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Kelley Simpson
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1 Interntionl Conference Click to edit Mster title style STABILISATION/SOLIDIFICATION TREATMENT AND REMEDIATION Advnces in S/S for Wste Click to nd edit Contminted Mster Lnd text styles April 2005 Cmbridge University UK Second level Third level Fourth level L Floridienne Fifth level The First Lrge Scle Immobilistion Project in Contct: Hven 1025 Fx: Stny Pensert R&D Mnger NV 1

2 Contct: Hven 1025 Fx:

3 Contct: Hven 1025 Fx: History site L Floridienne Production fcilities inorgnic metl compounds: Ferro- nd ferric cynides grey wste tip Led, led chloride nd led crbontes red wste tip In opertion between 1930 nd 1961 Pollution sources: Grey wste tip: gypsum-lime nture. Red wste tip: dust nture. Ruins former production plnt Storge nd smll disposl res round production plnt. 3

4 Pollution sources on site slurry wll Former plnt re Contct: Hven 1025 Fx: Quywll combined with slurry wll Red wste Grey wste Blck wste 4

500-2000 0,05-0,5 Cynide totl 1 mg/l 500

5 Composition min sources Immobilistion trget (DIN S4) Concentrtion mg/kg Red wste Lechbility mg/l Concentrtion mg/kg Grey wste Lechbility mg/l ph , ,5 12,7 Arsenic 1 mg/l ,01-0,05 Led 2 mg/l ,1-0, ,1-10 Zink 10 mg/l ,1-0, ,05-0,5 Cynide totl 1 mg/l 500 0,01-0, Contct: Hven 1025 Fx:

6 Soil contmintion Contct: Hven 1025 Fx: rsenic complex cynides 6

7 Groundwter contmintion Contct: Hven 1025 Fx: Arsenic upper quifer complex cynides upper quifer complex cynides deep quifer 7

8 Hedlines remedition Contct: Hven 1025 Fx: Verticl nd horizontl isoltion soil nd groundwter within site s boundries. Immobilistion lechble wste products nd storge within isoltion. Removl contminted soil outside site s boundries nd storge within isoltion. Pump-nd-tret groundwter contmintion outside site s boundries. Permnent lowering groundwter within site s boundries in order to prevent contct with stored wste nd soil, nd prevent outwrd flow contminted wter. 8

9 Contct: Hven 1025 Fx: Immobilistion red nd grey wste: contrctul obligtions Contrctor is responsible for design nd ppliction immobilistion recipes: only one prty involved. Contrctor hs to gurntee proposed trget levels for immobilistion: - control smples with tender - entrnce exm 200 m³ red nd grey wste % contrct wrd points on immobilistion. - High risk nd libility for contrctor: extremely high penlties for non-conformnce immobilized wste. Miniml geotechnicl stbility within 28 dys: 9 17 MP compressibility modulus

10 Contrctors risks Contct: Hven 1025 Fx: gurnteed most stringent levels 1 mg/l for lixivition rsenic nd cynides. From contrctul side gurntee remins vlid irrespective chemicl qulity wste tht would be encountered in wste tips. The gurnteed execution period ws very short: only 9 months for totl project, which only 4 months for immobilistion: - Prllel mixing red nd grey wste. - mixing plnt cpcities 200 tons n hour. 10

11 Immobilistion red wste Contct: Hven 1025 Fx: Mobile form rsenic is rsente (H 2 AsO 4-, HAsO 4 2- or AsO 4 3- in function ph) or rsenite (AsO 3 3- ). In presence iron vrious interctions with se rsenic compounds cn occur: dsorption nd chemisorption nionic rsenic compounds on positively chrged Fe(OH) 3 Chemicl rection nd crystllistion iron-rsenic compounds on iron oxides. At low ph red wste, ferric rsente will be most fvourble compound to be formed: Fe 3+ + AsO 3-4 FeAsO 4 K = 5.3 x 1020 zerovlent iron 11

12 Immobilistion grey wste: which cynides? Contct: Hven 1025 Fx: Origin: Prussin Blue Fe 4 (Fe(CN) 6 ) 3 At high ph grey wste Prussin Blue is rmodynmiclly unstble nd will dissocite into soluble hexcynerrte Fe(CN) 6 4- nions in pore wter nd Fe(OH) 3. Hrdly no free cynides re present since Fe(CN) 6 4- is strong complex nd n excess ferrous ions is present. 12

13 Contct: Hven 1025 Fx: Immobilistion grey wste: options investigted. Lowering ph mixture in order to stbilize cynides s insoluble Prussin Blue. Fixing cynides with ddition ctionic exchnge resins. Ide from wter tretment plnt s re ionic exchnge is used. Trnsforming wste mtrix to n impermeble cemented mtrix in order to reduce cynide mobility within this mtrix substntilly. Cement & wter repellent dditives 13

14 Red wste: mobile mixing plnt m³ treted 1200 tons zerovlent iron Contct: Hven 1025 Fx:

15 Grey wste: semi-mobile plnt m³ treted tons cement + dditives Contct: Hven 1025 Fx:

16 Contct: Hven 1025 Fx:

17 Results immobilistion Red wste: Arsenic in lechte: 8 mg/l < 0.1 mg/l Efficiency on rsenic: > 98.5 % incresing with time. Efficiency on or metls: > 70 % Contct: Hven 1025 Fx: Grey wste: Cynide in lechte: mg/l 0.15 mg/l Efficiency on cynide: > 99 % 17

18 Finl cpping site: 8 h HDPE 2.5 mm Contct: Hven 1025 Fx:

19 Some dt Strt works: Jnury 2004 End works: September 2004 Costs Preventive mesures (slurry wlls, first wter tretment) Remedition Environmentl consultnt Contct: Hven 1025 Fx: Contrctor TOTAL ( ) (61% for immobilistion)

20 Thnk you for your ttention Questions? Contct: Hven 1025 Fx:

Create a pe ph diagram for the following solid and aqueous iron species:

Create a pe ph diagram for the following solid and aqueous iron species: Assignment 6 Crete pe p digrm for the following solid nd queous iron species: (O) 3 ferrihydrite (O) 3 (O) (O) 3 (O) 4 (O) solid O For solid queous species rections, plot stbility field boundries for queous