In summer, thermal power station of the average power can remove from the natural reservoir up to 100 000 cubic meters of water per day. The main part of the water is spent on the production of the energy steam and as a cooling agent in the turbine condensers. Return of the chilled water into the natural reservoir under the temperature that does not exceed accepted standards does not cause a violation of the biological equilibrium. Part of the water used in the production cycle is significantly contaminated by petroleum products (up to 150 mg/l) and by the products received after ion exchange filters washing during the chemical water treatment by the salts, acids, alkalis, and such water needs treatment.
The chemical water treatment department at the thermal power plants of average capacity 2 000 cubic meters of waste water with pH value ranging from 3 to 6 (while the pH value acceptable for the solutions to be discharged is ranging from 6,5 to 8,5) are produced and discharged per day.
Various amounts and the uneven time of the flow of acid and alkaline wastewater from the power plants are unable to neutralise them mutually and in full. For neutralisation, the waste water is often poured into one tank with the bubblers to accelerate mixing. It takes a long time to finish this operation because it is not the kinetics of chemical reactions who limits the process but the averaging rate of the concentrations of the reactive environments throughout the volume of the reactor.
In 2006, thanks to the joint efforts of the researchers from the Chemical Engineering Faculty and the engineering group from the “InTrek” Company the technology for the wastewater neutralisation was developed and implemented at the Baltic TPP in Estonia.
Our scientists won the tender among the five declared competing firms.
Testing the machine for the effluent neutralisation allows seeing next results after its industrial implementation:
- Guaranteed exception of dumping waste waters with unacceptable concentrations of chemically aggressive components. The pH value is in the range of 6,5 ... 8,5.
- Time to enter the technological regime in the alkali neutralisation does not exceed 4-5 minutes, and in the lime milk neutralisation, it is not more than 10 minutes, which is in the range of 3,5-8% of the total processing time. Transient water is returning for the second neutralisation.
- Parameters of the sewage at the main stages of the process are automatically monitored and their values are simultaneously displayed on a mimic and secondary devices control panel.
- The machine is protected from the unauthorised interference in the automatic control mode.
- The use of manual labour is minimised and significantly improved in accordance with the health working conditions.
Technical solutions of this method of installation are patented. Unfortunately, in Ukraine, there is no such implementation.
For a broad introduction to the Ukrainian market, our scientists need to conduct scientific and technical research and develop technical solutions for the individual specifications. Such work needs to expand the scientific and technical base of the laboratory with environmentally-friendly technologies (LEFT), CEF, which is the primary task of the immediate future.