A Gift From Deep Inside the earth
August 29, 2013
Wiesław Bujakowski, Ph.D., from the Polish Academy of Sciences’ Mineral and Energy Economy Research Institute in Cracow, southern Poland, talks to Karolina Olszewska.
You manage a research project that aims to find new uses for geothermal water, or ground water that is heated by the Earth’s energy. Is it possible to improve the country’s overall water balance using geothermal water?
The aim of the project is to bring about a situation in which this type of water would be used by Polish geothermal facilities not only for heating purposes and not only for balneological [therapeutic use of thermal baths] and relaxation purposes. It is worth remembering that thermal water used by these facilities is usually injected back into the rock mass. Of course, this involves certain technological problems, and thus higher costs. Or the water is simply discharged into natural reservoirs.
Such a system is usually at work in heating plants. The water flows there reach several hundred cubic meters per hour. So it’s a high-capacity kind of system. I should add that geothermal water has a varying degree of mineralization, depending on the nature of the rocks from which it comes.
On the other hand, companies in the balneological, recreational sector use smaller streams of water of a few dozen or just several cubic meters per hour. These streams of water have specific physicochemical properties and mineral content. After being used they are treated in treatment plants or fed into surface waters. We were wondering if these two methods of utilization could be combined. We considered physical, chemical, membrane-based and thermal methods. The idea was not to waste the extracted water and to make sure that at least a part of it is fit for other uses, for example for drinking. And this angle of research was one of the goals of our project.
Why did you adopt this approach?
Poland, compared with other European countries, has relatively small drinking water resources. So we wanted to check if geothermal waters could be treated in order to obtain potable water fit for consumption. This is how a country’s water balance could be improved. That objective was part of our research-and-development project. If we recovered part of the water and made it suitable for drinking, that would automatically help reduce the amount of thermal water used and then injected back into the rock mass, or, in other words, into the bed. This would mean less hassle for those operating the installation, because it would increase the efficiency of the plant and, crucially, translate into lower costs.
Why did the National Center for Research and Development decide to finance your research project?
Our institute specializes in the use of energy and geothermal water. In 1993, we designed and launched Poland’s first geothermal installation in [the southern] Podhale area. We also helped launch other geothermal systems in the country, in locations such as Mszczonów, Pyrzyce and Uniejów. We have extensive expertise in this field. Hence the idea to optimize the functioning of geothermal water installations. We received about zl.1.5 million from the NCBiR for this purpose. The project started in 2008 and ended in 2012. Together with Barbara Tomaszewska, Ph.D., who was the main contractor, we set up a research team. It is composed of 12 people from our institute and several outside experts from institutions including the AGH University of Science and Technology in Cracow, the Silesian University of Technology [in the southern city of Katowice], and the Veolia Environnement company.
How did you spend the money?
We conducted a lot of research as part of the project. We also built mobile experimental equipment. This enabled us to conduct research into different types of water. We installed this equipment mainly in our geothermal laboratory in Podhale. There the main body of research was conducted into the geothermal waters from the Podhale Basin rock mass.
As a result, we obtained pure water, so-called permeate, as well as brine concentrate. We are now trying to find a use for this brine concentrate for therapeutic purposes. This way of using thermal water may begin to play an important role in Poland in the near future.
So what is innovative about the method proposed by our research team and what is innovative about the installation we constructed as part of the project? Our installation is a typical research installation. It can take in about one cubic meter of water per hour. This is a very small amount, but if it were expanded, for example to 100 cubic meters of water per hour and operated on a 24/7 basis, it could supply drinking water to a town of more than 10,000. Of course, the main problem is the cost of obtaining such water and the cost of such an undertaking in general. Technology in this area is still developing around the world. The membrane-based methods are entering our homes. Many private buildings have reverse osmosis systems. These are not too expensive, and at the same time protect the house against many harmful ingredients and the unwanted process of precipitation of carbonates, for example in household appliances.
What is reverse osmosis all about?
This is one of many membrane-based methods. It is based on the separation of monovalent ions of the substances contained in saline water when it passes through the membrane, as a result of applying a pressure greater than the osmotic pressure of the sea water. The membrane is permeable to water, but is impermeable to salts dissolved in it. In this way, two fractions are obtained: pure water, the so-called permeate, and a concentrated salt solution called retentate or concentrate. Such technologies are used, for example, in ships where sea water is converted into potable water. But they have not been used for geothermal waters so far. We had to adapt the existing technologies and processes to the conditions and parameters we have in specific geothermal systems. Our research station comprised a filter for removing iron from water, an ultrafiltration module, a reverse osmosis system and containers for the permeate and concentrate. The permeate is directed to a mineralizing filter and an UV sterilizer. This arrangement makes it possible to separate ingredients specific to geothermal water, obtain drinking water with appropriate mineralization and a retentate containing concentrated amounts of therapeutic minerals.
Can the equipment developed at your institute be used in industry?
Commercial application was not the aim of the project. We set out to solve technical issues. An investor is needed to put our method to commercial use. We are in talks with companies that exploit thermal waters for recreational purposes and are planning to launch an additional service—balneological therapy sessions. By using our equipment, which has been modified and upgraded in order to adapt it to the conditions at a specific site, they would be able to obtain a concentrate for therapeutic purposes.
Together with several research institutions and companies, we have filed an application for financing such an undertaking as part of the Applied Research Program [run by the National Center for Research and Development]. This would make it possible to lay the groundwork and work out the technical designs for putting our method to practical use. Three geothermal plants, in Podhale, Mszczonów and Uniejów, are our commercial partners in this project.
On the other hand, if we wanted to become engaged in issues related to the supply of drinking water, we would have to talk with local governments and water supply companies. For the time being we are not delving too far into this area. Companies that use geothermal waters are primarily interested in expanding their services. If, in the process, they obtain a product in the form of pure water that they can add to their range of products, this would only strengthen the appeal of our proposal. A businessman who owns swimming pools and bathing facilities can use this pure water on his own for his own technological processes as well. We believe that we will be able to move from the stage of laboratory research to technical design and feasibility studies. And finally to the implementation of the method.
How big are Poland’s thermal water resources compared with those in other countries?
The deposits in rock pores and crevices up to 4,000-5,000 meters deep under the ground are gigantic. Some scientists vividly define them as “another Baltic Sea.” But it is better to talk about resources available in specific sites, which means the wells in specific geological conditions. The best well in terms of resources is in Podhale and has a capacity of 550 cubic meters of water per hour. There is a huge amount, and in addition this is water with a low level of mineralization. In most other sites, for example Uniejów, the capacity is much lower, at about 100-150 cubic meters of water per hour. We also have a lot of small-capacity wells, for example in [the southern resort of] Rabka—in the order of several cubic meters per hour. This water could be treated, especially with a view to obtaining a concentrate for therapeutic purposes.
Is similar research conducted abroad? Does your institute have any foreign competitors when it comes to putting your method to commercial use?
The results of our research were presented in 2010 at the World Geothermal Congress in Bali, Indonesia. They generated a lot of interest there. We have also published a number of articles in specialist publications, including those included on the Thomson Reuters Master Journal List [known as the “Philadelphia List” in Poland]. In response to individual invitations we have contributed a chapter to a specialized book edited by Professors Jochen Bundschuh and Jan Hoinkis from Germany.
Rational and optimal use of water resources available in Europe and worldwide is a research field that is being very intensely developed. We took it up as one of the first research teams worldwide, in the context of using geothermal waters available deep underground in reservoirs and used for energy and medical purposes. We are also thinking of joining an international consortium that will work further on this problem in Europe.
Geothermal water is widely used for heating and therapeutic purposes. Wiesław Bujakowski’s team wants to upgrade the therapeutic value of geothermal water and also use it for consumption in the same way as ordinary drinking water is used. The project is entitled The comprehensive utilization of geothermal waters in the context of improving the water balance and reducing or eliminating the amount of injected water. The Mineral and Energy Economy Research Institute in Cracow has developed and launched a special research installation that makes it possible to treat geothermal water and improve its therapeutic value. The project has been financed by the National Center for Research and Development (NCBiR).