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BZ572 - Phytoremediation

BZ572 - Phytoremediation. Elizabeth Pilon-Smits Biology Department E413 ANAZO 491-4991 epsmits@lamar.colostate.edu. Let’s hear from you. Please write on piece of paper: Degree, major/department, reg./auditing? What is your career goal? How does phytoremediation fit in?

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BZ572 - Phytoremediation

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  1. BZ572 - Phytoremediation Elizabeth Pilon-Smits Biology Department E413 ANAZO 491-4991 epsmits@lamar.colostate.edu

  2. Let’s hear from you • Please write on piece of paper: • Degree, major/department, reg./auditing? • What is your career goal? • How does phytoremediation fit in? • Any particular aspects of phytoremediation • you are most interested in?

  3. BZ572 – Course Info webct Text: No book, only papers from course website • Topics: • Intro to phytoremediation • Phyto of inorganics*) • Phyto of organics*) • 1 Lab expt, 1 trip to a lab, 1 field trip (if interest), • 5 guest lectures, in-class exercises, job info • *) mechanisms of uptake, translocation, detoxification, • effects of soil, microbes on remediation, approaches to enhance phyto efficiency, including genetic engineering

  4. Grading: Conventional, no curving Exams:50% of total grade - 1 midterm + 1 final exam (not comprehensive) essay questions • Term paper & presentation:30% of grade • write web page/proposal/review + present • In-class participation:20% of grade • lab report, in-class group assignments, literature discussions

  5. Introduction to Phytoremediation • History • Status • Uses • Advantages • Limitations • Phytoremediation strategies

  6. History of phytoremediation • for centuries: wetlands used for • waste treatment in Europe • last century: metal hyperaccumulator • plants discovered - used as indicators for mining • 1970s: - clean water act, clean air act • 1980s: • - superfund act (1986 - 8.5 billion $) • - idea to use hyperaccumulator • plants for metal cleanup (Chaney)

  7. 1994: phytoremediation term coined • (Ilya Raskin) phytoremediation takes off History of phytoremediation (cont.) massive interest from gov. & industry - DOE phytorem. workshop - first phytorem. company (Phytotech) • 1995: first phytorem. conference

  8. History of phytoremediation (cont.) • (Raskin) • 1994: Term phytoremediation first used • 1995: First phyto conference Columbia MO • 2000: EPA phyto conference • 2000: 1st phyto faculty positions • 2000: 1st phyto course (this one) • 2001, 2003: 1st, 2nd phyto call for proposals • (NSF/EPA/DOE) • 2000, 2001: 1st, 2nd professors in phyto • (U Mich, U S-Carolina)

  9. Status of phytoremediation • U.S. phytoremediation market (Glass, 1999, 2004 pers. comm.) 1999 $ 30 - 49 million / yr 2004 $ 100-150 million / yr • World phytoremediation market 1999 $ 34 - 58 million • Total remediation market US: $ 6-8 billion/yr World: $ 25-50 billion/yr

  10. Status of phytoremediation (cont.) • 9 purely phytorem. companies • 7 constructed wetland companies • > 40 consulting/engin. companies • that also do phytoremediation • ~200 field projects • - funded mostly by EPA, DOD, DOE • - some commercial/joint projects

  11. Uses of phytoremediation Remediation of different media: • air • soils, sediments • groundwater • wastewater streams • - industrial • - agricultural • - municipal, sewage

  12. Uses of phytoremediation (cont.) Remediation of different pollutants: • organics: • - PCBs • - PAHs • - TCE • TNT • MTBE • - pesticides • - petroleum • hydrocarbons • Etc. • inorganics: • - metals (Pb, Cd, Zn, Cr, Hg) • - metalloids (Se, As) • - “nutrients” (K, P, N, S) • - radionuclides (Cs, U)

  13. Uses of phytoremediation (cont.) Remediation using different systems: • farming polluted soil • irrigation with polluted groundwater • letting trees tap into groundwater • letting plants filter water streams • constructed wetlands, hydroponics

  14. different systems: Hydraulic barrier

  15. different systems: • Vegetative cap

  16. different systems: • Constructed wetlands

  17. different systems: hydroponics with polluted wastewater

  18. Roots of mustard Extend into effluent Acting as filters for heavy metals

  19. Uses of phytoremediation (cont.) Remediation using different plants Properties of a good phytoremediator: • high tolerance to the pollutants • high biomass production, fast growth • large, deep root system • good accumulator/degrader of pollutant • able to compete with other species • economic value

  20. Uses of phytoremediation (cont.) Popular plants for phytoremediation • trees various organics metals gum tree poplar yellow poplar willow

  21. Uses of phytoremediation (cont.) Popular plants for phytoremediation (cont.): Brassicaceae: • grasses • For inorganics Thlaspi Alyssum Brassica juncea

  22. Uses of phytoremediation (cont.) Popular plants for phytoremediation (cont.): various grasses for organics hemp buffalo grass red fescue for inorganics kenaf bamboo

  23. Uses of phytoremediation (cont.) salicornia Popular plants for phytoremediation aquatic plants cattail parrot feather halophytes for inorganics for organics reed spartina poplar, willow

  24. Advantages & Limitations of Phytoremediation

  25. In situ Solar energy Ex situ Fossil fuels for energy Phytoremediation Mechanical/chemical treatment • Soil washing • Excavation + reburial • Chemical cleanup of soil/water • Combustion

  26. Phytoremediation vs. Mechanical/chemical treatment Advantages of phytoremediation ~10 - 100x • Cheaper Excavation & reburial: up to $1 million/acre Revegetation: ~$20,000/acre

  27. Phytoremediation vs. Mechanical/chemical treatment Advantages of phytoremediation (cont.) • Less intrusive • Can be more permanent solution • Better public acceptance

  28. Phytoremediation vs. Mechanical/chemical treatment (cont.) Limitations of phytoremediation • Can be slower Limited by rate of biological processes • Accumulation in plant tissue: slow • e.g. metals: average 15 yrs to clean up site - Filter action by plants: fast (days) - Metabolic breakdown (organics): fairly fast (< 1yr)

  29. Max depth ~5 m Can be increased up to 20m with “deep planting” Phytoremediation vs. Mechanical/chemical treatment (cont.) Limitations of phytoremediation (cont.) • Limited root depth Trees > prairie grasses > forbs, other grasses

  30. Phytoremediation vs. Mechanical/chemical treatment (cont.) Limitations of phytoremediation (cont.) • Plant tolerance to pollutant/conditions - Bigger problem with metals than organics - Can be alleviated using amendments, or treating hot spots by other method • Bioavailability of contaminant - Bioavailability can be enhanced by amendments

  31. So, when choose phytoremediation? • Sufficient time available • Pollution shallow enough • Pollutant concentrations not phytotoxic • $$ limited Note: Phyto may be used in conjunction with other remediation methods For very large quantities of mildly contaminated substrate: phytoremediation only cost-effective option

  32. Phytoremediation processes

  33. Phytoremediation processes phytostabilization

  34. - Metals - Non-bioavailable organics • Plants reduce leaching, erosion, runoff •  pollutant stays in place • 2. Plants + microbes may transform pollutant • to less bioavailable form • (e.g. metal precipitation on roots) • Phytostabilization: • pollutant immobilized in soil

  35. Phytoremediation processes phytostimulation

  36. Organics e.g.PCBs, PAHs bacteria, fungi • Phytostimulation: plant roots stimulate • degradation of pollutant • by rhizosphere microbes

  37. Phytoremediation processes phytodegradation

  38. in tissues or in root exudate Via enzymes, e.g. oxygenases nitroreductase • Phytodegradation: • plants degrade pollutant, • with/without uptake, translocation Certain organics e.g.TCE, TNT, atrazine

  39. Phytoremediation processes phytoextraction accumulation

  40. mainly inorganics: metals metalloids radionuclides Plant biomass may be used (e.g. to mine metals, or non-food industrial use) or disposed after minimizing volume (incineration, composting) • Phytoextraction: pollutant accumulated • in harvestable plant tissues

  41. Phytoremediation processes phytovolatilization

  42. some metal(loid)s: Se, As, Hg some volatile organics: TCE, MTBE • Phytovolatilization: pollutant released • in volatile form into the air

  43. Phytoremediation applications may involve multiple processes at once accumulation volatilization degradation stabilization

  44. Rhizofiltration water

  45. for inorganics Plant roots & shoots harvestable (may be used to mine metals) or disposed after minimizing volume • Rhizofiltration: pollutant removed from • water by plant roots in hydroponic system metals metalloids radionuclides

  46. Hydroponics for metal remediation: 75% of metals removed from mine drainage Rhizofiltration • Involves: • phytoextraction • phytostabilization

  47. Constructed wetland for Se remediation: 75% of Se removed from ag drainage water • Involves: • phytoextraction • phytovolatilization • phytostabilization • (rhizofiltration) • (phytostimulation)

  48. with/without adding clean topsoil • Natural attenuation:polluted site left alone • but monitored • Vegetative cap: polluted site revegetated, • then left alone, monitored

  49. H2O Hydraulic barrier Water flow redirected Pollutants intercepted

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