1. Modeling Phytoremediation of Heavy Metal Contaminated Mine Spoil Dumps
Parikshit Verma
EIA and Sustainability Assessment – Asian EIA and Effective Tool Development
Seol, Korea,
June 5, 2007
National Environmental Engineering Research Institute (NEERI), Nagpur

2. Barren Manganese Mine Spoil Dump

3. After 10 years - Revegetated Manganese Mine Spoil Dump

4. Definitions / Terminology
Phytoremediation
Use of plants / vegetation for in situ treatment of wastewater, contaminated soils or sediments.
Some plants shows the capability to withstand relatively high concentration of chemicals without toxic effects (Hyperaccumulators).
It is applied at sites with contamination of
Organic Chemicals – BTEX, TNT, RDX, PCBs
Nutrient – Ammonia, Phosphate, Nitrate
Metal pollutants – Lead, Cadmium, Zinc, Arsenic, Chromium

5. Chemical uptake and translocation in the plant body

6. Unsaturated / Vadose zone

7. Processes that takes place in the root zone

8. Soil Water Partitioning

9. Metal Uptake by Plant Root
Michaelis and Menton Type of Reaction

10. Plant Root Growth

11. Saturated and Unsaturated Zone
Soil
Water
Soil
Air
Thin film of Water around soil particle

12. Saturated and Unsaturated Zone
Residual Moisture
Saturation Moisture

13. Moisture Retention Characteristics Curve

14. Moisture flux in Unsaturated Zone
Relationship between Soil Moisture and Suction Head is called Soil Moisture Retention Characteristics (MRC)

15. Mathematical models used in the Metal Uptake model
Richards Equation
Water uptake by plant root
Metal uptake by plant root
Root growth with time
Plant root properties
Moisture Retention Characteristics (MRC)
Soil properties – Bulk Density, Clay content, Carbon content etc.
Pedotransfer Function
Soil Water Partition of pollutants
Hydrodynamic Dispersion
Moisture flux joining groundwater
Chemical species flux joining groundwater

16. Pedotransfer Functions
Expensive and time consuming
Bulk density
Clay content
Carbon content
Particle size distribution
MRC Parameters
θs, θr, n, m, α f

17. Space – Time Domain of One Dimensional Transient Metal Uptake Model

18. Richard’s Equation descritized using Implicit scheme
Computational Scheme
Richard’s Equation descritized using Implicit scheme

20. Techniques of Phytoremediation
Applicability
– Other treatments are not cost effective
Very large sites
Low concentration of contaminants
Only polishing treatment is required
Where vegetation is used as final cap / site closure
Limitations
Limited regulatory acceptance
Long duration of time for cleanup
Potential contamination of fodder crop and food chain
Techniques of Phytoremediation
Phyto-transformation
Rhizosphere Bioremediation
Phyto-stabilization
Phyto-extraction
Rhizo-filtration

21. Why Phytoremediation Model Software ?
Design of experiments to determine the parameters of sub-surface phenomenon.
Preparation of irrigation schedule for plantation on mine spoil dump.
Decision on harvesting time of plants.
Estimation of amount of heavy metal present in the plant.

22. NEERI PHYTOREM Model Software Demonstration