WERF Report (Project 98-HHE-2)
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Available as an ebook
Please purchase via www.iwaponline.comOpens in new window
Also part of Water Intelligence Online Digital Reference Library
Standard ePrice: £29.00
+ VAT
Disinfection of wastewater is a necessary treatment process for protecting the public from potential exposure to pathogenic microorganisms. Two common forms of disinfection are chlorine and ultraviolet (UV) light. However, microorganisms differ in their susceptibility to UV and chlorine disinfectants. It is necessary to understand how different classes of pathogens respond to UV and chlorine disinfection processes in wastewater to better develop strategies for optimizing the treatment of pathogens in wastewater. It is also recognized that water quality may impact disinfection effectiveness, such as protection of pathogen by particles and disinfectant demand.
This study investigated bacteria, viruses and protozoan pathogens. All species of bacteria tested were susceptible to both UV and chlorine, despite differences in antibiotic resistance and tendency to aggregate. Upon exposure to disinfection conditions that could indicate viability of the bacteria tested, but not culturability using common methods, it was found that UV and chlorine were effective in eliminating the capability of viable but non-culturable bacteria to resuscitate. Clostridium spores were resistant to free chlorine and UV disinfection but found to be susceptible to long exposure to monochloramine. Cryptosporidium was resistant to all chlorine forms but very susceptible to UV irradiation. Pathogenic and indicator viruses tested were very susceptible to free chlorine and UV disinfection. UV radiation throughout the 200 to 300 nm range was effective for inactivation of viruses and C. parvum, but wavelengths between 260-270 nm and below 220 nm appeared to be more effective for viruses, suggesting a possible advantage for polychromatic UV sources.
Sequential disinfection strategies were proposed and tested to enhance inactivation of various microorganisms. One scenario integrated UV disinfection followed by dynamic chloramination through addition of free chlorine and subsequent transformation to combined chlorine. Further, disinfection of microorganisms in wastewater presents challenges that are inherent to the water matrix, such as pathogens associated with particles. UV and chlorine were both effective for disinfection of coliform in wastewater but chlorine was found to be more effective during long contact times for inactivation of particle associated coliform. In addition to coliform, both Cryptosporidium parvum and Salmonella typhimurium were identified as being particle associated in wastewater using molecular approaches developed to detect microbes in environmental samples
To protect aquatic ecosystems from stresses induced by toxic chemicals, risk models must be developed, calibrated and verified for feral populations. Although risk models require good estimates of...
This report presents the methodology and findings of the Collection System Ventilation Research project completed in Phase II of the WERF initiative Minimizations of Odors and Corrosion in...
Sustainable water management is increasingly important for utilities and is driving efforts to reduce energy consumption and residuals production in domestic wastewater (DWW) treatment without...
Characterizes sources of WET test variability and evaluates existing and new methods that integrate variability into decision making. Will identify technically defensible methods to improve the...
Metals and Related Substances in Drinking Water comprises the proceedings of COST Action 637 – METEAU, held in Kristianstad, Sweden, October 13-15, 2010
This book...
Preventing Legionellosis covers the biology of Legionella and presents a comprehensive review of best practices for legionellosis prevention from around the world.
...This project addresses the need to remove trace organic compounds (TOrC) from wastewater, as well as potentially hazardous oxidation products. The general goal was to evaluate the efficacy of UV-...
Pharmaceutical wastewater is now a major concern due to the improper legislation around the globe and the poor implementation of existing laws. This book covers the various aspects of...