USE OF SHREDDED END-OF-LIFE TYRES FOR DRAINAGE IN LEACHATE RECIRCULATION TRENCHES, BIOGAS DRAINAGE AND DRAINAGE OF WATER UNDER COVER IN MSW LANDFILLS

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1 USE OF SHREDDED END-OF-LIFE TYRES FOR DRAINAGE IN LEACHATE RECIRCULATION TRENCHES, BIOGAS DRAINAGE AND DRAINAGE OF WATER UNDER COVER IN MSW LANDFILLS Session G13 15:30 17:10 G. DIDIER*, R. MORETTO**, A. BUDKA***, A. de CAZENOVE**** *EEDEMS/LGCIE-INSA de Lyon, Bâtiment J.C. Coulomb, 34 avenue des Arts, Villeurbanne Cedex, France **EEDEMS, 66 boulevard Niels Bohr, BP 2132, Villeurbanne Cedex, France ***SITA FRANCE, 132 rue des 3 Fontanot, Nanterre Cedex, France ****ALIAPUR SA, 71 cours Albert Thomas, Lyon, France With participation of the French Environmental Agency

2 Contents Introduction Shredded tyres size characterization Geotechnical properties : density, compressibility and permeability Mutual impact between leachates and shredded tyres Conclusion 2

3 Introduction

4 Partners, Laboratory ADEME : French Environmental Agency ALIAPUR : Company in charge of the recycling of 85% of the tyres on the French market in 2005; SITA : French waste management company in charge of more than 70 landfills i.e. 7.8 Mt EEDEMS/INSA : Research network specialized in environmental impact assessments of waste, materials and polluted soils and geotechnical approaches 4

5 Use of shredded End-of-Life Tyres (ELT) as drainage materials in MSW landfills Waste Drainage layer 0,5 m Geomembrane Clay 1m (10-9 m/s) Natural soil 5

6 Use of shredded End-of-Life Tyres (ELT) as drainage materials in MSW landfills : available literature data US publications mainly (Geosynthec consultants) : elevated hydraulic conductivity : average = 0.07 m/s equivalent to gravels In needs of complementary information about Performance in relation with the use Puncture behaviour Environmental impacts assessments Design rules / recommendations 6

7 Objectives Program undertaken in a perspective of end-of-life shredded tyres usage in MSW landfills included the assessment of : Physical and mechanical performances of different types of shredded tyres in terms of drainage of water and leachates and of biogas Impact of the use of shredded tyres on the physico-chemical quality of leachate Impact on the physical and mechanical properties of shredded tyres after being in contact with leachates On site design in relation with the characteristics of tested shredded tyres. 7

8 Shredded tyres size characterization

9 Why do we need to characterize the ELT chips? Several American studies exist on the subject often using ASTM Standard D6070 to define the particle size (average size of the chips, size of the reduction process, ) Density? 4 mm 35 mm 50 mm 51mm mm mm mm Permeability Does the term average size means something? How were these measurements done? (dimension of the screens?) Are similar chips sizes available from one production site to another within a country? How are protruding wires evaluated? (visual control?) 9

10 To validate the use of shredded ELT as drainage material, waste management companies and authorities must be sure of the reproducibility of the experiments At first, to measure all the pieces of a sample ALIAPUR developed a manual method, time-consuming and fastidious but efficient In July 2006, AFNOR (French Standardization Body) published a technical standard XP T (available in English on AFNOR website) ALIAPUR identified is own products, representative of the production of the majority of French Operators 10

11 To better improve measurement and evaluation of the protruding wires ALIAPUR developed a automatic method (image processing system - VISIOPUR) VISIOPUR automatically calculate chips dimensions and their protruding wires VISIOPUR edit a report in conformity with the XP T AFNOR Standard (translation in progress) 11

12 Since February 2007, each producer, subcontractors of ALIAPUR, analyses its own production at least once a week 11 VISIOPUR Chambers in France and 2 in Spain Samples weigh 4 to 12 kg in order to obtain more than 100 pieces longer than 20 mm 12

13 Identified possible uses of shredded End-of-Life Tyres (ELT) in MSW landfills Shredded tyres type Bottom leachate drainage layer Leachate recirculation trenches Biogaz drainage Surface run off water drainage Large B x Large A x Medium A x x x x TDF A x x x x A : Passenger Car ELT Tyres B : Trucks ELT Tyres 13

14 In accordance with the XP T (automatic method), the 4 products used for the study have been measured LARGE A and LARGE B characteristics : More than 70 % of chips length are between 50 and 200mm Less than 7 % of chips are over a max of 230mm Less than 5 % of the weight are chips smaller than 20mm MEDIUM A characteristics : More than 70 % of chips length are between 40 and 140mm Less than 7 % of chips are over a max of 160mm Less than 5 % of the weight are chips smaller than 20mm TDF A characteristics : More than 70 % of chips length are between 30 and 80mm Less than 7 % of chips are over a max of 100mm ALIAPUR analyzed for each sample the percentage of pieces of shredded tyres having protruding wires over 30mm: LARGE A: 15% maximum LARGE B: 15% maximum MEDIUM A: 3% maximum TDF A: 3% maximum 14

15 Geotechnical properties : density, compressibility and permeability

16 Geotechnical characterizations : Solids density Tests done in a 30cm-diameter by 50cm height tank including : a cover watertighted with bentonite cement; a piezometer tube to monitor the water level in the tank; A hole to ensure the vacuum Shredded tyres are put in a grid bag before being introduced in the tank. 5 tests were done to ensure the repeatability of the measurement. Gs m Mean density Standard deviation on 5 samples TDF A Medium A 1, Large A Large B

17 Geotechnical characterizations : Compressibility permeability tests Piezometer tubes 1 Hydraulic jack Incremental position sensor Loading plate 158 cm 138 cm 110 cm cm 118 cm 108 cm 98 cm 88 cm 78 cm 100 cm 30 cm 0 : Reference level 48 cm Control valve Meter Pump Banc hydraulique Hydraulic bench 17

18 Geotechnical characterizations : Compressibility tests Example : MEDIUM A (Passenger Car tyres) Stress applied to shredded tyres Medium A put in place in 3 compacted layers. Settlements in relation with the applied stress 18

19 Geotechnical characterizations : Compressibility - permeability Water permeability tests : Step by step compression stress (10 kpa, 20 kpa, 50 kpa, 100 kpa, 200 kpa, 300 kpa, 500 kpa) For each step : hydraulic conductivity was tested with variable load 19

20 Geotechnical characterizations : Results summary Constraint (kpa) Permeability (m/s) Density (kg/m 3 ) Total Porosity (%) Constraint (kpa) Constraint (kpa) 20

21 Geotechnical characterizations : Results σ (kpa) Density (kg/m 3 ) Total porosity (%) Permeability (m/s) LARGE A LARGE B MEDIUM A LARGE A LARGE B MEDIUM A LARGE A LARGE B MEDIUM A n.d n.d n.d n.d n.d n.d «TDF A» 300 kpa Final density (kg/m 3 ) 929 Final porosity (%) 15.5 Final permeability (m/s) Compressibility (%) 64 21

22 Geotechnical point of view Compressibility : whatever type of shredded tyres considered, high compressibility rate observed under low to average levels of stress : most of the tested samples lost 50% of their initial height at the end of the test (30 % for the TDF) Permeability : Shredded tyres permeability do not seem to be impacted by the increase of the stress (# m/s under 10 kpa to 10-5 m/s for an average stress of 300 kpa to 500 kpa). Results in accordance with literature data (Holtz et Kovacs, 1991) in which the lowest measured value is m/s for shredded tyres of 4 mm size under a stress above 350 kpa. Geotechnical information : shredded tyres types LARGE A, LARGE B and MEDIUM A seem to be adapted for uses : At the bottom of a landfill (leachate drainage layer) for a maximum waste mass height of 30 m for the other identified applications without any other criteria 22

23 Mutual impact between leachates and shredded tyres

24 Impact of the shredded ELT on the physicochemical quality of leachate and vice versa : 6 months-experiments Gas Event evacuation gaz Leachates Pompe de recirculation des pumps lixiviats Thermometer Sonde T Sonde Thermometer T Control Chauffage heating thermostaté system Each tank contains 500 kilos of chips in Cuves contact PUNR with + young Lixiviats leachates anciens Recirculation Hot air circulation air chaud Each Cuves tank contains PUNR Lixiviats kilos of chips jeunes in contact with old leachates 24

25 Analytical program For TDF A shredded tyres sample type, determination of the following parameters Sample mass Compressibility Porosity Permeability Leachate quality evolution monitoring after being in contact with shredded tyres Analytical program : ph, BOD, COD, TOC, Conductivity, Phenol, PAH, THC, Heavy metals (As, Ba, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Sn, Zn), CN, Nitrates, Ammonia, Sulfates 25

26 Results Impacts on shredded tyres : «TDF A» «TDF A»- LJ «TDF A»- LV Final density (kg/m 3 ) Final porosity (%) Final permeability (m/s) Compressibility (%) Impacts on leachate quality : No major changes in leachate quality Young leachate more aggressive than mature leachate 26

27 Conclusion

28 General conclusions Mechanical and physical properties in compliance with the French legislation request for drainage layers (K > 10 4 m/s) for Medium A and Large A & B classes of shredded tyres Long term behavior of shredded tyres used as drainage materials in landfill sites : study in progress very positive first results on TDF Impact of shredded tyres on leachate quality : a low impact identified (needs to be confirmed). But no impact on treatability of leachate from a landfill using shredded tyres compared with leachate from standard landfill site. 28