Cyanide Groundwater Remediation in Stockach with Microbiomes

Sensatec’s Field Work in the MIBIREM Project

In the MIBIREM project, our partner Sensatec plays a key role in translating microbiome research into real-world applications. The company is responsible for piloting remediation technologies in the field, building on many years of experience in contaminated site remediation.

Sensatec’s work spans the entire remediation process—from laboratory feasibility studies and pilot tests to full-scale remediation projects. Alongside conventional remediation techniques, the company also develops biological treatment approaches for specific pollutants. Their expertise also includes drilling technologies, site characterization, and injection methods for remediation compounds.

Within MIBIREM, Sensatec contributes its knowledge in the enrichment and cultivation of pollutant-degrading microbial consortia and applies this expertise to practical remediation scenarios.

One important demonstration site for this work is a former gasworks site in Stockach (District of Konstanz, Germany).

In the MIBIREM project, innovative microbiome-based solutions for environmental remediation are being tested under real field conditions. At a former gasworks site in Stockach, Germany, our partner Sensatec  is piloting an in-situ bioremediation approach to tackle cyanide contamination in groundwater. By combining microbial processes with advanced monitoring and injection technologies, the project aims to demonstrate how naturally occurring microorganisms can help restore contaminated environments and protect valuable water resources.

A Challenging Remediation Site

The former gasworks site covers an area of around 7,200 m² and lies within a designated drinking water protection area. The nearest drinking water abstraction well is located approximately 765 meters away, making careful remediation particularly important.

Although the gasworks ceased operations in 1958, the legacy of historical gas production remains. At its peak, the facility produced up to 282,000 m³ of gas per year, leaving behind contamination typical for such industrial sites—including cyanide compounds in the groundwater.

Today the area contains a mixture of historic structures and newer infrastructure, including administrative buildings, workshops, and protected monuments.

Understanding the Subsurface

Beneath the site, the ground consists mainly of alluvial sediments such as loam, gravel, sand, and marl. A gravel aquifer, between 6 and 14 meters thick, forms the main groundwater-bearing layer.

This aquifer is divided into upper and lower gravel layers, separated by a thin silt horizon. However, this layer does not act as a complete barrier, allowing contaminants to migrate between the aquifers. As a result, cyanide contamination has been detected in both layers.

Groundwater in the region generally flows southwards, while locally beneath the site it shows an additional westward component.

Bioremediation in Action

The remediation approach focuses on stimulating natural microbial degradation processes directly in the groundwater.

To achieve this, oxygen and a cosubstrate are injected into the aquifer through specially designed pressure injection lances. These lances are built for long-term operation and can remain in place for five to ten years.

The system is controlled through a technical container equipped with monitoring equipment and remote data transmission, allowing continuous tracking of system performance and groundwater conditions. To further support microbial activity, a solid oxygen source (calcium peroxide) is injected downgradient of the treatment area.

The goal is to create optimal conditions for microorganisms capable of degrading cyanide compounds, enabling biological cleanup of the groundwater within approximately three years.

Monitoring the Cleanup Process

Regular monitoring is essential to evaluate remediation progress. Groundwater samples are collected every three months and analyzed for key parameters such as:

• cyanides
• dissolved organic carbon (DOC)
• sulfate
• nitrate
• ammonium
• additional hydrochemical indicators

Quality control measures, including duplicate and blank samples, ensure reliable results. The monitoring data are compiled in annual reports documenting remediation progress.

Bringing Microbiomes to the Field

Sensatec also leads Work Package 5 of MIBIREM, which focuses on bringing microbiome-based remediation strategies from research into real-world application.

Key objectives include:

• assessing safety aspects of microbial remediation approaches
• comparing the degradation performance of different microbiomes
• scaling up biological and technical processes
• conducting field trials to validate remediation effectiveness

Through these activities, the project aims to demonstrate how microbial communities can be harnessed as powerful tools for environmental remediation, helping restore contaminated sites while protecting groundwater resources.

Video footage from Stockach site

Author: Jessica Beyert, Sensatec

Edited by RTDS Group