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 12-13 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: +32 3 250 52 53 Stny Pensert R&D Mnger NV 1
Contct: Hven 1025 Fx: +32 3 250 52 53 2
Contct: Hven 1025 Fx: +32 3 250 52 53 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
Pollution sources on site slurry wll Former plnt re Contct: Hven 1025 Fx: +32 3 250 52 53 Quywll combined with slurry wll Red wste Grey wste Blck wste 4
Composition min sources Immobilistion trget (DIN 38414-S4) Concentrtion mg/kg Red wste Lechbility mg/l Concentrtion mg/kg Grey wste Lechbility mg/l ph 4-13 3,82 4 12,5 12,7 Arsenic 1 mg/l 35000-40000 6-8 500-1000 0,01-0,05 Led 2 mg/l 2000-10000 0,1-0,5 10000-25000 0,1-10 Zink 10 mg/l 500-5000 0,1-0,5 500-2000 0,05-0,5 Cynide totl 1 mg/l 500 0,01-0,1 500-8000 10-300 Contct: Hven 1025 Fx: +32 3 250 52 53 5
Soil contmintion Contct: Hven 1025 Fx: +32 3 250 52 53 rsenic complex cynides 6
Groundwter contmintion Contct: Hven 1025 Fx: +32 3 250 52 53 Arsenic upper quifer complex cynides upper quifer complex cynides deep quifer 7
Hedlines remedition Contct: Hven 1025 Fx: +32 3 250 52 53 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
Contct: Hven 1025 Fx: +32 3 250 52 53 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. - 50 % 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
Contrctors risks Contct: Hven 1025 Fx: +32 3 250 52 53 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
Immobilistion red wste Contct: Hven 1025 Fx: +32 3 250 52 53 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
Immobilistion grey wste: which cynides? Contct: Hven 1025 Fx: +32 3 250 52 53 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
Contct: Hven 1025 Fx: +32 3 250 52 53 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
Red wste: mobile mixing plnt 30.362 m³ treted 1200 tons zerovlent iron Contct: Hven 1025 Fx: +32 3 250 52 53 14
Grey wste: semi-mobile plnt 51.537 m³ treted 30000 tons cement + dditives Contct: Hven 1025 Fx: +32 3 250 52 53 15
Contct: Hven 1025 Fx: +32 3 250 52 53 16
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: +32 3 250 52 53 Grey wste: Cynide in lechte: 10 300 mg/l 0.15 mg/l Efficiency on cynide: > 99 % 17
Finl cpping site: 8 h HDPE 2.5 mm Contct: Hven 1025 Fx: +32 3 250 52 53 18
Some dt Strt works: Jnury 2004 End works: September 2004 Costs Preventive mesures (slurry wlls, first wter tretment) Remedition 7.400.000 Environmentl consultnt 850.000 Contct: Hven 1025 Fx: +32 3 250 52 53 Contrctor TOTAL ( ) (61% for immobilistion) 11.000.000 19.250.000 19
Thnk you for your ttention Questions? Contct: Hven 1025 Fx: +32 3 250 52 53 20