Features

November 2009, Vol. 21, No.11

The Right Pipe at the Right Time 

Improved condition assessment technologies can help utilities fix larger portions of their systems than before 

feature 1 Bryon L. Livingston and David C. Vidikan

Before the decision is made to rehabilitate any pipe in a buried water distribution or wastewater collection system, it is necessary to determine the current condition of the pipe. Rehabilitation includes repair, relining, replacement, and other methods to restore and extend the service life of the pipe. The key to successful rehabilitation is proper evaluation of the data from the condition assessment performed on the pipeline.

Condition assessment, therefore, becomes more than evaluating the pipe age, material, and number of leaks — or running a closed-circuit television unit through the pipe. Remarkable improvements have been made in the tools available to the engineer for evaluating the condition of the pipe in the last 40 years.  Read full article  (login required)

 

In Search of a Sustainable Future

Population, water issues prompt South Florida to expand water reuse

feature 2 Anthony D. Greiner, Jayson J. Page, Richard H. Cisterna, Enrique Vadiveloo, and Patrick A. Davis

 According to a U.S. Census Bureau projection, the United States must find water for another 2.5 million people per year for the next 50 years (this is equivalent to adding 50 cities the size of San Diego to the nation). South Florida’s population alone is expected to increase by 5 million during the next 25 years. So, to maintain a sustainable 21st century, municipalities must ensure that they will have adequate water supplies.  Read full article  (login required)

 

More Than Overflow Management

The benefits of green infrastructure don't stop with sewer overflow control

feature 3 Gary Swanson, Brian Marengo, Tom Heinemann, and Patricia Nelson

 For 30 years, many North American communities have constructed deep-tunnel storage and conveyance systems to control combined sewer overflows (CSOs). They are a practical solution in large urban areas and will remain a critical part of wet weather management and flood control. In the past decade, however, a complementary technology has emerged: green infrastructure.

According to the U.S. Environmental Protection Agency, the green infrastructure approach to wet weather management is cost-effective, sustainable, and environmentally friendly. While green infrastructure usually cannot eliminate CSOs in highly urbanized areas, it reduces stress on the traditional drainage system (storm sewers and combined sewers), as well as providing other environmental benefits.  Read full article  (login required)

 

Operations Forum Features

Thinking Inside the Box

Retrofit provides low-cost alternative to traditional construction

feature 4 art Carla Mary

Greenville, N.H., located west of Nashua, N.H., and about 10 miles (16 km) from the Massachusetts border, experiences cold winter temperatures — typically in the teens (Fahrenheit). These frigid winters created maintenance problems for the wastewater treatment plant staff. The plant’s two chemical feed systems were housed outdoors, and the extreme cold would freeze the lime-slurry solution and made it difficult to transport 55-gal (208-L) drums of polyaluminum chloride across frozen terrain. The freezing led to process upsets and the potential for compliance exceedences on the plant’s discharge.

The obvious solution was to move the two systems indoors, but the cost to construct a building was too high. However, the town’s water and wastewater operations firm devised a common-sense, cost-effective, “in-the-box” solution, Greenville and the company teamed up to convert a used shipping container into a structure to house the chemical feed systems.  Read full article  (login required)

 

Worried About Wireless Networks?

Today's technologies and practices provide strong security

feature 5 art Robert L. George

Interested in a wireless local area network (WLAN) but concerned about security? This article contains some of the things to consider before deploying a WLAN for a process control or supervisory control and data acquisition (SCADA) system.  Read full article  (login required)

 

 

How To Troubleshoot an Underperforming Pump Station, Part 2 

feature 6 art Derek L. Morin, Tim Kelleher, Paul Tomaskovic, Dave Lookenbill,

Evaluating an underperforming pump station can be divided into two phases that are easily delineated by effort, cost, and time. Phase 1 of a pump station investigation includes inspection of basic tools and installed equipment, such as gauges and flowmeters. The cost, time commitment, and effort are relatively minimal. Many pump station flow problems are resolved in Phase 1.

Phase 2 is reached when Phase 1 does not resolve the issues. The Phase 2 evaluation is characterized by increased diligence, time, cost, and planning. Planning is important; during this phase, costs accumulate if testing is conducted inefficiently.

This article describes the Phase 2 measures used to investigate a 20,000-gal/d (75,700-L/d) duplex submersible pump station performing at 50% design capacity at startup. The investigators found that degraded pump station performance resulted from construction defects in both the pumps and the 4-in., 5500-linear-ft (100- mm, 1680-linear-m) force main.  Read full article  (login required)