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SUSTAINABLE MANAGEMENT OF TANNERY HAIR WASTE THROUGH COMPOSTING ARTHUR ONYUKA Overview • Background • Aims and Objectives • Why composting? • Experimental • Results and Discussion • Concluding Remarks Tanning process Unhairing Liming Bovine hide Beamhouse process • Large amount of liquid and solid waste generated. • Main cause for environmental concern. Solid waste arising Solid waste from 1 tonne of raw hides Tanning 17% Wet end 2% Finishing 1% Characteristics of beamhouse solid waste: • Fleshing and fats • Solid hair • Trimmings • Sludge Total = 700 kg Beamhouse 80% Source: Puntener, A. (1995). JALCA, 90: 206 Disposal and Treatment options Treatments Disposal Thermal Biological • Landfill • Incineration • Composting • Land spreading • Pyrolysis • Anaerobic digestion • Dumping • Gasification • MBT Main Disposal and Treatments Environmental concerns Landfill disposal • Green House Gas emissions. Risk of global warming. Health risks • Risk of water pollution. Health risks • Non-sustainable use of land and loss of resources. Legislation • Legislation Integrated Pollution Prevention & Control 96/61/EC - aim to prevent and reduce pollution caused by production. Waste Framework Directive 75/442/EEC - sets out key objectives based on a hierarchy of options. Landfill Directive 99/31/EC - sets targets for the reduction of biodegradable wastes sent to landfill. Waste minimisation strategies • Based on Waste Framework Directive 75/442/EEC. Forms key part of BAT Aims and Objectives Key Aim Key Objectives • Sustainable management of tannery hair waste through composting. • Identify suitable biological treatment to enhance hair degradation. • Develop favourable conditions for composting of hair waste. Why composting? • Environmentally acceptable. Stabilised product • Valuable product for the market. Hair contains about 15% nitrogen • Ability to utilise the bulk of hair. • Inexpensive and adaptable Potential Markets A C B A. Agriculture B. Landscaping C. Sport turf Understanding composting • Biological process Organic matter (including carbon, chemical energy, protein, nitrogen) Minerals (including nitrogen & other nutrients) water Heat Compost pile Water CO2 Organic matter (including carbon, chemical energy, nitrogen, protein), minerals, water, micro-organism Micro-organism Raw materials Oxygen Composted organic material Experimental Experimental model FEEDSTOCK PHASE 1 PHASE 2 PHASE 3 Composting • Static: 40-50C Microbial degradation Enhanced composting Apply optimised parameters, Phase 1 & 2 Bovine hair, sawdust/ wood chips, dry leaves & soil • Rotary drum Optimise hair degradation through control of: Culture (C:N = 35:1) Temperature Isolate Moisture & pH Agitation Identify Composting vessels Static process Drum process Analyses • Microscopy: light & scanning electron microscopy (SEM). • pH: electrochemical method. • Moisture (% RH). Analyses • Nitrogen: Total Kjeldahl Nitrogen Method. • Biochemical Tests: Folin-Lowry method, Gram staining, selective culture media. • Carbon: weight loss on-ignition of dry sample @ 560C then cooling to constant weight (% Carbon = Organic matter x 100/1.8). Results and Discussion Properties of the micro-organism Growth Microscopic observations Aerobically @ 40 – 50C Rod shaped and stains gram +ve Species Bacillus pH range 7.5 – 10 pH of optimum activity 9.0 Optimum temperature 50C Substrate specificity Inhibition Keratinolytic + general protease E.D.T.A Microbial properties Crude Microbes: on keratin azure Purified: optimum pH 2 1 Blank Treated Treated 3 4 Collagen hydrolysed Inhibition Microbial degradation of hair Hair degradation Intact hair 5 6 (Mag. X400, 5.0kV) 7 (Mag. X600, 5.0kV) (Mag. X1.0K, 5.0kV) Composting parameters Control pH Temperature Treated Temperature (°C) 9 8 7 pH 6 5 4 3 2 1 70 60 50 40 30 20 10 0 0 0 7 15 21 30 40 50 60 70 Composting days 80 90 100 110 120 0 7 15 21 30 40 50 60 70 80 90 100 110 120 Composting days • Compost achieved self-buffering at pH 7.0 and 8.0 • Average temperature maintained @ 49C • Thermal destruction of pathogens @ > 55C Control Treated Composting parameters % Moisture (RH) Control Treated • Supports microbial activity % Moisture (RH) 60 58 • Must be balanced to allow oxygen transfer. 56 54 52 • Excessive: anaerobic process 50 48 0 7 15 21 30 40 50 60 70 80 90 100 110 120 Composting days • Average moisture: 55% RH Structural modification Control: 15 days Treated: 15 days 9 8 (Mag. X800, 5.0kV) 10 (Mag. X800, 5.0kV) 11 60 days (Mag. X600, 5.0kV) 60 days (Mag. X600, 5.0kV) Final products Control: 120 days Treated: 120 days 13 12 (Mag. X300, 5.0kV) 14 (Mag. X600, 5.0kV) 15 Compost sample (Mag. X40, 5.0kV) Compost sample (Mag. X40, 5.0kV) Final product 16 • Dark and tacky • Nitrogen content: 1.4 - 1.5% per gram of sample. • Carbon content: 39 - 41% per gram of sample. Product Remarks • An environmental-friendly technology to manage tannery hair waste has been demonstrated. • Future merits includes: environmental and economic benefits through cost-saving and saleable product. • The decomposition of hair can be enhanced through the use of specific micro-organisms and optimisation of the environmental processing parameters. Acknowledgements Dr. Paula Antunes Dr. Margaret Bates Prof. Geoff Attenburrow Prof. Anthony Covington Pat Potter (Mrs) Mandy Taylor (Ms) Tanya Hayes (Mrs) Annie Lama (Ms) Thank you