Remediation of Contaminated Land Technology Implementation

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Federal Environmental Agency, Germany

2002

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Several billion EUROS are spent in the EU each year on the remediation of land affected by

contamination. It is an important goal from all perspectives that this money is spent wisely and

appropriately. A risk based decision-making process for remediation is now the norm across most

EU member states (CLARINET and NICOLE, 1998). In this process, risk assessment and the

subsequent step of risk management are intimately related elements that form the basis for a

fitness-for-use approach to land affected by contamination. Risk assessment was the focus of

CARACAS, the Concerted Action, which was a forerunner of CLARINET (FERGUSON 1998,

FERGUSON & KASAMAS, 1999).

CLARINET through its Working Group “Remediation Technologies” has surveyed state-of-the-art of

implemented remediation technology in the European countries represented in CLARINET. The

survey was based on the use of questionnaires circulated to CLARINET’s national country

representatives. The responses to these questionnaires have been compiled and peer reviewed, and

are available through this final working group report. This report on remediation technologies

presents a State-Of-the Art (SOA) review of implementation of remediation technologies in the

different European countries. It comprises a description of the key elements for describing and

selecting remediation technologies, and their principle categories. It goes on to provide a detailed

inventory, by country, of technology development programmes, pilot scale projects and the use of

remediation technologies. As remediation technology is an extensive topic, these country reviews

are by necessity overviews. Further information can be obtained by referring to the existing

national documents provided for each country (Annex 1), and the references given in the

document.

Planned land use, time available for remediation, developers knowledge and understanding and the

money available for development, are powerful controlling the remediation solutions. There is a

constant pressure for reducing remediation costs, both to improve the economics of brownfield re-

use for "hard applications" such as housing or commerce; and for "softer" uses such as nonfood

agriculture and recreation. There is growing pressure to develop more cost-effective remediation

technologies. Cost effectiveness is not just a product of reducing remediation costs, but also of

finding remediation approaches that provide an additional enhancement to the value of the land.

The highest cost reducing potential can be achieved by reducing the volume of soil needing

treatment and by increasing the proportion of materials to be recycled and reused. Experienced and

professional project management, relevant and adequate site investigations, improved knowledge

of the performance and efficiency of remediation processes can significantly enhance the

accuracy of forecasting remediation costs. This information needs to be addressed not only from

“problem definition” or “solution provision” perspectives, but as interdependent issues. For example,

appropriate site investigation not only highlights problems, it also acts as a CLARINET -

Remediation Technologies Umweltbundesamt/Federal Environment Agency – Austria 2 guide to the

solution. Inappropriate site investigation does neither. All procurement of services needs to be done

with a view to value, not cost. In current terms this is “intelligent procurement”, concentrating on

value and confidence in achievement of objectives.

There are two further factors that impact on the cost-effectiveness of remediation technologies that

are outside the remit of most CLARINET participants. The first is the impact of waste legislation

and regulation that, in certain nations, determines the fate of contaminated soil, and the potential

for its treatment, disposal, recovery, recycling and reuse. The second is the designated land-use of

a remediated site; this has a profound effect on site values and hence the options available for

remediation.

There are large differences in practice throughout Europe, and some examples of aspects

contributing to these differences can be given:

• In some countries waste licence is needed to treat contaminated soil on site, making time

constraints a problem for on site treatment technologies,

• There are large differences in prioritisation of protection of groundwater, very much dependent on

the degree of utilisation of groundwater, e.g. in countries like Norway, where only 15% of the

groundwater resource is utilised for water supply, remediation is rarely initiated to protect the

groundwater.

• The economic framework differs, e. g. differences in landfill taxes in the countries

• The policy framework differs, e.g. some European countries (e.g. Portugal, Greece, and Hungary),

have not implemented Risk Based Land Management (RBLM) for decision-making. There are large

differences in economic framework, i.e. for supporting innovative technology implementation,

sustainable remediation solutions, or remediation of derelict land or brownfields.

Remediation technologies can be defined in accordance to the type of treatment processes taking

place, such as:

• Biological

• Chemical/Physical

• Solidification/stabilisation (S/S)

• Thermal

Remediation solutions are also referring to where the action is taking place:

• On site

- In situ

- Ex situ

• Off site

- Ex situ

In general, it can be stated that technologies are by far the most widely applied remediation solution

in Europe. technologies are currently in the early stage of implementation, and a number of

constraints must be resolved before they are readily implemented. Assuming that a remedial

approach can be adequately monitored and controlled, there is an increasing desire to promote

solutions and on site solutions over solutions based on removal off site. However, there are often

conflicting pressures affecting whether or not an on-site or off-site approach is taken. In some

cases stakeholders may express a preference for a solution based on removing materials off site.

This may be related to concerns over residual liabilities, which in turn are related to concerns over

the duration, feasibility or completeness of on site solutions. Conversely, removal of materials off

site may be problematic because of the transportation and related problems, or because excavation

is not considered technically or economically feasible. Offering previously validated solutions and

developing an appropriate verification strategy for the sites in question are key steps in dealing with

these concerns.

Technologies are often being referred to as:

• Emerging technology (E);

• Some field applications, but not widely used (FA);

• Widely used (WU).

Emerging technologies have only been applied in laboratory- or pilot scale/demonstration plants. A

technology, which has been used in some field applications for solving a particular problem, or

addressing a specific type of matrix, could be emerging when it comes to another application. The

above categorisation is rapidly changing, and it is not the intention of the working group on

remediation technologies to keep this source of information updated, and the reader needs to

consider this document as a state-of-the art in present time, and look for updated references in the

future. This document describes in short the different technologies, and advices on literature where

more detailed information can be found, some of which is readily updated. A summary of the

degree of implementation of remediation technology in Europe is given below:

Civil engineering techniques are by far the most widely applied technologies throughout Europe,

including:

• Excavation and related materials handling (WU);

• Disposal of contaminated soil (WU); Infilling void (WU); Cover systems (WU); Vertical barriers

(WU).

Another important group of remediation technologies are those protecting against development of

hazardous gases in the ground, including:

• Barriers beneath buildings (WU); Gas Barriers in the ground (WU); Monitoring systems and gas

alarms (WU).

technologies vary more in their degree of implementation and include processes like:

• Soil vapour extraction / bioventing (WU);

• Air / biosparging (WU); Soil flushing, pump and treat (WU); Permeable reactive barriers (E) / (WU);

Redox amendments for bioremediation (WU); oxidation (WU); Electro-remediation

(FA);Phytoremediation, (E); Monitored Natural Attenuation (MNA) (WU).

The following group of technologies are predominantly technologies:

• bioremediation (WU); Soil washing & related techniques (WU); Solidification and stabilisation

(WU); *Thermal treatments, (FA); Vitrification (FA); groundwater treatments (WU).

The results of the questionnaire illustrated the difficulties in obtaining comparable cost figures for

different technologies. Cost figures vary dependent on their origin.

General remediation cost figures are high, but when cost figure are taken from bids on large clean-

up projects, the figures are generally lower. The cost figures for the same technology varies

several orders of magnitude, illustrating these differences, but also illustrating the lack of

availability of the technologies in some countries, and the size of a commercial remediation marked

in other countries. Differences in technology definitions might also be a source of error to the cost

figures. Prior to this investigation, some of the authors had the general feeling that technologies

would be cheaper than technologies, but the investigations showed that this was not always the

case. technologies are mostly applied in projects where technologies were not so easy

implemented, e.g. difficult clean-up projects (beneath existing buildings etc.). The cost figures for

different technologies are only considered to be comparable, and are summarised below:

Predominantly :

• Bioremediation: 20-40 Euros/t, assuming that:

- Low cost figures are referring to composting, and

- High cost figures are referring to bioslurry or reactor treatment system

• Soil washing 20-200 Euros/t

• Stabilisation/solidification 80-150 Euros/t

• Incineration treatment 170-350 Euros/t

• Thermal treatment 30-100 Euros/t technologies:

• 20-60 Euros/t depending on technology and application at site. Many remedial treatments operate

over the shorter term and require relatively high cost and energy inputs. These are referred to as

"intensive" treatment technologies. Extensive technologies operate over a longer period with low

maintenance, cost, and energy requirements. Examples in current use include phytoremediation and

monitored natural attenuation (MNA).

In general, concerns over feasibility tend to be greater for innovative remedial approaches, even if

these have long standing track records in other countries.

However, there are often these innovative solutions that are seen to offer more in terms of

reducing wider environmental impacts and furthering the cause of sustainable development.

A range of pilot scale studies and demonstration programmes are ongoing in Europe.

Some of the programs are internationally oriented with partners from outside Europe.

One major international programme is the NATO/CCMS pilot study. In this programme a broad range

of countries have been and are demonstrating different technologies. The study covers a broad