Full Description

A long-range water supply plan was prepared for the Tarrant Regional WaterDistrict of Tarrant County, Texas, in 1990. The Plan concluded that the primaryapproach to obtaining required additional water was to divert water from theTrinity River, which is largely treated wastewater return flows, into two of theDistrict's four water supply reservoirs to provide a supplemental yield of115,500 acre-feet/year. The District's plan to supplement its water supply withreclaimed water involves a multiple barrier approach that includes: advancedwastewater treatment; retention in the Trinity River; treatment in a constructedwetland system; dilution (maximum of 30 percent of reservoir capacity duringdrought conditions); and, water treatment. Data regarding treatment efficienciesfor human pathogens from the pilot-scale constructed wetland facility and theproposed field-scale constructed wetland facility will be utilized to determinepotential changes in treatment requirements and/or the required dilution rate. Aconstructed wetland was one of three potential alternatives selected for furtherinvestigation to remove nutrients and potential toxins from the diverted water.The other alternatives were chemical precipitation and a fish-periphyton study.Treatment is needed since the Trinity River at the point of diversion isdominated by highly treated wastewater flows from the Fort Worth-Dallas metroplexarea, with variable flows contributed by surface reservoir releases, groundwater,rainfall, and storm runoff from both urban and rural areas. The point ofdiversion is approximately 60 miles downstream of the Fort Worth-Dallasmetroplex. Treatment to control nutrient and potential toxicant inputs to thereservoirs is necessary to protect the water quality of the drinking water supplyreservoirs. The District formulated a staged program to perform research toexamine the financial aspects, operation and maintenance issues, and treatmentperformance of the constructed wetlands. The staged program involved initiallyconstructing, operating, and testing of a pilot-scale constructed wetlands.Subsequent to gaining required information from the pilot-scale wetlands, afield-scale wetlands will be constructed to perform further research regardingthe treatment expectations of the wetlands. This paper discusses the results ofthe pilot-scale constructed wetlands program. Includes tables, figure.

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Edition: Vol. - No. Published: 01/01/2000 Number of Pages: 12File Size: 1 file , 250 KB