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John Wiley & Sons, publishers of "Water Treatment Plant Performance Evaluations and Operations", 2009, has generously posted the following excerpts from this volume on their website, free for downloading.

 

The WTP Preface provides the outline and summarizes the 12 chapters of a volume created for water treatment plant operators and managers focussed on scientifically monitoring and improving plant process performance.

 

Perhaps of greatest scientific value in this release are the WTP Figures. This central element of the book provides 28 highly detailed, color micrographs of particles and organisms observed in water at various stages of collection and treatment. The descriptions accompanying each figure represent an attempt to put the information conveyed by each micrograph to practical operational use.

 

Appendix A (appA) describes the apparatus needed and basic procedures for conducting bacterial cell counts by epifluorescence microscopy.

 

Appendix B (appB) lists potential studies that a water utility might perform using microscopic particle analysis.

 

Appendix C (appC) starts with a discussion of operator responsibilities and operational data collection. This is followed by an extensive photographic tour of an operator 'making the rounds' to directly observe the functioning of the water treatment plant unit processes.

 

 

 

John O'Connor

Turbidity

Posted by John O'Connor Jul 16, 2015

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In the production of municipal drinking water, nothing is monitored more assiduously than turbidity.

 

Why is this so? Just what is turbidity? And why is this quality parameter so critical that it rates designation as a microbiological surrogate and primary drinking water standard?

 

Direct microscopic examination of drinking waters reveals that turbidity is caused by stuff - stuff that absorbs or scatters light. As you might imagine, light-scattering stuff may include silt, clay, cyanobacteria, precipitated carbonates, sulfides, metal oxides (e.g., rust and corrosion products), plant fibers and organic debris, microfloc, activated carbon 'fines', paint chips, nematodes, protozoans, cysts, bacteria, virus, ... (Oddly, while they may sometimes be present in large number, bacterial cells are so translucent that they contribute little to either the turbidity of natural - or treated drinking waters.)

 

The attached report, "The Effect of Lower Turbidity on Distribution System Water Quality", (AWWARF, 1993), includes analyses of sets of operational data from a broad range of major U.S. water utilities (Kansas City, MO; St. Louis, MO; St. Louis County (MO) Water Company; New Orleans, LA; Boston, MA; Baltimore, MD; New Haven, CT; Cleveland, OH; Louisville, KY; Dallas, TX; Phoenix, AZ; Oakland, CA; Los Angeles, CA; Metropolitan Water District of Southern California).  From this data, the seasonal relationship between each utility's treated ('finished') water turbidity and the frequency of recovery of total coliform and heterotrophic plate count (HPC) organisms in monitoring samples from the water distribution system could be determined.

 

Of special interest, a comparison of data from various utilities indicated a very distinct advantage in maintaining control over total coliform in the distribution system using chloramine as opposed to chlorine.