Is Contaminated Land Remediation Sustainable?

1. Is Contaminated Land Remediation Sustainable? Damn Lies and Statistics, A Tale of Two Sites John W Hunt, Thiess Services Tracey Bauer, EESI Louise Cartwright, EESI

2. Thiess Services Definitions Remediation Scenario Remediation Methods Damn Lies and Statistics (Remediation Metrics) A tale of two sites (Rhodes Peninsula Retrospective) Discussion and Conclusions Outline of Presentation

3. 1. Thiess Services

4. Thiess Services • Australia’s leading remediation contractor • owned by Thiess, owned by Leighton • core businesses • waste management • site remediation • other services • started with Rum Jungle 1984 • successfully remediated over 70 sites • remediation projects values at $50M /yr

5. John Hunt Technical Services Manager, Remediation Problem Definition Uncertainty Analysis Remediation Technologies Licensing and consultation $1,000,000,000 remediation projects since 1993

6. 2. Definitions

7. Definitions • Remediation • Management or removal of contaminants from environmental media for the protection of human health and the environment, or to make a site safe for use • Sustainability • meeting the needs of the present without compromising the ability of future generations to meet their own needs

8. 3. Remediation Scenario

9. Hypothetical Project • High-value capital city water front property • 100,000 m3 of contaminated material to be treated or landfilled • 20,000 mg/kg TPHs, or PAHs, 12 to 15% moisture • Remediation methods • Offsite landfill with and without immobilisation and levy • Onsite cell with and without immobilisation • Onsite treatment by bioremediation • simple (TPHs), biopile (TPHs) and complex (PAHs) • Onsite treatment by exsitu rotary thermal DTD plant • 5 Ha site with 2 Ha encapsulation

10. Hypothetical Project Quantities

11. 4. Remediation Methods

12. Lined Landfill / Monocell / Encapsulation • Clay and synthetic liners • Drainage layers • Capping • Sterilised land

13. Immobilisation • Pugmill – diesel fuel • Calcium oxide / magnesium oxide / cement • Typically 3 to 5% addition • Immobilises but does not destroy contaminants • 100 t/hr throughput

14. Bioremediation - simple • Aerobic process to destroy TPHs – diesel range • Stimulation / availability – fertilizer, compost, surfactants • Soil consistency – ameliorants, mixing with Roterra (MUST) • Moisture and oxygen control - turning with excavator • Destroys contaminants – CO2 • Sensitivity - contaminant concentration and complexity - duration • Emission controls – tent with filter or none, site specific • Energy – diesel plus site electricity

15. Bioremediation - complex • Aerobic process to destroy TPHs and PAHs – gaswork tars • Stimulation / availability – fertilizer, compost, surfactants, solvents • Soil consistency – ameliorants, mixing with Roterra (MUST) • Moisture and oxygen control - turning with excavator • Destroys contaminants – CO2 • Sensitivity - contaminant concentration and complexity - duration • Emission controls – tent with filter or none, site specific • Energy – diesel plus site electricity

16. Bioremediation – engineered cell • Aerobic process to destroy TPHs – diesel range • Stimulation - fertilizer amendment • Moisture and oxygen control – irrigation and fan to increase air flow • Destroys contaminants – CO2 • Sensitivity - contaminant concentration and complexity • Emission controls - blower and carbon beds or none, site specific • Energy - electricity and diesel, site electricity

17. Thermal Treatment - ETC • Batch thermal desorption plant – 600 tonnes • Destroys contaminants in thermal oxidiser – DTD plant • Sensitivity - moisture and organic content • Energy - gas and electricity, 2 GJ/t • 2 to 3 t/h equivalent throughput

18. Thermal Treatment - DTD • Pre-treatment building – filters and carbon beds • Continuous thermal desorption plant • Destroys contaminants in thermal oxidiser – DTD plant • Sensitivity - moisture and organic content • Energy - gas and electricity, 4 to 5 GJ/t • 10 to 25 t/h

19. 5. Damn Lies and Statistics(Remediation Metrics)

20. Sustainability Fundamentals • The 3 pillars are • Financial • Environmental • Social • Many different aspects • Headlines and indicators • Some can be measured • Some are subjective • eg POPs should be destroyed not landfilled • eg should treatment be onsite or offsite

21. Financial • Direct costs only - plant and equipment, fuel, labour • No carbon cost or other environmental costs included • Onsite cell and bioremediation lowest costs • Thermal costs intermediate • Landfill costs highest • Levy makes landfill very unattractive, promotes treatment

22. Financial - energy used • Thermal is 5 to 20 times higher the other options • Immobilisation is proportional to thermal • Biological methods low energy • Landfill and cell low energy

23. Environmental - carbon footprint, CO2e • Direct energy use only: transport, plant, additives (ex compost) • Thermal DTD is the highest • Biopile, immobilisation and thermal ETC intermediate • Landfill and onsite cell are the lowest • Immobilisation: tonne additive used = thermal tonne treated • Labs: <0.5% of total for landfill

24. Carbon Footprint considerations • CO2e contributions • Transport, electricity and gas for all • What about contamination destruction • Generally 100% • ?0% for immobilisation • ?50% for thermal • What about volatile losses? • before, during, after • What about methane generation? • landfill and cell

25. Carbon Footprint considerations • Ce = cement, F = fertiliser, S = surfactant, 5% = methane (hypothetical, methane CO2e factor = 21 • What just happened? The boundary was shifted.

26. Social • Social • Destruction preferred over landfill • Onsite not offsite • Duration • Jobs created • Social positions enshrined in regulation and conventions • Eg Stockholm Convention – destruction of PoPs • National Guidelines and NEPMs • State Acts and Regulations

27. Social • Landfill and cell could be accelerated • Biological could be accelerated if space available • ETC could be accelerated if space available • Labour similar for all options except ETC

28. 6 A Tale of Two Sites (Rhodes Peninsula Retrospective)

29. Rhodes Peninsula • Contaminated by OCCs / Dioxins from Union Carbide operation • Allied Feeds Site • 100,000 m3 above 1 ug/kg dioxins and 2 mg/kg SCW • Lednez Site (Union Carbide) • 350,000 m3 above 1 ug/kg dioxins and 2 mg/kg SCW • Homebush Bay • 50,000 m3 above 1 ug/kg dioxins

30. Solution • Social objectives drive solution • SXW compounds – reduce and eliminate, no landfill or cell • Allied Feeds Site ($20M) • Treat 100,000 m3 to <1 ug/kg dioxins and <2 mg/kg SCW • Reuse 100,000 m3 <1 ug/kg dioxins, <100 mg/kg SCW • Lednez Site (Union Carbide) ($109M) • Commercial constraint – land value • Treat 100,000 m3 to <1 ug/kg dioxins and <2 mg/kg SCW • Reuse 250,000 m3 – site specific risk based criteria • Homebush Bay ($21M) • Commercial constraint – government contribution • treat 50,000 m3 (1500 m x 90m) • risk based criteria to reduce surface concentrations

31. Lednez Site • Site Specific Human Health Risk Assessment • Landuse specific and layered reuse criteria • Best return for the money available

32. Remediation Works

33. Wins and Losses • Allied Feeds Site • STT = 550 oC to get dioxins to <1 • Aspirational criterion increase volumes, more GJ and $ • Lednez Site • TO >1020 C and 99.9999% DRE • Best practice from incineration, more GJ and $ • Minor compounds drive treatment volumes • Refine risk assessment • Plant Issues • STT - 25% increase in energy use for 2% less mass • TO - 15% increase in energy use for 0.0001% less mass • What is more sustainable?

34. Redevelopment

35. 7 Discussion and Conclusions

36. Discussion • Cost / Ha and CO2e / Ha • Onsite Cell: lowest cost and CO2e per Ha • Biological methods perform well • Immobilisation and thermal ETC similar • Thermal DTD CO2e payback 35 years assuming : • High density residential development • 80 vkms / household /day

37. Conclusions • A range of factors have to be considered • Financial • Environmental • Social • The most sustainable solution will be site and time specific • Setting the boundaries is important • Only a few factors can be easily measured • They represent only part of the answer • Many factors are subjective • Different stakeholders may have opposing views • Many factors are competing • – eg destruction efficiency vs carbon vs cost

38. The End - Thankyou