Anaerobic Biochemical Reactor (BCR) Treatment of Mining-Influenced - - PowerPoint PPT Presentation

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Anaerobic Biochemical Reactor (BCR) Treatment of Mining-Influenced - - PowerPoint PPT Presentation

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Anaerobic Biochemical Reactor (BCR) Treatment of Mining-Influenced Water (MIW): EvaluaAon of ReducAon in ConcentraAons of Metals and AquaAc Toxicity Presented in Webinar Series: FRTR Presents...Heavy Metals-Mining Site Characteriza:on and

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Office of Research and Development

  • Dr. Barbara Butler, USEPA

July 26, 2016

FRTR Presents...Heavy Metals-Mining Site Characteriza:on and Treatment Session 2

Anaerobic Biochemical Reactor (BCR) Treatment of Mining-Influenced Water (MIW): EvaluaAon of ReducAon in ConcentraAons of Metals and AquaAc Toxicity

Presented in Webinar Series:

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The views expressed in this presenta0on are those of the author’s and do not necessarily represent the views or policies of the U.S. Environmental Protec0on Agency.

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  • BCR Treatment
  • Research Ques0ons
  • Study Sites
  • Methods
  • Metals Removal
  • Aqua0c Toxicity (Acute)
  • Concluding Remarks

PresentaAon Outline

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  • Passive / semi-passive treatments

§ May be completely anaerobic, aerobic, or combina0on of both § Natural processes § Minimal or no energy requirement

  • Solar power has been used
  • Anaerobic biochemical reactor

§ Previously (and some0mes s0ll) called sulfate-reducing bioreactor

  • A primary mechanism is microbial sulfate reduc0on to sulfide that

precipitates metal sulfides

§ Some0mes called anaerobic wetland

  • But, no vegeta0on

BCR Treatment

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  • Chemical, biological, and physical processes

§ Reduc0on, precipita0on, adsorp0on, reten0on

  • Hay, straw, wood chips, sawdust, compost, limestone, manure,

ethanol, waste milk…

  • Aerobic polishing

§ Increase oxygen § Decrease biochemical oxygen demand (BOD) § SeTle solids

  • Some release of sulfide precipitates, which will oxidize and re-

precipitate as metal oxyhydroxides

§ Degas sulfide and ammonia

BCR Treatment

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  • Overall goal of remedia0on is to minimize environmental and

human health impacts

  • Evalua0on of BCR treatment generally through metal removal

efficiency

§ Percentage of dissolved metals removed by the system

  • 100% * [(influent concentra0on – effluent concentra0on) / influent

concentra0on]

BCR Treatment

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  • Are the effluents from the different pilot BCRs toxic (i.e., are

there adverse effects to either test species that is sta0s0cally different from control water)?

  • Is the toxicity reduced, rela0ve to the influent?
  • If effluents are toxic, is a toxicant iden0fiable?

Research QuesAons Asked

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  • LuTrell Repository, Helena, MT
  • Peerless Jenny King, Helena, MT
  • Park City Biocell, Park City, UT
  • Standard Mine, Crested BuTe, CO

Study Sites

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  • Upper Ten-Mile Creek Superfund site
  • 7,644 h AMSL
  • 2002
  • 1.5 gpm treated
  • Al, As, Cd, Co, Cu, Fe, Mn, Zn

LuLrell Repository, MT

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  • Upper Ten-Mile Creek Superfund site
  • 7,600 h AMSL
  • 2003
  • 20-25 gpm treated
  • Cd, Fe, Zn

Peerless Jenny King, MT

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Sampling hose

  • Upper Ten-Mile Creek Superfund site
  • 7,600 h AMSL
  • 2003
  • 20-25 gpm treated
  • Cd, Fe, Zn

Peerless Jenny King, MT

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  • Prospector drain in Silver Creek Watershed
  • 2002
  • 6,900 h AMSL
  • 29 gpm treated
  • Cd, Zn

Park City Biocell, UT

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  • Prospector drain in Silver Creek Watershed
  • 2002
  • 6,900 h AMSL
  • 29 gpm treated
  • Cd, Zn

Park City Biocell, UT

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  • Crested BuTe
  • 2007
  • 11,000 h AMSL
  • 1.2 gpm treated
  • Cd, Cu, Fe, Pb, Mn, Zn

Standard Mine, CO

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  • Crested BuTe
  • Aerobic polishing cells added in 2008

Standard Mine, CO

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Methods

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  • Triplicate influent and effluent samples from LuTrell, PJK, and

Park City

  • Duplicate influent and effluent samples from the Standard Mine

BCR and from the APC

Methods

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  • Filtered metals (0.45 µm) – induc0vely coupled plasma – op0cal

emission spectroscopy (ICP-OES)

  • Sulfate – ion chromatography
  • Total sulfide – ion selec0ve electrode
  • Total ammonia – gas sensing electrode

Methods

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  • Whole effluent toxicity tests [WET]

§ Series of dilu0ons of the influent and effluent water samples

  • Acute 48-hr LC50

§ Percentage of water mixed with moderately hard dilu0on water

  • Ceriodaphnia dubia [water flea]
  • Pimephales promelas [fathead minnow]

§ Control survival > 90%

Methods

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Results - Metals

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Influent Metals ConcentraAons

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Influent & Effluent pH and DO

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Percentage of Metals Removed

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Results - Acute AquaAc Toxicity

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Effluent samples more toxic to fathead minnow Influent samples more toxic to water flea Highest dilu0on volume tested (25%) had 35% mortality LC50 below lowest volume tested < 0.1%

Gray – water flea Black – fathead minnow

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Not different from control Influent samples more toxic to water flea

Gray – water flea Black – fathead minnow

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Not different from control Influent samples more toxic to water flea Highest dilu0on volume tested (20%) 35-45% mortality

Gray – water flea Black – fathead minnow

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Not different from control

Gray – water flea Black – fathead minnow

1% 2% 35% mortality BCR effluent samples more toxic to fathead minnow than to the water flea Influent samples more toxic to water flea

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  • What caused acute toxicity in LuTrell and Standard Mine BCR

effluent samples?

  • Low dissolved oxygen?

§ SM-BCR field average 0.6 mg/l DO; LuTrell field average 0.3 mg/l DO § Test units must have > 4 mg/l

  • Generally > 6 mg/l
  • Metals, sulfide, ammonia?

Acute AquaAc Toxicity

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Acute AquaAc Toxicity

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Effect of Aeration

20 40 60 80 100 L R

  • A

L R

  • B

L R

  • C

L R

  • A

a e r a t e d L R

  • B

a e r a t e d L R

  • C

a e r a t e d S M

  • A

S M

  • B

S M

  • A

a e r a t e d S M

  • B

a e r a t e d

Sample ID Percent Survival (100% sample)

~2% ~66% <20%

Test species: fathead minnow

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Reference Toxicity Levels 2 ug/l H2S .2 to 5 mg/l NH3

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Reference Toxicity Levels 2 ug/l H2S .2 to 5 mg/l NH3

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  • Results suggest toxicity from dissolved hydrogen sulfide gas

§ Effluents more toxic to fathead minnow than to the C. dubia § Fathead minnow known to be more sensi0ve to dissolved gases than

  • C. dubia

§ Dissolved H2S concentra0ons above species mean acute values § Toxicity from 100% sample removed with aera0on at Standard Mine and reduced at LuTrell

  • Other BCRs may have different toxicants, depending on:

§ Contaminants present and efficiency of removal § Concentra0ons of dissolved gases and pH of the effluent

Concluding Remarks

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  • BCR treatment is effec0ve at removing significant propor0ons of

metals from MIW, but aqua0c toxicity may s0ll be present

  • Sufficient in-field aera0on following BCR treatment is an

important step to remove poten0al toxicants resul0ng from the processes occurring within the BCR cells

  • Combining chemical and biological monitoring can lead to beTer

treatment system designs

§ To meet the goal of minimizing environmental and human health impacts

Concluding Remarks

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  • Co-authors:

§ David Reisman – U.S. EPA ORD (re0red) § Jim Lazorchak – U.S. EPA ORD, NERL § Mark Smith – McConnell Group [deceased, prior contractor to U.S. EPA ORD]

  • Others:

§ Pegasus and McConnell Group – contractors to EPA § Regional RPM’s § City of Park City, UT

Acknowledgements

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Butler, BA, Smith, ME, Reisman, DJ, Lazorchak, JM. 2011. Metal removal efficiency and ecotoxicological assessment of field-scale passive treatment biochemical

  • reactors. Environmental Toxicology & Chemistry. 30(2):385-392.

Thank you!

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