International Conference: WASCON'97
Location: Houthem - St. Gerlach (NL)
Date: 04-06 06 1997
Organization: ISCOWA
Proceedings
are published by Elsevier Science Publishers, Amsterdam, in Studies in Environmental Science Nr. 71.
WASCON'97 participants will recieve this book in December 1997. You may also take a look at the Conference Programme of Wascon'97.
All WASCON'97 participants should have recieved the Elsevier's WASCON'97 proceedings by now. If you have not recieved them by now, you are kindly requested to send a notifying message to the secretariat.
Selected papers of Wascon 1997 will be published in a special issue of Pergamon's journal "Waste Management". A special strongly reduced subscription price applies for members of ISCOWA. More information on current subscription rates (and information on how to become a member of ISCOWA) can be obtained from our secretariat.
ISCOWA-members may access the participants-list. For access to the list you must enter the ISCOWA-password, that is mentioned in the last paragraph of ISCOWA's New Year Letter (has been sent to all ISCOWA members on Dec. 21, 1998). If you have not received this letter, please ask our secretariat.
Last revision: 8 February 1998
1. Organisational Aspects.
2. Scientific Summary
2.1 Plenary opening
2.2 Workshop on MSWI-byproducts
2.3 Demonstration Projects
2.4 Harmonisation of Leaching Testprocedures
2.5 Construction raw materials from Coal fired Powerstations.
2.6 Concrete applications.
2.7 Modeling of leaching/laboratory field relations.
2.8 Re-use as raw materials.
2.9 Soil leaching and organic leaching.
2.10 Quality Control and Certification.
2.11 Immobilization.
2.12 Policy and Economy.
General Conclusions
WASCON'97 was visited by over 180 delegates from Europe, Eastern
Europe and other countries (Belgium, Denmark, France, Germany,
Italy, Spain, Finland, Sweden, Norway, the Netherlands, England,
Yugoslavia, Poland, Canada, Japan and the USA).
From most countries also delegates presented papers. In total
100 papers and 25 posters have been presented. Various topics
were presented in topic orientated workshops, running in three
parallel sessions.
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At WASCON'97 various themes have been presented in topic orientated
workshops, running in three parallel sessions. In this synopsis
the most interesting results per theme are presented.
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2.1 In the plenary opening Dr. M Quevauviller gave an outline
of the EC SMGT programme and indicated the importance of research
leading to harmonisation and standardisation.
Mr. Ch J. Nemmers presented the results of a OECD
study on recycling for road improvement. He concluded that it
is of utmost importance, in terms of realisation of market results,
that cooperation between parties (research, demand and supply)
is improved significally.
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2.2 In the workshop on MSWI-byproducts the state of the
art regarding various techniques for the treatment of by-products
was presented. It can be concluded that for bottom ash, by making
use of quality systems, application in road construction is a
growing market. Several methods to improve environmental quality,
either by treatment with chemicals or by sintering, are being
developed. For MSWI-fly ash procedures like melting and vitrification
are being developed.
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2.3 Demonstration Projects
Compared to the total amount of papers presented, the scientific
committee noticed, that in this workshop relatively few papers
were available. This might indicate, that more effort is needed
to stimulate industry to use by-products. Results from the cases
presented indicate that, based on available data from technical
and environmental research, application of various by-products
is feasible. Mr J. van Leeuwen (Public Works Rotterdam, The Netherlands)
presented a practical scheme for project development, taking into
account all aspects required for projectplanning and realisation.
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2.4 Harmonisation of Leaching Testprocedures
In this workshop results were presented of an international
project, supported by EC DGXII
SMT, on this
problem. Project results have been published in Elseviers Studies in Environmental Science (issue NR. 70).
The most important conclusion is the fact that pH can be used
as a common basis of reference for the leaching behaviour of inorganic
constituents. This is a major step in the process of harmonisation,
whereas additional work has to be done regarding the relationship
between laboratory generated data and field information.
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2.5 Construction raw materials from Coal fired Powerstations.
A comprehensive overview of the state of the art regarding
powdercoal fly ash in the Netherlands was presented. This can
be looked upon as a clear example of how to direct research and
development towards application and marketing. The main conclusion
is, that by-products can indeed become construction raw materials
and supplied to the market under certification, both technical
and environmental, via a quality control system. This case clearly
demonstrates, that recycling of by-products can be environmentally
and economically beneficial and is thereby an example for other
materials.
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2.6 Concrete applications.
Various papers gave data about the beneficial properties of
cement in which fly ash from several sources was used. Application
of these cements in concrete resulted in products of technical
good quality and showed strong retention of inorganic constituents.
As was concluded in the workshop on harmonisation, the pH in these
systems is supporting retention.
It can therefore be concluded, that the cement/concrete system
is, in terms of environmental aspects, one of the major procedures
to recycle by-products. The industry has to be stimulated to increase
activities on this point.
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2.7 Modeling of leaching/laboratory field relations.
Development in modeling of leaching is fast, indicated by
the fact that most of the recent work is aimed at the application
of models for predictions and simulations. Based on previous research
work and available data-bases, simulation models have been developed.
Verification of these models with field experiments is in progress.
Together with the results from field studies and the reported
work on harmonization, it is concluded, that environmental aspects
with respect to the re-use of secondary materials in various applications,
can be calculated and simulated in an adequate manner. The general
conclusion from studies on laboratory-field relations is, that
available research data support the view that re-use in an environmental
acceptable way is feasible e.g. in applications like road construction
and solidification systems. However, more work on verification
and standardization is needed to further improve quality and to
construct user oriented models.
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2.8 Re-use as raw materials.
In this workshop research results were presented, showing
that all kinds of by-products can be processed or used directly
in construction materials. Generally, when used in concrete as
substitute of one of the mixture components, technical good products
are obtained. Due to the concrete system also the environmental
performance is good. It can be concluded, that in these cases
industry needs to be stimulated to accept more of these materials
in their production processes in order to support sustainable
development.
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2.9 Soil leaching and organic leaching.
Presented research results indicate, that knowledge from previous
research from other fields, can be applied successfully to soil
systems. Leaching test procedures are now used to investigate
the effect of solidification of contaminated soils. This leads
to the conclusion, that using these tests it is possible to optimize
procedures like thermal treatment. Compared to the knowledge of
leaching of inorganic components, the knowledge of organic leaching
is rather poor. To stimulate the re-use of sieve sand from demolition
waste or of contaminated soil more research needs to be done.
This is also clear from the fact, that development of models for
these cases is only beginning. International co-operation and
preparation of standards is necessary.
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2.10 Quality Control and Certification.
The main conclusion from this session is the fact, that, at
least for inorganic components, leaching test procedures and available
models are applicable in certification schemes. Mr F. Lamers (KEMA,
The Netherlands) presented a clear case of environmental certification
of bottom ashes from coal fired powerplants in the Netherlands.
Mrs L. Heasman (M. J. Carter Associates, England) indicated that
transfer of know-how to potential users is very important. A well
set up training programme is very useful in this respect. The
conclusion is that this type of activities needs further stimulation,
also in the EC. A conclusion in line with the suggestion made
in the plenary opening.
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2.11 Immobilization.
In this session current methods for stabilisation like inorganic
stabilisation with cement or vitrification, were presented. In
addiction, current procedures in e.g. The Netherlands, France
and Northern America, were high-lighted. From these aspects it
is concluded that immobilisation / stabilisation is a fast developing
area. In many countries, mainly for contaminated soil and waste
materials for which no other process is available. In these cases
environmental improvement is the driving force. The main conclusion,
based on presented research data, is, that cement-based solidification
processes are very promising. Environmental studies indicate a
good long term performance, based on model results. In order to
stimulate application of developed techniques, field experiments
and demonstration projects need to be stimulated. This is also
necessary in order to obtain guidelines and to derive legislation,
aspects needed for a real break-through.
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2.12 Policy and Economy.
Results presented in this session, taking into account also
relevant papers from other sessions, lead to the overall conclusion
that, although in general re-use is a policy goal, this is not
enough driving force for the realisation of a major break-through.
On the other hand it is clear from technical and environmental
papers presented at WASCON'97, that profound progress has been
made. This leads to the conclusion that re-use of secondary materials
still needs to be stimulated by governmental measures. Environmental
economics, as presented by A. Craighill, England, support this
conclusion. Furthermore it is necessary that standards and guidelines
are being developed to support the application of secondary materials
in the construction industry.
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From the presented work on environmental aspects it can be concluded,
that leaching data for materials, models and testing procedures
are generated, which form a good basis for quality control and
certification, at least for inorganic components. The next step
to be taken is to stimulate the industry to make use of this know
how. Legislation can support this process. Further improvement
can be reached by harmonization and the development of standards.
For organic components more work has to be done, but much can
be learned from previous research.
Important is the transfer of this environmental and technical
know how to all parties involved in the implementation process.
This point needs stimulation.
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