Re-use of wastewater: preventing the recovery of pathogens by using medium-pressure UV lamp technology

2004 ◽  
Vol 50 (6) ◽  
pp. 337-344 ◽  
Author(s):  
B.F. Kalisvaart
Keyword(s):  
Wastewater Treatment Plants ◽  
Uv Light ◽  
Low Pressure ◽  
Energy Output ◽  
Uv Spectrum ◽  
Medium Pressure ◽  
Uv Lamp ◽  
Cellular Dna ◽  
Uv Technology ◽  
Term Performance

Ultraviolet (UV) light has become widely accepted as an alternative to chlorination or ozonation for wastewater disinfection. There are now over 2,000 wastewater treatment plants worldwide using either low- or medium-pressure UV technology. Recent studies investigating UV lamp technology, configuration, cleaning requirements and ageing, as well as long-term performance tests, have demonstrated beyond any doubt the effectiveness of UV in inactivating pathogens in wastewater. Research has also shown that, to ensure permanent inactivation and prevent the recovery of microorganisms following exposure to UV, a broad, “polychromatic” spectrum of UV wavelengths is necessary. These wavelengths inflict irreparable damage not only on cellular DNA, but on other molecules, such as enzymes, as well. Only medium-pressure UV lamps produce the necessary broad range of wavelengths; low-pressure lamps emit a single wavelength peak which only affects DNA. Polychromatic medium-pressure UV light is so effective because of the lampÕs exceptionally high UV energy output at specific wavelengths across the UV spectrum. It has been shown, for example, that pathogenic E. coli O175:H7 was able to repair the damage caused by low-pressure UV, but no repair was detected following exposure to UV from medium-pressure lamps.

Photobiological effects of polychromatic medium pressure UV lamps

2001 ◽  
Vol 43 (4) ◽  
pp. 191-197 ◽  
Author(s):  
Ben F. Kalisvaart
Keyword(s):  
Uv Light ◽  
Biological Effects ◽  
Disinfection Byproducts ◽  
Biological Molecules ◽  
Energy Output ◽  
Irradiation Damage ◽  
Uv Spectrum ◽  
Medium Pressure ◽  
Micro Organisms ◽  
Uv Lamps

Ultraviolet (UV) light has become widely accepted for the disinfection of potable water, process water and wastewater as an alternative to chlorination. To avoid the failure of a UV disinfection system due to the recovery of micro-organisms, certain additional wavelengths in the UV area are emitted by newly developed UV lamps. To reduce the chance of microbial recovery after ultraviolet irradiation, damage must be inflicted in as many areas of the micro-organism as possible. The effective killing of micro-organisms by improved polychromatic medium pressure UV lamps is due to their exceptionally high UV energy output at specific wavelengths across a broad section of the UV spectrum. The combination of these properties results in several different lethal effects in small and large micro-organisms. Important biological molecules other than DNA are likely to be damaged, which helps to prevent the recovery of irradiated micro-organisms. Absorption line spectra of absorbing nucleotide bases, DNA and other biological molecules, including proteins and enzymes, show how effective UV light can be. Recent findings on the biological effects of short wavelengths on Bacillus subtilis, Cryptosporidium parvum and Escherichia coli confirm the effect of short wavelengths. Practical comparisons with conventional low pressure UV lamps at equal UV dosages show better killing rates from polychromatic medium pressure lamps, without formation of disinfection byproducts (DBPs).

scholarly journals Molecular Indications of Protein Damage in Adenoviruses after UV Disinfection

2010 ◽  
Vol 77 (3) ◽  
pp. 1145-1147 ◽  
Author(s):  
Anne C. Eischeid ◽  
Karl G. Linden
Keyword(s):  
Cell Culture ◽  
Viral Proteins ◽  
Low Pressure ◽  
Protein Damage ◽  
Uv Disinfection ◽  
Medium Pressure ◽  
The Difference ◽  
Uv Lamp ◽  
Detailed Work

ABSTRACTAdenoviruses are resistant to monochromatic, low-pressure (LP) UV disinfection—but have been shown to be susceptible to inactivation by polychromatic, medium-pressure (MP) UV—when assayed using cell culture infectivity. One possible explanation for the difference between UV lamp types is that the additional UV wavelengths emitted by MP UV enable it to cause greater damage to viral proteins than LP UV. The objective of this study was to examine protein damage in adenoviruses treated with LP and MP UV. Results show that MP UV is more effective at damaging viral proteins at high UV doses, though LP UV caused some damage as well. To our knowledge, this study is the first to investigate protein damage in UV-treated adenovirus, and the overview presented here is expected to provide a basis for further, more detailed work.

Photodegradation of sulphadimethoxine in water by medium pressure UV lamp

2008 ◽  
Vol 58 (5) ◽  
pp. 1147-1154 ◽  
Author(s):  
Y. Lester ◽  
I. Gozlan ◽  
D. Avisar ◽  
H. Mamane
Keyword(s):  
Reaction Rate ◽  
Uv Light ◽  
Acid Base ◽  
Direct Photolysis ◽  
Medium Pressure ◽  
Ph Values ◽  
Photodegradation Rate ◽  
Photodegradation Products ◽  
Uv Lamp ◽  
The Impact

The photodegradation rate of sulphadimethoxine (SMT) in water was studied under polychromatic UV light, in a bench scale apparatus. SMT photolysis was carried out at pH levels of 2.5, 6.5 and 10 to study the impact of acid base properties on the degradation of SMT. The highest SMT photolysis fluence based rate was found at pH = 2.5 (k=7.22 × 10−4 cm2/mJ) and the lowest rate at pH = 10 (k=4.72 × 10−4 cm2/mJ), thus the reaction rate decreases with an increase in pH between pH values of 2.5–10. Results indicated that direct photolysis is not satisfactory for degradation of SMT by polychromatic UV lamp as a fluence of approximately 7,000 mJ/cm2 is needed to break down 99% of SMT at pH 6.5. The photodegradation products of SMT were studied at various pH values. Photodegradation of SMT results in dissimilar relative amounts of intermediates formed at different pH values which may exert a photon demand and impact on SMT photodegradation rate.

scholarly journals Potential Repair of Escherichia coli DNA following Exposure to UV Radiation from Both Medium- and Low-Pressure UV Sources Used in Drinking Water Treatment

2002 ◽  
Vol 68 (7) ◽  
pp. 3293-3299 ◽  
Author(s):  
J. L. Zimmer ◽  
R. M. Slawson
Keyword(s):  
Escherichia Coli ◽  
Drinking Water ◽  
Water Treatment ◽  
Uv Radiation ◽  
Drinking Water Treatment ◽  
Low Pressure ◽  
Plate Count ◽  
Treatment Technology ◽  
Medium Pressure ◽  
Uv Lamp

ABSTRACT The increased use of UV radiation as a drinking water treatment technology has instigated studies of the repair potential of microorganisms following treatment. This study challenged the repair potential of an optimally grown nonpathogenic laboratory strain of Escherichia coli after UV radiation from low- and medium-pressure lamps. Samples were irradiated with doses of 5, 8, and 10 mJ/cm2 from a low-pressure lamp and 3, 5, 8, and 10 mJ/cm2 from a medium-pressure UV lamp housed in a bench-scale collimated beam apparatus. Following irradiation, samples were incubated at 37°C under photoreactivating light or in the dark. Sample aliquots were analyzed for up to 4 h following incubation using a standard plate count. Results of this study showed that E. coli underwent photorepair following exposure to the low-pressure UV source, but no repair was detectable following exposure to the medium-pressure UV source at the initial doses examined. Minimal repair was eventually observed upon medium-pressure UV lamp exposure when doses were lowered to 3 mJ/cm2. This study clearly indicates differences in repair potential under laboratory conditions between irradiation from low-pressure and medium-pressure UV sources of the type used in water treatment.

UV light irradiation combined with nitrate for degradation of bisphenol A: kinetics, transformation pathways, and acute toxicity assessment

2022 ◽  
Author(s):  
Zhiquan Li ◽  
Congwei Luo ◽  
Fengxun Tan ◽  
Daoji Wu ◽  
Xuedong Zhai ◽  
...  
Keyword(s):  
Acute Toxicity ◽  
Bisphenol A ◽  
Human Health ◽  
Endocrine Disruptor ◽  
Uv Light ◽  
Low Pressure ◽  
Toxicity Assessment ◽  
Light Irradiation ◽  
Uv Light Irradiation ◽  
Uv Lamp

As an endocrine disruptor, bisphenol A (BPA) is a severe threat to human health. In this study, nitrate (NO3-) photolysis with a low-pressure UV lamp (LP-UV) was employed to degrade...

scholarly journals Researching CdZnS/ZnS (GT) Quantum Dots in Cathodoluminescent Mode

2019 ◽  
Vol 8 (9S2) ◽  
pp. 841-843
Keyword(s):  
Quantum Dots ◽  
Research And Development ◽  
Uv Light ◽  
Spectral Characteristics ◽  
Light Sources ◽  
Application Field ◽  
Medium Pressure

Application field of UV light sources is getting larger at the last decades. Among the most widespread are high and medium pressure vacuum lamps. But there currently is a trend of moving away from using mercury both in household applications and manufacturing. This creates a necessity to conduct research and development for UV sources made and operating without Hg. Cathodoluminescent UV sources are in this category. One of the possible ways to create a viable UV anode phosphor is using quantum dots with needed spectral characteristics.

Cockayne Syndrome: A Cellular Sensitivity to Ultraviolet Light

PEDIATRICS ◽  
1977 ◽  
Vol 60 (2) ◽  
pp. 135-139
Author(s):  
R. D. Schmickel ◽  
E. H. Y. Chu ◽  
J. E. Trosko ◽  
C. C. Chang
Keyword(s):  
Ultraviolet Light ◽  
Uv Light ◽  
Cockayne Syndrome ◽  
Fibroblast Cultures ◽  
Cellular Sensitivity ◽  
X Irradiation ◽  
Increased Sensitivity ◽  
Cellular Dna ◽  
Thymidine Dimer ◽  
Enzymatic Defect

Two unrelated children, a boy 2½ years old and a girl 4 years old, were affected with the cachectic dwarfism of Cockayne syndrome. Fibroblast cultures derived from these patients exhibited increased sensitivity to ultraviolet (UV) light, but not to x-irradiation, as measured by colony-forming ability. In both Cockayne fibroblast cultures, the rate of removal of thymidine dimer from the irradiated cellular DNA was normal. This demonstration of a cellular defect in Cockayne cells suggests that there may be an enzymatic defect in the repair of UV light-induced damage.

Application of Medium Pressure UV Lamp for Wastewater Disinfection of Milk Production Industry

2006 ◽  
Vol 6 (4) ◽  
pp. 731-734 ◽  
Author(s):  
H. Kamani ◽  
F. Vaezi . ◽  
R. Nabizadeh . ◽  
A.R. Mesdaghinia . ◽  
M. Alimohammadi .
Keyword(s):  
Milk Production ◽  
Medium Pressure ◽  
Wastewater Disinfection ◽  
Uv Lamp ◽  
Production Industry

scholarly journals Application of a Krypton-Chlorine Excilamp To Control Alicyclobacillus acidoterrestris Spores in Apple Juice and Identification of Its Sporicidal Mechanism

2020 ◽  
Vol 86 (11) ◽  
Author(s):  
Jun-Won Kang ◽  
Hak-Nyeong Hong ◽  
Dong-Hyun Kang
Keyword(s):  
Thermal Treatment ◽  
Apple Juice ◽  
Radical Scavenging ◽  
Total Phenolic ◽  
Alicyclobacillus Acidoterrestris ◽  
Content Type ◽  
Inactivation Mechanism ◽  
Uv Lamp ◽  
Uv Technology ◽  
Inactivation Effect

ABSTRACT The aim of this study was to investigate the sporicidal effect of a krypton-chlorine (KrCl) excilamp against Alicyclobacillus acidoterrestris spores and to compare its inactivation mechanism to that of a conventional UV lamp containing mercury (Hg). The inactivation effect of the KrCl excilamp was not significantly different from that of the Hg UV lamp for A. acidoterrestris spores in apple juice despite the 222-nm wavelength of the KrCl excilamp having a higher absorption coefficient in apple juice than the 254-nm wavelength of the Hg UV lamp; this is because KrCl excilamps have a fundamentally greater inactivation effect than Hg UV lamps, which is confirmed under ideal conditions (phosphate-buffered saline). The inactivation mechanism analysis revealed that the DNA damage induced by the KrCl excilamp was not significantly different (P > 0.05) from that induced by the Hg UV lamp, while the KrCl excilamp caused significantly higher (P < 0.05) lipid peroxidation incidence and permeability change in the inner membrane of A. acidoterrestris spores than did the Hg UV lamp. Meanwhile, the KrCl excilamp did not generate significant (P > 0.05) intracellular reactive oxygen species, indicating that the KrCl excilamp causes damage only through the direct absorption of UV light. In addition, after KrCl excilamp treatment with a dose of 2,011 mJ/cm2 to reduce A. acidoterrestris spores in apple juice by 5 logs, there were no significant (P > 0.05) changes in quality parameters such as color (L*, a*, and b*), total phenolic compounds, and DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity. IMPORTANCE Alicyclobacillus acidoterrestris spores, which have high resistance to thermal treatment and can germinate even at low pH, are very troublesome in the juice industry. UV technology, a nonthermal treatment, can be an excellent means to control heat-resistant A. acidoterrestris spores in place of thermal treatment. However, the traditionally applied UV sources are lamps that contain mercury (Hg), which is harmful to humans and the environment; thus, there is a need to apply novel UV technology without the use of Hg. In response to this issue, excilamps, an Hg-free UV source, have been actively studied. However, no studies have been conducted applying this technique to control A. acidoterrestris spores. Therefore, the results of this study, which applied a KrCl excilamp for the control of A. acidoterrestris spores and elucidated the inactivation principle, are expected to be utilized as important basic data for application to actual industry or conducting further studies.

scholarly journals ANALISIS KERUSAKAN DAN PERBAIKAN OIL PUMP STEAM TURBINE 32-K-101-P1-T DALAM PLATFORMING UNIT-NAPHTA PROCESSING UNIT (NPU)

ROTASI ◽  
2016 ◽  
Vol 18 (2) ◽  
pp. 44
Author(s):  
Norman Iskandar ◽  
Ardha Ridho Pangeran
Keyword(s):  
Steam Turbine ◽  
Ball Bearing ◽  
Low Pressure ◽  
Processing Unit ◽  
Medium Pressure ◽  
Oil Pump ◽  
Carbon Ring ◽  
Pressure Steam ◽  
Split Face

Oil pump steam turbine (OPST) adalah sebuah turbin uap jenis impuls yang digerakan oleh medium pressure steam (MPS) dengan tekanan 15–21 kg/cm2G dan temperatur kerja 250–370 oC. Uap ekstrasi dari turbin uap adalah low pressure steam (LPS) dengan tekanan 3.8–6.3 kg/ cm2G. Dalam proses perawatannya, OPST diinspeksi setiap 2 minggu sekali dengan melihat kondisi oli, trending getaran, dan putaran poros turbin. Pada saat operasi OPST mengalami kenaikan vibrasi yang melebihi batas toleransi (vs 2.82 mm/s) dan keruhnya oli pelumasan OPST. Dalam hal ini dilakukan sebuah penelitian guna mengetahui indikasi kerusakan OPST dan analisis perbaikan yang tepat guna mengembalikan performa dari OPST. Dalam mengidentifikasi kerusakan tersebut metode yang dilakukan adalah analisis trending spektrum menggunakan software omnitrend yang nilainya akan dibandingkan dengan hasil perhitungan bearing. Analisis tersebut menghasilkan bahwa terjadi vibrasi 1X RPM dikarenakan kerusakan pada ball bearing yang diakibatkan oleh pelumas bearing yang sudah keruh karena tercampur air. Untuk mengetahui masuknya air ke dalam oil chamber dilakukan dua cara yaitu percobaan hydrotest dan pengukuran clearances carbon ring seals. Setelah dilakukan dua percobaan tersebut didapatkan hasil penyebab masuknya air ke oil chamber karena overclearances pada carbon ring seals (vs 0.120-0.145 mm). Masalah yang terjadi ini mengakibatkan uap masuk ke penampungan oli sehingga pelumasan pada bearing tidak berjalan dengan baik sehingga terjadi kerusakan pada bearing. Setelah teridentifikasi kerusakannya, dilakukan pergantian komponen bearing inboard dan bearing outboard serta laping split face pada carbon ring seals. Setelah mengalami perbaikan vibrasi pada OPST kembali normal dari 3.72 mm/s menjadi 0.93 mm/s.

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