Combination Of Ozone Research Articles

Efficacy of aqueous ozone combined with sodium metasilicate on microbial load reduction of fresh-cut cabbage

ABSTRACT The mechanism behind the sterilization effects of ozone in combination with sodium metasilicate (SM) is still unknown. Therefore, the effects of treatments of fresh-cut cabbage with aqueous ozone combined with SM on microbial growth, and produce quality were evaluated in detail during storage. The results indicated that treating the cabbage with 2 ppm aqueous ozone combined with 0.4% SM for 2 min achieved acceptable microbial quality, and reduced E. coli O157:H7 counts by 3.33 logs compared with the control samples after 12 d of storage. This combination treatment had no negative effects on sensory characteristics (appearance and off-odor), color, and the contents of vitamin C, total phenols and carotenoids. The combined ozone-SM treatment was more effective than individual treatments in controlling the pathogens and native microorganisms on fresh produce and could extend the storage up to 12 d. This hurdle treatment may be used as a processing intervention to control microorganism.

Effect of ozone and ultrasound treatments on polyphenol content, browning enzyme activities, and shelf life of tender coconut water

The sweet, clear, aqueous part inside the immature green coconut is referred as tender coconut water (TCW). Although several processing techniques have been attempted, preserving the TCW with its wholesome natural property is yet to be achieved. In the present investigation, the nonthermal treatments (ozone and ultrasound) in combination with nisin were used to extend the shelf life of TCW, and the results were compared with heat-treated TCW. The reduction in microbial counts, retention of phenolics (64%) and flavonoids (70%), and inactivation of polyphenol oxidase and peroxidase enzymes of the fresh TCW by ozone with nisin treatment indicated its superiority over other treatments for preservation. The heat-treated and ozone with nisin-treated TCW were sensorily acceptable for 3 weeks, whereas, ultrasound with nisin-treated TCW was unacceptable after 2 weeks of refrigerated storage. Hence, ozone with nisin can be used for the preservation of TCW under refrigerated conditions. Practical applications The work described here shows that the preservation of highly perishable TCW is possible by the use of nonthermal processing methods. The currently used thermal processing of TCW alters its sensory quality; however, use of ozone in combination with nisin was not only able to preserve its nutritional and sensory quality but was also extended its shelf life at refrigerated temperature. Ozone can be easily used at the industrial level to preserve the quality of TCW.

Development of a full-cycle water remediation process

Abstract A full-cycle water remediation process has been developed by expanding the capacity of an existing water treatment technology that uses combined ozonation and ultrafiltration membrane processes. The developed water reclamation process treated the effluent of a full-scale wastewater treatment plant in Canada that uses biological treatment processes to treat municipal wastewater, and reduced the colour, turbidity, suspended solids, iron and pathogen content of the effluent. The removal of hardness from the wastewater effluent was accomplished by the precipitation process. The use of lime (0.2 g/L) in the presence of NaOH operating at pH 11 showed the best results, reducing the water hardness by 89.1%. The advanced treatment capability of ozonation (8–10% w/w) and polyvinylidene fluoride (PVDF) hollow fiber ultrafiltration (UF) membrane produced a reliable source of water for municipal, industrial and agricultural use. The developed process offers important environmental benefits by reducing the diversion of water from sensitive ecosystems, decreasing wastewater discharge and preventing pollution.

Antimicrobial efficacy of aqueous ozone in combination with short chain fatty acid buffers

SummaryBackgroundMitigating surface contamination by microbes such as S. aureus, Salmonella enterica, or Klebsiella pneumoniae, is an ongoing problem in hospital and food production environments.AimTo determine whether addition of buffering solution to source water used for manufacture of aqueous ozone increases ozone efficacy against ozone-resistant bacterial species.MethodsAntimicrobial effects of aqueous ozone were studied in combination with acetate, propionate, or butyrate short chain fatty acids (SCFA) as well as citrate or oxalate buffer formulations against Staphylococcus aureus on glass coupons. Aqueous ozone combined with an acetate buffer was also evaluated against Salmonella enterica and Klebsiella pneumoniae.FindingsThe acetate, propionate, and butyrate buffered aqueous ozone combinations had a significant 3–4 log reduction of S. aureus (P<0.05) colony forming unit (CFU), while citrate or oxalate buffered aqueous ozone, although statistically significant versus buffer alone, had less activity. Treatment of S. aureus, S. enterica, or K. pneumoniae with acetate buffered aqueous ozone also resulted in a 4 log or greater reduction in CFUs post-treatment for all three species, versus treatment with water alone.ConclusionsAll buffer systems tested had a significantly greater reduction in CFUs following treatment with the combination of buffer and ozone, compared to treatment with buffer or ozone individually, which has not been previously reported for hard surfaces. These results suggest that SCFA buffered ozone has greater anti-bacterial activity relative to either agent alone, and the activity is independent of the buffering activity. Thus, these formulations have potential to sanitize without residues, using an environmentally conscious formulation.

Fetal growth outcomes following peri-implantation exposure of Long-Evans rats to noise and ozone differ by sex

BackgroundExposure to air pollution and high levels of noise have both been independently associated with the development of adverse pregnancy outcomes including low birth weight. However, exposure to such environmental stressors rarely occurs in isolation and is often co-localized, especially in large urban areas.MethodsThe purpose of this study was to compare the effects of combined exposure to noise (N) or ozone (O3), compared to either exposure alone. Long-Evans dams were exposed to air or 0.4 ppm ozone for 4 h on gestation day (GD) 5 and 6, coinciding with implantation receptivity. A subset of dams from each exposure group was further exposed to intermittent white noise (~ 85 dB) throughout the dark cycle following each inhalation exposure (n = 14 − 16/group). Uterine artery ultrasound was performed on GD 15 and 21. Fetal growth characteristics and indicators of placental nutrient status were measured at GD 21.ResultsExposure to ozone + quiet (O3 + Q) conditions reduced uterine arterial resistance at GD 15 compared to air + quiet (A + Q) exposure, with no further reduction by GD 21. By contrast, exposure to air + noise (A + N) significantly increased uterine arterial resistance at both GD 15 and 21. Notably, while peri-implantation exposure to O3 + Q conditions reduced male fetal weight at GD 21, this effect was not observed in the air + noise (A + N) or the ozone + noise (O3 + N) exposure groups. Fetal weight in female offspring was not reduced by ozone exposure alone (O3 + Q), nor was it affected by air + noise (A + N) or by combined ozone + noise (O3 + N) exposure.ConclusionsThese data indicate that exposure to ozone and noise differentially impact uterine blood flow, particularly at mid-gestation, with only ozone exposure being associated with sex-dependent fetal growth retardation in male offspring.

Profitable sludge management via novel combined ozone disperser pretreatment coupled with membrane bioreactor for treating confectionary wastewater

Abstract In this study, two lab scale membrane bioreactor (MBR) with working volume of 12 L were used to study the effect of sludge pretreatment over period of 120 d. Among the two MBRs one was used as a control (U-MBR) and another one was used as experimental (P-MBR). After attaining stable operation, 540 mL/d of mixed liquor was withdrawn and subjected to Ozone Disperser Pretreatment (ODP). ODP results with 22% of Chemical Oxygen Demand (COD) solubilisation and 19% of solids reduction. Upon recycling ODP sludge, 36% of sludge reduction was achieved in P-MBR, when compared to U-MBR. The yield observed of P-MBR (0.165 g SS/g COD) is lower than U-MBR (0.254 g SS/g COD). The effluent organic concentration of both MBRs is in the range of 6–12 mg/L COD. Incorporation of ODP in P-MBR, reduces the cost to manage sludge for treating 1 m3 of wastewater from −0.0334 to −0.0276 USD.

New approaches to solar Advanced Oxidation Processes for elimination of priority substances based on electrooxidation and ozonation at pilot plant scale

Abstract The main objective of this work is to compare various Advanced Oxidation Processes based on solar photo-Fenton at circumneutral pH (by adding EDDS as iron complexing agent), such as solar photo-electro-Fenton process and solar ozonation in combination with Fenton like processes (O3/Fe2+/H2O2, O3/Fe3+/H2O2 and Solar/Fe3+/O3/H2O2), for the elimination of four microcontaminants (MCs) (Terbutryn, chlorfenvinphos, pentachlorophenol and diclofenac) at 200 μg/L each and in different water matrices. These compounds were selected as Priority Substances listed in European Commission directives (2013/39/EC and 2008/105/EC Directives). Research was carried out at pilot plant scale in a 30 L electrochemical system (cells made by an anode of boron-doped diamond thin film on a niobium mesh (Nb-BDD) and a carbon-polytetrafluoroethylene (PTFE) GDE as the cathode), a 20 L ozone reactor and three different solar photoreactors (39 L, 45 L and 120 L) based on compound parabolic collectors (CPC) and connected to the non-solar oxidation systems. Results showed successful elimination of at least 80% of MCs for all the technologies tested. However, solar photo-Fenton at circumneutral pH showed better performance than solar photo-electro-Fenton and even electro-Fenton processes. In addition, the combination of ozone with solar radiation showed promising results since almost a complete elimination of MCs was attained with a significant lower ozone consumption than when applying ozone in the dark (with or without the assistance of Fenton´s reagent).

Options for Removing Refractory Organic Substances in Pre-Treated Process Water from Hydrothermal Carbonization

Granular activated carbon (GAC) adsorption, as well as ozonation in combination with biodegradation was investigated in order to remove refractory organics from biologically pre-treated process waters (PW) produced by the hydrothermal carbonization (HTC) of spent grains and fine mulch. Kinetic tests revealed that the organics in spent grains PW had much lower molecular weights than organics in fine mulch PW. Moreover, isotherms showed that they were more strongly adsorbable. This was confirmed in GAC column experiments, where the breakthrough curves could be predicted fairly well by a dynamic adsorption model. On the other hand, ozonation had a stronger effect on fine mulch PW with respect to an enhancement of the aerobic degradability. Thus, the type of input material determines the properties of soluble reaction products from the carbonization process that must be accounted for when selecting the most suitable post-treatment method for HTC PW. However, adsorption on granular activated carbon should always be the final stage.

Comparative Clinical Study the Effectiveness of Plasmapheresis with Ozone Therapy in the Prevention of Ocular Herpes Recurrence

The purpose. To study the clinical efficacy of plasmapheresis in combination with ozone therapy in the prevention of ocular herpes recurrence.Patients and methods. There were 108 patients with relapsing forms of eye herpes (herpes keratitis, keratouveitis, uveitis) under our observation. 56 men and 52 women, aged between 37 and 62 old (47,6 ± 11,5) were involved into the research. The number of patients included into the main group were 54 (54 eyes), and also 54 patients (54 eyes) were in the comparison group. Results. In the main group, the patients undergone a course of anti — relapse therapy with plasmapheresis in combination with therapeutic ozone in combination with traditional treatment from 54 persons — the expressed therapeutic effect was registered in 48-and (88.8 %) patients, the partial therapeutic effect (decrease in the frequency of relapses) was observed in 6 (11.1 %) patients, the absence of effect was not registered in any patient. In the control group, consisting of 54 patients, which undergone anti-relapse therapy with plasmapheresis in combination with traditional treatment, expressed therapeutic effect (no exacerbations) was observed in 31 (57.4 %) patients, a partial therapeutic effect (decrease in the frequency of relapses) was observed in 17 (31.5 %) patients, and the absence of effect — in 6 (11.1 %) patients.Conclusions. For prevention of ophthalmic herpes recurrence and optimal results of anti-relapse therapy of patients with recurrent ophthalmic herpes were shown concurrently with the beginning of the standard antiherpetic treatment courses of plasmapheresis with ozone therapy and spend it as monotherapy at the end of treatment.

Ozone-based treatments for inactivation of Salmonella enterica in tree nuts: Inoculation protocol and surrogate suitability considerations

The feasibility of using gaseous ozone, alone or in combination with other treatments, to decontaminate in-shell almonds and pistachios, prepared under different pathogen-inoculation conditions, was explored. Nuts were inoculated with either Salmonella enterica serovar Enteritidis or a potential Salmonella surrogate, Enterococcus faecium OSY 31284. The effect of inoculation method (with or without vacuum application), and of drying inoculated nuts (up to three days) on treatment efficacy was investigated. Inoculated nuts were subjected to gaseous ozone alone (almonds, pistachios) or ozone in combination with heating in brine solution (pistachios). Ozone treatment included application of vacuum (10 in Hg), followed by vessel pressurization to 12.5 psig with ozone‑oxygen mixture (160 g ozone/m3 gas mixture) and holding for 30 min. Heating was conducted in a brine solution (5% NaCl) at 70 °C, for 10 min. Ozone-based treatments were significantly more effective (P < 0.05) on almonds than pistachios, with maximum S. Enteritidis reduction of 2.9 vs. 0.8 log CFU/g, regardless of inoculation method or the drying time. Treatment of inoculated pistachios with heated brine and gaseous ozone reduced S. Enteritidis population by 5.0 to 7.0 log CFU/g and was not significantly more effective than treatment with heated brine alone (reduction of 4.8 to 7.1 log CFU/g). Application of vacuum during inoculation increased bacterial population on nut kernels by approximately 1.2 log CFU/g, but the increase in inoculum population had no effect on inactivation of either species of inoculated bacteria. Decontamination treatments were less effective against both bacteria by up to 2 log CFU/g when drying time of inoculated nuts increased. E. faecium was significantly more resistant to heat and ozone treatment (P < 0.05) than was S. Enteritidis on pistachios, but not on almonds. Results of this study show that laboratory methodology affects observed treatment effectiveness. Considering its high resistance to the heat-ozone combination, E. faecium may not be a suitable surrogate for S. Enteritidis during processing of pistachios by this treatment. Efficacy of ozone gas to decontaminate S. Enteritidis-inoculated nuts depends heavily on the type of nut. Although reductions of S. Enteritidis populations on in-shell pistachios are low, treatment of in-shell almonds resulted in greater reductions, indicating the promise of this technology to enhance the safety of specific nut products.

Cascaded Plasma–Ozone Injection System: A Novel Approach for Controlling Total Hydrocarbon Emission in Diesel Exhaust

The hydrocarbons present in diesel exhaust, although treated as minor pollutants, are equivalent to some of the major pollutants in terms of toxicity, contamination and harmfulness to the environment and hence, any effort towards treating hydrocarbons is a welcome step before letting the same into the atmosphere. In this current work two non-thermal plasma techniques viz., electrical discharge plasma (direct plasma) and ozone injection (indirect plasma) were coupled while treating the diesel exhaust for possible mitigation of total hydrocarbons (THC). The work is intended to provide a cleaning system which is non-catalytic, non-adsorbent and non-thermal plasma based one leading to less utilization of electrical energy and long lasting. The study was conducted at laboratory level with controlled flow conditions of the diesel exhaust. It was observed that the combined discharge plasma and ozone injection has resulted in more of THC reduction/conversion to the tune of 95% at about plasma specific energy of 55 J/L and with an injection of 1656 ppm of ozone. The individual as well as cascaded treatment techniques are discussed in detail and a comparative analysis of the same has been provided.

Short-term effects of combined elevated ozone and limited irrigation on accumulation and allocation of non-structural carbohydrates in leaves and roots of poplar sapling

Short-term effects of combined elevated ozone and limited irrigation on accumulation and allocation of non-structural carbohydrates in leaves and roots of poplar sapling

The efficacy of intra-articular PRP, Ozone and Ozone+PRP injections in patients with osteoarthritis.

Osteoarthritis (OA) is the most common form of arthritis and some joints are effected more than others. The prevalence of OA increases with age and it represents the major problem for functional impairment in older patients. Non-surgical treatment with oral drugs is not suitable for many patients suffering from gastric disorders, high blood pressure or different heart diseases. Intra-articular injections are a promising solution in these cases.&#x0D; This study was performed to compare the efficacy and safety of ozone injections, PRP (platelet rich plasma) injections and combined ozone plus PRP injections in patients with symptomatic knee OA. &#x0D; 120 patients were diagnosed of OA according to the criteria of the American College of Rheumatology and included into this study. Patients were randomly divided into three equal groups (40 patients each group). We include patients whose VAS score was 5 or above. Patients with inflammatory, endocrine and metabolic disturbances, and patients who had meniscectomy within the past 10 years, extra articular surgery within the last year, arthrocentesis in last 6 months or any drug given intra-articular were not included. We did not include either patients with misalignment.&#x0D; Patients in the first group were treated with intra-articular injections of ozone/oxygen gas mixture 2 times/week, at 10 µg/mL concentration and a volume of 5 mL for a total of 12 injections.&#x0D; Patients in the second group were treated only with PRP injections once a week for a total of 3 times.&#x0D; Patients in the third group were treated with intra-articular injections of Ozone+PRP (10 µg/ml concentration, 5 ml volume) once a week for a total of 3 times.&#x0D; The pain levels of patients were measured with Visual Analog Scale (VAS). Side effects were collected using an open list record.&#x0D; All the groups improved their baseline VAS in a significant way, although the group with the best results was group 3 with the combination of ozone and PRP in the same injection.&#x0D; We are planning further studies including systemic ozone in order to improve more the pain in our patients.

Shelf Life Extension of Greenhouse Tomatoes Using Ozonation in Combination with Packaging under Refrigeration

ABSTRACTGreenhouse tomatoes were exposed to gaseous ozone for 1 h at different concentrations (0.5, 1, and 2 mg/L), packaged in low-density polyethylene (LDPE) bags and stored at 4 ± 1 °C for 49 days. Peel firmness, color parameter, browning index values, weight loss, acidity, total viable count, psychrotrophs, yeasts and molds, and sensory analyses were carried out. Results showed significant differences on parameters determined, depending on storage time and treatment (p < 0.05). Sensory evaluation showed that ozonated tomatoes (especially at 2 mg/L) retained a fresh character compared to untreated samples, for an extended period of ca. 15 days.

Ozonized water with plant antimicrobials: An effective method to inactivate Salmonella enterica on iceberg lettuce in the produce wash water

Post-harvest washing of produce is performed to remove physical debris and to lower microbial load. The use of ozone in combination with plant-based antimicrobials was evaluated as an alternative to conventional sanitizers such as chlorine. Plant based antimicrobials that were evaluated in combination with ozone included oregano oil, carvacrol, Quillaja saponin and olive extract. Ozone was dispersed in phosphate buffered saline (PBS), following which individual antimicrobials or their combinations were added. Iceberg lettuce leaves (10 g portions) inoculated with Salmonella enterica serotype Newport (6.5 ± 1 log CFU/g) were added to the wash suspension. The leaves were tested for reduction in S. Newport population after 60, 90 and 120 min of treatment. Exposure to ozonized water for 120 min resulted in a 2.1 log CFU/g (p < 0.05) reduction in S. Newport population. The addition of 0.1% oregano oil to ozonized water resulted in 3 log CFU/g reduction after 120 min but a 4.1 log CFU/g reduction after 60 min, indicating that the antioxidant property of oregano oil might have diminished ozone activity and resuscitated injured S. Newport cells. The addition of 5% olive extract to ozonized water resulted in 4.2 log CFU/g reduction of S. Newport after 120 min (p < 0.05) of treatment. While 5% olive extract did not confer protection to S. Newport cells from ozone, 1% olive extract resulted in higher S. Newport survival after 120 min treatment than the 60 min treatment. The use of carvacrol (0.1%, 0.3% and 0.5%) in ozonized water reduced the pathogen population to below the limit of detection (10 CFU/g) (p < 0.05) which was in excess of 6 log CFU/g. These results indicate that the efficacy of ozone is compounded by the addition of certain plant-based antimicrobials when used at optimum concentrations. Ozone combined with plant antimicrobials could serve as an effective alternative to sanitizers currently used for washing and processing of produce.

Molecular response of poplar to single and combined ozone and drought

High concentration in ground-level ozone (O3) and water deficit affect forest ecosystems service. Previously we found intercellular CO2 concentration and isoprene emission were affected by the combination of O3 and drought, but the molecular mechanisms controlling these phenotypes are still open questions. In this study, we investigated the stomatal conductance (gs) and transcriptome changes in an O3-sensitive hybrid poplar exposed to two O3 levels [charcoal-filtered ambient air (CF) and non-filtered ambient air plus 40 ppb (NF40)] and two water conditions [well-watered (W) and moderate drought (D)]. NF40 reduced the gs more under D than W. We identified the differentially expressed genes (DEGs) from pairwise comparisons and found the poplar's molecular response to drought was counteracted by elevated O3. From nine clusters obtained through K-means clustering, 12 core transcription factors were identified. DEGs involved in isoprene biosynthesis and phytohormones signal pathways indicate the molecular response and stomatal closure of poplar under O3 and/or drought might be through MEP/DOXP and ABA-dependent pathways. In addition, 102 Helitrons capturing DEGs were involved in response to O3 and/or drought and related with ABA-dependent pathway. This integrated analysis provides multi-dimensional insights to understand the molecular response to the combination of O3 and drought.

Temporal regulation of terpene synthase gene expression in Eucalyptus globulus leaves upon ozone and wounding stresses: relationships with stomatal ozone uptake and emission responses

Ozone and wounding are key abiotic factors but, their interactive effects on temporal changes in terpene synthase gene expression and emission responses are poorly understood. Here, we applied combined acute ozone and wounding stresses to the constitutive isoprenoid-emitter Eucalyptus globulus and studied how isoprene, 1,8-cineole, and isoledene synthase genes were regulated, and how the gene expression was associated with temporal changes in photosynthetic characteristics, product emission rates, and stomatal ozone uptake through recovery phase. Photosynthetic characteristics and emission rate of isoprene, 1,8-cineole, and isoledene were synergistically altered, while three TPS gene expressions were antagonistically altered by combined stress applications. A time-delay analysis indicated that the best correspondences between gene expression and product emission rates were observed for 0 h time-shift for wounding and 0–2 h time-shifts for separate ozone, and combined ozone and wounding treatments. The best correspondence between ozone uptake and gene expression was observed for 0–4 h time-shifts for separate ozone and combined ozone and wounding treatments. Overall, this study demonstrated that expression profiles of isoprene, the monoterpene 1,8-cineole, and the sesquiterpene isoledene synthase genes differentially influenced their corresponding product emissions for separate and combined ozone and wounding treatments through recovery.

Ozone/peroxide advanced oxidation in combination with biofiltration for taste and odour control and organics removal

The objective of this pilot-scale study was to investigate the effectiveness of incorporating ozone (O3) and advanced oxidation (hydrogen peroxide/ozone: H2O2/O3) in combination with biofiltration for taste and odour control, organic carbon removal, and disinfection byproduct (DBP) precursor reduction. Implementation of O3 and H2O2/O3 with and without biofiltration was investigated at pilot-scale in terms of geosmin, 2-methylisoborneol (MIB), and DBP precursor removal efficiency. Two media types (granular activated carbon and anthracite) were compared in conjunction with investigating the impact of pre-oxidation with O3 (2 mg/L) and varying H2O2/O3 mass ratios (0.1, 0.2, 0.35, and 0.5 mg/mg). When O3 preceded biologically active carbon (BAC) or biologically active anthracite, geosmin removals of 80% and 81%, respectively, were observed at 10 °C; this increased to 89% and 90%, respectively, at 16 °C. Optimal MIB removal (67%) was achieved with 0.1 H2O2/O3 (mg/mg) in combination with BAC at 16 °C.In general, geosmin proved to be more amenable to biodegradation than MIB. BAC without pre-oxidation removed 87% geosmin and 85% MIB, at 22 °C. MIB removals decreased to 60% and 46%, respectively at 16 °C and 10 °C. The application of 0.2 H2O2/O3 (mg/mg) prior to BAC provided treatment which effectively removed geosmin and MIB. However, in terms of DBP precursor reduction, there was no beneficial impact of H2O2 addition on trihalomethane or haloacetic acid formation potentials.

Identifying technical synergy effects for organic micro-pollutants removal

Abstract Processes for the removal of organic micro-pollutants (OMPs) from wastewater treatment plant's (WWTPs) effluents have been tested over decades, and have recently found their way into practice. Operators of WWTPs are confronted with the question of efficiency and the choice of economical process (combination). So far, a systematic approach regarding the selection of the appropriate process (combinations) is missing. There is no information available which technology is best suited for removal of OMPs and other conventional pollutants for good conditions in waterbodies. This study evaluates 52 pilot and full-scale studies regarding their removal efficiencies of various OMPs by advanced processes (adsorption and ozonation) in combination with/without filtration. The results provide a comprehensive picture of the complex state of knowledge and show that technical synergy effects enable the reduction of a wide range of OMP in combination with other conventional parameters, e.g. solids and phosphorous.

Ozone injection with or without percutaneous microdiscectomy for treatment of cervical disc herniation

This retrospective study compared the efficacy of combined percutaneous ozone injection and percutaneous discectomyto percutaneous ozone injection alone for the treatment of cervical disc herniation. Patients with cervical disc herniation who were enrolled in our hospital from October 2010 to June 2015 were divided into two groups: 1) treated with percutaneous ozone injection alone (control; n= 19); and 2) those treated with combined ozone injection and percutaneous microdiscectomy (combined treatment; n= 28). The efficacy of the combined treatment was evaluated relative to the control by visual analogue scale (VAS) and the modified Macnab standard. Effective treatment was defined as excellent or good, and ineffective as fair or poor. No major complications occurred in either group. For the control group, the VAS scores dropped from 6.75 ± 2.34 before surgery to 2.78 ± 1.85 immediately after surgery, and to 4.18 ± 1.46 during the follow-ups. For patients who received the combined treatment, the VAS scores were 7.12 ± 2.03 before surgery, 3.86 ± 2.87 immediately after surgery, and 3.27 ± 1.53 during the follow-ups. At the 6-month follow-up, 73.7% (14 from 19 patients) in the control group and 89.2% (25 from 28 patients) in the treatment group were judged to have received effective treatment. Difference in efficacy between two groups of treatment was statistically significant (P= 0.033). The rate of effective treatment in patients who received combined percutaneous microdiscectomy and ozone injection was higher than that of patients who received ozone injection alone. Combination of percutaneous microdiscectomy and ozone injection might be an effective method to treat patients with cervical disk hernia.