March 2011, Vol. 23, No.3

Sizing UV disinfection systems

A method for comparing apples to oranges

Charnas Cody Charnas, Jed Chambers, Dale Adams, Pat Schmidt, Dan Hammer, Dean Cohrs, and Katherine Bell

There are a number of methods for sizing ultraviolet (UV) light disinfection systems to meet permit limits, but many result in inappropriately sized systems. During a recent design–build project, however, the project team developed a method for determining a reasonable minimum design UV transmittance and minimum required UV dose. The team also found a way to directly compare UV disinfection systems from various manufacturers. The simplified approach enables design engineers to select an appropriate system based on projected plant flows, third-party validation relationships, and UV transmittance. Read full article (login required)


Not just for milk anymore

Pasteurization for disinfection of wastewater and reclaimed water

Salveson Andrew Salveson, Nitin Goel, and Greg Ryan

What’s the best disinfection method? Where chlorine was once the ultimate (and immediate) “go to” disinfection method, the challenges of reduced pathogen kill and the formation of disinfection byproducts and N-nitrosodimethylamine require a better answer. The industry is responding with innovations in ultraviolet light (UV) technologies, the re-emergence of more-efficient ozone, and now pasteurization. Read full article (login required)


How well do you know your customers?

Surveys make it easy to identify public opinion

Dubose Karen DuBose

Public meetings are an essential part of the public education and outreach toolbox, helping utilities inform the public of upcoming plans and get their feedback.

But given the small number of people who attend public meetings, how can you be sure that the opinions and ideas generated at your meeting are representative of the entire population and not a skewed response that will cause complications further down the road? The answer: Do a survey. Read full article (login required)


The communication-centered utility

Empowering employees to engage the public

Frank Matthew Frank

In Spartanburg, S.C., everyone at the water utility communicates with the public. That strategy represents a huge change from the silent utilities of the past. Rebecca West, deputy general manager of engineering and technical services at Spartanburg Water, sat down to discuss this new way of communicating. Read full article (login required) 


Operations Forum Features

Your pumps may be stealing from you

The operations and maintenance practices that increase efficiency 

Walski Tom Walski

There are thieves in your collection system. These thieves are the pumps that are wasting energy and costing you money every day they run. Like many thieves, these energy thieves don’t advertise their presence. They look, sound, smell, and feel just like any other pump in the system. It’s up to the system operator to be a conscientious detective and ferret out these bad guys.

While most features of pump system efficiency are determined during design and construction, a number of operations and maintenance practices can be implemented to either improve pumping system efficiency or restore original system efficiency. Read full article (login required)


Taking control of corrosion

A primer on protective coatings

Morris Kevin Morris

The annual cost of corrosion in the United States is a shocking statistic. According to a study covering the years 1999 to 2001 (Corrosion Costs and Preventive Strategies in the United States. Houston: NACE International, 2002), the total annual direct cost of corrosion to metallic surfaces in the U.S. is estimated at a whopping $276 billion. This equates to approximately 3% of the U.S. gross domestic product and does not account for the cost of corrosion to the most widely used construction material in the world, concrete. Read full article (login required) 

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