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Central Gardens, TX, United States

McPherson D.L.,Alan Plummer Associates Inc.
Pipelines 2014: From Underground to the Forefront of Innovation and Sustainability - Proceedings of the Pipelines 2014 Conference | Year: 2014

Cement mortar, used as a lining on the interior wall of metallic pipe, has proven to be beneficial in the passivation of metal corrosion in the presence of water. For many owners/agencies the use of cement mortar lining has become a standard when ductile iron or steel pipe is specified. The lining is traditionally applied with a minimum thickness of 0.25 in. by centrifugally casting the cement to the interior wall or, in larger diameters and at joints, field applied. The lining's performance in operation has proven its benefit over time. However, in large-diameter systems that have been in the presence of persistent hydrodynamic loads there have been recorded failures of cement mortar lining. The failure of the cement mortar lining leaves the pipeline exposed to corrosion and potentially exacerbates the problem. In larger-diameter pipelines with aggressive water, it has become common to specify thicker cement lining (>0.25 in.). The concept of the greater lining thickness is to allow erosion of the lining to occur over time while remaining lining continues to passivate the corrosive environment. This is intended to result in an extension of the pipeline's service life. This paper summarizes the development of an analytical approach to evaluate the sensitivity of cement mortar lining in the presence of hydrodynamic (i.e., hydraulic transient) loads. The equation represented in the paper allows a designer to assess the thickness of the lining and the potential of the lining to fail in the presence of a differential pressure caused by a downsurge or negative transient pressure condition. This analytical approach will help refine the evaluation of using a thicker cement mortar lining in lieu of treating the aggressive fluid, assess the sensitivity of the thicker lining in the presence of dynamic loading, identify what transient controls may be required if thicker linings are specified, and better define the extension or potential reduction of a system's operating life through the use of a thicker cement mortar lining. © 2014 American Society of Civil Engineers. Source

Martin C.,Alan Plummer Associates Inc.
Pipelines 2010: Climbing New Peaks to Infrastructure Reliability - Renew, Rehab, and Reinvest - Proc. of the Pipelines 2010 Conference | Year: 2010

The North Central Texas Metroplex, which includes the cities of Dallas and Fort Worth, has seen record growth during the past 10 years and landscape irrigation needs are a big part of the regional water demand. Fort Worth Village Creek Wastewater Treatment Plant provides a high quality source of effluent that is currently discharged to the Trinity River. In 2007, the Fort Worth Water Department completed a "Reclaimed Water Priority and Implementation Plan" to evaluate potential reuse projects that have a high probability of being implemented. The Eastern Reclaimed Water System had the most viable customer base and lowest capital cost of all alternatives evaluated in this plan. The system includes a 10-mile pipeline and was envisioned as a regional project primarily serving wholesale customers, including the City of Arlington, City of Euless and Dallas-Fort Worth International Airport (DFWIA). The ultimate capacity of the pump station is 18 million gallons per day (mgd). The pipeline has a reducing capacity at various take points. The pipeline sizes are 36-inch (steel), 30-inch (ductile iron), 24-inch (ductile iron and PVC), 20-inch (PVC), and 16-inch (PVC) (Reference Figure 1). Implementation of the project required collaboration between Fort Worth and each of the wholesale customers. In order to facilitate initial discussions about the project, the City prepared preliminary estimates of potential rates and identified key issues requiring consensus in order to proceed with subsequent discussions. Initial meetings with the customers were positive and the framework for a wholesale contract was laid out. Development of an equitable rate structure that could be agreed upon by all parties was a key component of contract negotiations. Key contractual issues for Fort Worth were a minimum payment (i.e., "take or pay") provision to ensure a minimum level of cash flow to the utility, and a commitment to a systemwide rate from all customers. While the City was willing to subsidize the system in the initial years, it was committed to a goal of operating a system that would ultimately be self-sufficient with rates based on cost-of-service principles. In order to accommodate customer concerns, the City agreed to limit the percentage increase of the rate in any given year and provide an upper limit on the rate equal to its wholesale water rate for potable water. © 2010 ASCE. Source

McPherson D.L.,Alan Plummer Associates Inc. | Charles T.J.,Camp Dresser and McKee Inc.
Pipelines 2010: Climbing New Peaks to Infrastructure Reliability - Renew, Rehab, and Reinvest - Proc. of the Pipelines 2010 Conference | Year: 2010

The nature of transient hydraulics in a pipeline system is often very difficult to identify and fully quantify. As a result, surge control strategy is often a compromise on providing the greatest benefit for the lowest cost while also considering the full range of alternatives and operational constraints. This may be difficult to do, especially with staged facility expansion that must address near and long term flow projections. Design often relies on a maximum flow rate that is identified as a "worst case" scenario surge control based on this assumption. However, these simplifications, when considered in a system with near and long-term projected flow rates, may be incorrectly defining the best surge control strategy, particularly if the highest projected flow rate is never realized. This paper will use case studies to compare two different approaches with regard to surge control protection while considering near and long term flow rates and the associated flexibility or lack thereof that is related to the surge control. Pros and cons will be discussed for each approach and discussion will be developed for reader consideration. © 2010 ASCE. Source

Noack T.J.,Alan Plummer Associates Inc.
American Society of Agricultural and Biological Engineers Annual International Meeting 2010, ASABE 2010 | Year: 2010

The North Texas Municipal Water District (NTMWD) recently completed construction and began initial operations of the East Fork Raw Water Supply Project (EFRWSP). At the heart of the project is an 810 hectare (2,000 acre) constructed wetland, the key component in one of the largest indirect potable reuse projects in the country. The NTMWD uses this wetland to improve the quality of wastewater treatment plant effluent return flows diverted from the East Fork Trinity River prior to pumping to its primary water supply reservoir. Water produced by this project nearly doubles the yield of the reservoir. Located on a former cattle ranch southeast of Dallas, Texas, the EFRWSP was fast-tracked so that it could be developed from concept to operation in just four years. This was necessary to meet rising water demands generated from rapid growth within its service area and to augment the NTMWD's surface water supplies that were being strained by a region-wide drought. This paper details the steps taken from conceptual study to initial operation, including addressing major challenges such as identifying and obtaining a site suitable for the project; securing the necessary state and federal permits; developing the design criteria and features to be incorporated into the wetland to achieve the water quality and hydraulic delivery goals; developing two on-site aquatic plant nurseries; constructing the project within the shortest time-frame possible; and start-up and initial operations of a large-scale constructed wetland. Source

McPherson D.,Alan Plummer Associates Inc. | Walker B.,Underground Solutions
Pipelines 2012: Innovations in Design, Construction, Operations, and Maintenance - Doing More with Less - Proceedings of the Pipelines 2012 Conference | Year: 2012

In the water and wastewater industry, the sustainable properties of pipe materials are often presented in a form not suitable for a quantifiable comparison of alternate pipe materials. To quantify how and where a pipe material would impact the environment is very complex. The complexity is not only in the collection and evaluation of pertinent data, but is also characterized by the variety of materials involved and the differences in design, manufacturing, and installation processes of various pipes for the intended purpose. Embodied Energy (EE) analysis affords a methodology for quantifying the differences between various pipe alternatives for specific specifications. The EE is a parameter that can be used in a more comprehensive Life Cycle Analysis (LCA). While EE can be broadly defined to include raw resources, manufacturing, installation, operation and end-of-life recycling and/or disposal; as a first step the ASCE Task Committee for the Sustainable Design of Pipelines (SDP) has elected to limit the scope of the EE parameter to cradle-to-gate with selective consideration of end-of-life parameters. The boundary of the cradle-to-gate EE parameter terminates at the point where the pipe product leaves its manufacturing facility. With this limited boundary, EE is defined by the amount of energy consumed in acquiring all necessary raw materials, the production of intermediate products, and the manufacturing of the finished pipe product that has been designed for its intended use. It should be noted that EE alone has no consideration of emissions or the impact of by-products to the environment and as a result does not replace or substitute for a Life Cycle Cost (LCC) analysis. However it should be noted that as the EE parameter is developed, it can be associated with environmental impact markers to allow a more comprehensive input parameter to a project's LCA and/or a Carbon Footprint Analysis. © 2012 American Society of Civil Engineering. Source

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