Notable case, Bitterfeld-Wolfen, Sachsen-Anhalt, Germany

Bitterfeld-Wolfen

One of the world's oldest chemical complexes, set among open-cast lignite mines later used as dumps. It left regional groundwater contamination by chlorinated solvents, chlorobenzenes and pesticide residues, and became Germany's test bed for reactive barriers and constructed wetlands.

Phytoremediation Microbial bioremediation

Status: Contained
Area: 2,500 ha on land¹
Media: groundwater, soil, surface water
Kind of site: chemical works, agrochemicals, mining, landfill

Area. About 25 km² of regionally contaminated groundwater, with a volume of roughly 200 million m³ (figure from the SAFIRA projects, read from a search extract).

Contaminants

Organic compounds

Status

Contained

The groundwater contamination is too widespread to be removed: it is watched through some 250 observation wells (Wycisk et al. 2006) and managed on a risk basis. We found no up-to-date official source on costs and progress.

Story

Production of chlorinated chemicals began at the end of the nineteenth century with chlor-alkali electrolysis; in 1895 Agfa built a dye factory at Wolfen. For more than a century the chemical industry lived alongside lignite mining, which lowered and disrupted the aquifers. North-west of Bitterfeld several worked-out pits were filled with chemical waste in GDR times: the "Antonie" landfill alone holds about 6 million tonnes of residues, including waste from lindane and DDT production.

The dumps are not sealed and the groundwater, in two stacked aquifers, carries a mixture of about 180 organic substances. Among the most frequent: tetrachloromethane, trichloroethene (up to 21,000 µg/l), cis-dichloroethene, vinyl chloride (up to 41,000 µg/l), monochlorobenzene (up to 23,000 µg/l) and benzene.

The UFZ research centre used Bitterfeld as the model site of the SAFIRA project, with a pilot plant for testing reactors and barriers under real groundwater conditions.

Timeline

1895Agfa builds a dye factory at Wolfen.
2006The 3D model of the contaminated aquifers and exposure routes is published (Wycisk et al.).
2008Results of the pilot wetland for chlorobenzenes are published.

Remediation

—monitoring and pilot treatmentRegional monitoring network and the SAFIRA pilot plant with anaerobic and aerobic reactors and activated carbon.

Plants and fungi at this site

PhytoremediationField pilot

Phragmites australis

Pilot horizontal subsurface-flow constructed wetland planted with common reed and fed with site groundwater (20 mg/l monochlorobenzene, 0.19 mg/l 1,2-dichlorobenzene, 0.25 mg/l 1,4-dichlorobenzene), compared with an unplanted bed.

Outcome After 2 m of flow path the planted bed removed on average 48% of the monochlorobenzene and 38% of the 1,4-dichlorobenzene; the unplanted one needed twice the distance. No removal of 1,2-dichlorobenzene. Aerobic degrading bacteria were found.

Chlorobenzenes

Braeckevelt M. et al. Treatment of chlorobenzene-contaminated groundwater in a pilot-scale constructed wetland. Ecological Engineering 33(1), 2008

Microbial bioremediationField pilot

SAFIRA pilot plant: two-stage treatment of groundwater, an anaerobic stage for reductive transformation of resistant compounds and an aerobic one for low-halogenated ones, with activated carbon as adsorbent and support for the microorganisms.

Research project SAFIRA, tu-dresden.de

From the literature

Species that acted on one of this site's contaminants in at least one study. The list is automatic and takes no account of this site's soil, concentrations or climate.

Plants

Cucurbita pepoZucchini, pumpkinDDT and breakdown productsEvidence: field
Populus × generosaHybrid poplar (P. trichocarpa × P. deltoides)Chlorinated solvents (TCE, PCE, chloroform)Evidence: field
Ricinus communisCastor beanDDT and breakdown productsEvidence: greenhouse
Populus × canadensisCanadian poplar (P. deltoides × P. nigra)Chlorinated solvents (TCE, PCE, chloroform)Evidence: laboratory

Fungi

Phanerochaete chrysosporiumDDT and breakdown productsHexachlorocyclohexane (lindane)Evidence: laboratory
Bjerkandera adustaSmoky bracketHexachlorocyclohexane (lindane)Evidence: laboratory
Fomitopsis pinicolaRed-belted conkDDT and breakdown productsEvidence: laboratory
Gloeophyllum trabeumDDT and breakdown productsEvidence: laboratory
Scedosporium apiospermumBTEX (benzene, toluene, ethylbenzene, xylenes)Evidence: laboratory
Trametes versicolorTurkey tailChlorinated solvents (TCE, PCE, chloroform)Evidence: laboratory