After nearly 50 years, settling basins at Mníšek pod Brdy are environmentally safe
More than 23,000 tonnes of waste and 272 tonnes of waste water have been removed by a JV of HOCHTIEF CZ and EKOM CZ from the settling basins in the premises of ÚVR Mníšek pod Brdy a.s. In less than a year, a site of over 4 square km that had been used for disposal of waste from 1967 was subject to a complete environmental remediation.
The settling basins I and II were used for disposal of waste that in particular came from processing of non-ferrous materials, e.g. magnesite, limestone and dolomite. The main contaminants were arsenic, cadmium, chrome, mercury, lead, nickel, copper, but also cyanides or petrochemicals.
“Heavy metal and petrochemical contamination was documented up to a level of two metres under the ground at the settling basin I and in a depth of two to four metres at the settling basin II. Since there are a stream – Bojovský potok and a pond – Sýkorník in a distance of one kilometre in the underground water flow direction, the contamination posed a serious hazard for the environment in the vicinity,” Director of Division Traffic Infrastructure of HOCHTIEF CZ, Ing. Pavel Kubasa, stated.
The remediation works comprised not only the actual excavation and safe disposal of the contaminated sludge, materials and water, but also continuous taking of samples from the bottom and the sides of the excavations. This was done to prove that the target remediation values were achieved. The works were completed by a backfill with almost 13,000 cubic metres of material. The remediation measures were started in December 2014 and finished in September 2015. Since completion of the remediation works until today, post-remediation monitoring of the quality of the groundwater has been carried out on the site.