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Packaging material in bio-filtration systems: Woodchip vs. Pumice

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Packaging material in bio-filtration systems: Woodchip vs. Pumice

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Packaging material in bio-filtration systems: Woodchip vs. Pumice

  1. 1. Packing material in biofiltration systems: Woodchip vs. pumice Presenter: Dr. Wan Li Low Date: 16th September 2014
  2. 2. Introduction • Odorous emission source - manufacturing, petrochemical, food, solid waste, sewage treatment and agricultural activities • Treatment methods - scrubbing, incineration, thermal oxidation, biofiltration and adsorption • Air pollution compounds - VOC, sulphurous compounds, ketones, aldehydes, lower molecular weight fatty acids, ammonia and amines • Odorous air pollutants - NH3, VOC, sulphur-containing compounds such as H2S, S2- and mercaptans (R-SH) • Irritants and some may be hazardous to health at higher exposure • Modernization of biotechnology - biofiltration systems gaining popularity
  3. 3. Introduction to biofiltration • Biofiltration – biological system, relies on microorganisms to metabolise/neutralise the malodorous compounds • Mixed population can develop over time from the indigenous microorganisms present - natural selection • Ensure stable environment for microorganisms to proliferate and establish growth • Controllable parameters - temperature, pH, oxygen and moisture content • Benefits include: o economical – does not involve complex chemicals o controllable system - lower maintenance o does not produce secondary pollutant o usually requires ambient temperature and pressure
  4. 4. Mechanics of a functional biofilter • Biofilter filled with packing material - containing microorganisms/biofilm • Odorous air stream into moist environment • Transfer of compounds from gaseous phase into aqueous phase. Example of biofilter configuration: • Increases availability of compounds - serves as alternative energy source for microorganisms. • Absorption of the compounds into aqueous phase within the biofilm: o increases interaction and contact time o enhance the rate of degradation of odorous compounds
  5. 5. Biofilter media • Availability of suitable media to allow the microorganisms to attach, grow and develop into a well-established biofilm • Common choices of packing materials: o organic : peat, compost, woodchip, agricultural waste materials, seashells o non-organic : plastics, pumice
  6. 6. Biofilter media • The feasibility of microorganisms to establish a biofilm on the packing material depends on properties such as: o high surface area - for microbial cell colonisation o porosity - increase surface area o degree of compaction - media degradation o moisture retention - condition for microbial growth, aqueous phase for reaction • Commonly used effective biofilter packing material: o woodchip (organic) o pumice (non-organic)
  7. 7. Woodchip vs. Pumice Woodchip Pumice o wide availability - economical prices o presence of some natural microbial diversity o availability of nutrient contents o biodegradable - prone to loss of structural stability, microbial degradation/ chemical degradation o some may contain antimicrobial components - natural essential oils, hinder microbial colonisation o self odour – e.g. pine wood o high surface area - promote microbial colonisation o lack of natural microbial diversity o porous structure, light weight o not biodegradable - no loss of structural stability o high silica content (depending on geography) - chemically inert, hence less prone to chemical degradation o odourless
  8. 8. Experimental analysis • Compare properties of woodchip and LavaRok® o Woodchip - common media used in biofilters o LavaRok® - pumice, used in OSIL’s high performance hybrid biofilter products • Analysis of: o Physical properties o Moisture uptake / retention o Rate of colonisation
  9. 9. Physical properties: Woodchip vs. LavaRok® • Structural condition – scanning electron microscopy (SEM) examination Photomicrographs of random woodchip samples
  10. 10. Physical properties: Woodchip vs. LavaRok® • Structural condition – scanning electron microscopy (SEM) examination Photomicrographs of random LavaRok® samples
  11. 11. Moisture: Woodchip vs. LavaRok® • Percentage moisture uptake Woodchip LavaRok® Normal air Moist warm air Normal air Moist warm air Day 1 134 % 129 % 92 % 52 % Day 7 188 % 176 % 105 % 57 % Day 14 197 % 188 % 114 % 61 % • Percentage moisture retention by media Woodchip LavaRok® Normal air Moist warm air Normal air Moist warm air Day 1 100 % 100 % 100 % 100 % Day 7 60 % 100 % 67 % 100 % Day 13 34 % 93 % 43 % 103 %
  12. 12. Colonisation: Woodchip vs. LavaRok® • Rate of colonisation on woodchip Day 1 oBubble-like structures - release of plant materials (oils)? oMay interfere with the availability of oxygen oMay also contribute to some antimicrobial activity Day 3 oDense, uncontrolled colonisation on the surface of the woodchip Day 6 oHigh diversity of microbes present on the woodchip sample
  13. 13. Colonisation: Woodchip vs. LavaRok® • Rate of colonisation on LavaRok® Day 1 oInitial incubation show some bacteria cells starting to colonize the surface Day 3 o Dense colonization on the surface of the LavaRok® Day 7 o Very dense microbial colonisation on the surface of the LavaRok® o Relatively uniform type of cells growing on the LavaRok® o Cells are starting to colonise the deeper fissures within the LavaRok® structure.
  14. 14. Research outcome • Woodchip and LavaRok® - suitable biofilter packing material • Moisture retention properties: o Woodchip can absorb more moisture compared to LavaRok® o LavaRok® slightly better at retaining moisture compared to woodchip • Surface colonisation properties: o Woodchip - can be “pre-loaded” with microbial diversity, good surface area for colonisation, possible competition due to fungal hyphae o LavaRok® - lack of “pre-loaded” microbial diversity, high porosity with good surface area • Physical properties: o Woodchip - prone to degradation (moisture, chemical and microbial activity), possible compacting of media bed, may contain self-odour o LavaRok® – inert to chemical reaction, not degradable by microbial activity, odourless
  15. 15. Future research • Investigate the feasibility of using other materials as biofilter packing media • Develop methodology to efficiently adapt biofilter conditions to promote rapid colonisation • Collect data to analyse the development/change of microbial population within a biofilter e.g. changes due to natural selection • Development of a ready-to-go freeze dried immobilized-cells to be used as an effective and rapid biofilter re-seeding methodology – OSIL RescuePack • Create an adaptable mixed culture of inoculums for the treatment of more complex odours coming from modern industrial processes
  16. 16. Conclusion • Biofilter performance relies on the healthy population of microorganisms living within the media bed to degrade the malodourous compounds • Important to control essential parameters to preserve microbial population health, hence leading to effective biofilter performance • There are advantages/disadvantages of using LavaRok® or woodchip media • Choice of biofilter packing material will depend on other limiting factors e.g. cost, maintenance and availability of media • Colonisation can be promoted by seeding biofilter bed with suitable inoculums • Optimum microbiological performance achieved by seeding LavaRok® • Healthy population of microorganisms = good biofilter performance
  17. 17. Collaborators • OSIL, U.K. o Matt Wilkes, Dr. Corby Lee, Dr. Wan Li Low • University of Wolverhampton, U.K. o Prof. David Hill and Dr. Clive Roberts • Knowledge Transfer Partnership, U.K. o Dr. Russ Bromley Reference 1. Anet, B., Couriol, C., Lendormi, T., Amrane, A., Le Cloirec, P., Cogny, G., & Fillières, R. (2013). Characterization and Selection of Packing Materials for Biofiltration of Rendering Odourous Emissions. Water, Air, & Soil Pollution,224(7), 1-13. 2. Frederickson, J., Boardman, C. P., Gladding, T. L., Simpson, A. E., Howell, G., & Sgouridis, F. (2013). Evidence: Biofilter performance and operation as related to commercial composting. 3. Lebrero, R., Estrada, J. M., Muñoz, R., & Quijano, G. (2014). Deterioration of organic packing materials commonly used in air biofiltration: Effect of VOC-packing interactions. Journal of environmental management, 137, 93-100. 4. Low, W. L., Lee, C., Wilkes, M., Roberts, C., & Hill, D. J. (2014). Development of a rapid, effective method for seeding biofiltration systems using alginate bead-immobilized cells. International Journal of Chemical & Environmental Engineering, 5(1).
  18. 18. Client using OSIL technologies
  19. 19. THANK YOU FOR YOUR TIME FOR MORE INFO PLEASE VISIT http://www.osiltd.com EMAIL US AT info@osiltd.com OR wanli.low@osiltd.com

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