The Combination of Ozone/Hydrogen Peroxide and Ozone/UV Radiation for Reduction of Trihalomethane Formation Potential in Surface Water

Applied ozone dosages of 20, 25, and 30 mg/L to lake water utilized by the city of Shreveport, LA produced no significant reductions in trihalomethane formation potentials (THMFP). However, the addition of 20 mg/L of hydrogen peroxide and/or 0.67 W/L of UV radiation (254 nm) in combination with ozone produced decreases in THMFP of over 60% in 60 minutes. Smaller THMFP decreases were seen with shorter contact times. The use of H₂O₂ and/or UV in combination with O₃ increased the percentage of applied ozone consumed by the lake water (i.e., enhanced the ozone mass transfer) five times over simple ozonation.     

Kinetic Study and Optimum Control of the Ozone/UV Process Measuring Hydrogen Peroxide Formed In-situ

This study was conducted to develop a kinetic model of the ozone/UV process by monitoring the trend of in-situ hydrogen peroxide formation. A specifically devised setup, which could continuously measure the concentration of hydrogen peroxide as low as 10 μg/L, was used. The kinetic equations, comprised of several intrinsic constants with semi-empirical parameters (k_chain and k_R3) were developed to predict the time varied residual ozone and hydrogen peroxide formed in situ along with the hydroxyl radical concentration at steady state,[OH°]_ss, in the ozone/UV process. The optimum ozone dose was also investigated at a fixed UV dose using the removal rate of UV absorbance at 254 nm (A₂₅₄) in raw drinking water. The result showed that the continuous monitoring of hydrogen peroxide formed in situ in an ozone/UV process could be used as an important tool to optimize the operation of the process.     

Kinetics of Estrone Ozone/Hydrogen Peroxide Advanced Oxidation Treatment

Ozone/hydrogen peroxide batch treatment was utilized to study the degradation of the steroidal hormone estrone (E1). The competition kinetics method was used to determine the rate constants of reaction for direct ozone and E1, and for hydroxyl radicals and E1 at three pH levels (4, 7, and 8.5), three different molar O₃/H₂O₂ ratios (1:2, 2:1, and 4:1) and a temperature about 20°C. The average second-order rate constants for direct ozone-E1 reaction were determined as 6.2?×?10³?±?3.2?×?10³ M^?1s^?1, 9.4?×?10⁵?±?2.7?×?10⁵ M^?1s^?1, and 2.1?×?10⁷?±?3.1?×?10⁶ M^?1s^?1 at pH 4, 7, and 8.5, respectively. It was found that pH had the greatest influence on the reaction rate, whereas O₃/H₂O₂ ratio was found to be slightly statistically significant. For the hydroxyl radical-E1 reaction, apparent rate constants ranged from 1.1?×?10¹⁰ M^?1s^?1 to 7.0?×?10¹⁰ M^?1s^?1 with an average value of 2.6?×?10¹⁰ M^?1s^?1. Overall, O₃/H₂O₂ is shown to be an effective treatment for E1.     

Application of Combined Ozone–Hydrogen Peroxide for the Removal of Aromatic Compounds from a Groundwater

Nitro and chlorobenzene compounds, which are widely used in dye industries, have been associated recently with groundwater contamination. Because of their potential toxicity and for taste and odor considerations, three main actions were undertaken to solve the problem. First, to follow the advance of pollution toward the wells, samples were collected automatically and analyzed using GC-MS. Results indicate that o-chloronitrobenzene was the main pollutant in concentrations ranging from 10 to 2000μg/L. Second, to monitor the drinking water quality, an on-line spectrophotometer was used to measure the optical density at 254 nm at the inlet and outlet of the plant. Third, the feasibility of using the O₃/H₂O₉ combination was determined at a 450 L/h pilot plant. Reduction of concentrations of chloronitrobenzenes from 1900 μ/L to less than 20 μg/L could be reached by the application of 8 mg O3/L and 3 mg H2O9/L with a 20-minute contact time. To avoid an eventual bacterial egrowfn in the network due to biodegradability of the oxidation by-products, sand and GAC filtration were tested after oxidation. An evaluation of the costs of these different treatments is also presented.     

Influence of Carbonate on the Ozone/Hydrogen Peroxide Based Advanced Oxidation Process for Drinking Water Treatment

The influence of carbonate on the ozone/hydrogen peroxide process has been investigated. Carbonate radicals, which are formed from the reaction of bicarbonate/carbonate with OH radicals, act as a chain carrier for ozone decomposition due to their reaction with hydrogen peroxide. The efficiency of bicarbonate/carbonate as a promoter for the radical-based chain reaction in presence of hydrogen peroxide has been calibrated and compared to a well-known chain promoter (methanol) and an inhibitor (tert-butanol). Relative to tert-butanol, the hydrogen peroxide induced ozone decomposition is accelerated by bicarbonate/carbonate. Relative to methanol, bicarbonate/carbonate in presence of hydrogen peroxide is less effective as a promoter under comparable experimental conditions.     

Ozone Versus Ozone/Peroxide Induced Particle Destabilization And Aggregation: A Pilot Study

This research compares the role of ozone and the conjunctive use of ozone plus hydrogen peroxide in particle destabilization and particle aggregation, and improvement in filtered water quality. Particle destabilization was observed at all doses of ozone and ozone/peroxide studied, whereas aggregation was observed with ozone only at lower doses (> 2 mg/L) and in conjunction with ozone/peroxide (all doses studied). As compared to alum alone, the ozone-plus-alum and ozone/peroxide-plus-alum treatments provided improved flocculation and better filtered water quality. In addition, each of these preoxidations significantly reduced alum requirements. Overall, in terms of particle destabilization and aggregation; i.e., effectiveness as a coagulation aid, Ozone/peroxide performed better than ozone.     

Improvement in the Effectiveness of Ozonation of Drinking Water Through the Use of Hydrogen Peroxide

Addition of hydrogen peroxide to water during ozonation increases the rate of oxidation of organic compounds and ozone transfer. Coupling ozone with hydrogen peroxide can increase the efficiency of a drinking water treatment line, for example in removing THM precursors. To optimize this oxidation process, the quantity of hydrogen peroxide added and the point of injection must be carefully selected.     

Ozone,Hydrogen Peroxide/Ozone And UV/Ozone Treatment Of Chromium- And Copper-Complex Dyes: Decolorization And Metal Release

Metal-complex azo dyes constitute a significant fraction of the dyes used in the textile industry and exhibit properties such as superior light- and wash-fastness. While effluent color is not always regulated, the textile finishing industry often decolorizes wastewater using processes including chemical oxidation. In this study, the use of ozone, hydrogen peroxide/ozone and UV/ozone oxidant systems was examined for treatment of two common metal-complex (premetalized) dyes, Acid Black 52 (chromium) and Direct Blue 80 (copper). Oxidant dosages required for decolorization of these dyes were determined. The effect of bicarbonate alkalinity on the ozonation and the hydrogen peroxide/ozone processes also was examined.     

Dyes Color Removal by Ozone and Hydrogen Peroxide: Some Aspects and Problems

Application of oxidation processes with the use of strong oxidizing agents, ozone and hydrogen peroxide, is limited because of high costs and some problems with parameters of discoloration reactions. This paper presents findings concerning the use of ozone itself and hydrogen peroxide in combination with Fe²⁺ catalyst for discoloration of dye solutions of concentration 100 mg/L and wastewaters from production of dyestuffs Reactive Orange 20, Reactive Blue 13, Direct Blue 74, and Acid Violet 1. Both agents discolored both the dye solutions and wastewaters successfully. The paper presents a discussion about some aspects and problems occurring in the use of those oxidative agents for discoloration processes in laboratories. There is also a presentation of the effects that such parameters as consumption of oxidants and the doses applied, pH and temperature, had on the time required for discoloration reactions.     

Removal Characteristics of Organic Pollutants in Sewage Treatment by a Pre-Coagulation,Ozonation and Ozone/Hydrogen Peroxide Process

The applicability of a sequential process of ozonation and ozone/hydrogen peroxide process for the removal of soluble organic compounds from a pre-coagulated municipal sewage was examined. 6–25% of initial T-COD_Cr was removed at the early stage of ozonation before the ratio of consumed ozone to removed T-COD_Cr dramatically increased. Until dissolved ozone was detected, 0.3 mgO₃/mgTOC₀ (Initial TOC) of ozone was consumed. When an ozone/hydrogen peroxide process was applied, additional COD_Cr was removed. And we elucidated that two following findings are important for the better performance of ozone/hydrogen peroxide process; those are to remove readily reactive organic compounds with ozone before the application of ozone/hydrogen peroxide process and to avoid the excess addition of hydrogen peroxide. Based on these two findings, we proposed a sequential process of ozonation and multi-stage ozone/hydrogen peroxide process and the appropriate addition of hydrogen peroxide. T-COD_Cr, TOC and ATU-BOD₅ were reduced to less than 7 mg/L, 6 mgC/L and 5 mg/L, respectively after total treatment time of 79 min. Furthermore, we discussed the transformation of organic compounds and the removal of organic compounds. The removal amount of COD_Cr and UV₂₅₄ had good linear relationship until the removal amounts of COD_Cr and UV₂₅₄ were 30 mg/L and 0.11 cm^?1, respectively. Therefore UV₂₅₄ would be useful for an indicator for COD_Cr removal at the beginning of the treatment. The accumulation of carboxylic acids (formic acid, acetic acid and oxalic acid) was observed. The ratio of carbon concentration of carboxylic acids to TOC remaining was getting higher and reached around 0.5 finally. Removal of TOC was observed with the accumulation of carboxylic acids. When unknown organic compounds (organic compounds except for carboxylic acids) were oxidized, 70% was apparently removed as carbon dioxide and 30% was accumulated as carboxylic acids. A portion of biodegradable organic compounds to whole organic compounds was enhanced as shown by the increase ratio of BOD/COD_Cr.     

Effect of Application of Ozone and Ozone Combined with Hydrogen Peroxide and Titanium Dioxide in the Removal of Pesticides From Water

The aim of this research work is to study the influence of hydrogen peroxide and titanium dioxide in the ozone-based treatment to degrade 44 organic pesticides present in natural water, which are systematically detected in the Ebro River Basin (Spain). The studied pesticides are: alachlor, aldrin, ametryn, atrazine, chlorfenvinfos, chlorpyrifos, pp'-DDD, op'-DDE, op'-DDT. pp'-DDT, desethylatrazine, 3,4-dichloroaniline, 4,4'-dichlorobenzophenone, dicofol, dieldrin, dimethoate, diuron, α-endosulphan, endosulphan-sulphate, endrin, α-HCH, β-HCH, γ-HCH, δ-HCH, heptachlor, heptachlor epoxide A, heptachlor epoxide B, hexachlorobenzene, isodrin, 4-isopropylaniline, isoproturon, metholachlor, methoxychlor, molinate, parathion methyl, parathion ethyl, prometon, prometryn, propazine, simazine, terbuthylazine, terbutryn, tetradifon and trifluralin. The ozonation using 3 mg O₃ L^?1 produces a pesticides removal close to 23%, whereas the application of O₃/H₂O₂ and O₃/TiO₂ treatments achieves average degradation yields lower than the ozonation. However, the application of O₃/H₂O₂ /TiO₂ process improves considerably the pesticides degradation and an average degradation yield of 36% is obtained.     

塑料规整填料分离器在双氧水生产中的应用

针对双氧水生产过程中原油水分离装置达不到设计要求的状况 ,采用塑料规整填料对其进行改造。生产实践表明 ,改造过程使用的新型填料分离效果很好 ,生产稳定 ,处理能力也比改造前有很大提高     

Ozone/H2O2 Performance on the Degradation of Sulfamethoxazole

This work aims to analyze the contribution of H₂O₂ on ozonation of Sulfamethoxazole (SMX). A single ozonation was able to totally remove SMX. TOC and COD depletion rates after a transferred ozone dose of 60 mg/L was related to the formation and decomposition of H₂O₂. An increase on O₃ gas inlet concentration from 10 g/m³ to 20 g/m³ improved COD abatement from 11% to 36%. When the presence of H₂O₂ at the beginning of ozonation was tested, it was verified that COD and TOC degradation were enhanced, attaining maximum values of 76% and 32%, respectively, when compared with 35% and 15% reached in a single ozonation.     

Removal Of Pesticides By Use Of Ozone Or Hydrogen Peroxide/Ozone

This article deals with the efficiency of an ozonation step in drinking water treatment plants remove pesticides. These tests are carried out with a laboratory technique, the “OZOTEST” method, which simulates operating conditions on site and allows a complete oxidation assessment.

Efficiency of the two oxidant systems – ozone and ozone coupled with hydrogen peroxide – is evaluated for 11 pesticides commonly analyzed in control laboratories. Comparison of the two systems is made in terms of pesticide removal, but also in terms of ozone consumption. Matrix effects and contact time are also taken into account, and an order of reactivity for each system considered is suggested.     

Oxidation of Methyl tert-Butyl Ether (MTBE) and Ethyl tert-Butyl Ether (ETBE) by Ozone and Combined Ozone/Hydrogen Peroxide

The aim of this work was to study the reaction of ozone and combined ozone/hydrogen peroxide on oxygenated additives such as methyl tert-butyl ether (MTBE) and ethyl tert-butyl ether (ETBE) in dilute aqueous solution using controlled experimental conditions. Experiments conducted in a semi-continuous reactor with MTBE and ETBE in combination (initial concentration: 2 mmol/L of each) showed that ETBE was better eliminated than MTBE with both ozone and combined O₃/H₂O₂. Batch experiments led to the determination of the ratio of the kinetic constants for the reaction of OH°-radical with MTBE and ETBE [k_OH°/ETBE/k_OH°/MTBE = 1.7). Tert-butyl formate and tert-butyl acetate were identified as the ozonation byproducts of MTBE and ETBE, respectively, while tert-butyl alcohol was found to be produced during the ozonation of both compounds.     

Bromate Control by Dosing Hydrogen Peroxide and Ammonia during Ozonation of the Yellow River Water

Ozonation of the downstream Yellow River water yields bromate with concentrations higher than China regulations. Bench tests demonstrated that dosing ammonia or hydrogen peroxide alone could not control the bromate concentration to below 10 μg/L. A pilot study showed that dosing hydrogen peroxide into the inherently ammonia-containing raw water at a dosage lower than 1.7 could effectively reduce the bromate concentration to below the detection limit when the ozone dosage was between 2 and 2.5 mg/L.     

The Disinfecting Action of Ozonated Water and of Hydrogen Peroxide/Silver Ions In Vitro

An in-vitro comparison was made between the disinfecting action of ozonated water and hydrogen peroxide/silver ion preparations using the “Quantitative suspension” test and Pseudomonas aemginosa. No microorganisms could be detected immediately after contact between ozonated water and the pseudomonadeae. In the case of the peroxide preparation, however, its action corresponded to that of aqua bidestillata (control experiment) and no disinfection had taken place. The use of hydrogen peroxide preparations in dental units for microbiological and toxicological reasons should therefore be reconsidered.     

Water Oxidation By Ozone Or Ozone/Hydrogen Peroxide Using The “Ozotest” Or “Peroxotest” Methods

This article presents a simple, rapid and efficient laboratory method permittingone to simulate the effects of ozonation (OZOTEST method) or of an oxidation by combined ozone/hydrogen peroxide (PEROXOTEST method) on an industrialscale. A critical analysis of the method is made (ozone transfer, validity of the results) and several practical applications are submitted for consideration (ozone demand, oxidation of atrazine and the DOC).     

Effects of Hydrogen Peroxide Residuals on Biologically Active Filters

The objective of this research was to obtain a better understanding of the effects of hydrogen peroxide (H₂O₂) residuals on the biological removal of certain biodegradable components in biologically active filters. Data were collected at lab scale using two parallel anthracite/sand filters. Both filter influents (dechlorinated tap water) were dosed with a biodegradable organic matter (BOM) cocktail, and one filter received additionally H₂O₂ at an influent concentration of approximately 1 mg/L. Measured parameters included carboxylic acids and hydrogen peroxide residuals. The results showed that the presence of H₂O₂ residuals (～ 1 mg/L) did not lead to a major inhibition of the biological removal of acetate and formate anions. After a period of biological acclimatization (colonization), H₂O₂ was removed rapidly within the biological filter, probably as a result of its reaction with the biomass or with catalase produced by certain bacteria.     

Impact of Ozone and Hydrogen Peroxide vs. UV and Hydrogen Peroxide on Chlorine Residual

The current study undertaken by the Walkerton Clean Water Centre (WCWC) is to evaluate the application of Advanced Oxidation Processes (AOPs) involving Ozone and UV with the addition of hydrogen peroxide, as one of the methods used in the process of the removal of PPCPs and EDCs, or taste and odor. The amount of hydrogen peroxide used with UV is much higher than that used with the ozone application. The concern is the impact of the hydrogen peroxide on the chlorine residual in the water that is pumped to the distribution system. One of the methods used to deal with this problem is to increase the chlorine addition to maintain the required residual. That could increase the disinfectant by-products (DBPs), namely Trihalomethanes (THMs), in addition to increase to the cost of operation. The findings of these experiments would provide useful information regarding the AOPs application using ozone vs. UV with hydrogen peroxide.