Acid waste lagoons to be cleaned for good

A major clean up will take place at a Latvian hazardous waste site. The work involves a series of operations to deal safely with a nasty cocktail of chemicals dumped there over four decades.

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Closed in 1986, the site lies some 30 to 35 km east of the nation’s capital, Riga. Its two lagoons are mainly filled with sulphuric acid tar, which will be ‘remediated’ and eventually turned into forestry land.

Mix of harmful chemicals

The Latvian government has listed Inčukalns as a top target for remediation. The lagoons there are known as ‘historically polluted’, a reference to the many sites left to the nation from its former political and economic system. Such sites were traditionally used by the military or were dumping grounds for local industries.

The goal of this part-EU funded project is to clean up an area of 25 000 square metres, in the Southern and Northern sulphuric acid tar lagoons within Inčukalns civil parish. Between the 1950s and 1980s, sulphuric acid tar and other waste – including medical and perfumery oil waste – generated by the petroleum processing and lubricating oil production plant in Riga were simply dumped in the area’s sand quarries.

The landfill was closed in 1986, but it had no waterproofed bases or sides, so the pollution has infiltrated near-surface groundwater and artesian water up to a depth of 70 to 90 m. The polluted artesian water is moving north towards the River Gauja at a speed of 25 to 35 m/year. Studies show that polluted groundwater extends 148 ha around the Northern lagoon and 139 ha around the Southern lagoon.

The project will focus over three and a half years on preventing further discharge of pollutants into the surrounding area. Work involves operations such as site preparation, excavation, water pumping, treatment, neutralisation and eventually the covering of the sites.

Readied for forestry

The project will provide employment for some 20 people during the implementation phase. Once it is completed, the quality of the near-surface groundwater, surface water, soil and subsoil adjacent to the hazardous waste dump will be improved to the extent that human health and the environment are no longer endangered.

Post-remediation monitoring and surveillance of the site will be carried out for 30 years after completion of the remedial works. The area in question should then be fit for use for forestry, in accordance with the Inčukalns local authority’s land-use plan. A further benefit of the project will be the site’s compliance with the EU’s drinking water and urban waste water legislation.

Draft date