Chemical effects on UV irradiation absorption of fouled quartz sleeves in ultraviolet disinfection

2008 ◽  
Vol 8 (2) ◽  
pp. 217-222 ◽  
Author(s):  
Beibei Zhu Sun ◽  
Ernest Blatchley ◽  
Mike Oliver ◽  
Cheng Zheng ◽  
Kristofer Jennings
Keyword(s):  
Statistical Analysis ◽  
Uv Disinfection ◽  
Uv Absorbance ◽  
Ultraviolet Disinfection ◽  
High Chemical ◽  
Chemical Surface ◽  
Chemical Effects ◽  
Uv Transmittance ◽  
Main Effects ◽  
Iron And Manganese

The effects of foulant chemical composition on ultraviolet (UV) absorbance of fouled quartz sleeves in UV disinfection systems were studied. Statistical analysis was conducted to examine the effects of nine fouling chemicals on the UV transmittance changes of fouled quartz lamp sleeves. The results demonstrated that the main effects were attributable to surface concentrations of iron and manganese. The surface concentrations of calcium and copper had no significant effects on the UV absorbance of fouled sleeves. The interaction effects of copper with iron and magnesium with manganese were also revealed from the statistical analysis. The model is able to give reasonable predictions of the UV absorbance characteristics of foulants from other UV systems. However, several limitations of this model were identified. First, the model does not accurately predict the absorbance at relatively high chemical surface concentrations. Second, the model does not account for the possible effects of anions and organics on UV absorption of fouled quartz sleeves.

Chemical Effects of Lubrication in Contact Fatigue—Part II: The Statistical Analysis, Summary, and Conclusions

1976 ◽  
Vol 98 (2) ◽  
pp. 299-305 ◽  
Author(s):  
S. Bhattacharyya ◽  
F. C. Bock ◽  
M. A. H. Howes ◽  
N. M. Parikh
Keyword(s):  
Statistical Analysis ◽  
Contact Fatigue ◽  
Chemical Effects

Influence of lamp intensity and water transmittance on the UV disinfection of water

1997 ◽  
Vol 35 (11-12) ◽  
pp. 113-118 ◽  
Author(s):  
R. Sommer ◽  
A. Cabaj ◽  
W. Pribil ◽  
T. Haider
Keyword(s):  
Supply Voltage ◽  
Uv Disinfection ◽  
Uv Detector ◽  
Uv Irradiance ◽  
Flow Through ◽  
Uv Lamp ◽  
Uv Transmittance ◽  
Two Parameters ◽  
Uv Lamps ◽  
Irradiation Chamber

The efficiency of UV disinfection devices depends on flow, lamp intensity and water transmittance. In practice the flow is controlled by suitable methods, whereas the other two parameters, to date, have not been taken into consideration sufficiently. The surveillance of the function of UV disinfection plants is routinely based on a sensor placed on the irradiation chamber wall. This measures changes of UV irradiance without differentiating if the effect is caused by transmittance or lamp intensity so that two different conditions of disinfection may occur at the same sensor readings. We investigated the influence of transmittance vs intensity on disinfection at the same sensor readings in a specially designed laboratory flow through UV irradiation system with one single UV lamp as well as in commercially available UV disinfection plants with multiple UV lamps. All devices were equipped with a calibrated selective UV detector connected to a UV radiometer. Lamp intensity was decreased by diminishing the supply voltage. UV transmittance was reduced by pumping aqueous sodium thiosulphate solution into the water inflow. The disinfection capacity was determined by measuring the reduction equivalent doses (RED) using a standardised biodosimetric method. We showed that equal sensor readings, either achieved by reducing the lamp intensity or by lowering the UV transmittance of the water, resulted in different REDs in one-lamp systems. The diminishing of UV intensity caused a greater decrease of REDs than reducing the water transmittance. However, in the multiple-lamp systems tested, equal sensor readings yielded equal REDs.

scholarly journals A Statistical Analysis of Evaporative Pattern Casting Process Parameters for the Production of Aluminum Alloy Components

2020 ◽  
Vol 4 (3) ◽  
pp. 41-47
Author(s):  
B. Victor Omidiji
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Statistical Analysis ◽  
Process Parameters ◽  
Casting Process ◽  
Pouring Temperature ◽  
Percentage Contribution ◽  
Hardness Property ◽  
Main Effects ◽  
Evaporative Pattern Casting

Four process parameters were investigated with the aim of determining their influence on the mechanical properties of some test castings, bars, cylinders and plates. The influence was quantified in terms of percentage contribution. Analysis of variance (ANOVA), regression, main effects and interaction effects plots were employed to carry out the statistical analysis. As regards the tensile strength of the test castings, the geometry of components (GOC) dominated, contributing 90.83% and the pouring temperature (PT) contributed 91.90% influence on the hardness property. These dominating potentials of these twoparameters limited the interaction of the parameters studied in the research.

Ultraviolet Disinfection of Secondary Wastewater

1983 ◽  
Vol 18 (1) ◽  
pp. 115-128
Author(s):  
Garry Palmateer ◽  
Walter G. Cook ◽  
G. Elliott Whitby ◽  
Jan Maarschalkerweerd ◽  
Doug Huber ◽  
...  
Keyword(s):  
Ultraviolet Light ◽  
Clostridium Perfringens ◽  
Full Scale ◽  
Fecal Coliforms ◽  
Treated Wastewater ◽  
Uv Disinfection ◽  
Ultraviolet Disinfection ◽  
Chlorine Disinfection ◽  
Pollution Indicator ◽  
Significant Mortality

Abstract A full-scale study involving the disinfection of secondarily treated wastewater with ultraviolet light was initiated to determine the efficacy of an ultraviolet device designed and engineered specifically for this purpose when operated in parallel with chlorine disinfection. Results consistently demonstrated the ability of the UV device to reduce pollution indicator bacterial levels to well below 2500 and 200 total and fecal coliforms, respectively per 100 ml as well as the more disinfectant resistant Clostridium perfringens. In caged fish-toxicity assays, no significant mortality was observed in the stream following UV disinfection; however, within 24 hours 100% mortality resulted from the chlorinated effluents.

scholarly journals ULTRAVIOLET DISINFECTION AS AN ELEMENT OF MULTI-BARRIER APPROACH TO THE WATER TREATMENT FOR THE PROTECTION AGAINST CHLORINE-RESISTANT PATHOGENS

2019 ◽  
Vol 96 (6) ◽  
pp. 531-535
Author(s):  
Z. I. Zholdakova ◽  
E. A. Tulskaya ◽  
S. V. Kostuchenko ◽  
Andrey A. Tkachev
Keyword(s):  
Wastewater Treatment ◽  
Water Treatment ◽  
Wastewater Treatment Plants ◽  
Uv Disinfection ◽  
Ultraviolet Disinfection ◽  
Water And Wastewater Treatment ◽  
Large Cities ◽  
Disinfection Methods ◽  
Wide Range ◽  
Water And Wastewater

Ultraviolet disinfection is the most efficient mode in combination with other disinfection methods within multi-barrier approach for the water treatment. UV disinfection being effective against a wide range of pathogens including the chlorine-resistant (viruses and protozoa) significantly reduces chlorine byproducts. This paper presents a review of results of the implementation of multi-barrier lay-out with the application of UV disinfection at water and wastewater treatment plants of large cities: St. Petersburg and Nizhniy Novgorod.

Recent developments in the design of field experiments: III. Fractional replication

1946 ◽  
Vol 36 (3) ◽  
pp. 184-191 ◽  
Author(s):  
D. J. Finney
Keyword(s):  
Statistical Analysis ◽  
Field Experiments ◽  
Block Size ◽  
Five Factors ◽  
Main Effect ◽  
Recent Developments ◽  
Four Blocks ◽  
Factor Interactions ◽  
Main Effects ◽  
Factor Interaction

When a factorial experiment involves many factors each of which is tested at two levels, economy of space and material may be effected by using only a fraction of a complete replicate of all possible combinations of levels of the factors. The consequence is that each main effect and each interaction has one or more aliases, and the experiment cannot distinguish which member of a set of aliases is responsible for an observed difference in yields. For less than five factors, this feature prevents fractional replicate designs from being much use; for five or more factors, the fraction can be so chosen that main effects and two-factor interactions have only higher order interactions as their aliases, and the possibility that these are important may often be ignored. Within the fraction of a replicate chosen for an experiment, confounding of interactions may be introduced in order to reduce the block size.Designs likely to be useful in field experiments are those for six factors in four blocks of eight, for seven factors in eight blocks of eight, and for eight factors in eight blocks of sixteen or in sixteen blocks of eight; in the first of these a two-factor interaction is amongst those confounded, but elsewhere all main effects and two-factor interactions are unconfounded. The method of construction of the blocks, for these designs and those involving more factors, has been described, and an example of the statistical analysis of experimental results (which presents no special difficulties) has been given.

Sign in / Sign up

Export Citation Format

Share Document