ISTR / Thermal refurbishment

Innovative solutions for complex contaminated sites

Cornelsen is setting new standards in the development of advanced water treatment technologies. Our solutions not only enable highly efficient cleaning, but also make an active contribution to environmental protection.

As a leading provider of remediation technologies, our team of experts will guide you through all phases of the remediation process. Whether it's a rental solution or an investment - we work with you to develop customised plant systems. We define precise performance parameters, evaluate the treatability of contaminated water and vapour phases and analyse the influence of site-specific geochemical conditions.

In close cooperation, we carry out systematic hazard analyses (HAZID), evaluate explosion protection requirements in accordance with ATEX directives and specify safety-critical components for comprehensive HAZOP studies. Our range of services includes complete project management: from pipework and pump installation to the provision of infrastructure (including safety technology and fencing), turnkey installation, commissioning and full maintenance service.

As standard, we integrate telemetric remote monitoring systems with real-time data visualisation and intelligent SMS alarm functions for optimum process control.

In-Situ Thermal Remediation (ISTR)

Technology leadership in thermal soil remediation

Over the last two decades, in-situ thermal remediation has established itself as a highly efficient technology for source remediation. Documented removal rates of over 99 per cent are achieved across all geological formations - right down to the crystalline bedrock.

Since our first ISTR project in 2007, we have seen exponential growth in our thermal remediation projects in the UK, Germany, France and Italy. As a strategic partner of renowned engineering firms, we realise these projects both as a direct customer service provider and in cooperation with specialised thermal technology partners.

Our thermal processes in detail

Steam Enhanced Extraction (SEE)

Steam Enhanced Extraction is based on the controlled injection of steam into contaminated formations for the thermal mobilisation of pollutants. This proven technology is particularly suitable for permeable substrates and low-volatility organic pollutants.

Technical advantages:

Highly efficient mobilisation of NAPL phases (non-aqueous phase liquids)
Applicability in heterogeneous lithological conditions
Accelerated heating kinetics of the treatment zone
Validated technology with documented refurbishment successes

Electrical Resistance Heating (ERH)

The electric resistance heating utilises the ohmic resistance properties of the floor matrix for homogeneous heat distribution through controlled current injection. This method enables precise temperature control and uniform thermal activation of the entire treatment zone.

Primary fields of application:

Contamination in clay-rich, low-permeability substrates
Chlorinated hydrocarbons (CHCs) and other persistent organic compounds
Sites with complex geological heterogeneities
Treatment zones with critical temperature requirements

Thermal Conduction Heating (TCH)

The conductive heat transfer method realises the direct thermal activation of the subsurface through heat transfer from heating elements installed in boreholes. Depending on requirements, these can be operated with gaseous, liquid or electrical energy sources.

Characteristic properties:

Direct conductive heat transfer with minimal energy losses
Flexible choice of energy source based on site-specific conditions
High-precision temperature control and monitoring
Suitability for deeper contamination horizons

STAR & STARex Smouldering Combustion

STAR - Self-sustaining in-situ combustion technology

STAR is a ground-breaking thermal in-situ technology based on the principle of self-sustaining smouldering combustion (smouldering fire), in which the pollutants themselves act as the primary fuel. Cornelsen co-operates as exclusive European partner with the patent holder Savron Solutions in the implementation of this innovative technology.

Smouldering combustion is an energy-efficient, autothermal oxidation process that continuously recycles the energy released during pollutant decomposition, thus ensuring controlled, safe and sustainable pollutant destruction.

Process engineering basics:

Active control of the combustion front through regulated air supply
Autothermal process after one-off thermal initiation
Energy recovery through the porous aquifer matrix
Elimination of external energy supply after successful process initiation
Total Remediation of soils with very high concentrations of hydrocarbon pollution

STARx - Ex-Situ application modality

STARx implements the identical patented process principle in designed soil excavation windrows that are positioned on modular Hottpad™ systems. These fully scalable treatment units can be flexibly adapted to treatment volumes, available area capacities and project-specific time requirements.

Optimum areas of application:

Deposits for contaminated excavated soil and storage sites
Addition of lime to the STARx cell to enable PFAS destruction in contaminated soils
Near-surface soil contamination
Used oil stocks and industrial sludge fractions
Scalable treatment capacities depending on project requirements
Total Remediation of soils with very high concentrations of hydrocarbon pollution

Other leading remediation technologies

Soil and groundwater remediation process systems

Soil Vapour Extraction (SVE): Vacuum-assisted extraction of volatile pollutants from the vadose (unsaturated) soil zone by controlled negative pressure generation and downstream vapour phase treatment.
Dual and Multi-Phase Extraction (DPE & MPE): Simultaneous multiphase extraction of soil vapours, groundwater and separate pollutant phases for integrated remediation optimisation.
NAPL Recovery (phase recovery): Specialised extraction systems for the selective removal of non-aqueous phase liquids from saturated and unsaturated soil zones.

Chemical and biological treatment process systems

In-Situ Chemical Oxidation (ISCO): Controlled injection of highly reactive oxidising agents for the direct chemical mineralisation of underground pollutants.
Gas Supersaturation Infusion: Introduction of supersaturated gas media to optimise microbial degradation processes through improved bioavailability of electron acceptors.
Enhanced biodegradation: Bioaugmentation and biostimulation through targeted nutrient and cofactor supply to accelerate autochthonous microbial degradation processes.

Water treatment and process technology

Pump and Treat (P&T) systems: Hydraulic groundwater extraction with downstream above-ground treatment using multi-barrier purification technologies.
Advanced Oxidation Processes (AOP): High-energy oxidation processes for the complete mineralisation of persistent and biorefractory organic pollutants.
Nano-filtration and membrane technologies: Pressure-driven membrane separation processes with molecular selectivity for the physical separation of pollutants.
Air stripping and adsorption process: Phase transfer extraction of volatile compounds combined with adsorption on highly specific sorption media.

PFAS special technologies

Innovative PFAS treatment systems: Cornelsen develops customised treatment solutions for per- and polyfluorinated alkyl substances (PFAS) using advanced sorption, membrane and destruction technologies.
Thermal removal & destruction of PFAS in soil

Exhaust air treatment

Catalytic thermal oxidation: High-temperature oxidation of organic vapours using catalytically activated combustion systems for maximum destruction efficiency with optimised energy consumption.
Condensation and vapour conditioning: Integrated cooling and condensation systems for selective solvent recovery and downstream vapour phase treatment.
Adsorption on GAK

Critical project parameters through piloting:

Required vacuum levels and hydraulic gradients

Realistic volume flows and mass balances

Effective radius of influence and treatment range

Expected pollutant concentrations and loads

Optimisation of process engineering parameters

Validation of treatability and process stability

Sound cost certainty for the main measure

Feasibility studies and pilot tests

Pilot tests are an essential tool for minimising project risk and enable the precise specification and cost calculation of full-scale remediation systems. They can also definitively validate or rule out the suitability of the planned remediation technology.

As standard, we integrate telemetric remote monitoring systems with real-time data visualisation and intelligent SMS alarm functions for optimum process control.

Project management and service

Integrated project management

Our multidisciplinary team of experts ensures seamless project realisation from initial concept development to final system handover:

Planning and concept phase: Detailed site characterisation, technology assessment, risk assessment (HAZID/HAZOP) and approval management.

Implementation and realisation phase: Customised system design, professional installation, systematic commissioning and training.

Operation and maintenance phase: Full-service operation with 24/7 availability, intelligent remote monitoring, preventive maintenance and continuous process optimisation.

Strategic advantages of rental solutions:

Significant reduction in capital employed (CAPEX)

Maximum flexibility when changing the system configuration

Dynamic adaptation to changing site conditions

Access to state-of-the-art technology without investment risk

Included maintenance and technical support

Investment and rental models

Inventory and customisation

Our comprehensive range of proven technologies is largely available as ready-to-use rental systems. Standard existing systems are routinely adapted for customer-specific applications, resulting in significant cost savings compared to complete new production.

Example of a control unit

What contaminants can be treated with thermal remediation?

Thermal works well for chlorinated solvents (TCE, PCE, etc.), petroleum hydrocarbons, and other volatile/semi-volatile compounds. It releases contaminants from the soil so they can be captured and treated. With recent developments, it is also possible to economically desorb and treat PFAS in soil.

Isn’t thermal remediation expensive?

Over time, many studies have shown that although the cost per week of running a thermal project is high; there are significant savings over long term operation of conventional remediation systems which also require long term sampling, analysis and data reporting which in turn adds cost. The short term nature of thermal also means that the site is ready for development far earlier.

How long does a typical project take?

Heating itself usually takes 3–6 months. With planning, installation and verification included, most projects run 6–14 months in total.

Is it safe for nearby buildings and infrastructure?

Yes. The heating zone is controlled, and temperatures are continuously monitored. Additionally it is possible to monitor movement to prevent unwanted movement or effects on surrounding structures.

How do we keep energy use efficient?

Through insulated systems, real-time monitoring and adaptive power control. Once target temperatures are reached, the system can automatically reduce energy input.

Do you guarantee an end target?

We do not, however our thermal vendor partners may do depending on the project specifics & level of site characteristics available. We will provide system performance guarantees to ensure that the project proceeds as planned and the client does not need to worry about system functionality risking their project.

Will you work with existing infrastructure?

Yes – we frequently do and prefer to where possible. For example if a site already has a steam boiler operating our preference is to utilise this. Similarly we can discharge semi-treated waters to an existing water treatment plant if this is more economical than us fully treating for discharge.

International expertise and partnerships

Cornelsen has long-term collaborations with leading engineering and environmental consultancies such as ERM, AECOM, Arcadis, Sodecon, Reconsite and Haemers. as well as strategic technology partners to successfully realise complex ISTR projects in the UK, France, Belgium, Italy and Germany.

As a market leader, we have delivered multiple ISTR projects with a comprehensive technology portfolio in many European countries, partnering with all forms of thermal remediation to deliver the most suitable approach for the site requirements, and we continue to transfer this proven expertise to the European markets.