THERMAL WATERS AND BALNEO LOGY IN BULGARIA · 1-Oil and Gas Production and Exploration, Ltd, 23 Sitnjakovo blvd., 1505 Sofia 2-Specialized hospital for physiotherapy and rehabilitation,

K. Bojadgieva, S. Dipchikova, A. Benderev, J. Koseva: BALNEOLOGY IN BULGARIA

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Chapter 1.3

THERMAL WATERS AND BALNEOLOGYIN BULGARIA

K.Bojadgieva1, S.Dipchikova2, A.Benderev3 and J.Koseva2

1-Oil and Gas Production and Exploration, Ltd, 23 Sitnjakovo blvd., 1505 Sofia2-Specialized hospital for physiotherapy and rehabilitation, 2B Ovcha kupel,1608 Sofia

3-Geological Institute, Bulgarian Academy of Sciences, Bl.24, G.Bonchev str.,1113 Sofia

INTRODUCTION

Bulgaria has a variety of mineral waterswith temperatures up to 100oC. Thermal wa-ters with high alkalinity and low level ofTDS are predominant. The country is situa-ted at the southern part of the Balkan Penin-sula and is an heir of ancient civilizations.

There are extremely good bio-climaticresources which combined with the existingancient Mediterranean traditions in thermalwater use, provide an have been based forthe balneological development in the coun-try. A number of big spa resorts have deve-loped on places of old Thracian or Romanresidential areas, like: Sandanski, Kjusten-dil, Hisarja, Velingrad, Sapareva banja, etc.Even the capital city of Bulgaria, Sofia, hasbeen established close to thermal springs oftemperature interval of 20oC-50oC by Thra-cian tribes in third century BC.

The most active development of our spasystem is in the time period of 1970-1980.Until 1990 about 40 resorts of local and na-tional significance were actively operatingin Bulgaria. In these spas a wide range of di-

seases are treated using scientific methodsand programs, confirmed by a long-termprofessional experience.

The economical and social changes inour country during the transition period to-wards the free market economy led to a dra-stic decrease in the governmental subsidiesfor balneology, to a deterioration of some ofthe resorts and even to a closure of some ofthem. The Bulgarian spas are under the Mi-nistry of Health governance and their spon-soring, management and exploitation is go-ing to be done according to the new lawsand regulations in the country.

In most of Bulgarian spas the thermalwaters are used partially and ineffectively.This is especially in the case of high tem-perature reservoirs (T>70oC), where the wa-ter is left in open tanks to cool down to thedesired temperature or is mixed with ex-pensive cold tap water. In this way, the wa-ter mineral composition has been changedand its healing agents have been diminished.At the same time the buildings are heatedwith conventional fossil fuel boilers usuallycoal or oil. This gives a situation of reduced

International Workshop on BALNEOLOGY AND WATER TOURIST CENTERS

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efficiency of the mineral application, wastedenergy and locally polluted environment.

Up until the 1980 thermal water was on-ly partially used for health and recreationalbathing, washing, swimming pools, green-houses, bottling of potable water and softdrinks production, derivatives, etc.

After the 1980s modern systems forspace heating, air conditioning and ventilati-on, indoor and outdoor swimming poolshave been constructed. Most of the geother-mal stations have been build on reservoirs oflow temperature (40oC-60oC) which are pre-vailing in our country. These systems are in-direct ones and are assisted by plate heat ex-changers and heat pumps. The total ins-tallled capacity of the geothermal systems inBulgaria is 95.35 MWt.

The construction of new cascade geo-thermal systems at these sites will improveconsiderably the efficiency of the medicaltreatment, improve the local air quality andsignificantly reduce the use of fossil fuels.

1. CONDITIONS FOR SPA DEVE-LOPMENT IN BULGARIA

Bulgaria is located on 111 000 sq kmand there is an extraordinary combination offactors providing perfect conditions for tour-ism, healing and recreation. The abundanceof thermal waters, their variety and purity,the moderate to transcontinental climate andthe Mediterranean influence as well as thenational traditions in thermal water healingin Bulgaria, are prerequisites for effectiveand complete use of our natural resources.

1.1. Thermal watersThe mineral waters are one of the most

precious natural resources in Bulgaria. Thereare more than 500 hydrothermal sourceswith a total flow rate of 3000 l/s, having dif-ferent temperature and mineral composi-tion. Almost all of them are thermal as thetemperature varies in a wide range from20oC to 100oC. About 33 % of the total dis-covered flow rate is of temperature between20oC-30oC, and 43% - between 40oC-60oC(Petrov et al.,1998), Fig.1.

0

5

10

15

20

25

30

35

% o

f th

e to

tal f

low

rat

e

20-30 30-40 40-50 50-60 60-70 70-80 >80temperature intervals, deg C

Fig. 1.Flow rate distribution (in %) for tem-perature intervals

About 70% of the thermal waters areslightly mineralized with fluoride concen-tration ranging from 0.1 to 17mg/l, vari-ousmetasilicic acid concentration (up to230mg/l) and of mostly low alkalinity. Incomparison to most of the European mineralwaters, the Bulgarian ones have a lot of ad-vantages: low TDS close to the optimal one,typical for the potable water, high puritylevel especially in terms of anthropologicalpollution, microbiolo-gical purity and a va-riety of water types (Vladeva, L., Kara-kolev,D.1996).

Besides using mineral waters in spa cen-ters, in most of the sites they flow out of thetaps. This allows a free of charge and mas-sive water use for drinking and disease pre-vention. In the capital city area only, thereare six mineral water springs provided withmany built fountains.

1.2. ClimateConsidering the small area of the coun-

try, its climate is very diverse: from moder-ate to transcontinental with Mediterraneaninfluence from south and local Black Sea in-fluence from east. The spa centers in Bul-garia are usually placed in mountain touristresorts and some are at the seaside. The al-titude varies in a wide range (from the sealevel up to 800 m) and this satisfies the spe-cific needs of the patients and provides goodconditions for treatment. In most of thehealing centers there are all year round ac-tivities: disease prevention, treatment andrehabilitation.


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1.3. Balneological traditionIn our biggest spa centers there are data

about using thermal waters both for healingand heating in the Roman baths in I-IVcentury AC. The remains as well as the lit-erature records show that these baths werealso social centers.

Until 1990 all spa centers were includedin the health care system and got regularlygovernmental subsidies. At the moment,privatization and reconstruction processesare taking place in all of these centers.

Highly experienced specialists are work-ing in our spas. They offer treatment of widerange malfunctions and diseases such as:chronic respiratory mal-functions, locomo-tory system problems; peripheral nervoussystem diseases; digestive system, gyneco-logical and kidney diseases; chronic intoxi-cation problems, etc. (Karakolev,D.1984).The treatment includes the use of mineralwater drinking in prescribed doses depend-ing on its composition. Water is used forhealing baths in tubes, showers, pools, aswell as for inhalation (mixed with herbs or

other medications), irrigation, etc. Thistreatment is combined with other physio-therapeutic or rehabilitation procedures, sunbaths etc.

The wide spread thermal waters therapyallows using an outpatient treatment thatkeeps the patients’ every day routine un-changed: one goes to work and comes fortreatment during suitable day hours. Thereare a lot of beaches created around indoorand outdoor geothermal pools, and this im-proves the prophylactics of many diseases.

2. SPA CENTERS IN BULGARIA

The spa centers in Bulgaria are of localand national significance and most of themare situated in South Bulgaria, Fig.2.

Seven national resorts are presented inmore details. They have been selected forseveral reasons: well-developed base fortreatment, big tourist centers and good pros-pects for further development under the newfree market policy in the country.

Fig 2. Location map of spas of national significance - ∗ n (∗- not discussed in the paper)


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Fig.3 Thermal bath (built in 1912)

Fig.4. A sanatorium, heated withgeothermal energy

THE TOWN OF KJUSTENDIL

The town of Kjustendil (50 000 resi-dents) (fig.2) is built on the place of the fa-mous ancient Roman town of Poutalia. Itprospered in the I century during the Ro-man rule when impressive balneo-therape-utic “temples” were built, being the secondin size on the Balkan Peninsula. The town isat the foot of the Ossogovo mountain at analtitude of 530-550m and there is a goodcommunication system between Kjustendiland Sofia, Greece and Macedonia in termsof railways and bus transport. In 1910 thewater of forty mineral springs was capturedin a common shaft. The total flow rate is 33l/s and its temperature is 71.5o-74.8oC. Thebalneo-logical complex is in the center of

the town and has been in operationsince1966.

• Chemical composition Most of the thermal waters in the regionare slightly mineralized and are of widetemperature range. The TDS values arewithin 0.276 to 0.920 g/l. The waters arehydrocarbonic-sulphate-sodium or only hy-drocarbonic-sodium ones. The mineral water tests done in Kjus-tendil region show a constant physical-chemical water composition, and stablecharacteristics in terms of mineral content.An additional advantage is that this watercovers the existing European sanitary andchemical criteria for level of purity. There is a big curative peat deposit inthe vicinity of the spa rich in biologicallyactive substances and humid acids. Thecombination of different natural factors inone and the same region creates exclusiveopportunities for versatile, complete andwide application of all of them. • Healing indicators The climate in Kjustendil is transcon-tinental with a Mediterranean influence. Thesummer there is long and warm, the winteris mild and short, and autumn is long andwarm. The mean annual air temperature is+10.9oC, the mean January one is (-0.6oC),and the mean July temperature is +21.o6C. The presence of hydrogene sulphide,hydrosulphide and sulphide in the mineralwater in Kjustendil and Sapareva Banjamade them very useful in bones-jointstreatment, peripheral nervous system, gyne-cological malfunctions cure, healing ofchronic lead based intoxication, etc. Thesewaters might be used in prophylactic treat-ment of osteoporosis, over dose radiationbased malfunctions, fluoride based cariesprevention, etc. • Thermal water application The existing geothermal station is of1.250 MWt installed capacity and providesspace heating and domestic hot water to onesanatorium, Fig.4. Two outdoor mineral wa-ter pools are built in the town.


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There are favorable conditions for cons-truction of a new integral system for com-plex geothermal energy utilization. This sys-tem is going to provide space heating, airconditioning, and domestic hot water to thewhole balneological complex: the polycli-nic, sanatoriums, public baths, etc. The newsystem capacity has been estimated to beabout 5 MWt. The thermal water from well 2 Neves-tino (about 10 km away from Kjustendil) isused for bottling of potable mineral water.There is an optimal fluoride ion concen-tration (1.0 to 1.2 mg/l) in it and the pro-duced quantities are both for local marketand export. THE TOWN OF SAPAREVA BANJA Sapareva banja (9 000 residents) is amountain resort and it is one of the biggestbalneological centers in Bulgaria, (Fig.2.)Ancient relics from Thracian settlement ofDjermaneja founded in I-II century BC havebeen found there. The town is situated inSouthwest Bulgaria in a valley between twoAlpine mountains – Rila and Pirin, at alti-tude of 745 m. There is a bus transport be-tween Sapareva Banja and Sofia (at a dis-tance of 60 km only) as well as to Greece. The highest for the country thermal watertemperature of 101oC has been registeredthere. The local water temperature in the

Fig.5. Well 4 (The Geyzir) in Sapareva

banja town

springs varies from 60oC to 86oC. At presentjust one well is in exploitation and it is selfflowing; its temperature is 97oC-98oC and itsflow rate is 16 l/s, (Fig.5).

Fig.6. A sanatorium heated with

geothermal energy • Chemical composition In this region, the water chemical com-position is similar to the one of the waters inKjustendil. The TDS is 0.69 g/l and the pHis 9.14. The water purity level covers theexisting sanitary and chemical criteria. • Healing indicators The climate in Sapareva Banja is trans-continental with some Mediterranean influ-ence. The mean annual air temperature is+10.6oC. The mean temperature in Januaryis (– 0.7oC), and in July is +20.2oC. The ex-isting spa center consists of a sanatorium(Fig.6), having three departments, poly-clinic, building of medical surgery and can-teen, and outdoor mineral water pool. Locomotory system and gynecologicaldiseases as well as peripheral nervous sys-tem disorders and chronic heavy metal poi-soning malfunctions are treated there. Thecenter has over 200 beds for extended staypatients and provides for thousands of out-patients. • Thermal water application The balneological center and the geo-thermal station are both built in the period of1954 – 1962. The total installed capacity ofthe geothermal station is 0.250 MWt and itprovides space heating and domestic hotwater for the balneological center as well asfor the greenhouses and the public bath. Anew installation was set up in 1997 at thebuilding with medical surgeries and a can-teen. The building was chosen for a demon-stration site as a part of the project: “Techni-cal and Economic Assessment of Bulgarian


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Renewable Energy Resources”, Phare Pro-ject, 1997 A Bulgarian team of experts presented aproject about a new modern geothermal dis-trict heating system (of about 11 MWt inst.capacity) for 14 downtown buildings in Sa-pareva Banja, (Bojadgieva et al.,1999) A lot of international organizations areinterested in Sapareva Banja in relation todevelopment a complex center of balneol-ogy, tourism and thermal water application. THE TOWN OF SANDANSKI

Fig. 7. Sandanski spa hotel The town of Sandanski (32 000 resi-dents) is a famous climato-balneologicalcenter, (Fig.2). It is situated at the foot of theAlpine Pirin mountain near the river San-danska Bistritca. There is a bus and railwaytransport between Sandanski and Sofia,Greece and Macedonia. The waters from Sandanski area wereused even in II millennium BC by the Thra-cian tribe “medi”. During the Roman andMedieval age the spa center prospered as itcould be seen from the temple-bath remains.There are more than 20 springs in the resort.The waters are of temperature ranging be-tween 35oC-83oC and total flow rate of 19l/s. • Chemical composition This region is characterized by a varietyof waters of different temperatures andchemical composition. The mineral watersare silicic, mildly fluorine, hydrocarbonic-sulphate-sodium-calcium and have a neutralto mild alkaline reaction with pH of 7.6 -9.0. From the sanitary point of view the water isunpolluted. The physical-chemical thermal

water composition and properties are stablefor the region. • Healing indicators The climate of Sandanski is Trans-Mediterranean. The mean annual air tem-perature is +13.9oC; the mean January tem-perature is +2.4oC and mean July is +24.6oC.Sandanski boasts the mildest climate in Bul-garia, the greatest sunny days per annum(2440 hours of sunshine) and the lowesthumidity - 66%. All chronic conditions ofrespiratory tract and bronchial asthma aresuccessfully treated. The combined climaticand balneological factors give good resultsin locomotory system diseases, peripheralnervous system and digestive disorders,some kidney disease, skin or allergic prob-lems, or acute bone-joint rheumatism attacktreatments. The set of curing and prophylacticmethods, used in Sandanski resort, are ofgreat interest. For instance, sun and airbaths, climatic influence combined withspecially designed walking routes, respira-tory directed gymnastics, acupuncture, min-eral water mixed with herbs (or medications)for inhalation procedures are often used.Hydrotherapy like underwater gymnastics,swimming in indoor and outdoor mineralwater pools, electrical and light healing pro-cedures, healing massages, special food di-ets, apitherapy using bee products and saunagive fantastic results. • Thermal water application The existing geothermal station is in useall year round. It provides space heating,domestic hot water, air conditioning andventilation for a vacation complex and is of2.1 MWt inst. capacity. An underfloorheating system is constructed in the build-ing. THE TOWN OF VELINGRAD Velingrad is well known for its beautifulsurroundings and excellent mineral springs,Fig.2. There are Roman baths and watersupply systems‘ remains found there.


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Fig.8.A view from the town of Velingrad

Fig.9. A sculptural composition of the

thermal water image

The town of Velingrad is situated on thewest side of the picturesque mountainRhodopes at 750-780 m altitude. There areover 70 hot mineral water springs on thetown territory of 132 l/s total flow rate. • Chemical composition The mineral water varies considerably intemperature, mineral content, radon, silicicacid and fluorine content. There are well-defined water temperature and chemicalzones in the town of Velingrad. From south(Chepino suburb) to north (Kametitca sub-urb) the mineral water temperature increases(from 20oC to 95oC), the quantity of the dis-

solved salts increases (from 0.21 to 0.75 g/l),as well as the quantity of fluoride (from 3.6to 10 mg/l), and silicic acid (from 36 to 129mg/l). The water in Chepino and Kamenitcasuburbs is of a higher radioactivity. Thepresence of radon (1.8 nC/l) and hydrogenesulphide (1.2 mg/l) improves the healingproperties of the mineral water in Kamenitcasuburb. The mineral water in Velingrad is sul-phate-hydrocarbonic-sodium-fluoride - sil-icic type. It is unpolluted according to thesanitary and chemical criteria. • Healing indicators The extremely favorable climate ofVelingrad combined with the Mediterraneaninfluence gives good opportunity of apply-ing the climatic- and balneotherapeutic pro-grams all the year round. The mean annualair temperature is +9oC; the mean tempera-ture in January is (- 1.8oC), and in July is+18.8oC. The sun shinning is significant,over 2000 hours in a year. The summer ismildly warm and the winter is mildly cold,the autumn is warmer than the spring. The combined climatic and balneologi-cal treatment is recommended for patientshaving chronic respiratory system disorders.There are very good results of treatment pa-tients with locomotory system and neuro-logical diseases. The gynecological mal-functions are of a special priority in the bal-neotherapeutic list of this region. Velingradspa serves as a prophylactic center as well.There is a well-developed balneologicalcenter with modern sanatoriums and hotels,working all the year round. • Thermal water application Geothermal energy is used for spaceheating of two buildings – a Youth Club anda School (Chepino suburb). The installedcapacity is of 0.150 MWt and 0.900 MWtrespectively. Mineral water is widely used inoutdoor and indoor pools, greenhouses andpublic taps. Since 1999 the mineral waterfrom Chepino suburb has been bottled forsale in the country and abroad.


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THE TOWN OF DEVIN

Fig.10. A view from the town of Devin

Fig.11.A rehabilitation hall

The town of Devin (7000 residents) islocated on the East Rhodopes of 710-780 mof altitude, Fig.2. The clear Devin Riverpasses through the town. Besides its pictur-esque placement Devin region is well knownfor its mineral waters that have been discov-ered by deep wells. Their temperature variesfrom 37oC to 44 oC and the total flow rate is18 l/s. • Chemical composition

The TDS values are low (from 0.29 to0.37 g/l), hydrocarbonic and sodium ions areprevailing over limited quantities of chlo-rides and sulfides. The fluoride ions (from1.8 to 7.7mg/l) are also found in the compo-sition. The hydrogene sulphade presence isvery useful for external balneotherapy. • Healing indicators Climate in Devin is transcontinental andupland one. Its main characteristic is a warmbut not hot summer and a warm, sunnyautumn. The mean annual air temperature is+10.5oC, as the mean January one is (-1.5oC), and the mean July one is +16oC. Thiscreates suitable conditions for both summerand winter tourism as well as for climatictreatment and prophylactic. The main dis-eases recommended for treatment by thismineral water are as follows: degenerativejoint diseases of the locomotory system;nervous system functional disorders as wellas mental ones; overweight problems, etc.This mineral water is suitable for prophy-lactics and recreation procedures in cases ofphysical and mental overstrain; post opera-tional rehabilitation; for advanced agingprevention; for fluoride caries prevention;for radioactive overdose exposure healing,and osteoporosis treatment. • Thermal water application A new modern mineral water bottlingfactory of 5,000, 000 liters monthly has beenrecently opened in Devin. Besides for localsale, these mineral water bottles are ex-ported to Kosovo and are going to be ex-ported to Germany and some Arabs coun-tries. THE TOWN OF HISARJA The town of Hisarja (15 000 residents)is one of the biggest spa known since an-cient times, Fig.2. It is situated in SouthBulgaria at the foot of the Sredna Goramountain at 364 m of altitude, close to theValley of Roses. There are 22 mineral watersources of total flow rate of 35 l/s and tem-perature of 27oC - 52oC discovered in thisarea.


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Fig.12. Ruins of an ancient Roman fortress

(Hisarja town)

Fig.13 Thermal water fountain (Hisarja

town) The town of Hisarja (15 000 residents)is one of the biggest spa known since an-cient times, Fig.2. It is situated in SouthBulgaria at the foot of the Sredna Goramountain at 364 m of altitude, close to theValley of Roses. There are 22 mineral watersources of total flow rate of 35 l/s and tem-perature of 27oC - 52oC discovered in thisarea. • Chemical composition There are a unique variety of mineralwaters of high content of some chemicalelements such as calcium (from 3 to 21mg/l) and sulphates (from 17 to 45 mg/l).The mineral water in Hisarja is famous forits radon content. Its highest concentrationhas been measured in the spring “Mominabanja”-180 emans and the lowest - in“Chuludja”- 30 emans. This composition is combined with verylow TDS of 0.256 g/l in a wide temperaturerange. The mineral water in this region is ofhydrocarbonic- sulphate- sodium - silicic

type, of high alkaline reaction (pH from 8.3to 9.02) and is extremely pure. • Healing indicators The spa climate is both sub-mountainand plain one with Mediterranean influence.The mean annual air temperature is +11,9oC, the mean July temperature is +23 oC, andthe mean January one is +0,4 oC. The sum-mer is very warm to hot, the winter is mild,the spring is early coming, and the autumn islong and sunny. This water is excellent for people suf-fering from kidney, liver, gall bladder anddigestive systems problems. Hisarja is alsovery suitable resort for prophylactic of os-teoporosis through the complex balneo-physical therapy leading to general body fit-ness. • Thermal water application A geothermal station of 0.260 MWt inst.capacity has been built in Hisarja. It pro-vides space heating and domestic hot waterfor a sanatorium. There is an underfloorheating system constructed in the building. Water from several sources (wells num-ber 3 and 7, “Choban cheshma”, etc) is usedfor bottling and sale to the local market. BLACK SEA RESORTS In the North Black Sea region there is aunique combination of sea resorts and spacenters for healing and prophylactic. Thethermal sources (wells) are located veryclose to the seashore and there are mineralwater showers on the beach. The geothermalpools (outdoor and indoor) are also closeplaced to the beach. Some modern interna-tional resorts are for example: Varna city,The Golden Sands, Riviera, St. Constantineand Elena, and Albena. (Fig.2). The attrac-tive combination of sea water baths withmud baths and mineral water baths as wellas the geothermal energy application makesthe resorts operation very effective all yearround.


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Fig.14. Center of balneotherapy (Albena re-sort)

Fig.15. Outdoor geothermal pool (Albenaresort) The thermal water temperature de-creases within the region from south to northas in Varna city it is 52oC (of 22 l/s flowrate), in “St. Constantine and Elena” - 48oC(of 43 l/s flow rate), and to the north in Al-bena it becomes 30oC (of 6 l/s flow rate). • Chemical composition The TDS is very low in these resorts andvaries in small range from 0.611 to 0.673g/l. Inorganic nitric compounds as nitrates

and nitrides have not been detected. Thesanitary and chemical tests prove the waterto be naturally pure. The low fluoride con-centration defines the water as drinking oneand acceptable for all age groups customers.The water is hydrocarbonic-sodium-calcium-magnesi-um; hydroarbonic-chloridic and suphatic-sodium magnesium. • Healing indicators These mineral waters could be used inthe treatment of: respiratory system diseasesas well as cardiovascular and nervous sys-tem functional disorders; blood circulationdiseases, second rate allergies; locomotorymalfunctions, gynecological disorders, etc. Healing and prophylactic centers are de-veloped in Varna city and Pomorie town,and in “St. Constantine and Elena”, Rivieraand Albena resorts. Sea water and climaticprocedures as well as balneotherapeutictreatment is offered in these centers makinguse of outdoor and indoor mineral water andsea water pools, thermal water baths, lyetreatment, manual therapy, herbal treatment,etc. • Thermal water application

Up-to-date geothermal stations operat-ing all year round have been built in thenorth Black Sea region after 1980. Theyprovide space heating, air conditioning andventilation, domestic hot water for hotelsand spa centers. The geothermal stations arelocated in Varna city (2.5 MWt and 3.5MWt), Chaika resort (2.0 MWt), “StConstantine and Elena” resort (15 MWt) and“Golden sands“ resort (0.35 MWt).

CONCLUSIONS

The wide variety and the high qualitypure thermal waters in Bulgaria combinedwith the extremely favorable natural andclimatic conditions as well as the good spabase plus mineral water healing traditionsjustify long term investment policy for de-velopment and improvement of the existingresorts. In parallel to that, there are permit-ting conditions to carry on small local cen-ters in the spirit of today’s tendencies in the


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so called “countryside tourism” and tradi-tional healing as well as to widely use therenewable energy sources in our every daylife.

REFERENCESBojadgieva,K., Shterev,K., Hristov.H., andM.Balabanov (1999). Complex utilization ofgeothermal waters in the town of Sapareva Banja(SW Bulgaria), High priority national project,World Solar Programme 1996-2005, Bulgaria.

Karakolev,D. (1984). Basis of balneol-ogy.Medicine and Sports,S. (in Bulgarian)Karakolev,D. (1994). Bulgaria-country of min-eral springs, S.(in Bulgarian)Petrov,P.(ed) et al.(1998). Reassessment of hy-drogeothermal resources in Bulgaria.1998. Re-port for the Ministry of Environment and Waters,National Geofund, Sofia,Bulgaria.(in Bulgarian)Vladeva,L.,D.Kostadinov (1996). Bulgarian po-table mineral waters, I part, S.(in German)

Documents

THERMAL WATERS AND BALNEO LOGY IN BULGARIA · 1-Oil and Gas Production and Exploration, Ltd, 23 Sitnjakovo blvd., 1505 Sofia 2-Specialized hospital for physiotherapy and rehabilitation,