A new well will help meet the increased water demand at the Bogácsi Spa

South of Noszvaj, at the foot of the Bükk Mountains, lies Bogács, a small village with a population of 200. Thermal water was discovered here in the 1950s whilst searching for oil. To make use of this, a thermal spa was soon built in the village: the first pool was completed in 1959, and a further three in 1973. By 2000, the thermal spa was welcoming visitors with six pools. Following the refurbishments carried out in 2011–2012, visitors are greeted by a modern environment, and the new attractions announced last year are also drawing people to Bogács.

Last year, we reported that a water castle had been built at the Bogács Spa and Lido, and a few months later we were able to write about the energy modernisation .

The spa will see further development this year too: a new well will provide an increased water supply to meet the needs of the growing number of pools. According to information published in the public procurement notice, 90 million forints will be made available to „OLVISZ”98” Olajipari VÍzügyi Szolgáltató Kft. to drill the spa’s new well, which will be more than half a kilometre deep.

The client, Bogácsi Thermal Baths Service Provider Kft., has requested the drilling of a third, high-yield well in addition to the existing one, with a capacity of at least 800 m³/day and a flow rate of 800 l/min during a 16-hour operating period.

We need to drill down to a depth of half a kilometre

The successful tenderer was asked to construct a 550-metre well at a designated point within the spa grounds. In the existing wells, Triassic limestone was encountered at depths of 438 and 466 metres respectively; based on experience, significant or even total loss of mud may occur during construction when the top of the Triassic formation is reached.

The expected water flow rate is 800–1000 l/min, with the water emerging above ground level. The temperature of the emerging water is expected to be around 70 °C. In unfavourable circumstances, or if the fracture system differs, the temperature and flow rate may, of course, be lower than this.

The electrical power required for the works can be supplied from the spa’s mains supply via a connection within 50 metres – rinse water can be drawn from the nearby cold-water well. The thermal water extracted during cleaning and test pumping can be channelled via a tank into the cleaning chamber of the drain carrying the spa’s used water, which discharges into the Hór Stream. The temperature of the water introduced must not exceed 30 °C; therefore, the pipe from the cold water well must also be connected to the tank.

A well that can be operated using a surface-mounted slide gate is being built

As the expected static and operating water levels of the well will be above ground level. The investor is therefore planning to install a self-producing thermal water wellhead, with a NA 150 body and NA 125 shoulder gate valves and fittings. A 2-inch gate valve is planned to be fitted into the wellhead body for the purpose of shutting off the well if necessary.

The assembly – comprising a water meter, a non-return valve, a pressure gauge and a water sampling tap – turns into the trench via a pipe bend and, at a depth of one metre, connects to the spa’s pipeline via a NA 150 heat-insulated steel pipe, approximately 20 metres away.

The well’s water flow must be adjusted using the control gate valve to the required flow rate for the plant; the expected wellhead pressure is 2–2.5 bar. When the water has cooled, the pressure resulting from the increase in specific gravity is 0.8–1.0 bar, calculated on the basis of a 400-metre water column. The well therefore starts up even when cold, so if water is not required, the well can be shut off.

It has been recommended that a concrete slab measuring 2.9 x 2.0 metres and 20 cm thick be laid around the well. The well must be fenced off. It is also advisable to install a removable wooden or sandwich-panel well house with a floor area of 2.8 x 1.9 metres and an internal height of 2 metres.