M.J. van Wijngaarden
Mors op het oppervlaktewater. Een model ter beoordeling van de effectiviteit
Report 2006.TL.7100, Transport Engineering and Logistics.
During the handling of bulk solid materials, some material is spilled. This
material ends up in the air, the bottom or the water. This emission can be
harmful for the environment. Rijkswaterstaat and the stevedore OVET B.V.
recently entered into a discussion about the amount of bulk solid material
that may fall into the surface water during handling. These discussion
results into the foundation of a project group, with Rijkswaterstaat, 12
stevedores, TU Delft and some other companies. One of the tasks of this
group is to develop a tool that assesses the effectiveness of emission
measures based on spillage reduction and costs.
This report presents a tool to assess the effectiveness of emission measures,
especially for the direct emission of bulk solid material into the surface
water. This tool can be used by Rijkswaterstaat and the stevedores. For the
realization of this model it is necessary to answer the next questions:
To answer these questions investigation was done. Legislation about emission
was studied and also the emission of dust particles into the air was
investigated. Risk assessment models were investigated and a new risk
assessment model was developed. As a case û study the spillage problem
of OVET B.V. was analyzed with this tool.
- Which legislation about spillage exists?
- How much bulk solid material is spilled into the surface water?
- How harmful is bulk solid material for the surface water?
- How should the emission measures be assessed?
All the European emission legislation should be based on the council
directive 96/61/EC concerning integrated pollution prevention and control
(IPPC directive). This directive prescribes that all the emission control
measures should be based on the best available techniques. It also says that
every permit should include emission limit values. At the moment this is not
From the analysis of various risk assessment models it is shown that a firm
model should contain risk estimation as well as risk evaluation. In the case
of the spillage model the estimation deals with the amount and the
harmfulness of the spillage. To give this an expression, the term
"spillage impact" is introduced. This term makes clear how much
spillage takes place somewhere and it makes clear, how harmful the spillage is.
There are two problems in practice. At first in most cases the amount of
spillage is not exactly known. Rough estimations suggests that, depending on
the type of bulk solid material, 0,1 to 0,001 mass percent of the grab
volume falls from a grab into the surface water during a grab cycle.
Secondly the harmfulness of bulk solid materials into the surface water is
not known. The problem is that the harmfulness of some elements, like
metals, is known, but harmfulness of bulk solid material itself is not.
The evaluation part of the model should answer the question why a measure
should be taken or not. To answer this question, it is important to
determine a reasonableness criterion. This criterion makes clear if it is
reasonable to take a measure or not. According to the IPPC directive the
best available techniques should be used. To determine if a measure is
reasonable the costs and effectiveness are important. In the model the costs
and effectiveness are put together into the cost effectiveness methodology
to help to make the decision.
To be able to use the model the following should be determined:
The amount of spillage should be measured by collecting the material from the
pontoon. The harmfulness of bulk solid materials should be determined by
analyzing the material. The costs and effectiveness of various measures
should be gathered by the stevedores.
- The amount of spillage.
- The harmfulness of each bulk solid material for the surface water.
- The costs and the effectiveness of each measure.
- The indicative reference values for the cost effectiveness methodology.
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