Features

November 2012, Vol. 24, No.11

New approach to project delivery 

Managing the challenges of a tunnel rehabilitation and sewer pipeline replacement project 

Feature 2 - Jurich - art David M. Jurich and Joseph N. McDivitt

The South Coast Water District (Laguna Beach, Calif.) operates the Beach Interceptor Sewer Tunnel in South Laguna, Calif. The pipeline running through the tunnel conveys, on average, 4.7 million L/d (1.25 million gal/d) of wastewater. Approximately 85% of the interceptor’s flow comes from an upstream force main; the remaining flow enters the pipe through 80 residential connections along the tunnel. But the tunnel itself is in an advanced state of deterioration.

To rehabilitate the tunnel before it deteriorated any further, the district adopted a risk management approach. This led to an emergency repair project for a 230-m (750-ft) length of the tunnel, as well as a full rehabilitation plan for the tunnel's full 3,192 m (10,474 ft.). Read full article (login required) 

 

Coordinated monitoring for stream condition

Multiple indicator assessments in the San Gabriel River watershed improve efficiency and provide a solid context for decision-making

Feature 5 - morris - art Kristy Morris, Scott Johnson, and Raphael Mazor
Before 2005, stream condition monitoring in the San Gabriel River Watershed involved numerous agencies independently collecting data from defined portions of the watershed — mostly around major discharges for permit compliance purposes. Inconsistencies among the programs, including differences in the constituents sampled and the frequency of measurement, resulted in limited data comparability, redundancies, and major data gaps. For more than 7 years now, a coordinated effort (the San Gabriel River Regional Monitoring Program) has been integrating permit-mandated and ambient monitoring. Read full article (login required)

 

Know your options 

A Florida utility selects the right remote-site wireless communication technology for its wastewater treatment systems 

Feature 6 - Sayre - art Dustin Sayre

The Collier County (Fla.) Public Utilities needed to remotely monitor and control lift stations close to its wastewater treatment plant. The utility wanted to prolong the life of its existing equipment at these stations and operate pumps more efficiently. Because Collier County is located in a hurricane-prone region, backup power and local data storage in case of power and communication loss also were important to the organization, as well as timely notification of equipment failures or alarms.

The utility had many things to consider before making its purchase. It required an understanding of its remote wireless communication needs, which equipped the organization with the knowledge needed to ask the right questions prior to selecting technology. Collier County carefully addressed the many factors any utility must consider when purchasing a wireless communications system. Read full article (login required) 

 

Operations Forum Features

Bursting with possibility 

Applicability of NESHAP to rehabilitating asbestos-cement pipelines 

 

Feature 1 - thomas - art Bill Thomas and Edward Alan Ambler

Asbestos, a naturally occurring mineral fiber, was used extensively in many building materials prior to the adoption of the National Emission Standards for Hazardous Air Pollutants (NESHAP). Its properties, such as fire and chemical resistance, flexibility, high strength, and a long and thin fibrous shape, made it a desirable component for many construction materials, including pipe.

Now, as these pipes reach the end of their useful lives, replacing them becomes a costly challenge. Today, asbestos-containing materials are controlled carefully under NESHAP regulations; its jurisdiction includes demolition and renovation activities.

Pipe bursting, however, could be an effective technique to replace asbestos-cement pipe. Some states already allow pipe-bursting of asbestos-cement pipe. However, pipe bursting has been severely limited by widely varying interpretations of NESHAP nationwide. But an example from Florida could hold the model for a solution. Read full article (login required) 

 

Less leaks, more capacity 

City of Manassas targets infiltration and inflow

Feature 3 - Manassas - art Tony H. Dawood and Mike Nicholson

Manassas, Va., covers approximately 26 km2 (10 mi2) near Washington, D.C. The city is not only historic, but also one of the fastest-growing suburban areas in the United States. This combination of age and rapid growth sets Manassas apart from many other municipalities, and creates unique challenges for sanitary sewer maintenance.

The City of Manassas Public Works Department continues to assess and resolve problems associated with excessive infiltration and inflow (I/I) into its sanitary sewer system. The sewer system assets are a critical element of the city’s infrastructure, and the proper operation of its wastewater collection and conveyance systems are vital to the city’s the health and welfare. Read full article (login required) 

 

Bolstering the first barrier   

Pilot testing by a Nevada utility finds that membrane filtration will greatly assist efforts to protect downstream water supplies 

Feature 4 - Drury - art Douglas D. Drury, LeAnna Risso, and Bill Shepherd
Located in southern Nevada’s Las Vegas Valley, the Clark County Water Reclamation District (CCWRD; Las Vegas) is among the largest dischargers of wastewater to the Colorado River, the most critical waterway throughout the arid southwestern United States. CCWRD discharges into the Las Vegas Wash, which enters the Colorado River — or Lake Mead, as it is known at that point — upstream from the drinking water uptakes operated by the Southern Nevada Water Authority (SNWA; Las Vegas). Although this example of large-scale indirect potable reuse has been practiced since the early 1970s, concerns arose in recent years regarding the need to control concentrations of total organic carbon (TOC) and endocrine disrupting compounds entering Lake Mead. Read full article (login required)