Particle counters as tools for managing Cryptosporidium risk in water treatment

1997 ◽  
Vol 36 (4) ◽  
pp. 143-149 ◽  
Author(s):  
Tom Hall ◽  
Brian Croll
Keyword(s):  
Water Treatment ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Operating Conditions ◽  
Water Supplies ◽  
Treatment Processes ◽  
Particle Counting ◽  
Particle Counts ◽  
The Uk ◽  
And Control

Outbreaks of waterborne cryptosporidiosis have been a major concern for the Water Industry in the UK and US over the past ten years. Management of risk from Cryptosporidium in water supplies relies heavily upon operation and control of water treatment processes to maximise oocyst removal. Difficulties in measuring oocyst concentrations in water supplies have led to evaluation of surrogate parameters with which to assess oocyst removal by treatment. Whilst turbidity measurement can give an indication of the risk of oocyst breakthrough from filters, a more sensitive indicator appears to be particle counts in filtered water. The paper gives a demonstration of the potential for particle counting as a tool for managing Cryptosporidium risk, and describe ways in which particle counting can be used for monitoring and controlling water treatment plant operation. With the present level of knowledge, the most suitable application for particle counting is as a diagnostic tool for the identification of operating conditions which reduce or minimise particle counts in filtered water at individual sites.

Scenario-based quantitative microbial risk assessment to evaluate the robustness of a drinking water treatment plant

2016 ◽  
Vol 51 (2) ◽  
pp. 81-96 ◽  
Author(s):  
Mohamed A. Hamouda ◽  
William B. Anderson ◽  
Michele I. Van Dyke ◽  
Ian P. Douglas ◽  
Stéphanie D. McFadyen ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Drinking Water ◽  
Water Treatment ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Operating Conditions ◽  
Quantitative Microbial Risk Assessment ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Treatment Processes

While traditional application of quantitative microbial risk assessment (QMRA) models usually stops at analyzing the microbial risk under typical operating conditions, this paper proposes the use of scenario-based risk assessment to predict the impact of potential challenges on the expected risk. This study used a QMRA model developed by Health Canada to compare 14 scenarios created to assess the increase in risk due to potential treatment failures and unexpected variations in water quality and operating parameters of a water treatment plant. Under regular operating conditions, the annual risk of illness was found to be substantially lower than the acceptable limit. Scenario-based QMRA was shown to be useful in demonstrating which hypothetical treatment failures would be the most critical, resulting in an increased risk of illness. The analysis demonstrated that scenarios incorporating considerable failure in treatment processes resulted in risk levels surpassing the acceptable limit. This reiterates the importance of robust treatment processes and the multi-barrier approach voiced in drinking water safety studies. Knowing the probability of failure, and the risk involved, allows designers and operators to make effective plans for response to treatment failures and/or recovery actions involving potential exposures. This ensures the appropriate allocation of financial and human resources.

Practical Guide to Determine the Impact of Radon and Other Radionuclides on Water Treatment Processes

1992 ◽  
Vol 26 (5-6) ◽  
pp. 1255-1264
Author(s):  
K. L. Martins
Keyword(s):  
Activated Carbon ◽  
Water Treatment ◽  
Environmental Protection Agency ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Packed Tower ◽  
Treatment Processes ◽  
Radioactivity Exposure ◽  
The Impact ◽  
Percent Removal

During treatment of groundwater, radon is often coincidentally removed by processes typically used to remove volatile organic compounds (VOCs)-for example, processes such as liquid-phase granular activated carbon (LGAC) adsorption and air stripping with vapor-phase carbon (VGAC). The removal of radon from drinking water is a positive benefit for the water user; however, the accumulation of radon on activated carbon may cause radiologic hazards for the water treatment plant operators and the spent carbon may be considered a low-level radioactive waste. To date, most literature on radon removal by water treatment processes was based on bench- or residential-scale systems. This paper addresses the impact of radon on municipal and industrial-scale applications. Available data have been used todevelop graphical methods of estimating the radioactivity exposure rates to facility operators and determine the fate of spent carbon. This paper will allow the reader to determine the potential for impact of radon on the system design and operation as follows.Estimate the percent removal of radon from water by LGAC adsorbers and packed tower air strippers. Also, a method to estimate the percent removal of radon by VGAC used for air stripper off-gas will be provided.Estimate if your local radon levels are such that the safety guidelines, suggested by USEPA (United States Environmental Protection Agency), of 25 mR/yr (0.1 mR/day) for radioactivity exposure may or may not be exceeded.Estimate the disposal requirements of the waste carbon for LGAC systems and VGAC for air stripper “Off-Gas” systems. Options for dealing with high radon levels are presented.

Monitoring On-Line and Control of Sludge Concentration in Sewage Treatment System

2013 ◽  
Vol 373-375 ◽  
pp. 897-901
Author(s):  
Lian Qing Yin ◽  
Chun Xiao Yin ◽  
Xue Zhou ◽  
Jia Liu
Keyword(s):  
Water Treatment ◽  
Sewage Treatment ◽  
Settling Tank ◽  
Great Influence ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Treatment System ◽  
On Line ◽  
And Control ◽  
Sludge Concentration

The reuse of industrial waste and urban sewage is a vital method for solving the shortage of water resource in China. Settling tank as a processing link in water treatment system widely used exercises a great influence on sewage treatment efficiency, and sludge emissions have a great influence on the operation of water treatment plant. Manual mud and mechanical dredge are widely used in most of the water treatment plants from the current domestic. The design used ultrasonic as a method for determination of sludge concentration, developped corresponding application control software, and finally completed a reasonable and feasible for settling tank intermittent discharge of sludge monitoring and emission control system.The result of our simulation system shows that the program operation is stable and maneuverability, and this set of monitoring on-line and control system has good application and development foreground.

Model-based pH monitor for sensor assessment

2009 ◽  
Vol 60 (3) ◽  
pp. 709-715 ◽  
Author(s):  
Kim van Schagen ◽  
Luuk Rietveld ◽  
Alex Veersma ◽  
Robert Babuška
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Mathematical Models ◽  
A Priori ◽  
Treatment Plant ◽  
Drinking Water Treatment ◽  
Water Treatment Plant ◽  
Treatment Processes ◽  
Online Measurements ◽  
Measurement Devices

Owing to the nature of the treatment processes, monitoring the processes based on individual online measurements is difficult or even impossible. However, the measurements (online and laboratory) can be combined with a priori process knowledge, using mathematical models, to objectively monitor the treatment processes and measurement devices. The pH measurement is a commonly used measurement at different stages in the drinking water treatment plant, although it is a unreliable instrument, requiring significant maintenance. It is shown that, using a grey-box model, it is possible to assess the measurement devices effectively, even if detailed information of the specific processes is unknown.

Quantifying human exposure to contaminants for multiple-barrier water reuse systems

2010 ◽  
Vol 61 (1) ◽  
pp. 77-83 ◽  
Author(s):  
S. J. Khan ◽  
J. A. McDonald
Keyword(s):  
Water Treatment ◽  
Water Reuse ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Disinfection Byproducts ◽  
Plant Performance ◽  
Advanced Treatment ◽  
Safe Drinking Water ◽  
Treatment Processes ◽  
Wide Range

Reliance upon advanced water treatment processes to provide safe drinking water from relatively compromised sources is rapidly increasing in Australia and other parts of the world. Advanced treatment processes such as reverse osmosis have the ability to provide very effective treatment for a wide range of chemicals when operated under optimal conditions. However, techniques are required to comprehensively validate the performance of these treatment processes in the field. This paper provides a discussion and demonstration of some effective statistical techniques for the assessment and description of advanced water treatment plant performance. New data is provided, focusing on disinfection byproducts including trihalomethanes and N-nitrosamines from a recent comprehensive quantitative exposure assessment for an advanced water recycling scheme in Australia.

scholarly journals Automation and control of water treatment plant for defluoridation

2016 ◽  
Vol 4 (26) ◽  
pp. 6-11 ◽  
Author(s):  
Swati Dubey ◽  
Madhu Agarwal ◽  
A.B. Gupta ◽  
Rajeev Kumar Dohare ◽  
Sushant Upadhyaya
Keyword(s):  
Water Treatment ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Automation And Control ◽  
And Control
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