Geosyntec Consultants Logo

Jutland

ISCO and Sequenced ISCO-Bioremediation for Remediation of Mixed Chlorinated Solvent DNAPL and Veterinary Antibiotics

2026-04-14T11:14:46-06:00June 26th, 2017|

Groundwater in Denmark that has been contaminated with chlorinated solvents is often remediated using in situ chemical oxidation (ISCO) with permanganate, or bioremediation via in situ enhanced biological reductive dechlorination (ERD).  Although ISCO using Fenton's reagent is a commonly used technology in North America for remediation of chlorinated solvents present in the subsurface as dense nonaqueous phase liquid (DNAPL), in Denmark the technology is still considered relatively unproven. 

In Situ Alkaline Hydrolysis of Organophosphorus Pesticides Enhanced by Acoustic Vibration and Surfactant Flushing

2026-05-26T09:08:39-06:00June 26th, 2017|

The Høfde 42 pesticide waste disposal site is recognized as the most toxic contaminated site in Denmark.  Between 1953 and 1962, the agrichemical manufacturing company Cheminova, with approval of Danish authorities, disposed of hundreds of tons of organophosphorus pesticide (OPP) and pesticide manufacturing wastes in pits at this site, which is located at a beach adjacent to the North Sea. 

Chlorinated Solvent DNAPL Bioremediation Pilot Test Demonstration in Denmark

2026-04-02T15:02:16-06:00February 23rd, 2016|Tags: , , , , , , |

Groundwater supplies beneath the Kærgård Plantage pharmaceutical waste disposal site in Denmark are contaminated with substantial quantities of chlorinated solvents (primarily tetrachloroethene, or PCE), which are present in the subsurface as dense non-aqueous phase liquids (DNAPLs). Contaminated groundwater from the site discharges to the nearby North Sea, creating a potential human health and ecological risk at a beach adjacent to the site. Since 2004, Geosyntec Consultants has advised the Danish government regarding the remedial strategy for cleaning up the site and mitigating risks at the beach. At Geosyntec’s recommendation, the Danish authorities retained a team of consultants with a goal of evaluating the feasibility of three technologies for remediating the primary DNAPL source areas at the site: in situ biological enhanced reductive dechlorination (ERD), in situ chemical oxidation with Fenton’s reagent, and in situ thermal remedial via steam flushing.

Pilot Demonstration of In Situ Alkaline Hydrolysis of Organophosphorus Pesticides in Denmark

2026-04-02T15:02:17-06:00February 23rd, 2016|Tags: , , , , , , |

The Høfde 42 pesticide waste disposal site is recognized as the most toxic contaminated site in Denmark. Between 1953 and 1962, the agrichemical manufacturing company Cheminova, with approval of Danish authorities, disposed of hundreds of tons of organophosphorus pesticide (OPP) and pesticide manufacturing wastes in pits at this site, which is located at a beach adjacent to the North Sea. A remedial feasibility study completed by the Danish government determined that in situ alkaline hydrolysis (ISAH) is the most cost effective technology for remediating groundwater and the residual wastes at the site. The Danish government, with funding by the European Union Life Program, selected the team of Geosyntec, COWI A/S, Tufts University, Nasus Water, and the University of Aalborg to conduct three pilot tests to compare three techniques for optimizing pesticide treatment by ISAH: 1) groundwater recirculation; 2) surfactant-enhanced flushing; and 3) acoustic vibration. In all three, tests a primary challenge is to inject strong base [caustic, or sodium hydroxide (NaOH)] to the in situ treatment zone while minimizing exposure of site workers to NaOH and pesticides.

Treatment of Organophosphorous Pesticides by Chemical Oxidation and Zero Valent Iron in Denmark

2026-04-02T15:02:29-06:00February 23rd, 2016|Tags: , , , , , , |

Groundwater beneath the Høfde 42 Harboøre Tange site is contaminated with some of the highest concentrations of organophosphorus pesticide wastes found anywhere in the world. From 1957 to 1962, pesticides and pesticide manufacturing wastes from a neighboring agrichemical plant were discharged to sand dunes at this site, which is located on the shore of the North Sea on the western coast of Denmark. Today, an estimated 267 tons of pesticides and pesticide manufacturing wastes remain at the site, primarily consisting of the highly toxic chemicals parathion, methyl parathion, and malathion. Largely immiscible in water, much of the pesticide contamination at the site is present as a dense, nonaqueous phase liquid (DNAPL). The site groundwater is highly acidic (pH of 3 to 4), and the groundwater toxicity is further increased by the presence of an estimated 60 Kg of mercury that is co-mingled with the pesticide wastes.

Go to Top