Optimizing re me dia tio n a ppro a c he s Optimizing re me dia - PowerPoint PPT Presentation

Optimizing re me dia tio n a ppro a c he s Optimizing re me dia tio n a ppro a c he s a t mine site s: ho w unde rsta nding b io g e o c he mic a l pro c e sse s a nd b io g e o c he mic a l pro c e sse s a nd mo de ling c a n g uide mine tre a tme nt K a te Ca mpb e ll US Ge o lo g ic a l Surve y Bo ulde r, CO

Me ta l tre a tme nt stra te g ie s Me ta l tre a tme nt stra te g ie s  Pump and Treat/ Conventional water treatment facilities treatment facilities  Groundwater and/or surface water treatment  Ion exchange, reverse osmosis, lime addition, etc.  Constructed wetlands, covers  Surface water Photo credit: Mike Hay  Mine wastes  I In Situ approaches - groundwat Sit ter  Reduction [U(VI)  U(IV)]  Biological: Organic carbon injection  Chemical: Sulfide injection  Chemical: Sulfide injection  Mineral Precipitation  Soluble phosphate injection ARCADIS, 2013  I In Situ : Reacti Sit tive B Barri iers

Me ta l mo b ility: impo rta nc e o f re do x Me ta l mo b ility: impo rta nc e o f re do x pH E ffe c t o f pH – re do x– lig a nds o n me ta l mo b ility Me ta l Me ta l- 1. E q uilib rium o xida tio n b inding sta te lig a nds g 2. Dise q uilib rium Dise q uilib rium yxwvutsrponmlihgfedcbaSRPOMLKIHGFDA Oppo rtunity fo r b io tic pro c e sse s K ine tic s o f re a c tio ns impo rta nt Mineral precipitation/dissolution and precipitation/dissolution and adsorption Mining and r e me diation ofte n pe r pe r tur tur bs r bs r e dox state of syste m e dox state of syste m

F F unda me nta l pro c e sse s a nd mo de ling n da me nta l pro c e sse s a nd mo de ling  I mpro ve mo de ling b y inc re a sing funda me nta l b io g e o c he mic a l pro c e sse s  I de ntify ke y re a c tio ns  Re a c tio n K ine tic s vs. e q uilib rium  Mic ro b ia l pro c e sse s  Pre c ipita tio n

Code: PHREEQC Bio g e o c he mic a l mo de ling

Co mple xity: la b o ra to ry  fie ld Co mple xity: la b o ra to ry  fie ld F F i ld ie ld L a b o ra to ry Ba tc h re a c to rs Ba tc h re a c to rs yxwvutsrponmlihgfedcbaSRPOMLKIHGFDA Pure c ulture s (b a c te ria ) I n situ e xpe rime nts Synthe tic wa te r Pure mine ra l pha se s Pilo t a nd full- Co lumn e xpe rime nts sc a le Mic ro b ia l c o mmunity Mic ro b ia l c o mmunity tre a tme nt/ re Site -spe c ific so lids me dia tio n He te r He te r oge ne ity oge ne ity Ke y pr oc e sse s R ate s and c omple xity

Ca se studie s Ca se studie s  Ca se study 1: Bio re me dia tio n o f a ura nium-c o nta mina te d a q uife r  Ca se study 2: Re mo va l o f disso lve d ura nium a nd surfa c e pa ssiva tio n o f o re b y pho spha te a me ndme nt  Ca se study 3: Ac id mine dra ina g e (AMD) pipe line sc a ling

Ca se study 1: Bio re me dia tio n a t Rifle , CO Ca se study 1: Bio re me dia tio n a t Rifle CO ) + sulfa te  F F e (I ( ) I I e (I ( ) I )-sulfide s ) (a q )  U(I U(VI V) (s)

zyxwvutsrqponmlkihgfedcbaXWVUTSRPONMLKJIHGFEDCBA In situ e xpe rime nt: U(I In situ e xpe rime nt: U(I V) re o xida tio n V) re -o xida tio n ra te s windows UO 2 Bio ma ss, o the r surfa c e re a c tio ns re ta rd o xida tive disso lutio n Ca mpb e ll, K M, e t a l., E S&T 2011, Ba rg a r e t a l., PNAS 2013

F ie ld-sc a le Bio re me dia tio n Mic ro b ia l U(VI Mic ro b ia l U(VI ) F ), F e (I e (I I I I I ), ) sulfa te re duc tio n Re mo va l: U, V, Se I I nc re a se : As A Geobacter spe c ie s we re SRB do mina nt during F e (I I I ) Geobacter a nd U(VI ) re duc tio n Po pula tio n shifte d to p sulfa te re duc e rs Anderson et al., AEM 2003

Ca se study 2: Pho spha te a me ndme nt 2 O  Ca 5 (PO 4 ) 3 OH + 4H 5Ca +2 + 3HPO 4 -2 + H + Hydr oxylapatite -3  H + + 2UO 2 +2 + 2PO 4 2H 2 (UO 2 ) 2 (PO 4 ) 2 Autinite 2 4 2 2 2 4 2  Pho spha te a me ndme nt e ffe c tive a s U(VI U(VI ) tre a t ) t tme nt t  Ca n Ca -PO4 pre c ipita tio n pa ssiva te pa ssiva te surfa c e o f U(I surfa c e o f U(I V) o re s? V) o re s?

Ra te s f re c ipita tio n a nd o xida tio n Ra te s o f pre c ipita tio n a nd o xida tio n o p Ne xt ste p: U o re c o lumn studie s

Ura nium re me dia tio n: c a se study 1&2 U i di ti t d 1&2  Bio re me dia tio n – re duc ing c o nditio ns  Cha lle ng ing to c o ntro l mic ro b ia l c o mmunity  Pho spha te a me ndme nt – o xidizing o r re duc ing c o nditio ns  Pa ssiva tio n o f U(I V) surfa c e s ma y pre ve nt c o ntinue d o xida tio n  Co mb ine d b io re me dia tio n/ pho spha te a me ndme nt  Applic a tio n:  I n situ re c o ve ry (I SR mine s)  Co nve ntio na l mining  L L e g a c y site s e g a c y site s

Ca se study 3: a c id mine dra ina g e Ca se study 3: a c id mine dra ina g e Sac r Sac r ame nto ame nto L e viathan Mine Ir on Mtn Mi Mine Map Ar e a

Pre c ipita tio n in AMD pipe line s – “sc a le ” Iron Mountain Mine Leviathan Mine Pipe sc a le re q uire s c o stly c le a n-o ut a t I Pipe sc a le re q uire s c o stly c le a n o ut a t I MM e ve ry 2 4 ye a rs a nd MM e ve ry 2-4 ye a rs, a nd c o mple te re pla c e me nt o f pipe s a t L M e ve ry ye a r – c ommon pr oble m in AMD pipe line s

Wa te r c he mistry a t I ro n Mo unta in Mine pH = 0.5-0.8 F e = 12,000 mg / L Sulfa te = 49,000 mg / L F e (I I I ) F e (I I ) F e (T ) SS2 18 mg / L g pH 2.96 950 mg / L 1111 mg / L pH 2.62 1034 mg / L 1028 mg / L pH 2.63 pH 2.71 977 mg / L pH 2.73 pH 2 73 962 mg / L 962 mg / L pH 2.74

Me c ha nism o f sc a le fo rma tio n only = Bio tic F e (I I ) o xida tio n Wate r Unfilte r e d + sc ale = Bio tic F e (I I ) o xida tio n, e ffe c t Wate r wate r o f sc a le 0.1 μ m ol = Ab io tic F e (I I ) Contr filtration o xida tio n o xida tio n Iron Mountain Mine and Leviathan Mine and Leviathan Mine samples

Me c ha nism o f sc a le fo rma tio n Dissolve d F e (II) 30 Ab io tic 25 c o ntro ls 20 20 e (II) mM 15 Unfilte re d wa te r wa te r F 10 5 Unfilte re d wa te r + sc a le Unfilte re d wa te r + sc a le 0 0 20 40 60 80 100 ti time (hour (h s) ) F e (II) oxidation pH< 5 is a biotic pr oc e ss

Sc a le c ha ra c te riza tio n XRD, SE M de io nize d wa te r L e ast aggr e ssive We t c he mic a l e xtra c tio ns 0.2M a mmo nium o xa la te 0.5M HCl T o ta l e le me nta l dig e stio n 0.5M HCl 0.5M hydro xy yla mine HCl C a nd N a na l sis C a nd N a na lysis M Most aggr t e ssive i Mic ro b ia l c o mmunity: Mic ro b ia l c o mmunity: • 16S rDNA b y 454-pyro se q ue nc ing Sc hwe r tmannite e 8 O 8 (OH) 6 SO 4 ) and • F e -o xidizing b a c te ria (MPNs) (F Goe thite (F e OOH) reference compounds

Sc a le c ha ra c te riza tio n Sc hwe r tmannite (br oad pe ak) + goe thite c o rundum inte rna l sta nda rd % Goe thite Goe thite Sc hwe rt. SS12 98.9% SS10 97.7% SS8 SS8 97.5% SS6 SS6 98.1% Bulk mineralogy is similar in all scale: Prima rily Sc hwe r Prima rily Sc hwe r tmannite [ide a l tmannite [ide a l e 8 O 8 (OH) 6 SO 4 ] with c o mpo sitio n: F minor Goe thite [F e OOH]

Ge o c he mic a l mo de l – b a tc h e xpe rime nts 0.03 0 03 3 0.025 2.8 M) 0 02 0.02 e (II) (M 2.6 pH 0.015 2.4 0.01 zyxwvutsrqponmlkihgfedcbaXWVUTSRPONMLKJIHGFEDCBA F 2.2 0.005 0 2 0.03 0 50 100 150 200 250 0 50 100 150 200 250 0.025 time (hour s) • Kine tic s for ) (M) Kine tic s for mic r mic r obial F obial F e (II) e (II) 0 02 0.02 oxidation 0.015 e (T - Ba se d o n Mic ha e lis-Me nte n 0.01 F e nzyme kine tic s e nzyme kine tic s - K ine tic s de pe nds o n sub stra te 0.005 (F e (I I )) a nd c e ll c o nc e ntra tio n 0 • Kine tic ally c ontr Kine tic ally c ontr olle d olle d 0 50 50 100 100 150 150 200 200 250 250 sc hwe r tmannite pr e c ipitation time (hour s)

Ge o c he mic a l mo de l – fie ld o b se rva tio ns -03 SS12 03 SS12 3.0E 3 0E “Slug”- style inje c tion of Dotted = field data c onse r vative tr ac e r L i Solid = model SS10 2.5E -03 SS8 • T T ra ve l time s ra ve l time s • Dispe rsivity SS6 2.0E -03 • 3 flo w re g ime s: i (M) SS2 1 5E 1.5E -03 03 • 75 g pm (4 7 L 75 g pm (4.7 L / s) / s) L • 150 g pm (9.5 L / s) / s) 1.0E -03 • 1075 g pm (67.8 L 5.0E -04 0.0E +00 0 20 40 60 80 100 120 time (min) > Va ria b le ve lo c ity in e a c h se c tio n o f pipe line > Va ria b le ve lo c ity in e a c h se c tio n o f pipe line

Re me dia tio n te st 1: inc re a se d flo w 90% 80% 70% 60% e (II) ) 50% PW3 o nly 75 g pm % F 150 g pm PW3 o nly 40% 1075 g pm PW3 + SCRR 30% 30% ywvutsrponmlkjihgfedcbaWUTSMLIHGFEDC 20% 10% 0% SS12 SS10 SS8 SS6 SS2 • • Do ub ling flo w fro m 75 to 150 g pm slig htly de c re a se d a mo unt o xidize d Do ub ling flo w fro m 75 to 150 g pm slig htly de c re a se d a mo unt o xidize d • Hig he st flo w ra te (1075 g pm) slo we d F e (I I ) o xida tio n  Mode l c an be use d to simulate e ffe c t of r unning pipe line at highe r flow r flow r ate s ate s  E ffe c t on tr e atme nt plant ope r ations