A remediation project called “Removing centres of contamination at the former wood impregnation factory on the premises of the ČD, a.s., Mostní obvod Brodek u Přerova” addressed the removal of an old environmental burden which arose as a consequence of the operations of a former factory for impregnating wood before its takeover into the ownership of Czech Railways (České dráhy, a.s., hereinafter ČD, a.s.) Several companies operated here from the end of the 19th century until the present day, but always with the same production emphasis. The focus on timber production and wood impregnation lasted until 1960, when the premises became the property of Czechoslovak State Railways and the Mostní obvod Brodek u Přerova facility was created. Since it has been in the ownership of ČD, a.s., the volume of work on the premises has gradually declined.
The facility has two focal points of massive soil contamination by organic materials with a carcinogenic effect. In particular, indicators of pollution by PAHs (polycyclic aromatic hydrocarbons) and hydrocarbons C10 – C40 were detected. Both materials posed an environmental risk, and the area has been and is monitored by the relevant state administrative bodies, in particular by the Environment Ministry. The premises are located inside a so-called protected natural water accumulation area, or water protection area.
In view of the fact that neither ČD, a.s. nor its legal predecessor is the originator of this contamination, it was possible in 2009 to submit a request to subsidise the project from European Union funds, specifically from the Operational Programme Environment as part of the Community’s intervention “For Water, Air and Nature”. In October 2011, the contractor Sdružení Brodek 2011 was selected in a competitive bidding process. In September 2012, ČD, a.s. received a decision on the allocation of a subsidy for this project from the State Environment Fund, at which point the remediation work, which had begun in January 2012, was already fully underway.
Prior to commencing the remediation of the unsaturated zone, the structures standing on the localised contamination points were demolished. To remove the contamination itself, the method of progressive selective excavation of the contaminated soil from the unsaturated zone to a depth of 5 metres or to the level of groundwater was then selected as the most suitable approach. Soil with concentrations below the established remediation limits was deposited at the locality and subsequently used for reverse filling; soil with concentrations above the remediation limits was removed and taken to a landfill.
During extraction, it came to light that the volume of contaminated soil was greater than that which had been assumed in the original project. After discussions with the contractor, a technical solution was proposed for completion of the project while maintaining the original volume of funds. The only possible way to achieve the project objective was to complement the existing method of depositing the contaminated soil in a landfill with the application of the method of enhanced ex situ attenuation.
Attenuation is the designation for a set of processes that occur naturally in the environment and lead to a reduction in the concentration, quantity, toxicity, or mobility of contaminants.
The principle of the method of enhanced attenuation is to support natural degradation processes and their intensification. In principle, this involves the acceleration of natural degradation processes by optimising the living conditions for autochthonous strains of bacteria that utilise organic pollutants as sources of carbon and energy for growth and multiplication. The final products of their activity (biological oxidation of organic pollutants) are CO2, H2O and bacterial biomass. The application of biological methods consists in ensuring sufficient microbial colonisation in the remediated material and optimising the environmental conditions for maximum biodegradation activity. In addition to natural biodegradation processes, additional processes of chemical and physical degradation (oxidation, decomposition by UV radiation, etc.) were applied as well.
The natural ability of bacteria to decompose contaminants present in the environment into harmless substances has been the subject of stringent laboratory tests since the beginning of the 1960s. The remediation technologies of bioremediation of contaminated soil and groundwater came into use in the early 1980s in the United States and subsequently in Western Europe.
The remediation of the premises was completed successfully according to Methodological Change No. 4, which had been approved by all the authorities involved, and the completed project was handed over in December 2013.
Total project expenses: CZK 66,396,381 without VAT
Total deductible expenses: CZK 63,893,757
Amount of the provided EU subsidy: 85% of deductible expenses
Amount of the provided state subsidy: 5% of deductible expenses
Overall amount of support: 57 504 381 Kč
Contact person:
Mgr. Simona Keller Nováková
KMP- 1. Department of Subsidies
kellernovakova@gr.cd.cz