For the case shown below, and assuming that the plant will cost and produce as expected, determine how much the City of Laredo will have to charge for a gallon of water to amortize the initial investment (operating costs excluded). Assume that the plant will last 20 years, that customers pay their bills monthly, and that the interest rate is 6% per year.
LAREDO CITY COUNCIL APPROVES BUILDING OF PILOT PLANT THAT WILL USE HOLTZAPPLE’S DESALINATION METHOD
Providing enough fresh water for residents is an issue for Laredo, Texas, a city of 200,000 on the Texas-Mexico border. Laredo is almost at the limit of water it can draw from the Rio Grande River, and groundwater in the area is brackish, or salty.
As a result, the Laredo city council has agreed to spend $1.6 million to build a pilot plant that will field test a new method of desalinating brackish water developed by a Texas A&M University researcher and commercialized by Terrabon L.L.C.
“This is one step in securing and providing water in the future for not only Laredo, but the entire state, with the development of this pilot project,” said Laredo city council member Gene Belmares.
The desalination plant, which will produce 50,000 gallons of water a day, will test water desalination technology developed by Mark Holtzapple, a professor in Texas A&M’s Artie McFerrin Department of Chemical Engineering.
“We desalinate using vapor compression, a method first employed on ships in World War II,” Holtzapple said. “We have updated this old approach using advanced technology such as high-capacity, non-fouling heat exchanger and a low-cost, high-efficiency StarRotor compressor.
“In addition we operated at higher pressures than is traditionally employed. Compared to traditional technology, these innovations lower both the capital cost and operating cost.”
The Texas Engineering Experiment Station (TEES) and The Center for Applied Technology (TCAT), a center within TEES, will act as the technology integrator and analyst for the project.
Additionally, Terrabon, L.L.C., of Houston, an energy and water treatment technology company, will design and construct the advanced vapor demonstration plant. The American Water’s Applied Water Management Inc., acting as a subcontractor for Terrabon will operate and monitor the demonstration plant.
The project will demonstrate the commercial viability of AdVeTM, a new technology that could reduce the capital and operating costs of water purification and provide a low-cost solution to Texas’ water problems. AdVeTM (advanced vapor-compression evaporation) uses low-cost, high-efficiency StarRotor compressors developed, by Holtzapple’s team and non-fouling heat exchangers to desalinate brackish and salty water at a cost that is significantly less expensive than desalination by reverse osmosis.
The Artie McFerrin Department of Chemical Engineering is part of the Dwight Look College of Engineering on the Texas A&M University campus in College Station, Texas.
The Texas Engineering Experiment Station is the engineering research agency of the State of Texas and a member of The Texas A&M University System.
Terrabon, L.L.C. was formed in 1995 to commercialize three technologies that share the same suite of patented intellectual property developed at Texas A&M University.Â
Written by: Tim Schnettler