Halff designed a new 0.95 million gallons per day (MGD) wastewater treatment plant to replace Hidalgo County Municipal Utility District No. 1’s existing 0.5 MGD plant. The project included preparing a financial assistance application, feasibility report, environmental assessment, and developing plans and construction documents for the construction of an extended aeration treatment plant. Project components included designing an influent lift station, headworks facility, carousel aeration basins, secondary flow splitter box, clarifiers, chlorination chamber, metering, return activated sludge and wasted activated sludge pump station, a chemical feed facility, SCADA system, emergency generator, and site improvements. The construction documents also included the extension of force mains to the influent lift station and a treated effluent outfall pond.