UTS - Under-the-Sea Water Recovery
By Pat Fetizanan

A technology for recovering freshwater from ocean springs has been pioneered in Macatang, Banton island, Romblon. Could this be applied to your locality?

Background

The fresh water spring has always been there at the ocean bottom. Formed eons ago, it might have existed while the dinosaurs were roaming the earth. It is located a mere 50 ft from the shore. However, it is totally submerged, about 5 to 15 ft below the sea surface depending on the tide. Decades ago at dawn, a local hurled a dynamite stick mistaking the whirlpool as schools of fish "biyanak".

The spring was never considered as a viable water source before. The challenge was just too great. How can this water source be tapped to benefit the community? During the driest summer months, most of the water sources dry up. The locals would spend long hours fetching their daily needs from the trickling flow of the remaining springs. They suffered in thirst. Yet on the ocean floor, the Macatang spring endlessly bubbled to the surface wasting the precious fluid into the vast sea. If there was just a way to harness the spring!

UTS Technology

Now there is a way to tap the Macatang spring and similar sources. The technology is called UTS (Under-the-Sea ) Water recovery system. This technology is applicable to freshwater springs located on the ocean floor within a reasonable distance from the shore. With some modifications, this may also be applied to coastal water sources that are accessible only during low tides but are submerged during high tides. There must be a number of ocean springs or submerged coastal water sources in Romblon and the rest of the world. See if your locality has one waiting to be tapped.

How it Works

The UTS water technology was developed by PFM Engineers, USA. First applied to the Macatang waterworks in 1996, it is reliable and easy to design and operate. The heart of the system is an ocean collector, an inverted concrete vessel laid on top of the spring. Water from this collector is piped and gravity flows to a beach tank. The beach tank serves as a reservoir for further distribution. The system makes the water available to users at all times.

Contrary to others' thinking, the system does not depend on the pressure of the spring water. Although a high pressure is desirable, it is not necessary. The system takes advantage of the difference in the density of water and the sea to separate the two streams. Water is lighter and therefore rises to the surface.

The ocean collector may be fabricated on land, brought to sea and slowly dropped on top of the springs. The sides may have to be buried about 6 inches into the ocean floor to create a "seal" between the freshwater and saltwater. With improved technology, the collector may be fabricated "in-sitiu" to avoid the problems of hauling it from dry land. Over the years, the Macatang collector has sunk lower into the sand bed. It is now covered with coral reefs providing fish a sanctuary, yet it still works.

The collector has two nozzles or openings. The first nozzle connects the collector to a beach tank through pipes. Water flows to the beach tank as long as the level inside is below that of the sea. When the level equalizes, the water will not flow and needs to go somewhere else. The somewhere is the vent or the second nozzle. The vent is provided with a special gizmo called check valve. This valve prevents seawater from getting into the collector and contaminating the freshwater stream.

System Issues

The Macatang system is a first-of-a-kind and potential improvements have been identified. First, the pipe from the ocean collector is made of 2" PVC. While PVC is resistant to the sea, it is light and needs to be anchored well. The yearly visit of the habagat has brought nothing but havoc to the piping system and needs to be constantly repaired. The original pump for Macatang was a homemade contraption from PVC, bamboo and a discarded basketball skin (for diaphragm). It uses the same principle as the pump used to bail the sailboats (lanzon) of the olden days. Obviously, this needs to be replaced with a hand or motor driven pump. The other problem was the beach tank was not buried deep enough due to the rocky bottom at the shore. Flow rate is therefore very low at low tides. The deeper this tank relative to the water level, the better is the design.

Macatang Waterworks Improvements

Significant improvements for the Macatang Waterworks are being planned. Using the UTS technology as the heart of the process, the improvements will seek to replace the beach tank with a larger reservoir and automate the pumping process. When completed, the process will pump water continuously on level control. The pump will be replaced with an electric pump powered from NAPOCOR or a supplemental generator. A larger tank located farther inland at higher elevation will provide additional storage capacity. Water will then be distributed to the rest of the Mainit users by gravity.

A project proposal detailing the economic benefits, project execution strategy and cost/schedule has been submitted and been well received by Congressman Ylagan. The locals are hopeful that funding from the government will materialize.

Consulting Services:

PFM Engineers is a nonprofit outfit devoted to developing community service projects. It will provide a free initial feasibility study. If your locality has an under the ocean spring waiting to be tapped, contact PFMEngineers@aol.com.