UV disinfection of wastewater effluents for unrestricted irrigation

2006 ◽  
Vol 54 (3) ◽  
pp. 83-88 ◽  
Author(s):  
A.M. Nasser ◽  
H. Paulman ◽  
O. Sela ◽  
T. Ktaitzer ◽  
H. Cikurel ◽  
...  
Keyword(s):  
Uv Irradiation ◽  
Wastewater Reuse ◽  
High Rate ◽  
Uv Disinfection ◽  
Secondary Effluent ◽  
E Coli ◽  
Uv Dose ◽  
Inactivation Efficiency ◽  
Transmission Of Disease

Wastewater reuse in arid regions is important for the production of a water resource to be utilised for non-potable purposes and to prevent the environmental transmission of disease-causing agents. This study was conducted to evaluate the effect of water quality on the comparative disinfection efficiency of viruses, bacteria and spores by UV irradiation. Furthermore, the microbial quality of effluent produced by coagulation, high rate filtration (HRF) and either UV irradiation or chlorination was determined. Using low pressure collimated beam, a UV dose of 80 mWs/cm2 was needed to achieve a 3-log10 inactivation of either rotavirus SA-11 or coliphage MS2, whereas over 5-log10 inactivation of E. coli was reached with a dose of only 20 mWs/cm2. B. subtilis inactivation was found to be linear up to a dose of 40 mWs/cm2 and then a tailing up to a UV dose of 120 mWs/cm2 was observed. It is worth noting that effluent turbidity of <5 NTU did not influence the inactivation efficiency of UV irradiation. Operation of a pilot plant to treat secondary effluent by coagulation, HRF and UV disinfection at a UV dose of 80 mWs/cm2 resulted in the production of high quality effluent in compliance with the Israel standards for unrestricted irrigation (<10 CFU/100 mL faecal coliform and turbidity of <5 NTU). Sulphite reducing clostridia (SRC) were found to be more resistant than coliphages and F coliform for UV irradiation. The results of this study indicated that UV disinfection is suitable for the production of effluents for unrestricted irrigation of food crops.

Research on Influencing Factors of Photoreactivation in Urban Sewage Treatment by UV Disinfection

2013 ◽  
Vol 361-363 ◽  
pp. 595-600
Author(s):  
Ji Ku Zhang ◽  
Hui Ye Wang ◽  
Hui Ting Shao ◽  
Zhi Biao Dong
Keyword(s):  
Experimental Study ◽  
Influencing Factors ◽  
Water Samples ◽  
Sewage Treatment ◽  
Uv Disinfection ◽  
Natural Light ◽  
E Coli ◽  
Urban Sewage ◽  
Uv Dose ◽  
Higher Doses

Test using CS-type UV sterilizer to do experimental study on the urban sewage , mainly research the influence of the placement time under natural light and the UV dose on photoreactivation. The results show that when disinfection ultraviolet dose is equal, bacteria photoreactivation phenomenon is more obvious with the increase of the placement time of water samples under natural light . When the placement time reaches at 3h, bacteria photoreactivation phenomenon is the most obvious. Under the same placement time, the ratio of bacteria photoreactivation decreases gradually with the increase of UV dose. When UV dose reaches at 80mJ /cm2 or the higher doses, the bacteria does not basically happen photoreactivation phenomenon. Photoreactivation phenomenon in E. coli is more obvious than that in bacteria under the same conditions.

scholarly journals Functional Properties of Borrelia burgdorferi recA

2004 ◽  
Vol 186 (8) ◽  
pp. 2275-2280 ◽  
Author(s):  
Dionysios Liveris ◽  
Vishwaroop Mulay ◽  
Ira Schwartz
Keyword(s):  
Gene Expression ◽  
Borrelia Burgdorferi ◽  
Uv Irradiation ◽  
Reca Protein ◽  
Primary Role ◽  
Rapid Loss ◽  
E Coli ◽  
Uv Dose ◽  
Null Mutants

ABSTRACT Functions of the Borrelia burgdorferi RecA protein were investigated in Escherichia coli recA null mutants. Complementation with B. burgdorferi recA increased survival of E. coli recA mutants by 3 orders of magnitude at a UV dose of 2,000 μJ/cm2. The viability at this UV dose was about 10% that provided by the homologous recA gene. Expression of B. burgdorferi recA resulted in survival of E. coli at levels of mitomycin C that were lethal to noncomplemented hosts. B. burgdorferi RecA was as effective as E. coli RecA in mediating homologous recombination in E. coli. Furthermore, E. coli λ phage lysogens complemented with B. burgdorferi recA produced phage even in the absence of UV irradiation. The level of phage induction was 55-fold higher than the level in cells complemented with the homologous recA gene, suggesting that B. burgdorferi RecA may possess an enhanced coprotease activity. This study indicates that B. burgdorferi RecA mediates the same functions in E. coli as the homologous E. coli protein mediates. However, the rapid loss of viability and the absence of induction in recA expression after UV irradiation in B. burgdorferi suggest that recA is not involved in the repair of UV-induced damage in B. burgdorferi. The primary role of RecA in B. burgdorferi is likely to be a role in some aspect of recombination.

Experimental Studies of CS Type UV Sterilizer for the Urban Sewage Treatment

2013 ◽  
Vol 361-363 ◽  
pp. 601-605
Author(s):  
Ji Ku Zhang ◽  
Yang Yang Li ◽  
Chen Zhang ◽  
Yan Bin Yang
Keyword(s):  
Removal Rate ◽  
Sewage Treatment ◽  
Experimental Studies ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Uv Disinfection ◽  
Secondary Effluent ◽  
Urban Sewage ◽  
High Doses ◽  
Uv Dose

By treating the secondary effluent of Sanbaotun sewage treatment plant in Fushun with the CS type UV Sterilizer, the experiment researches the influence on the removal rate which includes the factors of turbidity, chromaticity, initial E.coli concentration of raw water, UV dose. The results show that the turbidity does not influence on UV disinfection efficiency with the turbidity from 1.5NTU to 3.8NTU. In the low-dose UV disinfection process, the influent sewage turbidity should under 4NTU to ensure the disinfection efficiency. Low chromaticity does not affect the UV disinfection efficiency, with the influent sewage chromaticity is under 15 degrees.The initial E. coli has a certain impact on little doses of UV disinfection with the concentration from 175 × 104 A/ L to 230 × 104 A/ L, no impact on high doses of UV disinfection。

scholarly journals H-NS Regulates DNA Repair inShigella

1998 ◽  
Vol 180 (19) ◽  
pp. 5260-5262 ◽  
Author(s):  
Sunil Palchaudhuri ◽  
Brandon Tominna ◽  
Myron A. Leon
Keyword(s):  
Dna Repair ◽  
Uv Irradiation ◽  
Shigella Flexneri ◽  
Virulence Gene ◽  
High Rate ◽  
High Survival ◽  
Virulence Gene Expression ◽  
E Coli ◽  
X Irradiation ◽  
K 12

ABSTRACT We report a new role for H-NS in Shigella spp.: suppression of repair of DNA damage after UV irradiation. H-NS-mediated suppression of virulence gene expression is thermoregulated inShigella, being functional at 30°C and nonfunctional at 37 to 40°C. We find that H-NS-mediated suppression of DNA repair after UV irradiation is also thermoregulated. Thus, Shigella flexneri M90T, incubated at 37 or 40°C postirradiation, shows up to 30-fold higher survival than when incubated at 30°C postirradiation. The hns mutants BS189 and BS208, both of which lack functional H-NS, show a high rate of survival (no repression) whether incubated at 30 or 40°C postirradiation. Suppression of DNA repair by H-NS is not mediated through genes on the invasion plasmid of S. flexneri M90T, since BS176, cured of plasmid, behaves identically to the parental M90T. Thus, inShigella the nonfunctionality of H-NS permits enhanced DNA repair at temperatures encountered in the human host. However, pathogenic Escherichia coli strains (enteroinvasive and enterohemorrhagic E. coli) show low survival whether incubated at 30 or 40°C postirradiation. E. coli K-12 shows markedly different behavior; high survival postirradiation at both 30 and 40°C. These K-12 strains were originally selected fromE. coli organisms subjected to both UV and X irradiation. Therefore, our data suggest that repair processes, extensively described for laboratory strains of E. coli, require experimental verification in pathogenic strains which were not adapted to irradiation.

scholarly journals DETERMINATION OF STANDARDIZED DOSES OF ULTRAVIOLET DISINFECTION OF WATER FROM BACTERIAL, VIRAL AND PARASITIC CONTAMINATION

2019 ◽  
Vol 98 (12) ◽  
pp. 1342-1348
Author(s):  
Yu. A. Rakhmanin ◽  
Anzhelika V. Zagainova ◽  
T. Z. Artemova ◽  
E. K. Gipp ◽  
K. Yu. Kuznetsova ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Uv Irradiation ◽  
Bacterial Contamination ◽  
Tap Water ◽  
Uv Disinfection ◽  
Residual Chlorine ◽  
Special Role

Introduction. The proposed criteria for the sanitary-bacteriological assessment of the quality of tap water must ensure its epidemic safety. In conditions of intensive bacterial contamination of water bodies, a special role is played by the barrier function of water treatment plants in relation to infectious agents. The overall quality of microorganisms is the pronounced resistance in the aquatic environment, primarily resistance to a number of chlorine-containing disinfectants, which guarantee the preservation of the population in drinking water undergone a water treatment system. Therefore, it is necessary to consider other possible ways of disinfection, such as ultraviolet irradiation. Determination of the effective dose of ultraviolet (UV) disinfection against bacterial, viral and parasitic contamination of drinking water. Material and methods. Tap water was used as model water for research. The effectiveness of UV irradiation with doses of 25, 40, 60 mJ / cm2 against microorganisms was studied. Results. In the course of the work, it was established that the UV disinfection technology with a dose of at least 25 mJ/cm2 can be recommended as a disinfection method when used in conjunction with chlorination. Conclusion. In water treatment technology, a dose of at least 25 mJ/cm2 of UV irradiation can be recommended as a method of disinfecting water in case of microbial contamination by bacteria and viruses at a concentration not exceeding nˑ102 cells/virions in 100 ml, and at a concentration of microbiological contamination nˑ103 cells/virions in 100 ml of water, the use of UV disinfection can be recommended only in conjunction with chlorination and with the provision of indices on the residual chlorine in the distribution network before serving to the consumer. The presented scheme will increase the barrier role of water treatment facilities with respect to viral and bacterial contamination, provide a prolonged decontamination effect, contributing to the suppression of bacterial growth in breeding nets and limit the level of parasitic water contamination during water treatment.

Removal of enteric viruses and selected microbial indicators by UV irradiation of secondary effluent

2003 ◽  
Vol 47 (9) ◽  
pp. 193-198 ◽  
Author(s):  
J.G. Jacangelo ◽  
P. Loughran ◽  
B. Petrik ◽  
D. Simpson ◽  
C. McIlroy
Keyword(s):  
Wastewater Treatment ◽  
New Zealand ◽  
Clostridium Perfringens ◽  
Uv Irradiation ◽  
Secondary Effluent ◽  
Sufficient Information ◽  
Indicator Organisms ◽  
Microbial Indicators ◽  
Uv Dose ◽  
Specific Bacteriophage

The Watercare Mangere Wastewater Treatment Facility, which treats wastewater from the greater Auckland New Zealand region, is undergoing a major expansion/upgrading to add advanced treatment and disinfection prior to discharge into a harbor. One important goal of this project is to protect the receiving water from microbial contamination. Since sufficient information on the fate of various microorganisms through wastewater treatment plants in New Zealand was not readily available, extensive pilot- and bench-scale studies were undertaken to develop specific design criteria for the treatment and disinfection systems. The specific objective of this study was to evaluate the removal and inactivation of enteric pathogens and other microbial indicators through treatment processes that employs UV irradiation as a final disinfection process. The removal of indicator organisms through secondary treatment was typically between 2.5-log (99.7% removal) and 2.8-log (99.8% removal) for fecal coliforms and enterococci, respectively. Indigenous F-specific bacteriophage exhibited a mean removal of 1.6-log (i.e. 97.7% removal) and Clostridium perfringens spores showed a mean removal of 1.3-log (i.e. 95% removal). The UV dose required to achieve a one log reduction in the concentration of indigenous F-specific bacteriophage was found to be approximately 20 mWs/cm2 per log removal. The concentration of enterovirus and adenovirus were consistently reduced to the limit of detection (1 TCID50/100L) at UV doses of 35 to 40 mWs/cm2 and 40 to 45 mWs/cm2, respectively. Clostridium perfringens spores were the most resistant indicator organisms, being reduced to less than 200 MPN/100 mL at a UV dose of 75 mWs/cm2.

Experimental assessment of RSF, UF, RSF-O3 and RSF-H2O2/UV for unrestricted agricultural wastewater reuse in Italy

2013 ◽  
Vol 8 (1) ◽  
pp. 70-82
Author(s):  
C. Parabita ◽  
L. Guglielmi ◽  
L. Canovi ◽  
S. Sorlini ◽  
F. Gialdini ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Treatment Options ◽  
Wastewater Reuse ◽  
Complete Removal ◽  
Mineral Oil ◽  
Secondary Effluent ◽  
Total Coliforms ◽  
Log Reduction ◽  
Wastewater Quality ◽  
Uv Dose

In this paper, tertiary treatment processes aimed at achieving a wastewater quality suitable for reuse in agriculture in Italy have been investigated, with experimental results generated by means of pilot and bench scale tests. Studies were conducted to assess the removal of mineral oil, total surfactants, total coliforms, Escherichia coli and Salmonella using the following treatment options: rapid sand filtration (RSF), hollow fiber ultrafiltration (UF), RSF followed by ozonation (RSF-O3) and RSF followed by hydrogen peroxide combined with UV radiation (RSF-H2O2/UV). Mineral oil concentration, evaluated by means of the hydrocarbon oil index measurement, indicated an effluent concentration consistently below 0.05 mg/L for all processes studied. While total surfactants in the secondary effluent never exceeded the applicable limit of 0.5 mg/L during the studies, the degree of removal measured in studied treatments ranged from moderate to low, with the greatest removal observed using RSF-O3 (24%) and RSF-H2O2/UV (30%) under applied conditions. Overall, the optimal treatment performances were achieved by the RSF-H2O2/UV combined process using ≥1.5 mg/L H2O2 and UV dose ≥45 mJ/cm2, which provided adequate mineral oil and total surfactants removal, complete removal of measurable total suspended solids (TSS) and Salmonella, and greater than 4-log reduction in total coliforms and Escherichia coli.

scholarly journals Photoreactivation of Escherichia coli after Low- or Medium-Pressure UV Disinfection Determined by an Endonuclease Sensitive Site Assay

2002 ◽  
Vol 68 (12) ◽  
pp. 6029-6035 ◽  
Author(s):  
Kumiko Oguma ◽  
Hiroyuki Katayama ◽  
Shinichiro Ohgaki
Keyword(s):  
Escherichia Coli ◽  
Uv Irradiation ◽  
Genomic Dna ◽  
Uv Disinfection ◽  
E Coli ◽  
Medium Pressure ◽  
Pyrimidine Dimers ◽  
Sensitive Site ◽  
Uv Lamp

ABSTRACT Photoreactivation of Escherichia coli after inactivation by a low-pressure (LP) UV lamp (254 nm), by a medium-pressure (MP) UV lamp (220 to 580 nm), or by a filtered medium-pressure (MPF) UV lamp (300 to 580 nm) was investigated. An endonuclease sensitive site (ESS) assay was used to determine the number of UV-induced pyrimidine dimers in the genomic DNA of E. coli, while a conventional cultivation assay was used to investigate the colony-forming ability (CFA) of E. coli. In photoreactivation experiments, more than 80% of the pyrimidine dimers induced by LP or MPF UV irradiation were repaired, while almost no repair of dimers was observed after MP UV exposure. The CFA ratios of E. coli recovered so that they were equivalent to 0.9-, 2.3-, and 1.7-log inactivation after 3-log inactivation by LP, MP, and MPF UV irradiation, respectively. Photorepair treatment of DNA in vitro suggested that among the MP UV emissions, wavelengths of 220 to 300 nm reduced the subsequent photorepair of ESS, possibly by causing a disorder in endogenous photolyase, an enzyme specific for photoreactivation. On the other hand, the MP UV irradiation at wavelengths between 300 and 580 nm was observed to play an important role in reducing the subsequent recovery of CFA by inducing damage other than damage to pyrimidine dimers. Therefore, it was found that inactivating light at a broad range of wavelengths effectively reduced subsequent photoreactivation, which could be an advantage that MP UV irradiation has over conventional LP UV irradiation.

scholarly journals Urine treatment by solar disinfection for agriculture reuse purpose in a poor rural context: case of Burkina Faso

2020 ◽  
Author(s):  
Drissa Sangare ◽  
Alexis L. Brou ◽  
Mariam Sou/dakoure ◽  
Patricia V. Tagro
Keyword(s):  
Effect Of Temperature ◽  
Continuous Exposure ◽  
Solar Disinfection ◽  
E Coli ◽  
Pet Bottles ◽  
Exponential Decay Model ◽  
Inactivation Efficiency ◽  
Microbiological Analyses ◽  
Urine Treatment

Abstract The study aimed to reduce the storage time of urine treatment and assess the quality of treated urine following the Solar DISinfection (SODIS) method. Microbiological analyses were performed on urine samples taken before each sunlight exposure, between 10am and 4pm at a frequency of 1 h, during which temperature was measured in PET bottles (1.5 L). The initial concentrations of Escherichia coli (E. coli) and Salmonella in unstored urine were 106 and 103 CFU/100 mL respectively. The combined effect of temperature and UV radiation increased inactivation efficiency of E. coli at 5 log units. On the other hand, 98% of Salmonella were inactivated in less than 3 h of continuous exposure between 12am and 3pm with temperature varying between 50 and 65 °C in PET bottles. The k values showed that the inactivation rate of Salmonella tested was accelerated when the temperature was above 50 °C. Then, the results indicated that the first-order exponential decay model was the best method to predict the inactivation of Salmonella in urine by SODIS. General results showed that after 3 days of exposure to sunlight, urine collected via eco-toilet becomes bacteriologically sanitized and therefore can be used in agriculture.

Ultraviolet Disinefection of Secondary and Tertiary Effluent in the Mediterranean Region

1999 ◽  
Vol 40 (4-5) ◽  
pp. 253-260 ◽  
Author(s):  
A. Andreadakis ◽  
D. Mamais ◽  
D. Christoulas ◽  
S. Kabylafka
Keyword(s):  
Suspended Solids ◽  
Municipal Sewage ◽  
Uv Disinfection ◽  
Secondary Effluent ◽  
First Order ◽  
First Order Kinetics ◽  
Uv Dose ◽  
The One ◽  
Athens Area ◽  
Lamp Fouling

A study was undertaken to evaluate the efficiency of ultraviolet radiation in disinfecting secondary and tertiary effluents using wastewater from two full scale treatment plants located in the greater Athens area, the one receiving municipal sewage and the other receiving municipal sewage and septage. The effective UV dose for coliform removal, the effects of feedwater characteristics on UV disinfection and the lamp fouling potential were examined. For secondary effluent samples the required UV dose to achieve effluent fecal concentrations of less than 2,000 FC/100 ml varied from 30 to 60 mW-sec/cm2, depending on the water quality characteristics of the feedwater. High effluent suspended solids significantly increased the UV dose required to achieve adequate disinfection. For tertiary effluent the required UV dose to meet the 2000 FC/100 ml criterion was only 10 mW-sec/cm2, where as a dose of 40-50 mW-sec/cm2 was sufficient to achieve effluent coliform concentrations of less than 10 FC/100 ml. The inactivation of coliforms followed first order kinetics for relative low UV doses, with inactivation rates in the 0,107–0,303 cm2/mW-sec range for secondary effluent and 0,325 cm2/mW-sec for tertiary effluent. The lamp fouling potential was relatively high and the required lamp cleaning frequency was approximately twice per month.

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