potential health concern in recycled waters. In this study, the role of biotransformation of bulk organic matter and TOrCs was investigated considering different simulated treatment combinations, including soil passage (ARR) alone, ARR after ozonation (O₃-ARR), and ARR prior to ozonation (ARR-O₃). During oxic (aerobic) ARR simulations, soluble microbial-like substances (e.g., higher molecular weight polysaccharides and proteins) were easily removed while (lower molecular weight) humic substances and aromatic organic matter were not efficiently removed. During ARR-ozone treatment simulations, removals of bulk organic matter and TOrCs were rapid and effective compared to ARR alone. A higher reduction of effluent-derived organic matter, including aromatic organic matter and humic substances, was observed in the ARR-O₃ hybrid followed by the O₃-ARR hybrid. An enhanced attenuation of recalcitrant TOrCs was observed while increasing the ozone dose slightly (O₃: DOC = 1). TOrC removal efficiency also increased during the post-ozone treatment combination (i.e., ARR-O₃). In addition, the carcinogenic wastewater disinfection byproduct N-nitrosodimethylamine (NDMA) was eliminated below the method reporting limit (<5 ng L⁻¹) both during ARR treatment alone and the ARR-ozone hybrid.     

Identification of two new cytochrome P450 genes and RNA interference to evaluate their roles in detoxification of commonly used insecticides in Locusta migratoria

Composite samples of Australian farmed Yellowtail Kingfish (Seriola lalandi) (YTKF) (n = 27), Mulloway (Argyrosomus hololepidotus) (n = 6) and manufactured feed (n = 5) were analysed to benchmark levels of a broad range of residues and contaminants of potential public health and trade significance. A subset of these samples [YTKF (n = 5), Mulloway (n = 2) and feed (n = 5)] was analysed for dioxins and polychlorinated biphenyls (PCBs). The mean concentration of dioxins in YTKF was 0.6 pg TEQ g⁻¹ (range 0.22-0.8) and in Mulloway was 0.16 pg TEQ g⁻¹ (range 0.16-0.16). The mean concentration of dioxins and dioxin-like PCBs in YTKF was 2.6 pg TEQ g⁻¹ (range 1.4-3.5), while Mulloway had a mean concentration of 0.67 pg TEQ g⁻¹ (range 0.57-0.76). The mean concentration of PCBs in YTKF was 21 μg kg⁻¹ (range 8.6-29) and in Mulloway was 5.4 μg kg⁻¹ (mean 4.7-6). The mean concentration of dioxin-like PCBs in YTKF was 2.1 pg TEQ g⁻¹ (range 1.2-2.8) and in Mulloway was 0.51 pg TEQ g⁻¹ (range 0.41-0.61). The mean mercury concentration in YTKF was 0.03 mg kg⁻¹ (range 0.02-0.05) and in Mulloway it was 0.02 mg kg⁻¹ (range 0.02-0.04). There were no detectable levels of any pesticide or antimicrobial compounds in any sample of YTKF or Mulloway. Attention is drawn to technical differences in port of entry testing programs such as sampling strategies, portion tested, laboratory methodology, residue definitions and reporting conventions that exporters’ products may be subject to. All residues and contaminants were either undetectable or present at very low levels when judged against Australian, Japanese and European Union regulatory standards (where set).     

Linear and branched perfluorooctane sulfonate (PFOS) isomer patterns differ among several tissues and blood of polar bears

Perfluorooctane sulfonate (PFOS) is a globally distributed persistent organic pollutant that has been found to bioaccumulate and biomagnify in aquatic food webs. Although principally in its linear isomeric configuration, 21–35% of the PFOS manufactured via electrochemical fluorination is produced as a branched structural isomer. PFOS isomer patterns were investigated in multiple tissues of polar bears (Ursus maritimus) from East Greenland. The liver (n = 9), blood (n = 19), brain (n = 16), muscle (n = 5), and adipose (n = 5) were analyzed for linear PFOS (n-PFOS), as well as multiple mono- and di-trifluoromethyl-substituted branched isomers. n-PFOS accounted for 93.0 ± 0.5% of Σ-PFOS isomer concentrations in the liver, whereas the proportion was significantly lower (p < 0.05) in the blood (85.4 ± 0.5%). Branched isomers were quantifiable in the liver and blood, but not in the brain, muscle, or adipose. In both the liver and blood, 6-perfluoromethylheptane sulfonate (P6MHpS) was the dominant branched isomer (2.61 ± 0.10%, and 3.26 ± 0.13% of Σ-PFOS concentrations, respectively). No di-trifluoromethyl-substituted isomers were detectable in any of the tissues analyzed. These tissue-specific isomer patterns suggest isomer-specific pharmacokinetics, perhaps due to differences in protein affinities, and thus differences in protein interactions, as well transport, absorption, and/or metabolism in the body.     

Micropollutant removal during biological wastewater treatment and a subsequent ozonation step

The design criteria for wastewater treatment plants (WWTP) and the sludge retention time, respectively, have a significant impact on micropollutant removal. The upgrade of an Austrian municipal WWTP to nitrogen removal (best available technology, BAT) resulted in increased elimination of most of the analyzed micropollutants. Substances, such as bisphenol-A, 17α-ethinylestradiol and the antibiotics erythromycin and roxithromycin were only removed after the upgrade of the WWTP. Nevertheless, the BAT was not sufficient to completely eliminate these compounds. Thus, a pilot scale ozonation plant was installed for additional treatment of the effluent. The application of 0.6 g O₃ g DOC⁻¹ increased the removal of most of the micropollutants, especially for compounds that were not degraded in the previous biological process, as for example carbamazepine and diclofenac. These results indicated that the ozonation of WWTP effluent is a promising technology to further decrease emissions of micropollutants from the treatment process.     

Long-term effects of lead poisoning on bone mineralization in vultures exposed to ammunition sources

Long-lived species are particularly susceptible to bioaccumulation of lead in bone tissues. In this paper we gain insights into the sublethal effects of lead contamination on Egyptian vultures (Neophron percnopterus). Our approach was done on the comparison of two populations (Canary Islands and Iberian Peninsula) differing in exposures to the ingestion of lead ammunition. Blood lead levels were higher in the island population (Canary Islands range: 5.10-1780 μg L⁻¹n = 137; Iberian Peninsula range: 5.60-217.30 μg L⁻¹n = 32) showing clear seasonal trends, peaking during the hunting season. Moreover, males were more susceptible to lead accumulation than females. Bone lead concentration increased with age, reflecting a bioaccumulation effect. The bone composition was significatively altered by this contaminant: the mineralization degree decreased as lead concentration levels increased. These results demonstrate the existence of long-term effects of lead poisoning, which may be of importance in the declines of threatened populations of long-lived species exposed to this contaminant.     

Spatial distribution of ciguateric fish in the Republic of Kiribati

Ciguatera is food poisoning caused by human consumption of reef fish contaminated with ciguatoxins (CTXs). The expanding international trade of tropical fish species from ciguatera-endemic regions has resulted in increased global incidence of ciguatera, and more than 50 000 people are estimated to suffer from ciguatera each year worldwide. The Republic of Kiribati is located in the Pacific Ocean; two of its islands, Marakei and Tarawa, have been suggested as high-risk areas for ciguatera. The toxicities of coral reef fish collected from these islands, including herbivorous, omnivorous and carnivorous fish (24% [n = 41], 8% [n = 13] and 68% [n = 117], respectively), were analyzed using the mouse neuroblastoma assay (MNA) after CTX extraction. The MNA results indicated that 156 fish specimens, or 91% of the fish samples, were ciguatoxic (CTX levels >0.01 ng g⁻¹). Groupers and moray eels were generally more toxic by an order of magnitude than other fish species. All of the collected individuals of eight species (n = 3-19) were toxic. Toxicity varied within species and among locations by up to 10 000-fold. Cephalapholis argus and Gymnothorax spp. collected from Tarawa Island were significantly less toxic than those from Marakei Island, although all individuals were toxic based on the 0.01 ng g⁻¹ threshold. CTX concentrations in the livers of individuals of two moray eel species (Gymnothorax spp., n = 6) were nine times greater than those in muscle, and toxicity in liver and muscle showed a strong positive correlation with body weight. The present study provides quantitative information on the ciguatoxicity and distribution of toxicity in fish for use in fisheries management and public health.     

Photolytic degradation of decabromodiphenyl ethane (DBDPE)

The photolytic degradation of decabromodiphenyl ethane (DBDPE), an alternative flame retardant to decabromodiphenyl ether, was investigated in a variety of matrixes (n-hexane, tetrahydrofuran, methanol/water, humic acid/water, and silica gel) by irradiation under ultraviolet light and in n-hexane under natural light. Photolytic degradation of DBDPE occurs in all the matrixes investigated within the irradiation period (<320 min). The degradation experiments showed varied reaction rates, dependent on the matrixes, with increasing half-lives (t_1/2) in the order of tetrahydrofuran (t_1/2 = 6.0 min) > n-hexane (t_1/2 = 16.6 min) > humic acid/water (30 < t_1/2 < 60) > silica gel (t_1/2 = 75.9 min) > methanol/water (t_1/2 > 240 min). The reaction in tetrahydrofuran, n-hexane, and silica gel matrixes can be described by the pseudo first order kinetics. Nevertheless, the matrixes have little effect on the degradation product distributions of DBDPE. A numbers of debrominated intermediates were identified. The degradation involves the initial formation of nona-BDPEs and the subsequent decomposition of these congeners to lower brominated congeners (octa- and hepta-BDPEs) within the irradiation time. To our knowledge, the present work is the first attempt to investigate the photolytic degradation kinetics and the identification of intermediates, as well as the degradation mechanism, during the degradation of DBDPE. Further research is needed to understand the photolytic degradation pattern of DBDPE in the natural environment.     

Application of ozone for the removal of bisphenol A from water and wastewater – A review

The extensive use of Bisphenol A (BPA) in the plastics industry has led to increasing reports of its presence in the aquatic environment, with concentrations of ng L^?1 to μg L^?1. Various advanced oxidation processes, including ozonation, have been shown to effectively degrade BPA. This paper reviews the current advancements in using ozone to remove BPA from water and wastewater.Most of the published work on the oxidation of BPA by ozone has focused on the efficiency of BPA removal in terms of the disappearance of BPA, and the effect of various operational parameters such as ozone feed rate, contact time and pH; some information is available on the estrogenic activity of the treated water. Due to increasing operational reliability and cost effectiveness, there is great potential for industrial scale application of ozone for the treatment of BPA. However, there is a significant lack of information on the formation of oxidation by-products and their toxicities, particularly in more complex matrices such as wastewater, and further investigation is needed for a better understanding of the environmental fate of BPA.     

Fate of citalopram during water treatment with O3, ClO2, UV and Fenton oxidation

In the present study we investigate the fate of citalopram (CIT) at neutral pH using advanced water treatment technologies that include O₃, ClO₂ oxidation, UV irradiation and Fenton oxidation. The ozonation resulted in 80% reduction after 30 min treatment. Oxidation with ClO₂ removed >90% CIT at a dosage of 0.1 mg L⁻¹. During UV irradiation 85% reduction was achieved after 5 min, while Fenton with addition of 14 mg L⁻¹ (Fe²⁺) resulted in 90% reduction of CIT. During these treatment experiments transformation products (TPs) were formed from CIT, where five compounds were identified by using high resolution and tandem mass spectrometry. Among these desmethyl-citalopram and citalopram N-oxide have been previously identified as human metabolites, while three are novel and published here for the first time. The three TPs are a hydroxylated dimethylamino-side chain derivative, a butyrolactone derivative and a defluorinated derivative of CIT.