Disinfection Using Low-Pressure High-Intensity UV Lamps for Water Reclamation

2000 ◽  
Vol 2000 (2) ◽  
pp. 441-458
Author(s):  
Ziad El Jack ◽  
Ching-lin Chen ◽  
J.F. Stahl ◽  
R.W. Horvath ◽  
J.F. Kuo
Keyword(s):  
High Intensity ◽  
Low Pressure ◽  
Water Reclamation ◽  
Uv Lamps

Use of Low Pressure Mercury Lamps for the Photodecomposition of Iron Cyanide in Gold Mill Effluents

1985 ◽  
Vol 20 (2) ◽  
pp. 111-119 ◽  
Author(s):  
J.H. Carey ◽  
S.A. Zaidi
Keyword(s):  
Ultraviolet Light ◽  
High Intensity ◽  
Experimental Evaluation ◽  
Low Pressure ◽  
Pilot Scale ◽  
Weak Acid ◽  
Potassium Ferricyanide ◽  
Technical Feasibility ◽  
Iron Cyanide ◽  
Scale Test

Abstract The use of ultraviolet light (UV) from low pressure mercury lamps for destroying iron cyanide in synthetic and actual gold mill effluents was evaluated in this study. For the light intensities used in this study, UV irradiation was not able to efficiently destroy cyanide. However, it converted iron cyanide to a weak acid dissociable form which was destroyed by chlorine. Data from several bench-scale tests and one pilot scale test were used to estimate quantum efficiencies (moles iron cyanide destroyed/einstein). These efficiencies ranged from 0.2% to 1%; approximately 30% to 90% lower than those reported in the literature for potassium ferricyanide. The data collected during the study demonstrated the technical feasibility of using UV in conjunction with chlorination for destroying iron cyanide in gold mill effluents. However, low pressure mercury lamps do not appear to be a practical UV source for this purpose. Irradiation with high intensity lamps may be more practical and is recommended for experimental evaluation.

254 nm Radiant Efficiency of High Output Low Pressure Mercury Discharge Lamps with Neon-Argon Buffer Gas

2013 ◽  
Vol 325-326 ◽  
pp. 409-412
Author(s):  
Hao Jun Zhang ◽  
Qiu Yi Han ◽  
Shan Duan Zhang
Keyword(s):  
Mercury Vapor ◽  
Low Pressure ◽  
Input Power ◽  
Cold Spot ◽  
Outer Diameter ◽  
Buffer Gas ◽  
Uv Irradiance ◽  
Radiant Efficiency ◽  
Uv Lamps ◽  
High Output

High output low pressure mercury (LPM) discharge UV lamps have been briefly introduced. In order to measure the 254 nm radiant efficiency simply and preciously, Keitz formula was used and its advantage was illustrated. The LPM lamps had outer diameter of 19 mm (T6). The buffer gases are neon (65%) and argon (35%) with total pressure 1-10 Torr (133-1333 Pa). The lamps were operated with cold spot temperatures from 20°C to 80°C and discharge current from 0.8 A to 2.0 A. The electric field, input power, 254 nm UV irradiance and irradiance of other Hg lines from 265 to 579 nm in positive column were measured. The radiant power of each wavelength can be calibrated according to the 254 nm output and the Keitz formula. It was shown that the radiant efficiency of 254 nm can reach a maximum of above 40% at cold spot temperature 45-47 °C and current 1.6 A for filling pressure less than 3 Torr. The optimal mercury vapor pressure was 1.2 to 1.4 Pa. The output percentage of other Hg lines was below 5%. With the decrease of buffer gas pressure, the 254 nm radiant efficiency increased obviously.

Comparison of Low Pressure and Medium Pressure UV Lamps for UV/H2O2Treatment of Natural Waters Containing Micro Pollutants

2010 ◽  
Vol 32 (5) ◽  
pp. 329-337 ◽  
Author(s):  
Guus F. IJpelaar ◽  
Danny J.H. Harmsen ◽  
Erwin F. Beerendonk ◽  
Robin C. van Leerdam ◽  
Debbie H. Metz ◽  
...  
Keyword(s):  
Natural Waters ◽  
Low Pressure ◽  
Medium Pressure ◽  
Uv Lamps ◽  
Micro Pollutants

scholarly journals Effects of UV Radiation on Photolyase and Implications with Regards to Photoreactivation following Low- and Medium-Pressure UV Disinfection

2007 ◽  
Vol 74 (1) ◽  
pp. 327-328 ◽  
Author(s):  
Jiangyong Hu ◽  
Puay Hoon Quek
Keyword(s):  
Uv Radiation ◽  
Uv Irradiation ◽  
Flavin Adenine Dinucleotide ◽  
Low Pressure ◽  
Uv Disinfection ◽  
Medium Pressure ◽  
Uv Lamps

ABSTRACT Photolyase activity following exposure to low-pressure (LP) and medium-pressure (MP) UV lamps was evaluated. MP UV irradiation resulted in a greater reduction in photolyase activity than LP UV radiation. The results suggest that oxidation of the flavin adenine dinucleotide in photolyase may have caused the decrease in activity.

scholarly journals Phase transformation under beam-target interactions during high-intensity pulsed ion beam irradiation at low pressure

2011 ◽  
Vol 29 (3) ◽  
pp. 283-289 ◽  
Author(s):  
X.P. Zhu ◽  
F.G. Zhang ◽  
Y. Tang ◽  
M.K. Lei
Keyword(s):  
Phase Transformation ◽  
High Intensity ◽  
High Efficiency ◽  
Ion Beam ◽  
Low Pressure ◽  
Ion Source ◽  
Source Material ◽  
Gaseous Species ◽  
Titanium Target ◽  
Ion Species

AbstractNitrides and/or carbonitrides formation of high efficiency was found on titanium target under irradiation of high-intensity pulsed ion beam (HIPIB) with a few shots at a low pressure of 10−2 Pa order, which is extraordinary in comparison with conventional thermo-chemical diffusion process such as gas nitriding and/or carbonitriding of metals necessarily heated at high temperatures during a processing time of hours. The underlying mechanism of the nitrides and carbonitrides formation on titanium targets was explored by a comparative study on three typical HIPIB sources, i.e., TEMP-6, TEMP-4M, and ETIGO-II, varying the irradiation intensity within several J/cm2 per shot of a 60–70 ns pulse duration and the shot number of similar ion species. It is revealed that ambient gases and ion source material are the main sources providing the nitrogen and carbon species for the phase transformation on titanium target at the low pressures, whereas the ion species of HIPIB composition is negligible at a low implantation dose of 1013–1014 ions/cm2. The adsorbed gaseous species, the deposited layer of the ion source material, and in-situ formed compound top layer from reactions between ablation plasma and the ambient species during HIPIB irradiation, can be effectively incorporated into the irradiated target surfaces under a controlled HIPIB-target interaction.

A Refinement Of The Determination Method Of The Linear low-pressure Uv Lamps Radiant Flux

2021 ◽  
pp. 104-114
Author(s):  
Sergei V. Prytkov ◽  
Sergei S. Kapitonov ◽  
Alexei S. Vinokurov
Keyword(s):  
Entire Range ◽  
Statistical Data ◽  
Low Pressure ◽  
Radiant Flux ◽  
Intensity Curve ◽  
Radiant Intensity ◽  
Longitudinal Plane ◽  
Test Distance ◽  
Uv Lamps ◽  
Close Distance

For the measurement of linear low-pressure UV lamps radiant flux the method proposed by the IUVA, which is based on the Keitz method, has become widely used. For deriving the equation that connects the irradiance generated by a lamp at a close distance and its radiant flux, the authors of the method presume that the lamp is the cylinder of equal radiance. According to our estimates, this assumption leads to the inaccuracy of 3 % to 5 % with respect to goniophotometric measurements. In this research, a general formula is derived that connects the irradiance generated by a linear emitter and its radiant flux. This formula does not impose restrictions on the radiant intensity curve in the longitudinal plane. The Keitz equation is its particularcase. To reduce the inaccuracy of the IUVA method, the angular distribution of the radiant intensity of the UV lamps is proposed to be approximated by a cosine polynomial. In order to find the coefficients of the polynomial,clarify the Keitz formula, as well as to estimate the inaccuracy of the refined and classical versions of this formula, the series of goniophotometric measurements of the DB15, DB18, DB30 lamps at various distances was carried out. It was found that at a scanning step Δθ = 5° the first 9 terms of the trigonometric expansion are sufficient to describe the radiant intensity curve with accuracy satisfactory for practical use. It was also shown that the Keitz method needs to be refined only on the basis of goniophotometric data obtained upon condition r / l ≥ 6 where r is the test distance, l is the lamp length. It was identified that in the case of a differentiated approach, the approximation of the low-pressure UV lamps radiant intensity curve by a cosine polynomial makes it possible to provide an inaccuracy of simplified methods that does not exceed 1 % in relation to the goniophotometric method. It is in dicated that in order to find a universal factor applicable for the entire range of linear low-pressure UV lamps, the development and the analysis of statistical data is required.

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