Elimination of micro-organisms in water treatment

“The management of the microbiological drinking water quality in the
Netherlands has been changed in the past ten to fifteen years. One of the
major changes was the shift from curative quality management to a more
preventive strategy. In the first part of this first Chapter the historical
perspectives of the microbiological quality of drinking water from the late
19th Century untill the beginning of the beginning of the 21th is described.
Motives for the change from curative to preventive managements were
epidemiological studies on waterborne diseases, scientific knowledge on
the dose-response data of some waterborne pathogenic micro-organisms
and shortcomings in water quality control. In the Netherlands this resulted
in the introduction of a health based microbial target and the requirement
to assess this target with Quantitative Microbial Risk Assessment (QMRA)
in the revised Drinking Water Decree in 2001. Important requirement for
QMRA is quantitative information on the capacity of drinking water to
eliminate (remove or inactivate) micro-organisms.
Overall objective of the present study was to develop a generic
methodology to collect this information. The line of approach in this study
was to develop a method as closely related to the natural conditions in
water treatment and to the daily practice of microbiological water quality
monitoring. This is described and motivated in the second part of this
Chapter where the hypothesis was introduced that beside their role as
indicator of faecal pollution, faecal indicator bacteria can be used as process
indicators for the elimination of different waterborne pathogens. In the last
part of this Chapter the overall objective is specified in a number of subgoals
on the basis of research needs. In the outline paragraph the separate
Chapters are mentioned focused on the sub-goals of the study.”

(Citaat: Hijnen, W.A.M. – Elimination of micro-organisms in water treatment, 2009)