Lijun Fan

Lijun Fan, PhD
lijunfan@email.arizona.edu

University of Arizona
CALS
SWES

I'm focused on the fate of arsenic, iron, and sulfur before and after phytostabilization of mine tailings in the effect of redox change simulated in the flow-through columns. Now I have some cation data of the effluents from the column, which was packed of three kinds of tailings (untreated mine tailings, compost treated tailings, and compost + plant treated tailings). I want to know how to use PHREEQC, MODFLOW  or other tools to stimulate flow and reactive transport across the columns.  And I want to analyze the biodiversity of these tailings.

 

Initial Meeting  

I.  Who:

Client: Dr Lijun Fan

Consultants: Elmira, Hahn, Yuan, Phil

II.  When:

September 24, 2019

III.  What:

Executive Summary:

  • Ground water contamination (particularly arsenic) is a worldwide problem and research is occurring on what materials can absorb such contaminates
  • The client has implemented a laboratory experiment to simulate the absorption of arsenic (and other measurements such as pH) under different conditions and different absorption materials
  • The analysis approach for this type of experiment is process-based numerical modeling  using standard structural  models and prior data.  The experimental data is then fitted to the models and posterior parameters are generated based upon best fit to the simulations.
  • It is unclear the extent we can help the client without substantial effort in modeling and software implementation.

 

A.  Summary of Client’s Problem

Dr. Fan's study aims to determine the potential for labile carbon source and non-labile carbon (compost extracted) to affect the mobilization of As/Fe from the phytoremediation Iron King Mine Tailings under redox conditions.

Three mini columns were packed, and a peristaltic pump was utilized to drive a constant upward column through-flow of the sodium lactate solution. Control experiments were carried out by reacting with same electrolyte solution at the same pH (pH=7.0) with the same tailing material.

Characterization of tailings material

  • PCAM (mesquite + 15 % Compost + Tailings)
  • CA (15 % Compost + Tailings, no plants)
  • UA (unamended tailings, no plants, no compost)

The tailings were analyzed for initial physico-chemical characterization of sediments including pH, Eh, electrical conductivity (EC), total organic carbon, S (total), Fe (total), As(total) and water extractable constituents.

Dr. Fan has completed the experiment and requires assistant with putting the results in an informative manner and desires to use the approach documented in the attached paper (Sun 2018)

B.  Discussion

The majority of the discussion was focused upon the design of the experiment and what changed between measurements.  Greater clarity was later gained later on the receipt of a detailed document from Dr. Fan with an experiment description and numerical results.

IV.  Next Steps

  • ​​Write up our understanding of the experiment (in the format of Sun 2018) and share it with Dr. Fan for agreement/explanation.
  • Revisit the results received and see if they can be more clearly presented.
  • Investigate the time and effort to analyze the results in the standard approach and model (as detailed in Sun 2018).
  • Schedule a follow-up meeting the week of October 14.
  • Fan Summary
  • Fan Results
  • Fan Diagram
  • Fan - 2018 Sun Article

 

 

 

 

(Written by Phil)