Arsenic Technologies for Drinking and Industrial Water Treatment

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Arsenic Technologies for Drinking and Industrial
Water Treatment
Project Team Graham Gagnon Ken Reimer Chris
Le William Mohn William Cullen

• November 24, 2005
• Kananaskis Researcher Retreat

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Overall Goal

• This project will address the development and
  potential commercialization of innovative
  chemical and biological arsenic treatment
  technologies.
• End-users
• Rural communities for drinking water
• Mining industry / remediation of contaminated
  sites

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Trail 1904

• TeckCominco Ltd. lead-zinc smelter,Trail, B.C.

Trail 1984

• Nature Works Remediation Corporation contracted
  by TeckCominco to build a prototype biological
  water treatment system

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Research Team

• Key Participants

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Key Challenges/Goals

• 1. Development of innovative chemical treatment
  technologies to remove arsenic from water
• 2. Advancement of the understanding of
  biological treatment systems in order to provide
  recommendations for optimization
• 3. Advancement and applicability of analytical
  speciation methods for arsenic in liquids and
  solids.
• (a) Field speciation of arsenate and
  arsenite that can be translated to the water
  industry
• 4. Characterization of the environmental fate of
  the resulting sludge and recommendations for
  disposal

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Relevant State-of-The-Research

• Drinking Water Treatment
• Several new adsorbents have been developed for
  use in arsenic adsorption systems (i.e., GFH, AA,
  greensand)
• The goal is to develop and evaluate a new
  adsorbent mediasuitable for small-scale arsenic
  treatment
• Wastewater Treatment
• Developing a molecular understanding of
  biological treatment process in Trail, BC
• This will enable future method development work
  with PCR and enable the removal technology to be
  more robust

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Approach

• Combination of bench- and field-scale trials
• Field-scale bioreactor optimization
• Microbial analysis with molecular techniques
• As speciation and detection
• Bench-scale adsorprtion
• Rapid small-scale column tests (RSSCTs)
• XRF, SEM autopsy analysis

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Schematic of Field-Scale Reactor System at Trail,
BC
Input to system
Anaerobic Cell 1 (Anoxic Lime- stone Drain)
Plant Cell 1
Typha Cell
Anaerobic Cell 2
Plant Cell 2
Holding Pond
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Anaerobic Cell

• 600 m3 volume underground
• Celgar material and gravel (60/40)
• Flow enters bottom of cell and exits the top
• STINKS

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Bioreactors
System mimics Trail reactors Arsenic speciation
determined for effluent Initial studies looked
for any volatile emissions
New generation allows for better reproducibility
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Stage of Research

• Drinking Water Treatment
• Project has been commenced and initial batch
  adsorption results are promising
• Laboratory methods have been developed and
  analytical methods development is in progress
• Remediation Aspect
• Initial bioreactor trials completed
• Successfully removed arsenic for several weeks
• Arsenate, arsenite and some methylated species
  found in effluent
• Solid state (synchrotron studies) As-S compounds
  which are oxidized on exposure to air
• Residual material tested for leachability (i.e.
  waste disposal requirements) not hazardous
  waste
• Microbial aspect
• Optimized DNA extraction and PCR amplification of
  DNA from biomass samples from pilot-scale
  bioreactor in Trail. BC.
• Identified that the bacterial community varies in
  a gradient from bottom to top of the reactor.

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Key Findings/Observations

• Drinking Water Treatment
• Preliminary results show that the adsorptive
  media (WTRS) is capable of removing As (III) -
  usually very challenging without an oxidation
  step
• RSSCTs will compare arsenic adsorption between
  new and established materials
• Key questions
• Suitability of adobent material as a drinking
  water treatment material?
• Chemistry of adsorption process?
• Will the residuals from this treatment process be
  classified as hazardous waste?

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Key Findings/Observations

• Remediation
• Using universal bacterial primers for our
  microbiasl analysis, which could ultimately
  identify populations of interest that would be
  worth monitoring with Q-PCR
• Poised to compare bacterial communities in
  further samples from pilot- and lab-scale
  systems, to evaluate correspondence between
  bacterial populations and arsenic transformations
  and to identify key bacterial populations.
• Aim to use cultures (and ultimately primers) to
  develop a drinking water biofiltration system

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Insights on Knowledge Transfer

• At this point KT is occurring within the group
• As biofiltration
• As monitoring systems
• The adsorption media will require thorough
  testing before being marketed to potential
  commercial partners

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Opportunities

• International opportunities particularly with
  Canadian International Development Agency (CIDA)
• Identification of locations with high groundwater
  arsenic concentrations is on-going
• Opportunity for education of rural residents
  about arsenic contamination
• Widely untested in rural and decentralized
  communities

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Collaborative Interests

• Goal would be to be tap into public health
  particularly small-scale systems where arsenic
  may a non-quantified contaminant
• At International level this is of significant
  importance and the team is very interested in
  playing a larger role