Medium-pressure UV Lamps Research Articles

Inactivation efficacy and mechanisms of wavelength-specific UV sources for various strains of Legionella pneumophila serogroup 1

Infections of Legionnaires' disease in the United States caused by Legionella have increased ninefold between the years 2000–2018. Legionella harbored in biofilms or inside amoeba within premise plumbing can be more resistant to disinfectants, thus causing treatment challenges. Ultraviolet-light emitting diodes (UV-LEDs) are an emerging water disinfection technology with several advantages over conventional UV lamps. In this study, we evaluated the effects of UV-LEDs (255, 265, and 285 nm), a low-pressure (LP) mercury UV lamp (254 nm), and a bandpass filtered medium-pressure (MP) mercury UV lamp (220 nm) on properties and inactivation of three strains of L. pneumophila serogroup 1. The UV-LEDs emitting at 255 and 265 nm showed greater inactivation performance against all the strains compared to the UV-LED at 285 nm and the LP UV lamp at 254 nm. Our results showed that strains of the same serogroup exhibited different UV sensitivities. Analyses of DNA and protein damage revealed that UV exposure using 254, 255, and 265 nm predominantly causes DNA damage, while protein damage is predominant at 220 nm. Both DNA and protein damage were observed at 285 nm, but the extent of DNA damage was relatively less significant compared to the other wavelengths. Electric energy consumption analysis showed that water treatment using UV-LEDs is currently unsatisfactory compared to conventional LP UV lamps due to the mediocre wall plug efficiency (WPE) of UV-LEDs. However, recent studies indicate that the WPE of UV-LEDs is continuously improving. Overall, our study highlights that UV-LEDs are a promising technology for inactivating waterborne pathogens and have the potential to replace existing UV mercury lamps for water disinfection applications.

Comparative Evaluation of Low- and Medium-Pressure UV Lamps for Photo-degradation of RDX Wastewater

Comparative Evaluation of Low- and Medium-Pressure UV Lamps for Photo-degradation of RDX Wastewater

Photoinduced Reductive C-C and C-Heteroatom Couplings from Bis-cyclometalated Pt(IV) Alkynyl Complexes.

Unsymmetrical dicarboxylato complexes [Pt(tpy)2(O2CR)2] [tpy = cyclometalated 2-(p-tolyl)pyridine, R = Me, CF3] react with the terminal alkynes 4-methoxyphenylacetylene, phenylacetylene, 4-(trifluoromethyl)phenylacetylene or 3,5-difluorophenylacetylene in the presence of a base to produce complexes mer-[Pt(tpy)2(O2CR)(CCAr)], in which the metalated carbon atoms are in a meridional arrangement. Irradiation of the trifluoroacetato derivatives with a 365 nm LED source leads to isomerization to the facial complexes, which can be converted to chlorido derivatives upon reaction with NH4Cl. In contrast, irradiation of the acetato derivatives leads to four different processes, namely, reduction to cis-[Pt(tpy)2], annulations involving one of the tpy ligands and the Cα and Cβ atoms of the alkynyl to give benzoquinolizinium derivatives, isomerization to the facial geometry, or C-O couplings between the acetato ligand and one tpy. The first two processes are favored by the presence of electron-donating groups on the alkynyl, whereas electron-withdrawing groups favor the last two. Irradiation of complexes fac-[Pt(tpy)2(O2CCF3)(CCAr)] with a medium-pressure Hg UV lamp leads to a reductive C-C coupling involving the alkynyl Cα atom and one of the tpy ligands to give pyridoisoindolium derivatives, except for the methoxyphenylacetylide derivative, which is photostable. On the basis of TDDFT calculations, the photoreactivity of the mer complexes is attributed to 3LLCT [π(alkynyl) → π*(tpy)] excited states for annulations or 3LMCT [π(alkynyl) → dσ*] excited states for the rest of the processes, which are accessible through thermal population from 3LC(tpy) states. The C-C couplings from the fac complexes are attributed to photoreactive pentacoordinate intermediates.

UV inactivation of sewage isolated human adenovirus

Adenoviruses are known to be one of the most resistant viruses to UV disinfection. This study determined the inactivation kinetics of adenovirus freshly isolated from sewage samples, and compared the results with reference adenovirus stocks grown in the laboratory. Human adenoviruses were isolated from sewage samples using the HEK 293 cell line. Inactivation kinetics for UV irradiation was determined for monochromatic low pressure (LP) mercury UV lamp (254 nm) and polychromatic medium pressure (MP) mercury UV lamp for each sewage isolate. Eleven (11) isolates were obtained from nine (9) different sewage samples with most isolates belonging to the enteric adenovirus group, specifically adenovirus 41. The average dose required for 4 log inactivation using LP UV lamps for sewage isolates (220 mJ/cm2) was not significantly different (p > 0.1) from the average dose reported for lab-grown enteric adenovirus (179.6 mJ/cm2). Interestingly, the average dose required for 4 log inactivation using MP UV lamps was significantly higher (p = 0.004) for sewage isolates (124 mJ/cm2) when compared to the average dose reported for laboratory stocks of adenovirus 40 and 41 (71 mJ/cm2). Viral capsid analysis using the propidium monoazide (PMA)-qPCR method showed that adenovirus isolates from group F were less affected by exposure to MP UV Lamps than adenoviruses from group D and C. Adenovirus isolates obtained from sewage samples showed greater resistance to UV irradiation compared to laboratory grown strains, although required doses for MP UV were still considerably lower than LP UV. These data suggest that the required fluence for inactivation of adenoviruses in real-world waters may be higher than previously understood.

Effective UV wavelength range for increasing aflatoxins reduction and decreasing oil deterioration in contaminated peanuts

Many studies have demonstrated that UV radiation can degrade aflatoxins (AF) in contaminated foods. However, the effective wavelength ranges for AF decomposition and their impacts on the quality of foods have not been elucidated. This study investigated the AF reduction and oil quality change in peanuts subjected to three types of 17 W low-pressure (LP) UV lamps covering UV-A (Max. emission: 365 nm), UV-B (Max. emission: 310 nm), and UV-C (Max. emission: 254 nm) ranges and a 2000 W medium-pressure UV lamp covering from UV-A to UV-C. We used peeled-kernels for this study since the peanut skin represented an ability to protect AF from being degraded by UV. LP UV-A lamp treatment has shown the highest AF reduction in artificially spiked peeled-kernels and no detectable oil deterioration. With the same delivered UV dosage as LP lamp, MP lamp has shown the same level of AF reduction as LP UV-A lamp did, indicating such treatment was energy inefficient. Treating Aspergillus nomius inobulated peeled-kernels by two LP UV-A lamps (2.76 mW/cm2) for 1.0 h reduced 40% of AF if the kernels were milled into 1 mm-diameter particle, implying that exposing the interior part of kernels to UV radiation is necessary for an AF decontamination process. In the oil deterioration test, we found that UV-C strongly induced the oil oxidation of peanuts. Accordingly, we concluded that UV-A is the effective wavelength range to degrade AF as well as maintain the oil quality in foods allowing UV radiation to well penetrate the sample, such as liquid foods with low turbidity or solid foods in the particle form. These results also justify the use of solar radiation as an AF decontamination method, rendering this method to be employed in in areas that lack infrastructure.

UV/sulphite as alternative for UV/H2O2 for micropollutant degradation in drinking water

Abstract The UV/SO32– process can be applied to convert organic micropollutants (OMP). The reaction is induced by UV photolysis of sulphite (preferably using a medium pressure (MP) UV lamp). Although in general it is assumed that the UV/SO32− process is an advanced reduction process, our results show degradation of OMP under both anoxic and oxic conditions. Several recalcitrant OMP even show higher degradation rates under oxic conditions than under anoxic conditions. This conversion is affected by the presence of dissolved organic carbon (DOC), HCO3− and NO3−, and thus was more effective in drinking water than in Milli-Q water. The reaction rate constants of the oxic UV/SO32− process in general are lower than those of a UV/H2O2 process, but in cases where the use of H2O2 is not preferred, the UV/SO32− process may be an interesting alternative.

Comparison of the Efficiency of Ultraviolet/Ultrasonic (UV/US) and Ultraviolet/Zinc Oxide (UV/ZnO) Technologies as Advanced Oxidation Processes in the Removal of Linear Alkylbenzene Sulfonate (LAS), an Anionic Detergent, from Aqueous Media

Surfactants are one of the most commonly found xenobiotics in municipal and industrial wastewater. The purpose of this study was to compare ultraviolet/ultrasonic (UV/US) and ultraviolet/zinc oxide (UV/ZnO) processes in the removal of LAS from aqueous media.In this study, a medium-pressure UV lamp (125 W), an ultrasonic device (400 W and 42 kHz), and ZnO nanoparticles (NPs) were used. The concentration of LAS was 0.5, 14, and 21 mg/L in all experiments. Contact time of 8, 16, and 24 minutes, pH of 3, 7, and 11, and NP concentrations of 50, 100, 150 mg/L were selected. Detergent extraction was performed using methylene blue active substances.The results showed that the efficiency of UV/US process in the removal of LAS was 89.35%, while the removal efficiency of UV/ZnO process was 81.27%. In both processes, the rate of detergent removal increased by elongating the contact time from 8 to 24 minutes. The efficiency of UV/US process in LAS removal was greater than that of the UV/ZnO process. The findings showed that the removal efficiency of UV/US process was directly correlated with pH, while it had an inverse correlation with the removal efficiency of UV/ZnO process.

Colour Changes during the Carbamazepine Oxidation by Photo-Fenton

The oxidation of aqueous solutions of carbamazepine is conducted using the Fenton reagent, combined with the photolytic action of a 150 W medium pressure UV lamp, operating at T = 40 °C. The effect of acidity is analysed at an interval pH = 2.0–5.0, verifying that operating at pH = 5.0 promotes colour formation (Colour = 0.15 AU). The effect of iron is studied, finding that the colour of the water increases in a linear way, Colour = 0.05 + 0.0075 [Fe]0. The oxidising action of hydrogen peroxide is tested, confirming that when operating with [H2O2]0 = 2.0 mM, the maximum colour is generated (Colourmax = 0.381 AU). The tint would be generated by the degradation of by-products of carbamazepine, which have chromophoric groups in their internal structure, such as oxo and dioxocarbazepines, which would produce tint along the first minutes of oxidation, while the formation of acridones would slowly induce colour in the water.

Influence of medium pressure UV lamp in hot tub water treatment on disinfection by-products concentration

Influence of medium pressure UV lamp in hot tub water treatment on disinfection by-products concentration

Potential-Driven Electron Transfer Lowers the Dissociation Energy of the C-F Bond and Facilitates Reductive Defluorination of Perfluorooctane Sulfonate (PFOS).

The widespread environmental occurrence of per- and polyfluoroalkyl substances (PFAS) has attracted significant regulatory, research, and media attention because of their toxicity, recalcitrance, and ability to bioaccumulate. Perfluorooctane sulfonate (PFOS) is a particularly troublesome member of the PFAS family due to its immunity to biological remediation and radical-based oxidation. In the present study, we present a heterogeneous reductive degradation process that couples direct electron transfer (ET) from surface-modified carbon nanotube electrodes (under low potential conditions) to sorbed PFOS molecules using UV-generated hydrated electrons without any further chemical addition. We demonstrate that the ET process dramatically increases the PFOS defluorination rate while yielding shorter chain (C3-C7) perfluorinated acids and present both experimental and ab initio evidence of the synergistic relationship between electron addition to sorbed molecules and their ability to react with reductive hydrated electrons. Because of the low energy consumption associated with the ET process, the use of standard medium-pressure UV lamps and no further chemical addition, this reductive degradation process is a promising method for the destruction of persistent organic pollutants, including PFAS and other recalcitrant halogenated organic compounds.

Full-scale comparison of UV/H2O2 and UV/Cl2 advanced oxidation: The degradation of micropollutant surrogates and the formation of disinfection byproducts

The photolysis of chlorine by UV light leads to the formation of the hydroxyl radicals (OH) as well as reactive chlorine species (RCS) that can be effective as advanced oxidation processes (AOPs) for water treatment. Much of the research to date has been done at laboratory- or bench-scale. This study reports results from a model that demonstrates that the relative effectiveness of the UV/Cl2 AOP compared to the more traditional UV/H2O2 AOP is a function of optical path length. As such, the relative effectiveness of the two treatment options evaluated at small scale may not reflect the relative performance at full-scale, making results previously obtained at small-scale potentially less scalable. This study therefore compares the performance of UV/Cl2 to UV/H2O2 at a full-scale water treatment plant, using sucralose and caffeine as spiked surrogates for contaminants that are reactive solely to OH radicals, and to both OH and RCS, respectively. pH was varied between 6.5 and 8.0. The results demonstrated that when using a medium pressure UV lamp, UV/Cl2 might lead to approximately twice the production of OH radicals as UV/H2O2 at pH 6.5 when using the same molar oxidant concentration, but adding chlorine to the UV reactor at pH 8.0 had a negligible impact on OH radical concentration in comparison to UV alone. The study also confirmed previous small-scale results that RCS can be a major contributor to UV/Cl2 treatment for compounds such as caffeine that are susceptible to RCS, with UV/Cl2 effective at both pH 6.5 and 8.0 for such compounds. Disinfection byproducts were monitored, with adsorbable organohalide (AOX) formation increasing by approximately 10 μg-Cl/L due to chlorine photolysis, but only at pH 6.5 and not at pH 8.0. This implies that UV/Cl2 might increase AOX mostly due to reaction between OH and organic precursors to make them more reactive with chlorine, and not due to RCS. The formation of specific DBPs of current or emerging regulatory interest was minimal under all conditions, except for chlorate. Chlorate yields were in the order of 6–18% of the photolysed chlorine.

Mechanisms and toxicity evaluation of the degradation of sulfamethoxazole by MPUV/PMS process

In this work, a sulfate radical (SO4-)-based advanced oxidation process was applied to the degradation of sulfamethoxazole (SMX). In these experiments, a medium pressure UV (MPUV) lamp was employed to active peroxymonosulfate (PMS). It was found that 98% of SMX was removed by MPUV/PMS at a UV dose of 200 mJ cm−2 (3.95 μM SMX, 0.2 mM PMS, pH0 = 3.7). Direct MPUV photolysis played a remarkable role in SMX removal by MPUV/PMS process. As for the indirect photolysis, SO4- was the major reactive species under acidic and neutral conditions in MPUV/PMS system, while the hydroxyl radical (OH) became the predominant radical under alkaline conditions. The transformation products (TPs) of SMX that formed in the MPUV-only and MPUV/PMS experiments were identified, and the possible degradation pathways were proposed. Photoisomerization of the isoxazole ring was the major pathway of SMX during MPUV-only process. Hydroxylation/oxidation of the aniline and isoxazole ring was the predominant degradation mechanism of SMX by MPUV/PMS. Toxicity evaluation showed that MPUV/PMS was effective at reducing the antibacterial activity of SMX solutions, while MPUV-only was not. However, some TPs with equivalent or even higher antibacterial activity than SMX were formed during the initial degradation period in MPUV/PMS system. Ecotoxicity of SMX and its TPs was also hypothetically predicted via the ECOSAR program, and the results indicated that some TPs could be more toxic than SMX.

Degradation of naphthenic acid model compounds in aqueous solution by UV activated persulfate: Influencing factors, kinetics and reaction mechanisms

Naphthenic acids (NAs) are one of the constituents of concerns in oil sands process water (OSPW) because of their persistence and recalcitrance. Herein, we investigated the degradation of five model NA compounds by UV-activated persulfate (UV/persulfate) process under medium-pressure UV lamp irradiation at pH 8.0. UV/persulfate process showed higher degradation efficiency towards cyclohexanoic acid (CHA) compared to UV/H2O2 process under the same experimental conditions. CHA (0.39 mM) was completely removed within 30 min when 2 mM persulfate was used as oxidant, while more than 60 min were needed for the UV/H2O2 process. The removal of CHA decreased from 100% to 10% when 300 mM tert-butyl alcohol (TBA) was used as the scavenger, indicating that hydroxyl radical (OH) was responsible for the CHA degradation in the UV/persulfate process. Sulfate (SO4−) radicals reacted slowly with CHA in the UV/persulfate process with a second-order rate constant of k = 5.3 × 107 M−1s−1. Relative kinetics studies using binary mixtures of model NA compounds showed similar structure-reactivity to that under UV/H2O2 process. NAs with long carbon chain, cyclic ring, and aromatic ring were more reactive in the UV/persulfate process. The presence of high concentration of chloride ions dramatically inhibited the reaction. The OH radicals in the UV/persulfate process were generated by capturing OH− in solutions, as evidenced by the decrease of the pH value from 8.0 to 2.8 before and after treatment, respectively, in a pure water matrix. Primary intermediate products (oxy-CHA, hydroxyl-CHA, and dihydroxyl-CHA) of UV/persulfate process were confirmed by UPLC-MS.

Removal of Emerging Contaminants and Estrogenic Activity from Wastewater Treatment Plant Effluent with UV/Chlorine and UV/H₂O₂ Advanced Oxidation Treatment at Pilot Scale.

Effluent of a municipal wastewater treatment plant (WWTP) was treated on-site with the UV/chlorine (UV/HOCl) advanced oxidation process (AOP) using a pilot plant equipped with a medium pressure UV lamp with an adjustable performance of up to 1 kW. Results obtained from parallel experiments with the same pilot plant, where the state of the art UV/H2O2 AOP was applied, were compared regarding the removal of emerging contaminants (EC) and the formation of adsorbable organohalogens (AOX). Furthermore, the total estrogenic activity was measured in samples treated with the UV/chlorine AOP. At an energy consumption of 0.4 kWh/m3 (0.4 kW, 1 m3/h) and in a range of oxidant concentrations from 1 to 6 mg/L, the UV/chlorine AOP had a significantly higher EC removal yield than the UV/H2O2 AOP. With free available chlorine concentrations (FAC) in the UV chamber influent of at least 5 mg/L (11 mg/L of dosed Cl2), the total estrogenic activity could be reduced by at least 97%. To achieve a certain concentration of FAC in the UV chamber influent, double to triple the amount of dosed Cl2 was needed, resulting in AOX concentrations of up to 520 µg/L.

Meta-analysis of the reduction of antibiotic-sensitive and antibiotic-resistant Escherichia coli as a result of low- and medium-pressure UV lamps.

It is vital that harmful bacteria are removed from water and wastewater treatment plants to prevent human/environmental exposure. This paper examines the log reduction of antibiotic-sensitive (AS) and antibiotic-resistant (AR) Escherichia coli (E. coli) as a result of low-pressure (LP) and medium-pressure (MP) UV lamps. A meta-analysis was performed and a mixed-effect model was created in which 303 data points on the log reduction of E. coli from UV treatment were collected. The results show that in order to achieve a 6 log reduction using an MP lamp, on average a UV level of 7.3 mJ/cm2 for AS E. coli and 7.5 mJ/cm2 for AR E. coli were required. Using an LP lamp, a UV level of 8.1 mJ/cm2 for AS E. coli and 8.4 mJ/cm2 for AR E. coli were required. The results show there is no significant difference between the inactivation of AR and AS E. coli at different UV levels. The model predicts that AR or AS E. coli will be inactivated at UV levels lower than the recommended UV operation conditions (40 mJ/cm2), but it is important to use this UV level to inactivate other harmful microorganisms.

The importance of a photon-based approach to quantum yield determinations

It was recently reported that when using polychromatic light sources, a photon-based approach should be used to determine photochemical parameters instead of an energy-based approach, and that failure to do so would lead to errors. To illustrate whether the errors could be significant, the quantum yield of atrazine photolysis was determined by measuring its decomposition rate using a medium pressure UV lamp. The results showed that the use of the previously-reported method to calculate quantum yield introduced a 9% error. Furthermore, simplification of the equation via expanding the fraction of light absorbed as a Taylor series as previously-reported introduced a 3% error. The errors would be more significant when the photolyzed compound has a higher concentration or has a broader absorption spectrum.

Influence of ultraviolet wavelengths on kinetics and selectivity for N-gases during TiO2 photocatalytic reduction of nitrate

For drinking water applications, photocatalytic reduction processes beneficially transform aqueous nitrate to innocuous nitrogen gases (N-gases) but can produce nitrite and ammonia as undesirable aqueous by-products. We hypothesize that by-product selectivity is a function of light source and photon fluence dose, such that discrete wavelengths can increase yield of desirable N-gases. Experiments performed under different wavelength irradiation (ultraviolet- [UV] A, B, C) reduced nitrate in water to differing extents based on pH over the range of 1–8 or the presence of soluble organic electron donors. At an equivalent photon fluence dose, the most rapid nitrate loss in acidic solutions occurred using a combination of three UV-light emitting diodes (285nm, 300nm, 365nm) closely followed by a polychromatic medium pressure UV lamp. A polychromatic xenon light source was least effective in reducing nitrate. Nitrite is an important intermediate during photocatalytic reduction of nitrate. Nitrite absorbs 330–380nm light with high quantum efficiency. Thus, polychromatic or monochromatic light sources with strong UV-A emission more rapidly convert nitrite to by-products than UV-C monochromatic light sources. Nitrous acid (HONO) has a higher molar absorptivity (ε) and quantum efficiency than nitrite ion (pKa=3.39) around 350–370nm. Selectivity towards N-gases is bifurcated at the nitrite intermediate and is strongly influenced by direct photolysis instead of photocatalytic reduction. Thus, the selectivity of by-products can be controlled by delivering light in the 350–370nm wavelength range, where it enables photocatalytic processes to rapidly initiate NO3− reduction and delivers photons for direct photolysis of HONO.

Real olive oil mill wastewater treatment by photo-Fenton system using artificial ultraviolet light lamps

Large volume of untreated olive oil mill wastewater (OMW) is being stored in evaporation rafts. Given the high organic load and the presence of phenolic compounds in OMW, an effective treatment process should be implemented. In this work, an advanced oxidation process (photo-Fenton) operating in a batch reactor was used to treat OMW. All experiments were developed using FeCl3 as a catalyst. Different H2O2 concentrations (5.0, 8.0, 11.0, 15.0, 16.0, 21.0, 24.0 and 30.0 g/L) were studied as well as four commercial medium pressure UV-lamps (Standard, Z1, Z2 and Z3). The common operation conditions were: pH = 3, temperature 20 °C, [catalyst] = 3.0 g/L and direct ultraviolet light (UV-light). The samples were analysed at different times during the experiments to determine water quality parameters. In general, high total carbon, total organic carbon, total phenolic compounds and turbidity removal percentages (>90%) were registered in all experiments, at all oxidant concentrations studied. Increasing oxidant concentrations did not imply a noticeable rise on the final removal percentages (approximately 5% at these experimental conditions). Total nitrogen content removal percentages were determined and varied in the range of 62.5–75.5%. UV-lamps presented virtually similar removal percentages with the following averages COD = 95.7 ± 0.53%, total phenolic compounds = 93.6 ± 2.5%, total carbon = 94.0 ± 1.2%, total organic carbon = 96.3 ± 0.6%, total nitrogen = 74.9 ± 6.8% and turbidity 92.5 ± 1.9%.

Effect of medium-pressure UV-lamp treatment on disinfection by-products in chlorinated seawater swimming pool waters

Several brominated disinfection by-products (DBPs) are formed in chlorinated seawater pools, due to the high concentration of bromide in seawater. UV irradiation is increasingly employed in freshwater pools, because UV treatment photodegrades harmful chloramines. However, in freshwater pools it has been reported that post-UV chlorination promotes the formation of other DBPs. To date, UV-based processes have not been investigated for DBPs in seawater pools. In this study, the effects of UV, followed by chlorination, on the concentration of three groups of DBPs were investigated in laboratory batch experiments using a medium-pressure UV lamp. Chlorine consumption increased following post-UV chlorination, most likely because UV irradiation degraded organic matter in the pool samples to more chlorine-reactive organic matter. Haloacetic acid (HAA) concentrations decreased significantly, due to photo-degradation, but the concentrations of trihalomethanes (THMs) and haloacetonitriles (HANs) increased with post-UV chlorination. Bromine incorporation in HAAs was significantly higher in the control samples chlorinated without UV irradiation but decreased significantly with UV treatment. Bromine incorporation was promoted in THM and HAN after UV and chlorine treatment. Overall, the accumulated bromine incorporation level in DBPs remained essentially unchanged in comparison with the control samples. Toxicity estimates increased with single-dose UV and chlorination, mainly due to increased HAN concentrations. However, brominated HANs are known in the literature to degrade following further UV treatment.

Treatment of groundwater contaminated with high levels of explosives using advanced oxidation processes

Current and former military installations around the world have numerous sites with groundwater contaminated with explosive compounds polluted from military related activities. The test influent used in this study was a groundwater collected from an US Army facility that was contaminated with high levels of military derived explosives. The sample had a total explosive concentration in excess of 75 mg/l. Bench-scale evaluations were performed to determine the effectiveness of the candidate advanced oxidation processes for treatment of the groundwater in terms of removing the pollutants to method sub-detection limits with these results formulating the basis for comparison along with generating data that can be used toward increasing the understanding of treatment mechanisms associated with the various processes. Results indicate that the ozonated systems generally resulted in the removal of the explosives to the targeted levels with 1,3,5-trinitrobenzene removal lagging in terms of removal due to its simultaneous formation and degradation. The oxidation system that was irradiated using the medium-pressure UV lamp and dosed with hydrogen peroxide and ozone achieved the best performance with complete removal of all targeted pollutants within 10 min of treatment.