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Chapter No. 8. Pathogen removal


The fact that wastewater contains pathogenic organisms was the main reason for the start of big scale sewerage systems and wastewater treatment plants 150 years ago. This had been more or less forgotten until the middle of the 20th century when disinfection of effluents came into use.

Although humans are continually exposed to a vast array of microorganisms in the environment, only a small proportion of those microbes are capable of interacting with the host in such a manner that infection and disease will result. Disease-causing microorganisms are called pathogens. Infection is the process in which the microorganism multiplies or grows in or on the host. Infection does not necessarily result in disease since it is possible for the organism to grow in or on the host without causing or producing any illness. In the case of enteric infections caused by Salmonella (i.e. diarrhea), only half of the infected individuals develop clinical signs of illness. Pathogenic microorganisms usually originate from an infected host (either human or other animal) or directly from the environment.

With recent advances on wastewater reclamation, pathogen removal through disinfection processes and applications has gotten renewed attention lately. This chapter presents an overview of the enteric pathogens commonly found in sewage, their characteristics, occurrence, methods of detection and monitoring, expected pathogen removal rates in wastewater treatment processes, and disinfection processes.

This course consists of 3 video lectures recorded by Prof. Charles P. Gerba from University of Arizona in Tucson, US.

Time Framework for the Course: 1 week

Aims of the Course

  • To present an overview of the enteric pathogens most commonly found in sewage and their characteristics.
  • To briefly describe the main factors affecting the occurrence of enteric pathogens in sewage, methods for their detection and monitoring.
  • To depict the expected pathogen removal rates in different wastewater treatment systems.
  • To describe the most commonly applied disinfection processes and their expected pathogen removal rates as a function of the operating and environmental parameters.

Learning Objectives

  • To describe the importance of pathogen removal and assess the pathogen removal efficiencies from different wastewater treatment processes and commonly applied disinfection processes as a function of their disinfection principles and operating and environmental conditions.
Last modified: Saturday, 2 January 2016, 5:49 AM