UV-C Lamp Research Articles

Assessment of AOPs as a polishing step in the decolourisation of bio-treated textile wastewater: Technical and economic considerations

Abstract Biological oxidation processes have shown good results for the mineralisation of the non-recalcitrant fraction of textile wastewater. However, they do not always represent a feasible technique for colour removal, requiring a polishing step for decolourisation before the wastewater can be discharged into a receiving water body. In this study, UVC/H2O2 and photo-Fenton (PF) oxidation processes were used as a polishing step in the decolourisation of a bio-treated real textile wastewater. The photolysis of hydrogen peroxide using UVC radiation showed decolourisation efficiencies of 86% (Pt–Co method) and 96% (DFZ436nm), consuming 1.6 mM H2O2 after 0.9 kJUV L−1 (time = 35 min; UVC lamp power = 6 W; natural pH 7.8; T = 30 °C). The PF reaction was promoted by different radiation sources (UVC, UVA or UVA–vis), showing best results under UVC light. The efficiency of the UVC/Fe2+/H2O2 system was also studied for different iron concentrations, H2O2 availability and pH values. Decolourisation efficiencies of 78% (Pt–Co method) and 93% (DFZ436 nm) were achieved applying the UVC/Fe2+/H2O2 system at pH 2.8 and T = 30 °C, consuming 3.6 mM H2O2 after 0.6 kJUV L−1 (time = 25 min; UV lamp power = 6 W). To further investigate the use of solar energy, additional PF assays mediated by ferric-organic ligands under UVA–vis radiation were also performed, considering the effect of the type of ferric-organic ligand as well as the iron/ferric-organic ligand molar ratio, iron concentration and pH. Maximum values for the decolourisation with UVA–vis/Fe3+/H2O2/oxalic acid were 84% (Pt–Co method) and 94% (DFZ436 nm), consuming 1.9 mM H2O2 after 2.9 kJUV L−1 (pH 2.8). In addition, the costs associated with the processes studied were estimated. For the optimal conditions, aiming at achieving the legal wastewater discharge requirements, the total unit costs were: (a) 0.25 € m−3 (UVC/H2O2 at pH 2.8); (b) 0.16 € m−3 (UVC/H2O2 at natural pH); (c) 0.24 € m−3 (UVC/Fe2+/H2O2 at pH 2.8); (d) 0.61 € m−3 (UVA–vis/Fe2+/H2O2 at pH 2.8); (e) 0.79 € m−3 (UVA–vis/Fe3+/H2O2/oxalic acid at pH 2.8) and; (f) 0.83 € m−3 (UVA–vis/Fe3+/H2O2/oxalic acid at pH 5.0).

살균조건 및 UV-C 조사가 느타리버섯 병재배 오염율 감소에 미치는 영향

This study was conducted to reduce contamination ratio of oyster mushroom bottle cultivation. The optimalconditions of substrate sterilization for reducing of contamination ratio were at 121oC for 90min. In addition, UV-C irradiation isgood for lower contamination ratio to continue over 6 hours at cooling and inoculation room after sterilization. Thecontamination ratio and density of microorganisms of substrate were showed 0% after sterilization at 121oC for 90min.Trichoderma sp., main pathogen of mushrooms, was detected from substrate after sterilized during 2 or 4 hours at 101oC and 105oC,respectively. The amount of electricity used was the lowest at 121oC for 90min than that of other sterilization conditions. The UV-Cirradiation treatment was used UV-C lamp(40 watts) in the inoculation room(56m3). The density of bacteria did not detected after UV-C irradiation for 6 hours. And the death ratio of bacteria and Trichoderma sp. was 99.9% after UV-C irradiation for 6 hours. However,in the same UV-C irradiation time, the death ration of Cladosporium sp. was 90.9%. Therefore, the death ratio of fungi was lower thanthat of bacteria at the same UV-C irradiation treatment.

Electrochemical advanced oxidation processes for sanitary landfill leachate remediation: Evaluation of operational variables

The effect of various parameters on the performance of electrochemical advanced oxidation processes (EAOPs) like electro-Fenton (EF), photoelectro-Fenton (PEF) and solar PEF (SPEF) was assessed for the treatment of a sanitary landfill leachate previously subjected to biological and coagulation processes. The tested operational variables included: (i) anode material (boron-doped diamond (BDD) and Pt), (ii) initial total dissolved iron concentration (20–80mgL−1), (iii) pH (2.8–4.0), (iv) initial addition of 1:3 Fe(III)-to-oxalate molar ratio at various pH values (2.8–5.0), (v) temperature (15–40°C) and (vi) radiation source (UVA, UVA-Vis and UVC lamps and natural sunlight). The BDD anode showed high superiority over the Pt one for EF, PEF with UVA light (PEF-UVA) and SPEF processes, thereby advising an important role of the physisorbed hydroxyl radicals (OH) at the anode surface on landfill leachate oxidation even under the potent solar radiation. An initial total dissolved iron content of 60mgL−1 was chosen as the best dose for the PEF-UVA process with the BDD anode (PEF-BDD-UVA). While PEF-BDD-UVA without external addition of oxalic acid yielded the best results at pH 2.8, the initial addition of 1:3 Fe(III)-to-oxalate molar ratio allowed operating at pH 3.5 with even higher efficiency and at pH 4.0 with only slightly lower efficiency. Effluent temperatures from 20 to 40°C led to similar mineralization rates for the PEF-BDD-UVA technique. The use of UVA and UVC lamps and natural sunlight as radiation sources in PEF-BDD and SPEF-BDD systems led to similar mineralization profiles as a function of time. The UVA-Vis lamp induced lower effluent mineralization mainly for longer reaction times.

Photocatalytic degradation of cationic dye simulated wastewater using four radiation sources, UVA, UVB, UVC and solar lamp of identical power output

This study uses photocatalysis, classified under advanced oxidation processes, for the treatment of simulated cationic dye (methylene blue)-contaminated wastewater using TiO2 as the photocatalyst. Three parameters were manipulated throughout this study including the effects of ultraviolet irradiation wavelength (using UV-A, UV-B, UV-C and solar light), the initial dye concentration (2–10 ppm) and the initial pH (4–10), with a total reaction time of 1 h. The shortest wavelength irradiation (UV-C) proved to be the most effective yielding 100% degradation of MB was achieved within 14 min. Increasing the initial dye concentration proved reduced the degradation rate due to the inner photon filtering effect by the dye molecules and as a result of the reduced generation rate of hydroxyl radicals. Since MB is a cationic dye, by increasing the pH of the system, the degradation rate was enhanced requiring just 12 min to achieve complete degradation in the experimental photoreactor. This is due to the electrostatic attraction between the dye molecules and the negatively charged TiO2 particles. Kinetic studies showed that all experiments fulfilled an apparent first-order kinetics at MB concentrations less than 6 pp mmeaning the photocatalytic degradation of MB depended only on its concentration in the solution. Saturation kinetics (zero-order) was observed at MB concentration higher than 6 ppm and a reduction of the initial rate was observed at concentration higher than 10 ppm due the absorption of photon from the dye in solution. From the findings, photocatalysis using TiO2 is able to fully degrade organic compounds like dyes into degradable substance such as carbon dioxide, water and inorganics.

Application of concrete surfaces as novel substrate for immobilization of TiO2 nano powder in photocatalytic treatment of phenolic water.

BackgroundIn this study, concrete application as a substrate for TiO2 nano powder immobilization in heterogeneous photocatalytic process was evaluated. TiO2 immobilization on the pervious concrete surface was done by different procedures containing slurry method (SM), cement mixed method (CMM) and different concrete sealer formulations. Irradiation of TiO2 was prepared by UV-A and UV-C lamps. Phenolic wastewater was selected as a pollutant and efficiency of the process was determined in various operation conditions including influent phenol concentration, pH, TiO2 concentration, immobilization method and UV lamp intensity.FindingsThe removal efficiency of photocatalytic process in 4 h irradiation time and phenol concentration ranges of 25–500 mg/L was more than 80 %. Intermediates were identified by GC/Mass and spectrophotometric analysis.ConclusionsAccording to the results, photocatalytic reactions followed the pseudo-first-order kinetics and can effectively treate phenol under optimal conditions.

SANITATION OF PROCESS WATER FROM FRESH-CUT LETTUCE PRODUCTION BY MEANS OF UV-C

During fresh-cut production, the process water represents a major source of cross-contamination, facilitating foodborne pathogen transfer. Therefore, the efficacy of UV-C disinfection to reduce the microbiological load of lettuce wash waters was investigated. Wash water of iceberg and oak leaf lettuce was subjected to different doses of UV-C ranging from 34.8-174.2 J L-1. As shown by the inactivation kinetics of total mesophilic viable counts, UV-C was highly efficient in reducing the microbial load of both lettuce wash waters. At 174.2 J L-1, the initial viable counts were reduced by 3.2 and 2.1 log10 cfu ml-1 in iceberg and oak leaf lettuce process water, respectively. At this highest UV-C dose, members of the Enterobacteriaceae family were even reduced by 3.5 log10 cfu ml-1 in oak leaf lettuce wash water, while they were not detected in washing water of iceberg lettuce processing. Microbial loads in oak leaf lettuce wash water were higher than in that of iceberg lettuce processing, which was also reflected by a higher chemical oxygen demand (COD), higher absorption and turbidity. In the second experiment, conducted with iceberg lettuce and endive, UV-C lamps were installed in an industrial tubular washing system. Highly contaminated shredded lettuce was circulated six times in the tubes. Water and lettuce samples were analysed throughout processing. Despite high turbidities of up to 34.5±0.7 NTU, UV-C illumination reduced the viable counts in the water by 2.0 (endive) and 1.9 log10 cfu ml-1 (iceberg lettuce) after the sixth cycle compared to untreated process water. Both experiments proved UV-C treatment to be a promising option for product quality enhancement and sanitation of water during fresh-cut lettuce production, thus reducing the consumption of fresh water and microbial hazards. However, the efficacy of UV-C disinfection was shown to depend on physicochemical parameters, e.g., absorption, turbidity and COD of the water.

Mechanism and products of the photolysis of hexabromocyclododecane in acetonitrile–water solutions under a UV-C lamp

The photolysis of hexabromocyclododecane (HBCD), a new persistent organic pollutant (POPs), under a UV-C lamp (λmax 220–260nm) in a mixed solution of acetonitrile–water was investigated to clarify the contribution of direct and indirect photolysis on the decomposition of HBCD and the photolysis products. The results show that the photolysis reaction follows the pseudo-first order kinetics. Isopropanol inhibited the photolysis by scavenging hydroxyl radicals (HO), from which the contributions of direct and indirect photolysis to HBCD decomposition were determined to be 85.7% and 14.3%, respectively. Using a competitive reaction with Rhodamine B in a photo-Fenton system, the second-order rate constant of HBCD with HO was estimated to be 2.48±0.23×108Lmol−1s−1. Moreover, the effect of singlet oxygen (1O2) was investigated through a scavenging experiment (using NaN3 as scavenger) and a 1O2 generated experiment by using indirect photolysis of methylene blue. Results show that 1O2 cannot degrade HBCD directly, but has an indirect influence on photolysis of HBCD through reacting with the final debrominated products of HBCD, cyclododecatriene. Products of sequential debromination (tetrabromocyclododecene, dibromocyclododecadiene, and cyclododecatriene), and 1O2 oxidation products (dibromo-epoxy-cyclododecene and epoxy-cyclododecadiene) during photolysis were identified. Both direct photolysis and indirect photooxidation by HO and 1O2 should be taken into account when HBCD is exposed to UV-C light. The quantum yields for photolysis of HBCD were measured at wavelengths of 224, 240 and 254nm, which were 0.22, 0.15 and 0.033, respectively.

Effect of novel ultrasound based processing on the nutrition quality of different fruit and vegetable juices

Increasing consumer awareness regarding the health benefits of different nutrients in food have led to the requirement of assessing the effect of food processing approaches on the quality attributes. The present work focuses on understanding the effects of novel approaches based on the use of ultrasound and ultraviolet irradiations on the nutritional quality of different fruit and vegetable juices (orange, sweet lime, carrot and spinach juices) and its comparison with the conventional thermal pasteurization operated at 80°C for 10min. The ultrasound sterilization parameters were maintained at ultrasound frequency of 20kHz and power of 100W with treatment time as 15min. For the case of ultraviolet irradiations, 2 UVC lamps (254nm) of 8W were placed in parallel on either sides of the reactor. The treated juices were analyzed for total phenol content, antioxidant activity, vitamin C, carbohydrates etc. It has been established that ultrasound processed juice retained most of the nutrient components to higher extent in comparison to all the other techniques used in the work. Combination of ultrasound and ultraviolet irradiations used to achieve an effective decontamination of juices (recommended 5 log reduction of microorganisms) also retained nutrients to a higher level in comparison to the thermal method; however some losses were observed as compared to the use of only ultrasound which could be attributed to inefficient heat exchange in the combined approach. A scale up attempt was also made for treatment of spinach juice using ultrasonic reactors and analysis for quality attributes confirmed that the juice satisfied the criteria of required nutrient contents for 18days shelf life trial in refrigerated storage conditions. The present work has clearly established the usefulness of ultrasound based treatment in maintaining the nutritional quality of beverages while giving enhanced shelf life as compared to the conventional approaches.

Study of Fe(III)-NTA chelates stability for applicability in photo-Fenton at neutral pH

The stability of ferric nitrilotriacetate chelates (Fe(III)-NTA) was studied under thermal, oxidative and photochemical stress. The knowledge of chelate stability is fundamental to correctly implement the management system of wastewater treatment plant for application of chelates as catalyst in photo-Fenton process at neutral pH. Fe(III)-NTA solution stability was monitored under different temperature conditions (T=10–30°C), in presence and absence of UV-A irradiation and by adding three different concentrations of H2O2. The additional effect on chelate stability caused by different irradiation source (UV-A, UV-C and Xenon lamps) was also evaluated. Although the complexes were stable under the temperature test range, temperature control is crucial when stressing the solution by irradiation or by adding hydrogen peroxide. The solution was kept stable during two hours of reaction under UV-A irradiation only when temperature was set at 10–15°C while in presence of hydroxyl radicals (HO) the temperature control could only reduce the chelates decomposition. Fe(III)-NTA solution mineralization could be obtained under irradiation and radical strain. Thus, the production of organic radical from free ligands was also demonstrated. Finally, the suitableness of UV-C lamps as light source for the process application was questioned since they caused a strong degradation of the chelate solution. Indeed, only 30min of UV-C irradiation by adding 0.59mM of hydrogen peroxide caused almost 90% reduction of the chelate content in the solution.

Photocatalytic degradation of methylene blue dye over immobilized ZnO nanoparticles: Optimization of calcination conditions

In the present study, calcination conditions during the synthesis of zinc oxide nanoparticles were optimized using response surface methodology (RSM) based on central composite design (CCD). After that, the effect of the type of UV irradiation on the photocatalysis of methylene blue (MB) dye was studied based on the kinetic model obtained at optimum conditions. Analysis of variance (ANOVA) exhibited a reasonable high correlation coefficient between the predicted and experimental values (R 2 = 0.95). For a decolorization efficiency of 90%, the optimum calcination temperature and calcination time were identified to be 459 °C and 3.65 h, respectively. According to the reaction rate constant (k), the time required for the removal of MB using UVC lamps (0.027 1/min) was shorter than that of UVA lamps (0.0098 1/min), indicating higher exciting potential of the UVC irradiation for the generation of hydroxyl radicals through photocatalysis.

Photocatalytic degradation of acetone and methanol in a flow-through photoreactor with immobilized TiO2

Volatile organic compounds must be used in many industrial processes, involving their emission to the environment in gaseous form. This paper describes the degradation of vapors of acetone and methanol in air by photocatalysis. To achieve this, a tubular flow-through reactor with TiO2 photocatalyst irradiated by either UV-A or UV-C lamps is used. The irradiation wavelength was the main studied parameter. Equal volumetric feed of liquid in the air stream for both pollutants resulted in a concentration of acetone of about 275 ppm and of methanol of about 500 ppm. In separate experiments, using the UV-A lamps, the conversion of acetone was 29 %, while for methanol it was 72 %. The faster oxidation of methanol relative to acetone can be explained by their different molecular structure. For UV-C lamps, the conversion of acetone significantly increased (to 60 %), while that of methanol increased only slightly (to 80 %). The contribution of photolysis to the degradation of both compounds was considered and finally evaluated to be negligible in this setup.

UV-C irradiation enhanced ozonation for the treatment of hazardous insecticide methomyl

Decomposition of hazardous methomyl via ozonation (OZ) and ultraviolet photolysis OZ (UV-OZ) processes was studied. The decomposition efficiencies of methomyl (ηmet) and total organic carbon (ηTOC) were determined to measure the oxidative destruction ability. In the OZ process with pH 7 and 10, methomyl can be decomposed completely at the applied ozone dosage per volume of liquid (mA,in) of 300 mg L−1. At mA,in of 3600 mg L−1 with pH values controlled at 2, 7 and 10, the ηTOC values are 13, 26 and 43%, respectively, showing the great influence of pH value on the ηTOC for the OZ process. Combining the UV-C radiation in the OZ process can promote the decomposition of O3 to form OH˙ radical which has higher oxidizing ability than O3 and can further decompose the acidic intermediates, thus increasing the ηTOC. At mA,in of 3600 mg L−1 and UV-C lamp irradiation power of 16 W with controlled pH values at 2, 7 and 10 in the UV-OZ process, the ηTOC values are close to that (72%) without controlling the pH value. The results indicate that the UV-C radiation can enhance the mineralization with insignificant effect of pH value.

H2O2 and/or photocatalysis under UV-C irradiation for the removal of EDTA, a chelating agent present in nuclear waste waters

In this study, we compare the efficiency of photocatalytic processes based on TiO2 (Degussa P-25) and UV/H2O2 as a means of degrading and mineralizing ethylenediaminetetraacetic acid (EDTA) under UV-C irradiation. EDTA was the molecule studied here because it is present in high proportions at nuclear facilities, where it is used for cleaning and decontamination purposes because of its chelating properties. The photonic power of the UV-C lamps used (13 and 15W) was established using actinometric and Keitz's methods. The adsorption of EDTA on TiO2 Degussa P-25 corresponds to a Langmuir isotherm, and the photocatalytic degradation process is consistent with the Langmuir–Hinshelwood model. During the photocatalytic process, an increase in the initial EDTA concentration favors the formation of large quantities of intermediates, which occupy the active sites, thus delaying the production of detectable quantities of oxalic acid. The results obtained here also show that nitrogen originating from EDTA molecules is mainly converted into ammonium and nitrate ions with a conversion rate of 67%. In addition, the amount of oxalic acid formed increases with the pH. The efficiency of the UV/TiO2 and UV/H2O2 processes as a means of EDTA degradation was found to be similar, provided H2O2 was added continuously during the UV/H2O2 process. The quantum efficiency was calculated and found to be equal to 0.9% in the case of photocatalysis and 1.4% in that of UV/H2O2.

Synthesis of methyl ester sulfonate surfactant from palm oil methyl ester by using UV or ozone as an initiator

Methyl ester sulphonate (MES) derived from palm oil is environmental friendly and offers good detergent properties. Although Alpha methyl ester sulphonate (α-MES) has been produced by many producers in detergent industries, it has some problems such as disalt formation and low water solubility. In order to overcome these drawbacks, MES is synthesized via sulphoxidation by using different initiators. Ozone is one of the most interesting agents because of its highly oxidizing power, which can react with organic compound rapidly under mild conditions. In this work, ozone and UV are used as an initiator in order to generate radicals along carbon chain to react with sulphur dioxide and oxygen. The reaction is performed in a photochemical reactor with UVC lamps (253.7 nm). The outlet product is transferred to separation and purification steps by liquid extraction techniques. The obtained products are analysed by FT-IR and ESIMS to confirm MES products. When reaction time is fixed at 4 h, conversions are around 7.5, 6.9 and 13.5 wt% for UV, ozone and UV/ozone systems, respectively.

Fabrication of a Porous TiO2-Coated Silica Glass Tube and Its Application for a Handy Water Purification Unit

A simple, handy, reusable, and inexpensive water purification unit including a one-end sealed porous amorphous-silica (a-silica) tube coated with 2 μm of porous TiO2photocatalyst layers has been developed. Both TiO2and a-silica layers were formed through outside vapor deposition (OVD). Raman spectrum of the porous TiO2-coated a-silica glass tube indicated that the anatase content of the TiO2layers of the tube was estimated to be approximately 60 wt%. Developed porous TiO2-coated a-silica glass tube has been assayed for the tube filtering feature againstEscherichia coli(E. coli) solution used as one of the typical bacteria size species or Qβphage also used as typical virus size species and compared with the feature of porous a-silica tubes alone. The tubes removedE. colicompletely from the aqueous suspension which contained 106 CFU/mL ofE. coliwithout UV irradiation. The porous TiO2-coated a-silica glass tube with UV-C lamps successfully reduced the Qβphage amount in the suspension from 109to 103 PFU/mL.

High efficiency fluorescent excimer lamps: An alternative to mercury based UVC lamps

A high efficiency xenon excimer lamp radiating at 172 nm, with an internal phosphor coating shifting to UVC has been demonstrated, showing the feasibility of a cost effective alternative to UVC mercury lamps. Fluorescent lamps so designed can be fabricated in various geometries with high efficiency. Unlike other xenon excimer lamps based on dielectric barrier discharges this new system is highly compatible with existing and proposed phosphors as it operates in an inert gas environment at modest temperature and is subject only to 172 nm primary radiation. Using a lamp coated with a UVC phosphor we have demonstrated the feasibility of germicidal and curing lamps with 40% energy conversion efficiency and high power density. These lamps are rapidly switchable, have long projected lifetimes and are compatible with dimmers.

Degradation of the antibiotic chloramphenicol using photolysis and advanced oxidation process with UVC and solar radiation

In this work, an aqueous solution of the antibiotic chloramphenicol was treated by photolysis and an advanced oxidation process using hydrogen peroxide combined with UVC and solar radiation. In this system, a reactor containing three UVC lamps (30 W) was used. A factorial plan 22 was designed with the following variables: time and a concentration of hydrogen peroxide and evaluated using the percentage of chloramphenicol degradation as the response. Twelve hours of exhibition to UVC and solar radiation obtained 83 and 21% of chloramphenicol degradation, respectively. When H2O2/UV was used, 98 and 5% of degradation were obtained after one and a half hours of exhibition to UVC and solar radiation with 3 mmol L−1 of hydrogen peroxide. The time-based kinetic constant was calculated as 6.3 × 10−2 min−1 with r2 equal to 0.9878.

Photocatalytic oxidation air cleaner: Identification and quantification of by-products

Ultraviolet photocatalytic oxidation (UV-PCO) has been acclaimed to be a unique technology for decomposition of indoor environment VOCs while minimizing the building energy consumption. This paper addresses application of photocatalytic oxidation for indoor air treatment. Laboratory experiments were conducted in a pilot scale open test rig with an in-duct UV-PCO system. The UV-PCO reactors contain two types of flat commercially available catalyst substrates irradiated by two types of UV-lamps. UV-PCO system was challenged with aromatic: toluene, p-xylene; alcohol: 1-butanol; alkane: n-hexane, octane, and ketone: MEK, acetone. The main objectives of this study were to identify and quantify produced by-products in a large pilot scale reactor in the presence and absence of ozone. Moreover, a detailed investigation was made in order to reveal the effect of type of photocatalyst, UV-lamps as well as initial concentration on the distribution and production of by-products and removal efficiency. It was noticed that there were two common by-products including formaldehyde and acetaldehyde for all challenge compounds; moreover, some other by-products including propionaldehdye and crotonaldehyde were formed. More by-products were formed in the tested aromatic compared to the other compounds. Performance of UV-PCO system and generated by-products of challenge compounds were investigated and compared in the presence of UVC and VUV lamps, and two types of catalysts. Generally higher removal efficiency was achieved in the presence of ozone and VUV lamps compared to the UVC lamps.

Underwater Spatial Distribution of UVC Radiant Intensity in Different Water Environment for Ballast Water Treatment

UV radiation, as an effective method for bacteria inactivation, has been applied popularly on ballast water treatment. However, the inactivation efficiencies of UV radiation greatly depend on the UV intensity which distributed unevenly in water and can be deeply affected by the suspending particles in water. For better understanding of the spatial distribution of UV radiation, a 16W UVC lamp was measured underwater to detect the radiant intensity over horizontal and vertical distance. The distribution tendency of UV radiant intensity was probed behind large amounts of experimental data. In addition, four types of different water including tap water, clean seawater, seawater mixed with suspending substances (SS), and seawater mixed with typical algae, were studied to identity the influence of water environment on UV transmission. The impacting significances were compared among different water quality, to optimize the ballast water treatment methods combining with UV radiation.

Bromate Control by UVC and UVA Treatment in Drinking Water

In order to study the effect and influencing factors of bromate removal by ultraviolet treatment in drinking water, by carrying out laboratory test in simulated water and raw water samples, the action of UVC and UVA on bromate were investigated. The results indicated that bromate transformes into bromine ion under UVC treatment, but there was a small amount of UVA in the UVC lamp emission spectrum. Separate experiments on UVA treatment of bromate indicated that UVA could be considered as an interference factor for UVC treatment of bromate, and it should be restricted in the UVC lamp emission. The conversion of bromate to bromide was inhibited by suspended matter, which led to a rise of water turbidity and had influence on the reduction of bromate by UVC. When the water pH was 5.5~9 the same UV dose, the reduction of the bromate concentration by UVC treatment did not change significantly.