WERF Report (Project 98-HHE-2)
Available as an ebook
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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
Long Island Sound was designated as an "estuary of national significance" in 1998, and the Long Island Sound Study (LISS) was directed to develop a comprehensive conservation and management plan (...
Anaerobic biological treatment systems can offer a number of advantages over their aerobic counterparts. The operational costs associated with anaerobic systems are typically lower than with...
Rapid methods of water quality assessment are essential for informing the public and officials of sewage-polluted water in a timely manner. Since fecal indicator bacteria can be contributed to the...
This WERF sponsored research presents a preliminary screening process and ecological diagnostic approaches that could be used to help prioritize and evaluate treated wastewater-influenced sites...
Until recently only lipophilic compounds were analysed in any research on the occurrence of mutanogenic and carcinogenic compounds in water. They were isolated using XAD-resins. They contain...
This book is a Spanish translation of Faecal Sludge Management: Systems Approach for...
Ambient water quality criteria for recreational waters have been established based on epidemiologic studies of swimmers at beaches. Waters that cannot be used for full contact water recreation (...
This is the Portuguese translation of Manual on the Human...