Measurements and Activities for Mud Removal and Disposal of Sediments

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Novi Sad, 27. mart 2014.

„Environmentally friendly water management in plain areas„eWAM

HUSRB/1203/121/237

Dejan Krčmar, PhDPMF – Department of Chemistry, Biochemistry and Environmental

Protection

Why sediment?The dynamic component of all aquatic systems may be a reservoir of accumulated toxic and

persistent compounds of natural and predominantly anthropogenic origin due to the strongly expressed tendency of binding

In the sediment, there is a million times bigger concentration of pollutants (e.g. metal) than in the same volume of water

The source of secondary pollution “Time bomb”

Resuspension

– Flooding– Raising the floodgates - Mud removal– Bioturbation

Sediment Sustainable Management• When and where to monitor sediment quality? How often?• How to evaluate sediment quality? How does sediment affect water quality?

– Which methods should be used?– Which pollutants should be monitored?– Which quality criteria should be used? Is that sufficient for making

conclusions?• What should be done when the sediment quality does not satisfy?

– To remove the mud or leave it?• What to do with the removed material?

– Should it be disposed of? Or can it be spread onto the coast, adjacent land or move to another aquatic environment?

– Can it be used for material extraction?– What effect will sediment removal have on the aquatic system?

When and where?

1. Rating chemical status and trend of sediment quality - WFD (2000/60/EC)Each Member State should make the identification of contaminated sediment requiring remediation. If the quality of the sediment is bad and affects the achievement of good ecological status, Member State must, in accordance with Article 4 and Article 11, initiate appropriate action since contaminated sediments may pose a barrier to achieving good ecological status of water bodies.

2. In case of regular watercourse maintenance Maintenance of waterways Reducing the risk of flooding Coastal management...

WFD only implies monitoring the quality of sediments and provides a framework within which the problem of sediment must and can be handled at locations where the ecological status is disrupted due to the degraded quality of the sediment.

How?

System dynamics– Spatial (horizontal and vertical distribution of pollutants) - design of

monitoring – Weather (seasonal changes, the impact of sediment geochemistry and

the process of "aging" on the bioavailability of pollutants) – Environmental conditions

Discrepancies between the chemical and ecological status – The impacts caused by the presence of pollutants whose presence in the

sediments is not monitored,– The synergistic or antagonistic effect of the pollutants ,– The occurrence of pollutants in different chemical forms (e.g. metals),

which significantly affects their toxicity, – Different sensitivity of different organisms to different types of

pollutants.

The complexity of the process of quality assessment of sediment

Additional: Complex and incomplete regulation, The lack of data on the concentrations

of the compounds and elements in sediments,

Lack of data on reference conditions, There is no homogeneous

classification of sediment, There are no agreed criteria on

sediment quality, Conventional methods aim to

determine the concentrations of pollutants in the sediment, therefore they are not suitable since they overestimate the bioavailable fraction.

Available fraction

Total PAH concentration

Accumulated fraction

Receptor

Sediment (mud removed material) as waste

• Classification of mud removed material depends on the assessment of hazardous nature of waste by :

The European waste catalogue (2000/532/EC) Hazardous Waste Directive EU (91/689/EEC)

When does mud removed material become hazardous waste?

Clean and free of adverse ecotoxic effects

Contaminated with the expression of ecotoxic effects

Mud removed material

harmless hazardousWASTE

Sediment that is too contaminated to be transferred to another water environment, should not automatically be classified as hazardous waste!

Limit values for pollutants for assessing the status and trends of sediment quality, i.e. the target value, the maximum concentration value and remediation value

and the values of pollutants that are used in mud removal and dislocation of the sediment from the water stream, i.e. the target value and remediation, the limits value and verification level

Sediment quality standards in Serbia

Regulation on limit values for pollutants in surface and ground waters and Regulation on limit values for pollutants in surface and ground waters and sediments and deadlines for their achievement sediments and deadlines for their achievement (Official Gazette of RS, 50/2012)(Official Gazette of RS, 50/2012)

Status assessment

1. Rating chemical status and trend of sediment quality

Includes arsenic, heavy metals, PAHs, PCBs, organochlorine pesticides, mineral oils

Mud removal for maintenance

2. In the case of regular maintenance of waterways

Includes arsenic, heavy metals, PAHs, PCBs, organochlorine pesticides, mineral oils

What to do with mud removed material?Class Criterion Ways of dealing with mud removed sediment

0 Target value

Concentrations of contaminants in the sediment are at the level of natural background. Sediments can be displaced without any special protection measures.

1 > Target value Limit value Sediment is slightly polluted. During dislocation the

disposal without special measures of protection is permitted in the band width of up to 20 m in the vicinity of watercourses.2 > Limit value Verification limit

3> Verification level Remediation

value

The sediment is contaminated. Its disposal is not allowed without special measures. It is necessary to keep in the controlled conditions along with the special protection measures to prevent the spread of pollutants in the surroundings.

4 > Remediation value Extremely polluted sediments. Remediation is obligatory or keeping mud removed materials in controlled conditions with special protection measures to prevent the spread of pollutants into the environment.

Correction of metal content for the given sediment

1025

%%

VBА

ОМVglineBАGVGV SТК

Correction of organic substances for the given sediment.

10

%ОМGVGV SТК

Correction of threshold values

However, the quality of the sediment is not the list of chemical substances concentration

... The total concentrations of contaminants - despite correction, the

estimated risk often exceeds the actual risk.

Necessary research in order to fully understand the processes that define the bioavailability and the development of quantitative descriptive models for these processes.

It is necessary to develop chemical and biological tests for quick and easy assessment of the bioavailability and thus the quality and sediment assessment of risks to the environment.

Data on the natural level of pollutants (especially metals)

Eco-toxicity, benthic community structure, bioaccumulation

Safe mud removal and disposal of sediments

Selecting the right alternative for mud removal/ remediation is based on balancing the many demands in terms of:

•technical feasibility,

•economic feasibility and

•environmental protection including the DISABLING THE EXPANSION OF HARMFUL SUBSTANCES INTO THE ENVIRONMENT.

The basic roads of pollutant losses during mud removal, treatment and disposal of sediments

:1. Resuspension of sediment 2. Dissolution / desorption of the

pollutants 3. Leaching

PHASE I - PHASE I - Initial Initial charactericharacterissation and potential ation and potential

for desorpfor desorptiontion

PHASE II - PHASE II - works works control control on on mud mud

removalremoval

PHASE III - PHASE III - control of the control of the deposited material and deposited material and

leachate leachate from the landfill and from the landfill and protection measures protection measures

Yes

No

Yes

No

Yes

No

Surveillance monitoring of the landfill and groundwater

Continued work with occasional control of pore (leachate) water

The temporary interruption of work and review of some of the stabilisation options of

mud removed material. After that, work continuance with planned protection

measures.

Is there a leakage from the landfill?

Mud removal and deposition with special protection measures

Is there a risk of

desorption of pollutants

Sediment quality

satisfies the criteria?

INITIAL POLLUTION CHARACTERISATION

WORK PLANNING

Mud removal and deposition without any special protection

measures

PHASE IV - PHASE IV - surveillance surveillance monitoring monitoring

Thank you! Thank you!