NATO CCMS Pilot Study Meeting - Rehabilitation of Old Landfills Cardiff City Hall / 23 rd - 26 th may 2004 Thierry CHASSAGNAC 1/14 Presentation : Thierry CHASSAGNAC CSD AZUR

NATO CCMS Pilot Study Meeting - Rehabilitation of Old Landfills Cardiff City Hall / 23 rd - 26 th may 2004 Thierry CHASSAGNAC 2/14  Report The old landfills produce biogas and leachates The environment strongly decreases the impacts in particular conditions Several dozens thousand sites are concerned in France Interest to study and to develop the natural attenuation  Objectives of the study (ADEME) Estimate the number of sites concerned by the natural attenuation Identify the mechanisms of the natural attenuation Propose solutions adapted to old landfills

NATO CCMS Pilot Study Meeting - Rehabilitation of Old Landfills Cardiff City Hall / 23 rd - 26 th may 2004 Thierry CHASSAGNAC 3/14 34 evaluation criteria representative of 8 families - geologic substratum - sensibility of the landscapes and the environments - landfill dimensions - sensibility of groundwater - sensibility of habitat and population - deposit composition - sensibility of surface waters - landfill age Allocation of a raw note for every criterion (+1 note of doubt by criterion) 34 raw notes (+ 34 doubt notes) 4 environments Global risk category of the site = Risk category of the most affected environment Catégory of risk of environment : A, B, C or D Catégory of risk of environment : A, B, C or D Catégory of risk of environment : A, B, C or D Catégory of risk of environment : A, B, C or D CSD AZUR Method

NATO CCMS Pilot Study Meeting - Rehabilitation of Old Landfills Cardiff City Hall / 23 rd - 26 th may 2004 Thierry CHASSAGNAC 4/14  Principle of the statistical analysis 6 regional diagnoses of landfills : 1410 referenced sites 34 criteria aggregated in the form of risk notes by environments : zsurface waters, groundwater, natural environment, human environment 4 category of risks : A - emergency situation B - strong to average potential risk C - average to weak potential risks D - weak to no potential risks Study interest  Enumeration 18 % of sites are in direct and permanent connection with groundwater : z7 % spring zone z11 % backfilling of old water depressions (quarry) A : emergency B : strong C : middleD : weak

NATO CCMS Pilot Study Meeting - Rehabilitation of Old Landfills Cardiff City Hall / 23 rd - 26 th may 2004 Thierry CHASSAGNAC 5/14 > 20 m10 à 20 m2 à 10 m< 2 m 1 - no resource 2 - improbable resource 3 - likely resource of moderate importance, exploited or not 4 - important to average resource, recognized, not exploited 5 - important resource, exploited and recognized 1 - no resource 2 - improbable resource 3 - likely resource of moderate importance, exploited or not 4 - important to average resource, recognized, not exploited 5 - important resource, exploited and recognized < to to 10000>  Typology of sites in connection with groundwater (comparison to the other sites) : more risks ground waters : zpermeable substratum zpotential resources zsubsurface groundwater surface waters : znear streams zhigh flow zpotential resources nearness and density of population more vast and less thick

NATO CCMS Pilot Study Meeting - Rehabilitation of Old Landfills Cardiff City Hall / 23 rd - 26 th may 2004 Thierry CHASSAGNAC 6/14  Unitarian processes : filtration adsorption precipitation dispersal nitrification dénitrification degradation of the organic matter  Parameters : water oxygen geometry of the filter soil condition pollution burden to be treated temperature pH redox potential Mechanisms of natural attenuation for the leachates 1. Underground wet mechanism : the infiltration - percolation Mechanisms of natural attenuation for the leachates 1. Underground wet mechanism : the infiltration - percolation The infiltration percolation allows : to hold the polluting particulate elements to hold inorganic pollutants (sorption) the degradation of organic pollutants by microorganism the treatment of the nitrogenous compounds by particular microorganisms

NATO CCMS Pilot Study Meeting - Rehabilitation of Old Landfills Cardiff City Hall / 23 rd - 26 th may 2004 Thierry CHASSAGNAC 7/14 Mechanisms of natural attenuation for the leachates 2. Superficial wet mechanism : lagooning Mechanisms of natural attenuation for the leachates 2. Superficial wet mechanism : lagooning  Unitarian processes : consumption of nitrogen and phosphor degradation of organic matter decantation volatilization photolysis waters disinfection  Parameters : residence time oxygen pollution burden temperature pH redox potential The lagooning allows : the decantation of suspended solids and their trapping in the bottom of ponds the photolysis notably of halogen compounds the degradation of the organic compounds by microorganisms the consumption of nitrogen and phosphor by micro and macrophytes

NATO CCMS Pilot Study Meeting - Rehabilitation of Old Landfills Cardiff City Hall / 23 rd - 26 th may 2004 Thierry CHASSAGNAC 8/14 Mechanisms of natural attenuation for the leachates 3. The phytoremediation Mechanisms of natural attenuation for the leachates 3. The phytoremediation  Unitarian processes : phytostabilization in the rhizosphere adsorption on roots detention in the roots rhizodegradation phytovolatilization accumulation degradation action on the heat flows  Parameters : water oxygen chelates pollution burden to be treated plants cycles The phytoremediation allows : the consumption of nutriments (nitrogen, phosphor, potassium, micronutrient) the consumption of trace metals the degradation of the organic compounds by rhizospheric microorganisms “ The phytoremediation is the use of plants, their associated microbiote, amendments and agricultural technics to eliminate, contain, or make less toxic environmental pollutants ” (Cunningham).

NATO CCMS Pilot Study Meeting - Rehabilitation of Old Landfills Cardiff City Hall / 23 rd - 26 th may 2004 Thierry CHASSAGNAC 9/14 Mechanisms of natural attenuation for the gas releases  Parameters : thickness of the cover food continuance organic matter (  use of compost) vegetal density of the cover inhibitors  The properties of the cover : interception of meteoric waters limitation of the flight of wastes support of the vegetalization the oxidation of the methan : methanotrophic microorganisms

NATO CCMS Pilot Study Meeting - Rehabilitation of Old Landfills Cardiff City Hall / 23 rd - 26 th may 2004 Thierry CHASSAGNAC 10/14 Typical solution for sites in spring zone

NATO CCMS Pilot Study Meeting - Rehabilitation of Old Landfills Cardiff City Hall / 23 rd - 26 th may 2004 Thierry CHASSAGNAC 11/14 Typical solution for sites in backfilling of old water depressions

NATO CCMS Pilot Study Meeting - Rehabilitation of Old Landfills Cardiff City Hall / 23 rd - 26 th may 2004 Thierry CHASSAGNAC 12/14 Comparison of the costs of rehabilitation to those of the classic treatments 1. Case of sites in spring zone 2. Case of a backfilling of an old water depression  times less high investment costs  1,5 - 5 times less high costs Typical landfill of 2 hectars on 10 meters in thickness ( m 3 ) and having received tons of waste during 20 years

NATO CCMS Pilot Study Meeting - Rehabilitation of Old Landfills Cardiff City Hall / 23 rd - 26 th may 2004 Thierry CHASSAGNAC 13/14  Identical costs to those of a classic cover (600 k€ / 2 ha), supplement from 1 to 3 € / m 2 for organic amendment Treatment of the gas releases (case of the weak production of biogas) : methan oxidation in the cover Treatment of the gas releases (case of the weak production of biogas) : methan oxidation in the cover  Composition of the cover (from bottom to top) screen limiting water input drainage layer of infiltrated waters treatment layer of biogas : zmineral layer zorganic layer zvegetation

NATO CCMS Pilot Study Meeting - Rehabilitation of Old Landfills Cardiff City Hall / 23 rd - 26 th may 2004 Thierry CHASSAGNAC 14/14 Plans of the superficial filtration bed with macrophytes SECTION Surface filtration bed : channel type Surface filtration bed : baffle type DETAIL SECTION Soil baffle PLANE

NATO CCMS Pilot Study Meeting - Rehabilitation of Old Landfills Cardiff City Hall / 23 rd - 26 th may 2004 Thierry CHASSAGNAC 15/14 Plans of the underground filtration bed with macrophytes SECTION PROFILE Low permeability soil Gravel 0-30 Sand 0-10 Control piezometric tubes Distorsion of the clogged zone Clogged zone Piezometric level

NATO CCMS Pilot Study Meeting - Rehabilitation of Old Landfills Cardiff City Hall / 23 rd - 26 th may 2004 Thierry CHASSAGNAC 16/14 Plans of the peripheral lagoon with microphytes

NATO CCMS Pilot Study Meeting - Rehabilitation of Old Landfills Cardiff City Hall / 23 rd - 26 th may 2004 Thierry CHASSAGNAC 17/14 Plan of the lagoon with macrophytes Water level fluctuation zone Macrophytes zone Microphytes zone Macrophytes zone Optional overpit

NATO CCMS Pilot Study Meeting - Rehabilitation of Old Landfills Cardiff City Hall / 23 rd - 26 th may 2004 Thierry CHASSAGNAC 18/14 IN : Raw leachates OUT Phragmites Typha Willows 1 Biological treatment