Advanced Oxidation Processes for the Elimination of Drugs Resisting Biological Membrane Treatment

The recalcitrant pharmaceutical compounds carbamazepine, clofibric acid, diazepam, and diclofenac were monitored in municipal wastewater by ESI-LC-MS and -MS-MS in positive and negative mode. Although biological treatment by conventional and membrane bioreactor failed, the advanced oxidation methods using ozone (O₃), O₃/UV or hydrogen peroxide in combination with UV (H₂O₂/UV), successfully achieved their complete elimination. Target compounds could be confirmed as permanently present pollutants in Aachen-Soers wastewater in concentrations between 0.006 and 1.9 μg L^?1 prior to AOP treatment resulting in a complete elimination.     

The Return of Ozone and the Hydroxyl Radical to Wastewater Disinfection

The City of Phoenix, Arizona is investigating various disinfection technologies for its 91st Avenue wastewater treatment facility: (1) ultraviolet light (UV), (2) ozone, (3) UV/hydrogen peroxide, (4) ozone/hydrogen peroxide, (5) and UV/ozone. In addition to providing disinfection, the City would like to consider the removal of endocrine disrupting chemicals (EDCs) and personal and pharmaceutical care products (PPCPs) in the treatment technology evaluation. To identify the most economical disinfection system, the evaluation included bench-scale testing of the technologies considered and a year-long water quality monitoring study. This paper presents the results of the bench-scale analyses and estimated capital and O&M costs.     

Diclofenac removal from water by ozone and photolytic TiO2 catalysed processes

BACKGROUND: The aim of this work was to establish the efficiency of single ozonation at different pH levels (5, 7 and 9) and with different TiO₂ photolytic oxidizing systems (O₂/UV‐A/TiO₂, O₃/UV‐A/TiO₂ or UV‐A/TiO₂) for diclofenac removal from water, with especial emphasis on mineralization of the organic matter. RESULTS: In the case of single ozonation processes, results show fast and practically complete elimination of diclofenac, with little differences in removal rates that depend on pH and buffering conditions. In contrast, total organic carbon (TOC) removal rates are slow and mineralization degree reaches 50% at best. As far as photocatalytic processes are concerned, diclofenac is completely removed from the aqueous solutions at high rates. However, unlike single ozonation processes, TOC removal can reach 80%. CONCLUSION: In single ozonation processes, direct ozone reaction is mainly responsible for diclofenac elimination. Once diclofenac has disappeared, its by‐products are removed by reaction with hydroxyl radicals formed in the ozone decomposition and also from the reaction of diclofenac with ozone. In the photocatalytic processes hydroxyl radicals are responsible oxidant species of diclofenac removal as well as by‐products. Copyright © 2010 Society of Chemical Industry     

Advanced Oxidation of Textile Wastewaters

Model dyeing and laundering wastewaters produced during two basic technological operations of the textile industry were subjected to treatment by advanced oxidation processes (AOPs). The following agents were used: ozone (O₃), hydrogen peroxide (H₂O₂) and UV radiation. They were applied separately and in all possible combinations: O₃ + UV, O₃ + H₂O₂, UV + H₂O₂, as well as all three at the same time: O₃ + UV + H₂O₂. Effluents before and after the treatment were analyzed according to requirements of the Polish Standards that included pH, color threshold, COD and concentration of anionic and non-ionic surfactants. Ozonation was carried out in a lab-scale bubble column reactor with a centrally located UV burner. The most effective version of AOPs proved to be the simultaneous use of all three agents. In the case of such treatment of dyeing wastewaters nearly complete discoloration and full decomposition of surface-active substances were obtained at 80% reduction of COD. A similar tendency was observed in the case of laundering wastewater, though in that case the results were slightly worse, which may be explained by much higher initial concentrations of the pollutants. Good treatment effects have also been obtained in combined treatment by simultaneous use of hydrogen peroxide and ozone.     

Degradation of Carbamazepine by Photo-assisted Ozonation: Influence of Wavelength and Intensity of Radiation

This article presents the results of an investigation into the function of UV in a photo-assisted ozonation process for treatment of carbamazepine (CBZ) in treated domestic wastewaters. Experiments were conducted on synthetic spiked water and secondary treated municipal wastewater. Degradation of CBZ was studied for various combination of O₃ dosage ranging from 4.8 to 14.4 mg/h and UV intensities with varying intensity and wavelength (UVC: λ = 254 nm and UVA: 352 nm). In synthetic spiked water, CBZ was degraded to below detectable limits within 0.5 min for ozone dose of 14.4 mg/h. The rate of degradation of CBZ increased exponentially with increase in ozone dose following a zero-order rate at each dose level. The degradation rate of CBZ in wastewater was slower compared to deionized water (DI) water by 40–75% for various doses of ozone, presumably due to the presence of organic matter remaining in treated wastewater. Optimal UV intensities for UVA and UVC were obtained as 0.62 and 0.82 mW/cm² for all doses of ozone in synthetic spiked water samples and UV intensities beyond this resulted in lower rates of degradation of CBZ. For photo-assisted ozonation with ozone doses of 9.6 and 14.4 mg/L, rate constants were two times higher for UVA irradiations as compared to UVC irradiation. Contrary to observations in DI water, experiments in wastewater showed increase in rate of degradation with higher UV intensities. Overall, photo-assisted ozonation was found to be appropriate for both water and wastewater treatment by exploiting the benefit of direct attack of ozone and of produced ^?OH radicals to yield a greater extent of mineralization of CBZ.     

Applications of ozone for industrial wastewater treatment — A review

This paper presents a detailed review of published applications of ozone for treating many types of industrial wastewaters. Applications of ozone technologies to control pollution in full‐scale industrial wastewater treatment plants in the areas of recycling marine aquaria, electroplating wastes, electronic chip manufacture, textiles, and petroleum refineries, are discussed. The rising acceptance of ozone as a replacement bleaching agent for paper pulp to eliminate the discharge of halogenated effluents from pulp bleaching plants also is traced. Newer applications for ozone in treating rubber additive wastewaters, landfill leachates, and detergents in municipal wastewaters are summarized briefly. The combination of ozone oxidation followed by biological treatment has been installed full‐scale at a large German industrial chemical complex. Ozone coupled with ultraviolet radiation and/or hydrogen peroxide (advanced oxidation) is being utilized to destroy organic contaminants in groundwaters at munitions manufacturing plants and at Superfund sites (hazardous wastes). Ozone followed by activated carbon adsorption removes color and organics cost‐effectively from North African phosphoric acid.     

Pathogen Re-Growth in UASB Effluent Disinfected By UV,O3, H2O2, and Advanced Oxidation Processes

Disinfection of anaerobically treated effluent (UASB) was carried out to eliminate the enteric pathogens by using UV irradiation, peracetic acid, H₂O₂, O₃ and advanced oxidation processes (O₃/H₂O₂, O₃/UV and H₂O₂/UV). Re-growth potential of these pathogens was monitored in terms of time and temperature. Inactivation of pathogens by ozone at the rate of 300 mg/h for 20 minutes approached 99%. UV irradiation resulted in 99% pathogen removal at irradiation time of 120 seconds. A dose of 170 mg/L H₂O₂ eliminated more than 99% pathogens. Samples disinfected with UV, H₂O₂ and O₃ showed gradual re-growth with an increase in time and temperature (from 20 to 35°C). However, disinfection with AOPs proved to be the most effective tool resulting in reduction of treatment time taken by individual processes, also the disinfected samples showed minimal re-growth revealing the superiority of their combined effects.     

Oxidation of 1,3,5‐trichlorobenzene using advanced oxidation processes

The oxidation of 1,3,5‐trichlorobenzene (TCB) by ozone, ozone/UV, ozone/H₂O₂ and ozone/UV/H₂O₂ was studied. All studies were conducted in a continuously‐flowing completely mixed reactor (CFCMR), operated at steady‐state conditions using a hydraulic retention time of 10 minutes. The greatest removal of TCB using ozone/H₂O₂ treatment was achieved using a H₂O₂ concentration of 60 μM. At low pH values (approx. 2) ozone/UV performed significantly better than either ozone alone or ozone/H₂O₂. However, at circumneutral pH, the removal efficiencies of TCB by ozone/UV and ozone/H₂O₂ and ozone/UV/H₂O₂ were essentially equal (～ 97% for TCB). The removal efficiency of ozone alone was ～93% for TCB. At high pH (> 9) there was no advantage in supplementing ozone with either UV or H₂O₂ as the removal efficiencies for all processes studied were essentially equal.

The effect of humic acid and bicarbonate on the removal of TCB was studied. At 1.6 mg/L humic acid, 92–95% of the TCB was oxidized by the processes studied. The removal of TCB by ozone alone was significantly affected by the presence of bicarbonate ion. For the other processes at 10 mM bicarbonate, approximately 80% of the TCB was oxidized.     

Oxidation of Emerging Contaminants during Pilot-Scale Ozonation of Secondary Treated Municipal Effluent

The transformation of 41 target emerging contaminants in secondary treated municipal wastewater effluent in Canada was examined at pilot-scale, at transferred ozone doses of 2.8 mg/L (0.46 O₃/mg DOC) and 4.4 mg/L (0.72 mg O₃/mg DOC). In general, transformation efficiencies of CECs either increased or were retained at the higher ozone dose. The higher ozone dose of 0.72 mg O₃/mg DOC (Z_spec = 0.6 mg O₃/mg DOC) was sufficient to transform 21 of the 31 detected CECs by over 80% as well as achieving the disinfection target of < 200 MPN E. coli per 100 mL.     

Ozone Treatment of Secondary Effluent at U.S. Municipal Wastewater Treatment Plants

Ozone is a strong oxidant used to treat a variety of constituents in potable water, wastewater, water reuse, and industrial water treatment applications. Ozone is effective at oxidizing a wide range of organic and inorganic compounds and disinfection. Well-known in potable water treatment, with about 400 US installations and 3,000 world-wide, ozone has limited application at wastewater treatments, with less than 10 operating facilities in the US. The ability of ozone to significantly reduce low level concentrations of trace organic compounds, including endocrine disrupting chemicals (EDCs), pharmaceuticals and personal care products (PPCPs), and other emerging contaminants have increased interest in applying ozone in potable water and wastewater treatment. Treating at the point source discharge rather than the water supply intake may be more effective. A recent American Water Works Research Foundation (AwwaRF) report indicated high removals of many EDCs and PPCPs at typical disinfection doses. Several wastewater utilities have installed or are in the process of installing ozone to treat secondary effluent. These utilities are using ozone in a variety of ways: as a primary disinfectant, for treatment of microconstituents, and in combination with other processes (e.g. membranes and UV) to produce high-quality water for indirect potable reuse (IPR). The different applications, treatment goals and basis of process selection are compared and contrasted. Secondary benefits of ozone treatment of secondary effluent, including the use of off-gas in biological treatment is also discussed.     

臭氧氧化法深度处理城市污水厂生物处理出水研究

无锡市某城市污水处理厂一期和二期工程分别采用传统活性污泥(CAS)和厌氧-缺氧-好氧-缺氧-膜生物反应器(AAOA-MBR)工艺,以臭氧氧化法对2种工艺的生物处理出水进行深度处理批量试验,通过调整不同的反应时间来控制臭氧投加量。结果表明,臭氧对2种工艺出水中的细菌总数、总大肠菌群数、TOC、UV254和色度都具有较好的去除效果,去除率分别达到52.5%、68.5%、99.7%和99.8%和64.2%、96.4%、99.8%、100%。3维荧光光谱扫描结果表明,2种工艺处理出水中的有机物主要是蛋白类和腐殖质类有机物,荧光强度随着与臭氧反应时间的延长而逐渐减弱,臭氧可以有效地去除该类有机物。     

高级氧化技术处理制药废水研究进展

本文综述了高级氧化处理技术在制药废水污染防治中的应用,对各种制药废水处理技术的特点及其在国内外研究的状况进行了讨论,探讨了污染防治中存在的问题及解决办法,最后对高级氧化技术处理制药废水的研究进行了展望.     

Destruction of toxic organics in water by an injection‐type downflow UV/O3 oxidation reactor

An injection‐type downflow UV/O₃ oxidation reactor (IDUOR) was developed mainly with the combination of a configuration of two concentric cylinders with the UV lamp in the bottom axial position and a downflow mixing gas‐liquid injector. This configuration leads to atomizing of the solution resulting in higher levels of dissolved ozone which is then illuminated by UV light to generate hydroxyl radicals. Four different toxic wastewaters including 4‐chlorophenol, carbofuran, dye‐auxiliaries and pesticide wastewater with a COD range of 164 to 1602 mg/L and a microtoxicity (EC₅₀) range of 3.008% to 19.062% were used to investigate the performance of the device. It was found that the ozone utilization efficiency attained was more than 75% with very satisfying COD and TOC reduction for wastewater treated with IDUOR. The IDUOR when compared to a conventional stirred bubble UV/O₃ reactor exhibited increased efficiency for ozone utilization and COD, TOC, microtoxicity reduction. Also, the pseudo‐first rate constants on the basis of COD and TOC reduction indicated much higher oxidation rate of organics in IDUOR, providing additional evidence of the considerable treatment potency of IDUOR for destruction of toxic organics in water.     

An Automated Procedure for Monitoring the Effectiveness of Ozonation Processes

Measurement of the 254 nm absorption of organics was chosen for monitoring the ozonation processes used to remove organic matter in a drinking water because of its ability to reflect the performance of ozonation. Ozone flow rate, ozone concentration in the gas (phase, addition of H₂0₂ and seasonal variations on kinetics of the reduction of UV absorption were varied and the efficiency of ozonation was determined. For several yearst ozonation has been applied at different points in potable water treatment. The original goal of ozonation was reduction in taste and odor and disinfection without by products of organoleptic concern (e.g.. chlorophenols). Ozone also has the capacity to oxidize organic matter.     

城市污水消毒技术研究进展

城市污水消毒是城市污水处理厂必须的操作单元,目前,城市污水消毒方法主要为紫外消毒、氯消毒、二氧化氯消毒和臭氧消毒等,传统氯消毒由于产生有毒付产物而逐步为其它消毒方法所取代,二氧化氯和臭氧由于成本高,在城市污水消毒中应用较少,紫外消毒杀菌速度快、效率高、易于操作、运行费用低,基本没有消毒副产物,是近几年发展较快的城市污水消毒技术.     

消毒技术在饮用水处理中的研究现状

阐述了近年来国内外饮用水处理中消毒技术发展的一些新动向、新工艺,着重介绍了氯、氯胺、二氧化氯、臭氧和紫外线等消毒技术在国内外饮用水处理中的应用现状,最后详细阐述了寻求氯消毒替代品、开发消毒新技术和组合消毒工艺等3方面的饮用水处理中消毒技术的发展趋势。     

Wastewater Disinfection Using Ozone to Remove Free-Living,Highly Pathogenic Bacteria and Amoebae

This project set out to determine the effectiveness of ozone as a disinfectant against highly resistant micro-organisms in wastewaters. An ozone dose of 51.5 mg/L for different lengths of time and at pH 5 and 7 was applied to both synthetic and natural samples of V. cholerae and S. typhi bacteria and the Acanthamoeba protozoa, as well as to biological pollution indicators such as total coliform (TC) and fecal coliform (FC) bacteria. Simultaneous analysis was also made of various physical-chemical parameters that might interfere with the disinfection process. Results showed at 14 minutes, all bacteria and amoeba were completely destroyed. Results also demonstrated a clear reduction in some physical/chemical parameters.     

Advanced Treatment For Municipal Wastewater Reuse In Agriculture. III - Ozone Disinfection

Results of a pilot (100 m³/h) investigation on ozone disinfection of municipal tertiary effluents for reuse in agriculture carried out at West Bari (S. Italy) treatment plant are presented. Among dosages, contact times and advanced treatment schemes investigated it was demonstrated that ozone disinfection results in the achievement of the WHO microbial guideline (1,000 CFU/100ml for Fecal Coliforms) for unrestricted wastewater reuse in agriculture of both clarified and clarified-filtered municipal secondary effluents; it is very effective towards Pseudomonas aeruginosa, rather effective towards Giardia lamblia and substantially ineffective towards Cryptosporidium parvum and it forms limited amount of DBP (approx. 350 ppb of total aldehydes). O&M costs amount to 37 Euro/1000m³.     

Removal of phenolic compounds present in olive mill wastewaters by ozonation

The aim of this work is to study a pre-treatment process of olive mill wastewaters based on ozonation. The efficiency of the process depends on the removal of pollutants and on ozone mass transfer performance. In order to choose an appropriate gas/liquid contactor, the rate constants of three phenolic compounds (gallic acid, p-hydroxybenzoic acid and p-coumaric acid) were determined by using competition kinetic model. These constants, obtained at pH 5, were found to be high (from 3.8 × 10⁴ L/mol s to 2.9 × 10⁵ L/mol s), inducing a diffusion controlled regime (Ha > 3). Thus, to obtain an efficient ozonation process, gas/liquid contactor should be adapted to this regime. An ejector was chosen as gas/liquid contactor. In a first time, treatment of synthetic effluent containing the three phenolic compounds was performed to evaluate efficiency of the process. Experimental conditions were chosen to obtain a diffusion controlled regime (Ha > 3). It appeared that this gas/liquid contactor permits obtaining complete and fast removal of pollutants with a very efficient ozone mass transfer (up to 90% during removal of phenolic compounds). So, this process was used to perform the ozonation treatment of olive mill wastewaters from Sfax (Tunisia). It was proved to be very efficient: up to 80% of phenolic compounds were removed and ozone mass transfer reached 95% during this oxidation.     

A Survey of Occurrence and Risk Assessment of Pharmaceutical Substances in the Great Lakes Basin

The present study is an overview of the literature on the occurrence and potential risks of pharmaceutical substances in the wastewater treatment plants (WWTP), natural waters and drinking water treatment plants served by the Great Lakes Basin (Canada and the USA) between the years of 2007–2012. Large number of pharmaceutical substances, including anti-inflammatories, lipid regulators, antidepressants, antibiotics, beta blockers, anti-epileptics, anti-hypertensions and stimulants, in high ng/L concentrations, has been reported in the WWTP influents. Most of these compounds have also been detected in the WWTP effluents at comparable concentrations with the exception of caffeine, cotinine and salicylic acid suggesting the inefficiency of conventional treatment processes in the degradation of pharmaceutical compounds. Decreasing surface water concentrations have been observed with the distance downstream of the discharge point due to the dilution effect. Surface waters located around septic systems and agricultural areas have also been found to be contaminated with pharmaceutical substances. Carbamazepine, caffeine, its metabolite paraxanthine, ibuprofen, gemfibrozil and sulfamethoxazole have been frequently detected in the surface waters. The number of occurrences of carbamazepine, ibuprofen, naproxen, gemfibrozil, bezafibrate, sulfamethoxazole and macrolide antibiotics in drinking water sources, at ng/L concentration ranges, has been quite high. Although the detection frequencies in treated drinking waters were relatively low, the concentrations of the above mentioned pharmaceutical substances were at the same range as the source water concentrations.

Six of the detected pharmaceutical substances, namely, fluoxetine, sulfamethoxazole, clarithromycin, erythromycin, carbamazepine and esterone exhibit a high environmental risk in Great Lakes WWTP effluents and surface waters, while none of the pharmaceutical substances seem to pose a risk for human health at their highest reported concentrations in the drinking water sources from the Great Lakes.