The world’s reserves of clean drinking water are gradually diminishing, with desert like regions being most hard hit. For states like California, the problem is worse felt given the easy access to massive amounts of seawater from the Pacific.
It’s reported that although it is possible to convert salty seawater into drinkable water through desalination, the established processes are quite expensive to undertake and usually result in brine that may be dangerous to dispose of back in the ocean.
Desalination is considered by many to be the best solution to the problem of dwindling freshwater supplies. Unfortunately, the release of the resulting salty brine tends to affect the quality of coastal waters.
It is also believed that an increase in temperature results, further adding to the demand for drinkable water. Some desalination processes also make use of chemicals and heavy metals whose residual deposits contribute to the damaging effect on coastal waters and marine organisms.
Because of the environmental risks involved, it is good news that scientists at Humboldt State University, Colorado School of Mines and University of Southern California have come up with a new way to undertake desalination while limiting the environmental impact that may result.
The system as Reverse Osmosis-Pressure Retarded Osmosis, or RO-PRO water softner. The researchers involved in its development believe it will bring about lower costs in desalination and reduce environmental impact.
The already patented system involves the use of reverse osmosis and pressure retarded osmosis. Reverse osmosis is already used by established desalination systems. It involves the pushing of saltwater through a barrier to separate pure drinking water from the brine. It’s been confirmed that the amount of energy expended in this process is a big contributor to the high costs that are associated with desalination.
RO-PRO however works by combining freshwater and saltwater in a pressurized chamber. The water pressure spins a turbine whose energy is used to power the entire system. According to the researchers, this approach reduces the need for energy supply by about 30%, as compared with conventional desalination processes. Rather than having to exclusively rely on an external source of energy, It’s believed that the system is partially self-sustaining, reducing the need for externally sourced energy.
The system’s ability to allow for the highly concentrated saltwater being diluted back to seawater before it is returned to the ocean. The researchers believe that on a large scale, this strategy will certainly reduce the risk of environmental damage, while significantly reducing the costs involved in harvesting of drinkable water.
The system is currently still undergoing modifications, but once completed, will be assembled and tested at the Samoa Pump Mill. It is here that waters from the Mad River meet the Pacific Ocean, providing an ideal venue for the harvesting of adequate quantities of the salt and freshwater needed for the RO-PRO to be tested.
If the system works as expected, It’s believed that it will eventually be utilized in other desalination plants across the state, and possibly the country.
It’s believed that if this system is to be combined with solar energy to power the desalination plants, even more cost reductions can be achieved. There are already great strides being made in the development of more affordable photovoltaic cells and lower cost installations.
Research at the Aston University’s School of Engineering and Applied Science suggests it is possible to make use of solar energy to not only lower the cost of desalination, but also help neutralize the oceans’ acidity. Hydrolyzation of the brine can help turn it alkaline, and when released into the ocean, neutralize acidity that has built up, and cut carbon dioxide levels.