Plant for Demercurization
Development, Testing and Transfer to the «PKhZ» OJSC of a New Continuous Operating Full-Scale Industrial Vibro-Vacuum Plant for the Anthropogenic Waste Demercurization, and Organization of the Maintenance Personnel Training
Tech Area / Field
- ENV-EHS/Environmental Health and Safety/Environment
- ENV-RED/Remediation and Decontamination/Environment
- ENV-SPC/Solid Waste Pollution and Control/Environment
3 Approved without Funding
Institute for Metallurgy and Ore Concentration, Kazakstan, Almaty
- Pavlodar Chemical Plant, Kazakstan, Pavlodar reg., Pavlodar\nScience & Technology Center LAMA, Kazakstan, Almaty
- Brookhaven National Laboratory, USA, NY, Upton
Project summaryAs a consequence of the anthropogenic pollution of the environment with mercury, the environmental emergency has developed in the area of the «PKhZ» OJSC. According to the specialists’ estimates, the overall mercury emission into the human environment during the total period of the chlorine-alkali production facilities operation (1975-1993) amounted to over 900 tons.
On the territory beneath and adjacent to the Electrolysis Shop, extremely high concentrations of this toxic metal have been recorded in the soils, grounds, snow cover, surface-, ground- and subsurface waters, bottom sediments and building structures, which multiply exceed its natural level and environmental standards. Along with formation of the anthropogenic biogeochemical mercury-contaminated area in this region, a peculiar anthropogenic mercury deposit has developed there, which is comparable by these metal reserves with moderately sized mercury deposits occurring in nature. At the same time, the intensively contaminated facilities and components are the intense secondary sources of the mercury emissions into the surrounding landscape.
A range of works was performed at the anthropogenic mercury contamination site in recent years: dismantling the building structures that were technologically associated with caustic soda production; construction of landfills and burial of the contaminated reinforced concrete structures; encapsulation of the mercury containing slimes; construction of the protective barrier of the “wall in trench” type along the Electrolysis Shop perimeter; covering the surface of the Electrolysis Shop base with the insulating layer, and many others. This enabled to reduce ecological problems tension in the Northern Industrial Zone of Pavlodar, localize the primary mercury pollution focus and block up mercury migration with the underground waters towards the transboundary watercourse – the Irtysh River. Moreover, considering occurrence of the primary contamination source (the Electrolysis Shop) and secondary contamination sources (the Bylkyldak Lake, sediment and evaporation grounds, territory of the Chemical Plant, and etc.), the complete environmental remediation in the anthropogenic pollution zone remains to be the urgent problem. One of the ways for the problem solution is precise determination of the scale of contamination and mercury stocks in the soils and mercury removal using the method of demercurization at the industrial-scale thermal vacuum plant to ensure sustainable development of the “PKhZ” OJSC.
During 1980-2000 at the Institute of Metallurgy and Ore Benefication (Leading Institution), the scientific and technological fundamental principles were developed for the vacuum assisted thermal demercurization process and the associated batch-operated equipment was constructed for treatment of anthropogenic mercury contaminated materials from the representative lot of samples taken at the «PKhZ» OJSC.
Under this Project it is intended to carry out further improvement of the vacuum assisted thermal technology and equipment with the view of achieving deep demercurization of the contaminated materials at the brand-new continuous operating plant. It is projected to use the vibratory fluidized vertical columns of the initial soil and cinders as the barometric seals in order to make the assembly units for continuous charging of the soil from the atmospheric pressure conditions into the vacuum reactor and the cinder discharging from the vacuum into the atmospheric conditions. In this case, the advanced removal of mercury from the gases released into atmosphere up to the sanitary standards has been accomplished by using the solid sorbents. It is scheduled to develop the new full-scale industrial continuous operating vibro-vacuum plant based on a complex of the in-process tests and engineering developments, test this plant at the proving stand at the STC “Lama” LTD with engaging and training of the «PKhZ» OJSC personnel, and transfer this plant to the “PKhZ” OJSC for the operation and maintenance phase.
For implementation of the proposed project, considering some conflictive data, it is scheduled to conduct the required preliminary work associated with determining the real scale of contamination, specifying the polluted areas location and the vertical mercury distribution, and also building of the anthropogenic contamination 3D model using the modern computer technologies and high-accuracy global positioning systems (GPS). This will enable to determine the volumes of the contaminated soils excavation to a high precision.
The mercury ground monitoring for control over the environmental conditions during the demercurization work stages shall be the requisite part of activities to ensure the operative intervention in the event of a contingency situation occurrence associated with the environment contamination above the allowable pollution standards, for example, the atmospheric air and soils. The use of the continuous operating plant as compared with the batch-operated plant has a number of advantages both of the technological and environmental aspects. In this case there are no losses of mercury into the environment associated with the equipment depressurization when conducting the charging and discharging operations and also the rational use of the thermal power is ensured since there is no more necessity in the successive cooling and heating of equipment up to the process temperature that considerably reduces the specific power consumption. The introduction of the database at the Pavlodar Chemical Plant on the basis of the geoinformation systems (GIS) and the training of the «PKhZ» OJSC personnel to operate this database under the user mode shall be the topical tasks. The GIS implementation should provide conditions for systematization of information, prompt decisions making and the situation forecast at the site both at the demercurization stages and upon their termination up to the complete remediation of the contamination zone via the natural processes.
Highly qualified scientists and specialists concerned with the defense industry and being involved in this Project will be reoriented in their activities towards solution of important scientific, technological, ecological and social problems. Realization of such global international challenges will result in integration of scientists from various countries, new jobs creation, gain in population health and enhancement of the climate on the Planet.