gogga posts stuff

A though-provoking article, nothing less!

I recall reading about cholera outbreaks through infestation of drinking water. But that was so long ago! Surely by now we have much better treatment systems, do we not? Alas, bacteria and viruses are stronger, too.

I know I will repeat it for the millionth time, but as we get rid of weaker bacteria we make room for the stronger species. In some cases, far stronger ones. I am actually curios to see the outcome of all this.

Well, whatever the case, take a look at this article on wastewater treatment published on RedOrbit.

Posted on: Sunday, 15 April 2007, 03:00 CDT

Investing in the Science of Disinfection
By Rose, Joan B; Haas, Charles N

Early practices of wastewater collection and treatment were driven by aesthetics and by the belief that the “miasmas” emanating from wastewater resulted in disease. A significant turning point in protection of community health and epidemics came in the mid-19th century. During a pandemic of cholera that broke out in India in 1846, John Snow observed that the disease was transmitted through drinking water. He was then able to test his theory using one of the first engineering controls by simply removing the handle from the Broad Street pump, suspected as the cause of a cholera outbreak in London. Somewhat later, the achievements of Koch and Pasteur identifying pathogenic bacteria placed a scientific rationale to the use of adequate sanitation for disease prevention

These discoveries led to adequate treatment (including disinfection) of both water and wastewater. Early tests showed the dramatic benefit of adequate sanitation and treatment at reducing the burden of disease in the population. Thereafter, chlorination of drinking water was accepted as a primary measure throughout the world and is still protecting our health from waterborne disease epidemics in the 21st century. Other disinfection techniques were also introduced at the dawn of the 20th century, including UV and ozone. As a result of these advances, waterborne transmission of cholera, hepatitis, typhoid, and related diseases has been virtually extinct in the United States.

However, we have learned that these advances have not come without potential risks-from disinfection byproducts and ecological toxicity. We have become aware of more resistant and emerging pathogens such as Cryptosporidium, Adenovirus, and Norovirus, which make us reexamine and readapt our engineering designs. The protection of public health by water and wastewater treatment requires additional understanding of mechanisms, synergistic effects, kinetics, and interferences. We need to know more about the pathogens of concern and of new indicators for the presence and treatability of these pathogens. New molecular methods for microbiology are advancing our understanding of many of these issues.

We are also realizing that protection of water resources from pathogens requires attention to other sources, such as stormwater, runoff, and agricultural waste. As population pressures increase, we are forced to look at waters of reduced quality for sources of drinking water (including reclaimed water). We continue to balance the struggle between disinfection byproducts and “microbiologically safe water”. Globally, our challenge is simply to provide the poor and the developing world with approaches for achieving community- based disinfected water, sewerage, and treated wastewater. We would challenge the water industry and the chemical manufacturing industry to begin to look more critically and broadly at the field of water disinfection. The scientific advances needed to meet the challenges of safe water for the future need considerable investment. With multi-billion dollar investments to expand, update, and repair aging treatment plants and infrastructure anticipated, it would not be unreasonable that a fraction of these funds be used to improve the basic knowledge base of process design and performance. Because disinfection is the key process responsible for public health protection, a significant proportion of such funds should be invested in programs to improve our understanding of the fate of pathogens during disinfection. This research should be developed by the U.S. Environmental Protection Agency and the National Science Foundation as well as the Water Environment Research Foundation and the American Water Works Association Research Foundation. Those of us in the “microbial” world need to think about critical assessments and the development of research programs exploring the science of microbial inactivation in the water environment that will begin to advance this important field, which seems to have remained stagnant for far too long.

We hope the collection of papers in this special issue adds to some of the fundamental knowledge whereby such discussions can proceed.

Joan B. Rose, Ph.D.,

Nowlin Chair in Water Research & Director of the Center for Water Sciences

Departments of Fisheries and Wildlife and Crops and Soil Science at Michigan State University and

Co-Director of the EPA/DHS Center for Advancing Microbial Risk Assessment

Charles N. Haas,

LD Betz Professor of Environmental Engineering and

Head, Department of Civil, Architectural & Environmental Engineering at Drexel University, and

Co-Director of the EPA/DHS Center for Advancing Microbial Risk Assessment

Copyright Water Environment Federation Mar 2007
Source: Water Environment Research