Inorganic and organic amendments for bioremediation of hydrocarbon contaminated soil SCLF annual conference, Glasgow 5 th September 2018 Dr Thomas Aspray www.ersremediation.com
www.ersremediation.com Contents There is a market for bioremediation • Examples of successful bioremediation and timescales • ERS’ approach to soil bioremediation treatability testing • Current research • 2
www.ersremediation.com What is ex situ bioremediation?
www.ersremediation.com Aerobic biodegradation Oxygen Carbon dioxide Soil Microbe Contaminant Water Nutrients (e.g. N,P,K) Are microorganisms present and active? How active? Are the right microbes active?
www.ersremediation.com Ex situ bioremediation application in Scotland 32 councils contacted • Responses received (to date) from 12 • Onsite treatment reduced • Off site treatment? • Year Applications received by CLOs 2013 2 2014 4 2015* 1 2016 1 2017 2 2018 1 *Landfill tax devolved 5
www.ersremediation.com Bioremediation market drivers 2009 drivers 2018 drivers Economic uncertainty remains • Move toward treatment rather than • Cost effective for larger sites • disposal Hazardous waste soil subject to • End of landfill tax exemptions for • increasing landfill tax development sites Onsite treatment for retention or • non-haz disposal advantageous End of landfill tax exemption for • where no local STC No need to import replacement engineering materials • material Economic crisis means developers • Timescales are increasingly more • have more time to remediate sites predictable Sustainable solution and are looking for most cost • E.g. SURF1 case study (CL:AIRE) • effective method Bioremediation is a cheap • remediation technique Timescales are becoming more • predictable 6
www.ersremediation.com “Bioremediation doesn’t work” Wrong assumptions on % • degradation (total and fractions) Conditions not optimised for • degradation Environmental conditions inhibitory • Treatment not effectively monitored / • maintained Project issues e.g. reuse not planned • 7
www.ersremediation.com Ex situ bioremediation performance – case study 1 Project 46001 40000 35000 TPH concentration (mg/kg) 30000 Contaminants: TPH, PAH and B(a)P 25000 Quantity: ~1000 m 3 20000 15000 Treatment approach: 10000 biostimulation involving inorganic and organic amendment 5000 0 0 5 10 15 20 25 Project 46001 Time (months) 700 600 PAH concentration (mg/kg) 500 400 300 200 100 0 8 10 12 14 16 18 20 22 24 26 Time (months)
www.ersremediation.com Ex situ bioremediation performance – case study 2 4000 A Contaminants: TPH B C D Targets: 500 mg/kg TPH concentration (mg/kg) 3000 E F Quantity: >7500 m 3 G 2000 Treatment approach: biostimulation involving inorganic and organic 1000 amendment 0 Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Time (months) 9
www.ersremediation.com Ex situ bioremediation performance – case study 3 Contaminants: DRO and MRO Targets: GACs C12-C16 aromatic (10.7 mg/kg), • C16-C21 aromatic (133 mg/kg), • C21-C40 aromatic (157 mg/kg) • Quantity: 1000 m 3 Treatment approach: biostimulation involving organic and inorganic amendment
www.ersremediation.com ERS’ approach to bioremediation treatability testing and optimisation Basal respiration (BR) • Basal respiration is a measure of the • total biological activity of microorganisms Nutrient induced respiration (NIR) • Macro and micronutrient limitation •
www.ersremediation.com Nutrient Induced Respiration (1) Theoretically derived nutrient requirement • C:N:P ratio 100:10:1 • Shortcomings • Practically derived • Nutrient induced respiration •
www.ersremediation.com Nutrient Induced Respiration (2) Sandy loam (47001C) 125000 Cummulative O 2 consumption (µl) 105000 85000 Oxygen 65000 45000 25000 5000 Control 16 33 66 133 266 533 1066 2133 NH4NO 3 amendment (mg/kg soil) 140000 120000 Cumulative CO 2 production (µl) 100000 Carbon Dioxide 80000 60000 40000 20000 0 Control 16 33 66 133 266 533 1066 2133 NH 4 NO 3 amendment (mg/kg soil) Aspray et al., (2008) Chemosphere
www.ersremediation.com Nutrient Induced Respiration (3) Combining multigas analysis with kinetics • Respiratory quotient (RQ) = CO 2 /O 2 • Increased activity or changes in metabolism? • 1.6 1.5 1.4 1.3 RQ (CO2 ul/O2 ul) 1.2 1.1 1.0 0.9 0 0.25 0.5 0.8 1 2 4 0.7 8 16 32 0.6 24 30 36 41 47 53 59 65 Time (h) Aspray et al., (2008) Chemosphere
www.ersremediation.com Potential benefits of compost bioremediation Nutrient (N) addition • Improve porosity • Increase abundance of • degraders (i.e. augment the indigenous community) 15
www.ersremediation.com Composting and compost bioremediation Confusing terms • Composting bioremediation • Addition of significant quantities of compost feedstock • materials to contaminated soil Compost bioremediation • Addition of small quantities of composting material or • finished compost to contaminated soil 16
www.ersremediation.com Compost bioremediation literature Addition of composts to contaminated soil less • widely studied (Semple et al., 2001) ERS trailblazer project in 2006 • Financial benefit demonstrated • Potential technical benefit harder to • demonstrate (absence of control at full scale) Lab based studies • Sayara et al., (2010) used agricultural soil spiked • with PAH contamination, testing five different composts with varying stabilities. More stable composts, with higher humic acid content, were more effective at PAH removal than less stable composts Wallisch et al., (2014) compared mature and • immature compost. Composts had positive effect on alkane degrader ( alkB gene) abundance and diversity in soil. ‘Less mature’ sample had generally higher abundance 17
www.ersremediation.com Research project Main objective • Improve compost stability test • precision Secondary objective • Assess whether stability could be a • good indicator of compost maturity for soil bioremediation As with case study 2 soils may be • contaminated with both TPH and PAH Done on a shoestring budget! • Aspray, 2018 Peat control 50:50 peat:compost 18
www.ersremediation.com Compost sample characterisation Unpublished data removed 19
www.ersremediation.com Quantitative PCR (qPCR) PCR run DNA extraction PCR setup
www.ersremediation.com Catabolic gene targets and justification Primer name Target Reference alkB F Alkane hydroxylase gene Kloos et al., 2006 alkB R polyaromatic hydrocarbon (PAH) ring- PAH- RHDα GN F hydroxylating dioxygenases (RHD) genes Cebron et al., 2008 PAH- RHDα GN R (Gram negative population) polyaromatic hydrocarbon (PAH) ring- PAH- RHDα GN F hydroxylating dioxygenases (RHD) genes Cebron et al., 2008 PAH- RHDα GN R (Gram positive population) Primer set a b c d e f g h % strains amplified 18.6 18.6 20.9 23.3 48.8 44.2 18.6 44.2 Jurelevicius et al., 2013 21
www.ersremediation.com Catabolic gene targets and justification 2 Cebron et al., (2008) 22
www.ersremediation.com Degrader gene abundance Unpublished data removed 23
www.ersremediation.com Degrader abundance vs maturity (stability) – cross site comparison Unpublished data removed 24
www.ersremediation.com Degrader abundance vs maturity (stability) – within site comparison Unpublished data removed 25
www.ersremediation.com Compost sample bacterial diversity Unpublished data removed 26
www.ersremediation.com Conclusions Bioremediation when well managed with optimal amendment can • be the solution for your site Timescales from 6 months – 2 years depending on recalcitrance, • starting concentrations(s) and end target(s) The technique has moved on • Compost/composting materials are cheaper to source than many • other organic materials Commercial green waste composts are not the same! • Less stable samples do not necessarily have higher degrader (gene) • abundance N content and porosity varies • qPCR is a rapid technique for biological treatment evaluation and • monitoring 27
www.ersremediation.com Acknowledgements Diana Guillen Ferrari Heriot-Watt University Jennifer Pratscher 28
Thanks for Listening
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