And the contamination of Industrial Wasteland Adam Stanley Jonathan Beeson

Contamination History  Located in St Denis, Paris, France.  Large flat industrial area served by a Canal.  Previously provided utilities for the city during 19 th and 20 th centuries.  Majority of industries left during the 1970’s - 80’s leaving a contaminated wasteland.  As a result various contaminants remained in the soil.

Contamination History  The stadium itself is built on the site of a former gas works built in  Plant produced Coal Gas (Town/ Illumination Gas) used for lighting and heating throughout Paris.  Closed in the 1970’s as natural gas became the preferred option.

Process  Coal gas is produced by destructively distilling coal  Coal Gas consists of:  Hydrogen (H)  Carbon Monoxide (CO)  Methane (CH 4 )  Volatile Hydrocarbons (C n H m )  Also contains impurities:  Carbon Dioxide (CO 2 )  Nitrogen (N)

By-products  By-products of producing coal gas:  Coke:  Coal Tar:  Sulphur:  Ammonia:  Each have industrial uses, thus stored on site.  Environmentally hazardous and damaging.  Consequently the ground was left polluted. Combustible at high temperatures Group 1 carcinogenic Can form Sulphur Dioxide and Sulphuric Acid Hazardous to humans and aquatic animals

Scale of Project  Over 50,000 m 3 of soil had to be treated.  Contaminant concentrations of up to 50,000 ppm.  A strict construction deadline in time for the summer world cup:  31 month timeframe (full construction)  The area has a complex groundwater system, flowing in multiple directions transferring contaminants.

Remedial Measures: Phase 1  Soil/ Sediment Washing:  Removes the heavily polluted soil by ‘scrubbing’  Often used in conjunction with other remedial measures  Performed on site (In-situ)  Long but cheap process

Remedial Measures: Phase 1  Biological Treatment In-situ:  Cheap but often timely  Uses naturally occurring microorganisms to biologically degrade contaminants  Barrier:  Protective layer prevents pollutants from rising above the soil surface  Aeration:  In-situ process of injecting/ forcing air into the soil to degrade contaminants into CO 2 and water

Remedial Measures: Phase 2  Following the first remedial works, hydrocarbons were found during construction at a depth greater than 5m.  This presented two risks:  Emanation of odours  Risk of subsurface explosions  Remediation of this phase needed to be quick as construction had begun:  Groundwater and gases pumped from soil  Groundwater treated on site  Gases incinerated before release to atmosphere

Alternative Remedial Measures  Incineration of soil:  Not economically viable due to high volumes of soil needing treatment.  Solidification:  Binds the contaminant in place prevent re-entry to environment.  Soil Vapour Extraction:  Use of pipes to collect hazardous gasses.  Redistribution

Conclusions  The soil was successfully treated and all threats were mitigated / removed over a 2 year period.  The 80,000 capacity stadium was built in time for the French 1998 Football World Cup.  Now a 270-day a year facility, the stadium is a symbol for the regeneration of Saint Denis.