Atkinson, A.

Claisse, Peter A.

Dewnap, S.

Ganjian, Eshmaiel

Tyrer, M.

Waste materials have been used in concrete for many years, a typical example being fly ash from coal-fired power stations. The novel aspect of the concrete used in the work described in this presentation is that it is made entirely from industrial waste with no other materials except water. The resulting performance is not appropriate for use in typical structural applications but is well suited to waste containment. Research in the nuclear industry has shown that cementitious materials offer many benefits for waste containment. Concrete has, however, not previously gained acceptance as a material for the construction of mineral liners because of concerns over high cost. This project exploits recent changes in the regulatory and economic environment to overcome these concerns. In this presentation a programme to develop concrete landfill barriers will be described and the elements of the safety case for them will be presented. The safety case is based on predicting the transport of harmful species through the barrier. A model has been developed for the transport processes and, using data from laboratory tests, it has been validated against observations from site trials that have been in progress for the last five years. Each of the elements of the safety case will be introduced: - Laboratory tests for permeability, diffusion, adsorption and physical properties. - Site trials. - The computer model and validation of the model using the test cells and other codes. - Leaching from the barrier. - Long term chemical stability of the barrier itself. - Cracked samples. - Modelling transport in the new barrier and flow into the local environment

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 Coventry University    Coventry University Repository for the Virtual Environment (CURVE)  Author names:  Claisse, P.A., Ganjian, E. , Tyrer, M. , Atkinson, A. and Dewnap, S. Title: Waste to contain waste – containment systems for pollution prevention Article & version: Presented version of powerpoint slides  Original citation & hyperlink: Claisse, P.A. , Ganjian, E. , Tyrer, M. , Atkinson, A. and Dewnap, S. (2004, April). Waste to contain waste – containment systems for pollution prevention. Paper presented at the SCI conference: waste materials in construction, London UK.     Copyright © and Moral Rights are retained by the author(s) and/ or other copyright owners. A copy can be downloaded for personal non-commercial research or study, without prior permission or charge. This item cannot be reproduced or quoted extensively from without first obtaining permission in writing from the copyright holder(s). The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the copyright holders.  Available in the CURVE Research Collection: November 2012    http://curve.coventry.ac.uk/open  Novel Composite Landfill Liners MIRO Imperial College of Science,  Technology and Medicine         Prof. Alan Atkinson        Dr. Mark Tyrer Coventry University      Dr. Peter Claisse    Dr. Esmaiel Ganjian Minerals  Industry  Research Organisation       Research Co-ordinator: Alan Gibbon PSD  Associates   Sam Dewsnap S C I 1 April 2004 Chapter 1: Introduction   Chapter 2:  Materials and mix characteristics   Chapter 3: Laboratory test methods   Chapter 4: Site trials   Chapter 5: The Coventry computer model   Chapter 6: Validation of Coventry University model.   Chapter 7: Long term chemical stability of the barrier   Chapter 8: Physical stability of the barrier   Chapter 9:  Modelling transport in the Poplars site    Chapter 10: Landsim-2   Chapter 11: Quality assurance of the new barrier   Chapter 12: Work in progress  General description of barrier  • Current Barrier System: 30mm thick “Bentomat” geotextile with bentonite infill on 1 m of milled and compacted existing clay.  • Basic Design:  300mm concrete on 0.5 m of milled and compacted clay.  • Approximate area:   One hectare.  The principal intended benefits of the new barrier  • Low permeability combined with high cation exchange capacity to give improved containment. • Construction from waste materials which would otherwise go into landfills. • A relatively hard concrete surface to permit operation of vehicles and to prevent damage from large items of waste compacted onto it.  Chapter 1: Introduction   Chapter 2:  Materials and mix characteristics   Chapter 3: Laboratory test methods   Chapter 4: Site trials   Chapter 5: The Coventry computer model   Chapter 6: Validation of Coventry University model.   Chapter 7: Long term chemical stability of the barrier   Chapter 8: Physical stability of the barrier   Chapter 9:  Modelling transport in the Poplars site    Chapter 10: Landsim-2   Chapter 11: Quality assurance of the new barrier   Chapter 12: Work in progress  Candidate materials (1) • Sodium sulphate slag (Britannia Refined Metals Ltd.) • Spent borax slag (Britannia Refined Metals Ltd.) • Ferrosilicate slag (lumps from Britannia Refined Metals Ltd. sand size from Britannia Zinc Ltd.) • Ferrosilicate copper slag (IMI Refiners Ltd.) • Soda slag (Britannia Refined Metals Ltd.) • Chrome Alumina slag (London & Scandinavian Metallurgical Co. Ltd.) • Cement Kiln Dust ,CKD (Rugby Cement) • Run of station ash (Ash Resources Ltd.) • Lagoon ash (UK quality Ash Association) • PFA (Ash Resources Ltd.) • Steel slag (Tarmac Quarry Products Ltd.) • Granulated Blast Furnace Slag, GBS (Tarmac Quarry Products Ltd.)  Candidate materials (2) • Burnt Oil Shale (Tarmac Quarry Products Ltd.) • By-product Gypsum (Biffa Waste Services Ltd.) • Glass cullet (Mercury Recycling Ltd.) • GGBS (Ground granulated blastfurnace slag) • Limex70 (British Sugar Plc.) • Shell foundry sand (Bruhl UK Ltd., Hepworth Minerals & Chemicals Ltd.) • Green foundry sand (Castings Plc. And Bruhl UK Ltd.) • Fire kettle setting (Britannia Refined Metals Ltd.) • Fine rotary fascia bricks (Britannia Refined Metals Ltd.) • Sodium sulphate solution (Britannia Refined Metals Ltd.)   Material  Kg/m3  Total quantity Tonnes  Cement Kiln Dust  150  450  Steel slag Dust  (0-5mm)  700  2100  Conditioned ash  150  450  Shell sand  700  2100  Candidate Mix Design Chapter 1: Introduction   Chapter 2:  Materials and mix characteristics   Chapter 3: Laboratory test methods   Chapter 4: Site trials   Chapter 5: The Coventry computer model   Chapter 6: Validation of Coventry University model.   Chapter 7: Long term chemical stability of the barrier   Chapter 8: Physical stability of the barrier   Chapter 9:  Modelling transport in the Poplars site    Chapter 10: Landsim-2   Chapter 11: Quality assurance of the new barrier   Chapter 12: Work in progress  The High Pressure Through Flow Cell Water outlet Water inlet Drainage Plates Perforated disc Concrete Sample Hydraulic oil High pressure permeability measurement Narrow cracks induced in the mortar disc  Composite clay and concrete sample for high pressure test  Cracked sample after clay has sealed the cracks  The Diffusion Cells Chapter 1: Introduction   Chapter 2:  Materials and mix characteristics   Chapter 3: Laboratory test methods  Chapter 4: Site trials   Chapter 5: The Coventry computer model   Chapter 6: Validation of Coventry University model.   Chapter 7: Long term chemical stability of the barrier   Chapter 8: Physical stability of the barrier   Chapter 9:  Modelling transport in the Poplars site    Chapter 10: Landsim-2   Chapter 11: Quality assurance of the new barrier   Chapter 12: Work in progress  The Site Trial Cells Clay Concrete Concrete Waste Liquid waste (sodium sulphate) Concrete in cell 1 Filled cell ready for cover Sampling lines The purpose of the trial cells  • To  provide validation data for the modelling of the performance of the barriers in service. • To demonstrate a construction method. • To demonstrate that the novel mixes can be made in industrial quantities (150t of concrete was used in the three test cells). • To provided samples for on-site workability testing and long-term physical testing in the lab. • To provide samples for mineralogical analysis when the cells are dismantled.  Chapter 1: Introduction   Chapter 2:  Materials and mix characteristics   Chapter 3: Laboratory test methods   Chapter 4: Site trials   Chapter 5: The Coventry computer model   Chapter 6: Validation of Coventry University model.   Chapter 7: Long term chemical stability of the barrier   Chapter 8: Physical stability of the barrier   Chapter 9:  Modelling transport in the Poplars site    Chapter 10: Landsim-2   Chapter 11: Quality assurance of the new barrier   Chapter 12: Work in progress  Mechanisms used in calculation  • Advection in which the pressure of the leachate head causes water flow which carries dissolved ions through. • Diffusion in which the dissolved ions move through the water at a rate determined by the pressure gradient. • Linear adsorption in which a fixed proportion of the dissolved species are assumed to be immobile Applications of the model • The high pressure through-flow test • The diffusion test • The “8m” site trial cells at Risley • The “100m” barrier to be built at Poplars  Chapter 1: Introduction   Chapter 2:  Materials and mix characteristics   Chapter 3: Laboratory test methods   Chapter 4: Site trials   Chapter 5: The Coventry computer model   Chapter 6: Validation of Coventry model.   Chapter 7: Long term chemical stability of the barrier   Chapter 8: Physical stability of the barrier   Chapter 9:  Modelling transport in the Poplars site    Chapter 10: Landsim-2   Chapter 11: Quality assurance of the new barrier   Chapter 12: Work in progress  Fig. 6.4: Modelled 'K' concentration Vs. time in Diffusion cell for top layer mix of site cell 2 &3.05001000150020002500300035000.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16Time (years)Conc. (ppm)Model input conc.Model output conc.Experimental inputExperimental outputResults from laboratory diffusion test Fig. 6.11 : Modelled and experimental 'K' concentration Vs. time at different levels in site trial cell no. 2.02000400060008000100001200014000160000 1 2 3 4 5 6 7 8 9 10Time (year)Cs (ppm)Model top of clayModel bottom of clayExperimental top of clayExperimental bottom of clayResult from site trial Chapter 1: Introduction   Chapter 2:  Materials and mix characteristics   Chapter 3: Laboratory test methods   Chapter 4: Site trials   Chapter 5: The Coventry computer model   Chapter 6: Validation of Coventry University model.   Chapter 7: Long term chemical stability of the barrier   Chapter 8: Physical stability of the barrier   Chapter 9:  Modelling transport in the Poplars site    Chapter 10: Landsim-2   Chapter 11: Quality assurance of the new barrier   Chapter 12: Work in progress   Locations for the barrier  • Horizontal:  Failure by compression or punching shear. • 30 degree slope:  Compression and buckling • Vertical:  Compression and buckling  30 degree slope  • Slope length of 50m is considered giving a depth of 25m  • Before emplacement of waste: Assuming no friction with the substrate gives a  stress of 0.57 MPa in the concrete. • Waste emplaced: Assuming no slippage of the waste above the liner (very high friction) and the shear strength of the clay under the liner is 50 kPa gives a stress of 5MPa in the concrete.   Chapter 1: Introduction   Chapter 2:  Materials and mix characteristics   Chapter 3: Laboratory test methods   Chapter 4: Site trials   Chapter 5: The Coventry computer model   Chapter 6: Validation of Coventry model.   Chapter 7: Long term chemical stability of the barrier   Chapter 8: Physical stability of the barrier   Chapter 9:  Modelling transport in the Poplars site    Chapter 10: Landsim-2   Chapter 11: Quality assurance of the new barrier   Chapter 12: Work in progress  Use of CU model • Uses results from lab tests for diffusion and permeability • Validation from Risley trials • Uses linear adsorption isotherm. • Models 300mm concrete on 500mm clay Fig. 9.1 : Modelled 'Ca' concentrations for multi layer and clay only barriers using site leachate. 05001,0001,5002,0002,5003,0003,5004,0000 100 200 300 400 500 600Time (years)Cumulative output (g/m2)300 mm mortar + 500 mm clay800mm clay only300 mm mortar onlyOutput from CU model Fig. 9.6: Modelled 'Pb' concentrations for multi-layer and clay only barriers using toxic leachate.0.0500.01000.01500.02000.02500.03000.03500.04000.04500.05000.00.0 20.0 40.0 60.0 80.0 100.0 120.0 140.0 160.0Time (years)Cumulative output (g/m2)300mm motar + 500mm clay800mm clay only300mm mortar only30mm GCB + 500mm clayOutput from CU model Cumulative mercury outflow vs time02E-404E-406E-408E-401E-391.2E-391.4E-390 50 100 150 200 250 300Time / yearsCumulative total Hg / moles per square metreOutput from PHREEQE model Chapter 1: Introduction   Chapter 2:  Materials and mix characteristics   Chapter 3: Laboratory test methods   Chapter 4: Site trials   Chapter 5: The Coventry computer model   Chapter 6: Validation of Coventry University model.   Chapter 7: Long term chemical stability of the barrier   Chapter 8: Physical stability of the barrier   Chapter 9:  Modelling transport in the Poplars site    Chapter 10: Landsim-2   Chapter 11: Quality assurance of the new barrier   Chapter 12: Work in progress  Quality Assurance of the Barrier  • Generally follow the quality procedure for the geosynthetic barrier system. • Concrete cubes shall be made to EN12390 part 1  • Permeability may be measured to EN12390 part 8 if accompanied by an approved method of calculation to yield results in m/s or other approved method. Chapter 1: Introduction   Chapter 2:  Materials and mix characteristics   Chapter 3: Laboratory test methods   Chapter 4: Site trials   Chapter 5: The Coventry computer model   Chapter 6: Validation of Coventry University model.   Chapter 7: Long term chemical stability of the barrier   Chapter 8: Physical stability of the barrier   Chapter 9:  Modelling transport in the Poplars site    Chapter 10: Landsim-2   Chapter 11: Quality assurance of the new barrier   Chapter 12: Work in progress   Work plan  • Respond to input from the EA • Refine the input data to the Coventry model to provide a better explanation of the 8m trial cells and use this data to improve the modelling of the 100m cell. • Extend the application of PHREEQE to provide increased experimental validation. 

Waste to contain waste – containment systems for pollution prevention

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Waste to contain waste – containment systems for pollution prevention

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