Ozone Disinfection and Wastewater Treatment Importance of Interface Action

For potable water treatment, the intent of disinfection is to provide absolute safety in terms of pathogenic microorganisms or viruses. In the case of waste water treatment, the main goal of disinfection is to reduce the concentration of germs. The pratical conditions of ozone application can be changed, so that the necessary applied ozone dose is reduced. Certain polyelectrolytes have an effect on the mass transfer of ozone. That effect seems to be present both on bubble–water mass transfer and on disinfection. So the addition of polyelectrolyte before ozonation is able to reduce the applied ozone dose required ; that is to increase the efficiency of disinfection by ozone.     

Enhancement of Wastewater Disinfection Efficiency in Full-Scale Ozone Bubble-Diffuser Contactors

Tracer and disinfection tests were performed with the ozone bubble-diffuser contactors at the Belmont and Southport Advanced Wastewater Treatment Plants operated by the City of Indianapolis, Department of Public Works. The objective of the study was to develop a better understanding for the role of hydrodynamics and contactor design on the disinfection efficiency achieved in these contactors. Tracer tests were performed at varying gas and wastewater flow rates. The results indicated that high backmixing occurred within each chamber of the over-under ozone bubble-diffuser contactor trains. The addition of three baffles to one of the contactor trains resulted in a decrease in overall contactor backmixing. Low contactor backmixing was observed at high wastewater flow rates combined with high or medium gas flow rates for both the modified and original trains. Monitoring of effluent fecal coliform concentrations for both the original and modified contactor trains revealed lower average concentrations in the modified train effluent as compared to the original train.     

医院废水消毒处理技术及其发展方向

综述了国内外医院废水消毒工艺中常见的消毒方法,介绍了加热、紫外线、液氯、次氯酸钠、二氧化氯等消毒技术及其特点,并探讨了今后医院废水消毒技术的发展方向。     

Start-Up and Operation of the Indianapolis Ozone Disinfection Wastewater Systems

The two 125-mgd oxygen activated sludge wastewater treatment plants for the City of Indianapolis, Indiana use ozone disinfection. The process was constructed in 1983, and has maintained continuous, reliable operation since 1985. Disinfection is required at Indianapolis from April 1 through October 31. Equipment performance characteristics were evaluated during the 1985 disinfection season, and disinfection performance characteristics were optimized during the 1986 season. The evaluation documents the effect of cooling water temperatures on equipment performance, and the utilization of ozone contactor off-gas control of disinfection performance. The capital cost of both ozone systems represented about eight percent of the plants' total construction cost. The ozone system O & M cost represents about 1.9 percent and 3.7 percent of the total plant O & M cost at the Belmont and Southport plants, respectively.     

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.     

Wastewater Disinfection by Ozone: Influence of Water Quality and Kinetics Modeling

Wastewater disinfection by ozone was investigated at pilot scale on different effluents. The organic matter (COD and TOC) was shown to have the biggest influence on the ozone demand of the effluents. Disinfection of fecal indicators could be modeled as the reaction on a double population. The presence of more resistant microorganisms results in the need for higher treatment doses and a tertiary filtration when the effluent has to meet the stringent Title 22 standard. Eventually, the high virucidal power of ozone makes it very attractive when viruses are targeted.     

Wastewater Disinfection With Ozone - Process Control And Operating Results

The City of Indianapolis, Indiana operates two 125 mgd advanced wastewater treatment plants with ozone disinfection. The rated capacity of the oxygen-fed ozone generators is 6,380 Ib/day, which is used to meet geometric mean weekly and monthly disinfection permit limits for decal conforms of 400 and 200 per 100 mL, respectively. Since 1989, a disciplined process monitoring and control program was initiated. Records indicate a significant effect on process performance due to wastewater flow, contactor influent fecal coliform concentration, and ozone demand. Previously, ozone demand information was unknown. Several tasks/studies were performed in order to better control the ozone disinfection process. These include the recent installation of a pilot-scale ozone contactor to allow the plant staff to measure ozone demand on a daily basis. Also, tracer tests were conducted to measure contactor short-circuiting potential. Results demonstrated a noticeable benefit of adding additional baffles. Results also indicated operating strategies that could maximize fecal coliform removal, such as reducing the number of contactors in service at low and moderate flow conditions.     

臭氧消毒的控制参数选取和数学模型

对大庆油田六厂采油污水进行臭氧灭菌试验,结果表明,只要O3能够有效地传入污水中,则在2min内就能有效地杀死其中的细菌。在此基础上,对传统臭氧消毒模型进行修正;并提出,采用“即时O3需要量(X)”作为控制参数更利于O3利用效率的提高。     

Principles of Ozone Oxidation and Disinfection Design

The efficiency of ozone for different purposes can be determined by different laboratory tests. It is necessary to use a specific test for each aim of ozonation. Consequently, the design of commercial ozone–water contact systems can be determined in relation with the purpose of ozonation: virucide effect, oxidation of pollutant, clarification improvement or wastewater disinfection.     

Advanced Sewage Treatment with Ozone Under Excess Sludge Reduction,Disinfection and Removal of EDCs

A new advanced treatment system, which consists of biological nutrient removal process combined with reduction of excess sludge by ozonation and phosphorus recovery by crystallization and polishing-up ozonation process, was developed based on the fundamental studies and demonstrated by the demonstration plant set in AICHI EXPO 2005. Reduction of withdrawn excess sludge by 90% and phosphorus recovery by 70% were accomplished without any adverse effects on biological nutrient removal. The concentrations of SS, BOD, T-P and T-N in the effluent were less than 1.0, 3.0, 0.5 and 10 mg/L, respectively. EDCs were reduced to almost undetectable level and 2-log disinfection of Bacillus subtilis was established. The energy amount required for the operation was saved by 40% when compared with a conventional system to get the same level of water quality.     

Economic and Environmental Benefits of Ozone in Ozone Laundering Systems

Three primary benefits (advantages) of properly designed and operated ozone laundering systems have been proven in successful commercial installations – microbiological kills/inactivation of all microorganisms found in linens to be laundered; economic cost savings and significant environmental benefits. Each of these benefits of ozone laundering is described and quantified in the Ozone Laundry Handbook by Rice et al. (2009 Rice, R.G., Cardis, D., Daniels, R., Tapp, C., DeBrum, M. and Watt, J. 2009. The Ozone Laundry Handbook, A Comprehensive Guide for the Proper Application of Ozone in the Commercial Laundry Industry, San Luis Obispo, CA, , USA: Published by ClearWater Tech, LLC.  [Google Scholar]). In this paper, two of these benefits, Cost Savings and Significant Environmental Benefits are discussed.     

Changes in the Chemical Nature of a Biologically Treated Wastewater During Disinfection by Ozone

Pilot plant studies were carried out on the effect of ozone on the chemical content of a secondary domestic and industrial sewage. Results are expressed in terms of COD, BOD₅, nitrite ion concentrations, bacterial counts, XAD-4-extraetable compounds, and free amino acid concentrations. Ozone dosages of 6 to 12 mg/L were found to reduce levels of fecal bacteria, COD and nitrite ion concentrations significantly, to modify the nature and the concentration of XAD-4-extraetable compounds, and to increase the concentration of free amino acids.     

Ozone as a Pretreatment Method for Antibiotic Contaminated Wastewater and Sludge

ABSTRACT

The capability of ozone to reduce the hazardous impact of environmentally persistent antibiotic tiamulin in term of toxicity reduction and enhancement of biodegradability was investigated. Different ozone doses were applied but ozonation was not effective enough to increase the biodegradability of tiamulin in the aqueous phase. The opposite effect was observed in anaerobic digestion experiments, where ozonation as a pretreatment step of antibiotic-contaminated sludge detoxify tiamulin and improves biogas production for 75%. As confirmed by ¹H NMR and HPLC-HRMS analyses, the tiamulin molecule completely reacts with ozone at low ozone/COD molar ratio of 0.03, primarily attacking the vinyl double bond with further oxidation of sulfur and nitrogen atom, and gradual decomposition of tiamulin skeleton.     

Evaluation of Empirical Process Design Relationships for Ozone Disinfection of Water and Wastewater

A research program was undertaken to examine the dose-response of Escherichia coli ATCC 11775 in ozone demand-free phosphate buffer solution and in a high quality secondary wastewater effluent with a total organic carbon content of 8 mg/L and a chemical oxygen demand of 26 mg/L. The studies were conducted in benchscale batch reactors for both water types. In addition, studies using secondary effluent also were conducted in a pilot-scale, semi-batch reactor to evaluate scale-up effects. It was found that the ozone dose was the most important design parameter in both types of water. Contact time was of some importance in the ozone demand-free water and had no detectable effect in the secondary effluent.

Pilot-scale data confirmed the results obtained at bench-scale for the secondary effluent. Regression analysis of the logarithm of the E. coli response on the logarithm of the utilized ozone dose revealed that there was lack-of-fit using the model form which has been used frequently for the design of wastewater disinfection systems. This occurred as a result of a marked tailing effect of the log-log plot as the ozone dose increased and the kill increased. It was postulated that this was caused by some unknown physiological differences within the E. coli population due to age or another factor.     

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.     

氯胺消毒及高锰酸钾氯胺联用消毒

以城市污水处理厂二级出水为试验水样,观察了氯、氯胺单独消毒工艺以及高锰酸钾与氯胺协同消毒工艺的消毒效能,同时比较了投药总量相同条件下单独氯胺消毒工艺及高锰酸钾与氯胺协同消毒工艺的消毒效能以及对THMs生成的影响。结果表明,对于污染严重,尤其是耗氯物质含量较高的污水,氯消毒效果受到极大影响,氯胺消毒的效果要略好于氯消毒的效果,而高锰酸钾与氯胺协同消毒工艺的消毒性能明显优于单独氯胺消毒工艺,并且能够进一步降低THMs的生成量。因此,高锰酸钾与氯胺协同消毒工艺可以使处理后水质从微生物安全性到化学安全性两方面均得到提高。     

O3和Fenton试剂化学氧化处理酸性玫瑰红印染废水

针对酸性玫瑰红印染废水的高色度、难以生物降解的特点,采用O3和Fenton试剂进行氧化处理,通过实验确定了最佳运行参数。研究表明:在最佳运行参数下,O3处理废水的色度去除率大于99％,CODcr的去除率30％; Fenton试剂处理色度去除率大于99％,CODcr去除率47％。两种化学氧化处理都可以大大提高模拟废水的可生化性。     

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.     

Ozone Application for Postharvest Disinfection of Tomatoes

Ozone is an effective alternative for the postharvest treatment of fruits and vegetables. The purpose of this study was to evaluate the ozone application in gaseous or aqueous phases for postharvest disinfection of tomatoes (Lycopersicon esculentum Mill) cultivar FA-180. Fruits harvested at the breaker stage were exposed to ozone concentrations of 25 and 45 mg m^?3 for 2 h per day during 16 days, at non-controlled temperature and relative humidity. Exposure to ozone during storage extends the shelf-life of tomatoes, besides preserving its sensory attributes. Mature tomatoes, inoculated with Escherichia coli ATCC 25922, were washed with ozonated water containing 0.5 to 1.0 mg L^?1 during 15 to 30 min. To achieve an adequate disinfection, 1 mg L^?1 and 15 min are recommended. The disinfection with ozonated water was effective.     

Ozone Disinfection of Vibrio Vulnificus in Artificial Seawater

Disinfection experiments were performed using Vibrio vulnificus exposed to ozonated artificial seawater (ASW). Residual oxidant concentration was monitored using a modified neutral KI test. Inactivations of V. vulnificus cultures were performed in 500 mL flasks containing ozone-treated seawater. The laboratory scale trials reduced numbers of V. vulnificus an average of 8 log units after 240 seconds with an initial oxidant concentration of 5.3 mg/L. Ozone is a very effective bactericidal (Blogoslawski et al., 1975) and viricidal agent (Englebrecht and Chain, 1985; Farooq and Akhaque, 1983), and is able to degrade toxins (Blogoslawski et al., 1979; Thurberg, 1975). Ozone gas is one of the most powerful oxidizing gases known. When ozone comes in contact with bacteria it can react directly to inactivate the organism. When ozone comes in contact with the constituents of seawater it reacts with bromide ion to form hypobromous acid, hypobromite ion and bromate ion (Haag and Hoign6, 1984) which are stable and effective disinfecting agents.