Isil Akmehmet Balcioglu

Advanced oxidation of a reactive dyebath effluent: comparison of O3, H2O2/UV-C and TiO2/UV-A processes

In the present study the treatment efficiency of different AOPs (O3/OH- H2O2/UV-C and TiO2/UV-A) were compared for the oxidation of simulated reactive dyebath effluent containing a mixture of monochlorotriazine type reactive dyes and various dye auxiliary chemicals at typical concentrations encountered in exhausted reactive dyebath liquors. A525 (color), UV280 (aromaticity) and TOC removal rates were assessed to screen the most appropriate oxidative process in terms of reactive dyebath effluent treatment. Special emphasis was laid on the effect of reaction pH and applied oxidant (O3, H2O2) dose on the observed reaction kinetics. It was established that the investigated AOPs were negatively affected by the Na2CO3 content (= 867 mg/L) which is always present at high concentrations in dychouse effluents since it is applied as a pH buffer and dye fixation agent during the reactive dyeing process. The ozonation reaction exhibited almost instantaneous decolorization kinetics and a reasonable TOC reduction rate. It appeared to be stable under the investigated advanced oxidation conditions and outranked the other studied AOPs based on the above mentioned criteria. Besides, the electrical energy requirements based on the EE/O parameter (the electrical energy required per order of pollutant removal in 1 m3 wastewater) was calculated for the homogenous AOPs in terms of decolorization kinetics. In view of the electrical energy efficiency, ozonation and H2O2/UV-C oxidation at the selected treatment conditions appear to be promising candidates for full-scale dyehouse effluent decolorization.

TREATMENT OF PHARMACEUTICAL WASTEWATER CONTAINING ANTIBIOTICS BY O3 AND O3/H2O2 PROCESSES

Ozonation of three different synthetic pharmaceutical formulation wastewater containing two human antibiotics and a veterinary antibiotic has been studied to enhance the their biodegradability. The effects of pH and initial chemical oxygen demand (COD) value as well as addition of hydrogen peroxide on ozonation process were investigated. Total organic carbon (TOC), COD, biochemical oxygen demand (BOD), and aromatic content (UV254) were the parameters followed to evaluate the performance of ozonation process. Comparison of the biodegradability of selected wastewaters containing different antibiotics confirmed that the variation of biodegradability was associated with the target compound. While BOD5/COD ratio of veterinary antibiotic formulation wastewater was increased from 0.077 to 0.38 with an applied ozone dosage of 2.96 g/l, this ratio for human antibiotic I and human antibiotic II was increased from 0 to 0.1 and 0.27 respectively. Moreover the results of this investigation showed that the ozonation process is capable of achieving high levels of COD and aromaticity removals at about their natural pH values.

Investigation of the tetracycline, sulfonamide, and fluoroquinolone antimicrobial compounds in animal manure and agricultural soils in Turkey.

Occurrence of antimicrobial residuals in the environment is of concern because of the emergence and development of antimicrobial-resistance in pathogen bacteria, and the ecotoxicological behaviour of these compounds. Investigation of antimicrobial pollution in animal manure has special importance since they constitute the major source for the dissemination of these chemicals into the environment. Hence, eight animal manure and nine agricultural soil samples from the North part of Marmara Region (Turkey) were collected and analyzed for two tetracyclines (TCs), four sulfonamides (SAs), and two fluoroquinolones (FQs). At least one antimicrobial compound was detected in all the agricultural soil and animal manure samples. The highest antimicrobial concentrations were in general detected in the fresh poultry manure samples. Mean recoveries from spiked soil and manure samples ranged from 60 to 86% and 62 to 77% for TCs, 69 to 101% and 14 to 82% for SAs, and 46 to 55% and 24 to 42% for FQs, respectively. Relationship between the recovery rates of the antimicrobial compounds and sample characteristics was statistically evaluated by means of hierarchical cluster analysis (HCA), and principal component analysis (PCA) followed by multiple stepwise regression (MSR). HCA showed agricultural soil samples with higher di- and trivalent metal contents resulted in higher TC and lower FQ recoveries. TC recoveries from manure were highest in the samples with lowest K, Mg, and Ca content, while FQs were more efficiently extracted from the manure samples with less % organic carbon (OC) content. The findings of HCA for TCs were supported by those of MSR analysis, giving comparable results. In addition, MSR of SA recoveries revealed that the increasing amounts of manure % OC led to lower recoveries.

Effect of common reactive dye auxiliaries on the ozonation of dyehouse effluents containing vinylsulphone and aminochlorotriazine dyes

Abstract Ozonation of the commercially important reactive dyes Procion yellow HE4R (Reactive Yellow 84) and Remazol Black SB (Reactive Black 5) in actual dye rinse waters and simulated exhausted dye bath liquors has been studied. The effect of common dye auxiliaries (NaCl and Na2CO3) as well as the initial dye concentration on advanced oxidation kinetics was investigated. Decolourization was complete within a few minutes of ozonation in all cases whereas UV254 (absorbance at 254 nm wavelength), COD and TOC removals required higher ozone doses. It was found that NaCl did not affect the ozonation process at the present reaction conditions, whereas the addition of Na2CO3 resulted in a significant inhibition in the abatement of all selected process parameters except decolourization. Increasing the initial dye concentration had an even more negative effect on decolourization, oxidation and mineralization kinetics. A simple kinetic model describing the effect of inhibitor concentrations on COD and/or colour removal rate constants has been proposed.

Advanced oxidation of raw and biotreated textile industry wastewater with O3, H2O2 /UV-C and their sequential application

The advanced chemical oxidation of raw and biologically pretreated textile wastewater by (1) ozonation, (2) H2O2 /UV − C oxidation and (3) sequential application of ozonation followed by H2O2 /UV − C oxidation was investigated at the natural pH values (8 and 11) of the textile effluents for 1 h. Analysis of the reduction in the pollution load was followed by total environmental parameters such as TOC, COD, UV–VIS absorption kinetics and the biodegradability factor, fB. The successive treatment combination, where a preliminary ozonation step was carried out prior to H2O2 /UV − C oxidation without changing the total treatment time, enhanced the COD and TOC removal efficiency of the H2O2 /UV − C oxidation by a factor of 13 and 4, respectively, for the raw wastewater. In the case of biotreated textile effluent, a preliminary ozonation step increased COD removal of the H2O2 /UV − C treatment system from 15% to 62%, and TOC removal from 0% to 34%. However, the sequential process did not appear to be more effective than applying a single ozonation step in terms of TOC abatement rates. Enhancement of the biodegradability factor (fB) was more pronounced for the biologically pretreated wastewater with an almost two-fold increase for the optimized Advanced Oxidation Technologies (AOTs). For H2O2 /UV − C oxidation of raw textile wastewater, apparent zero order COD removal rate constants (kapp), and the second order OH· formation rates (ri) have been calculated. © 2001 Society of Chemical Industry

Homogenous and Heterogenous Advanced Oxidation of Two Commercial Reactive Dyes

Two commercial reactive dyes, the azo dye Reactive Black 5 and the copper phythalocyanine dye Reactive Blue 21, have been treated at a concentration of 75 mg l-1 by titanium dioxide mediated photocatalytic (TiO2/UV), dark and UV-light assisted Fenton (Fe2+/H2O2) and Fenton-like (Fe3+/H2O2) processes in acidic medium. For the treatment of Reactive Black 5, all investigated advanced oxidation processes were quite effective in terms of colour, COD as well as TOC removal. Moreover, the relative growth inhibition of the azo dye towards the marine algae Dunaliella tertiolecta that was initially 70%, did not exhibit an increase during the studied advanced oxidation reactions and complete detoxification at the end of the treatment period could be achieved for all investigated treatment processes. However, for Reactive Blue 21, abatement in COD and UV-VIS absorbance values was mainly due to the adsorption of the dye on the photocatalyst surface and/or the coagulative effect of Fe3+/Fe2+ ions. Although only a limited fraction of the copper phythalocyanine dye underwent oxidative degradation, 47% of the total copper in the dye was already released after 1 h photocatalytic treatment.

Application of Advanced Oxidation Processes to Different Industrial Wastewaters

Abstract This study examines the application of photochemical and non-photochemical advanced oxidation processes on the treatment of textile, Kraft bleaching, photoprocessing, and pharmaceutical wastewaters. Effects of reaction conditions on the treatment efficiency of industrial wastewater have been investigated. The results were evaluated in terms of biodegradability enhancement. The results indicated depending upon the composition of wastewater and applied pretreatment all applied AOPs had an ability to increase the biodegradability of studied wastewaters.

Comparison of the ozonation and Fenton process performances for the treatment of antibiotic containing manure.

An integrated treatment method based on magnesium salt extraction followed by chemical oxidation was used for the treatment of a veterinary antibiotic, oxytetracycline (OTC) contaminated cow manure since animal manure can be an important source for antibiotic pollution in the environment. Pretreatment with magnesium salt enhanced the efficiencies of subsequent oxidation processes by extracting 63.9% of OTC from the manure thereby making it more favorable for oxidation with the hydroxyl radicals produced by the Fenton and ozone oxidation processes. Both the 24 h Fenton oxidation process with 434 mM H(2)O(2) and 43.4 mM Fe(2+) doses and the 1-h ozonation process with an applied ozone dose of 2.5 mg min(-1) provided more than 90% OTC removal from the manure slurry. However, the second-order OTC removal rate constant of Fenton process (119 M(-1)s(-1)) was remarkably lower than that obtained with the ozonation process (548 M(-1)s(-1)). The oxidant dose was a significant factor for the efficiency of the Fenton treatment but not for the ozone treatment. The efficiencies of both the Fenton and ozone oxidation processes were not affected by the pH adjustment of the manure slurry.

Comparison of the effectiveness of chlorine, ozone, and photocatalytic disinfection in reducing the risk of antibiotic resistance pollution

Abstract Effectiveness of conventional chlorine and ozone disinfection on reduction of antibiotic resistance was compared with less commonly applied heterogeneous photocatalytic process. For this purpose plasmid DNA isolated from a multi-resistant Escherichia coli (E. coli) HB101 was treated in two different concentrations with the three oxidation processes. Oxidative damage on the plasmid DNA was analyzed with gel electrophoresis by comparing the extent of conformational changes in the DNA structure. The effectiveness of the applied oxidant in reducing the risk of resistance transfer was also evaluated by comparing the ability of treated plasmid DNA to transform competent cells. Chlorine did not affect plasmid DNA structure at the studied doses, while ozone and photocatalytic treatment resulted in conformational changes and the damage increased with increasing oxidant doses. Transformation experiments confirmed a similar trend. Chlorine did not affect the transformability and the cell counts of competent cells transformed with chlorine treated plasmid DNA were similar to those transformed by non-treated plasmid DNA in the control experiments.

Simultaneous removal of oxytetracycline and sulfamethazine antibacterials from animal waste by chemical oxidation processes.

Simultaneous degradation of oxytetracycline (OTC) and sulfamethazine (SMZ) antibacterials in synthetically contaminated cow manure (20 mg of antibacterials/kg of manure) in the presence and absence of bedding was investigated by the application of ozone, Fenton, and persulfate oxidation processes. Almost the complete removal of antibacterials was attained with all oxidation processes, which were combined with a pretreatment of manure with magnesium (Mg(2+)) salt desorption. Among the investigated oxidation processes, thermally activated persulfate oxidation with 25 mM Na(2)S(2)O(8) at 50 degrees C was also applied to the animal feeding operations wastewater, and the pseudo-first-order degradation rate constants of OTC and SMZ were found as 3.22 and 1.25 (1/h), respectively. Thermally activated persulfate treatment resulted in the reduction of 82% inhibition of OTC and SMZ to 7%, indicating the production of almost nontoxic degradation products in the wastewater.