The Desalination Business
Growing Population Makes Desalination an Increasingly Viable Alternative for Obtaining Fresh Water

October 17th, 2011
by Thomas Tomczyk

At the desalination machinery: Samuel Rivera (desalination operations supervisor), Junior Torres (desalination plant operator), Martir Serrano, municipal worker.

At the desalination machinery: Samuel Rivera (desalination operations supervisor), Junior Torres (desalination plant operator), Martir Serrano, municipal worker.

Utila has one, now Roatan has another. Desalination plants, while expensive, are postponing the looming water shortage crisis on the islands. Long gone are the times when fresh water was abundant.

Opened one year ago, the Coxen Hole desalination plant is estimated to be worth two million dollars in machinery and another million in generator, building and cisterns. The money for the project was paid by World Bank directly to SETA, a development organization of the Spanish government that constructs desalination plants all over Honduras.
Inaugurated on July 10, 2010, the Roatan desalination facility by the airport became operational on September 10, 2010. Today it produces 14,000 gallons of water an hour, and is capable of producing a maximum of 18,000 gallons. Samuel Rivera, ACME Environmental desalination operations supervisor of the plant, estimates that the current water production satisfies around 60%-65% of total water demand in Coxen Hole. “People are adjusting their consumption to what water is available,” says Rivera. The process produces four gallons every second and can max out at 430,000 gallons a day. The maximum demand is rarely reached except during Semana Santa and other holidays.

The entire desalination process begins with two wells, one 60 ft, the other 80 ft deep. The water is pumped through a sand filtration tank, a micro fiber sediment filter, and finally receives nano filtration through a reverse osmosis membrane. At this stage the 99.5% of the sediment in the water has been filtered out. Around 70% of all the welled water makes it to the system in a 15,000 gallon tank. The remaining 30% of reject water, containing elevated salinity and other impurities, is flushed out to a nearby creek. There, over its 900 ft run, it has a chance to reduce temperature and dilute salinity so that when it finally reaches the sea, the water is within the salinity of the seawater. “It’s clean enough. There are crab and fish living there,” says Dan Taylor, owner of ACME Environmental, a company that manages the plant. “As operators we don’t want to have any moral or legal issues associated with the plant.”

A small portion of Coxen Hole gets its water directly from the desalination plant, and that is likely the cleanest water in Coxen Hole. The majority of the water is pushed up to municipal water cisterns at Loma Linda and is mixed with well water that is sometimes of inferior quality to that of the desalinated water.

A variable speed pump reduces the wear and tear of the well pump as well as provides energy-savings of around 75%. Since the cleanliness of the piping between the plant and the homes cannot be guaranteed, chlorine is injected into the water and the PH level, an operation fully controlled from a computer interface at the plant.

“We are connected real time to manufacturers of the plant in Spain and Teguc people, so we can ask for help when we need it,” says Taylor.

Salaries, spare parts and consumables cost around $8,000 a month. Another $8,000 is spent on energy bills paid to RECO and back-up generator operations. With around 3 million gallons of water produced every month, the cost of production is around 5 cents a gallon.

“There are no water meters so everyone pays just a flat fee,” explains Mayor Julio Galindo. Galindo thinks that “unmonitored water use” is just not practical in keeping people accountable. The Roatan Municipality is considering installing several water meters to measure water usage in different Coxen Hole communities. “When they see a toilet that is leaking, they will fix it,” agrees Rivera.

“It’s really easy to say yes to a donation [of a desalination plant] but desalination is a short-term investment. The long term solution is water harvesting,” says Taylor, pointing out that Roatan’s 90 inches of rain is plenty to make the island self sufficient on rain water. “We could build 60-80 small dams to harvest water.”

Mayor Galindo is worried about the contamination of the island’s aquifers and rising water usage. “People move to places where water is scarce.” Very few water reservoirs replenishing the island’s deep aquifer exist on the island. Currently there is one water reservoir in West Bay’s Gumabalimba Park and another at the Jerry Hynd’s property near Mahogany Bay.

Other than the municipal plant there are two other private desalination plants on Roatan, both in West Bay at Keyhole Bay and at Infinity Bay. “Roatan has the capacity to be self sufficient on water. What it doesn’t have is the political will nor organizational skills to do that,” says Rivera.

ACME had finished its first Municipal contract and has now begun a second, year-long contract to run and maintain the facility. ACME is collaborating with SETA in bringing a desalination plant for French Harbour and Oak Ridge.

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