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 Large amount of liquid and solid waste generated. Unhairing Liming Bovine hide Beamhouse process Large amount of liquid and solid waste generated. Main cause for environmental concern.

Solid waste arising Characteristics of beamhouse solid waste: Fleshing and fats Solid hair Trimmings Sludge Wet end 2% Tanning 17% Finishing 1% Beamhouse 80% Total = 700 kg Source: Puntener, A. (1995). JALCA, 90: 206

Disposal and Treatment options Treatments Disposal Landfill Land spreading Dumping Thermal Incineration Pyrolysis Gasification Biological Composting Anaerobic digestion MBT

Main Disposal and Treatments

Environmental concerns Landfill disposal Green House Gas emissions. Risk of global warming. Health risks Risk of water pollution. 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. Key Objectives 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 B A C Agriculture Landscaping Sport turf

Understanding composting Biological process Heat water CO2 Organic matter (including carbon, chemical energy, protein, nitrogen) Minerals (including nitrogen & other nutrients) Water Micro-organism Organic matter (including carbon, chemical energy, nitrogen, protein), minerals, water, micro-organism Compost pile Composted organic material Oxygen Raw materials

Experimental

Experimental model FEEDSTOCK PHASE 1 PHASE 2 PHASE 3 Bovine hair, sawdust/ wood chips, dry leaves & soil (C:N = 35:1) Composting Static: 40-50C Rotary drum Microbial degradation Enhanced composting Optimise hair degradation through control of: Temperature Moisture & pH Agitation Culture Identify Isolate Apply optimised parameters, Phase 1 & 2

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 @ 560C then cooling to constant weight (% Carbon = Organic matter x 100/1.8).

Results and Discussion

Properties of the micro-organism Growth Aerobically @ 40 – 50C Microscopic observations Rod shaped and stains gram +ve Species Bacillus pH range 7.5 – 10 pH of optimum activity 9.0 Optimum temperature 50C Substrate specificity Keratinolytic + general protease Inhibition E.D.T.A

Crude Microbes: on keratin azure Microbial properties Crude Microbes: on keratin azure Purified: optimum pH 2 1 Blank Treated Treated 3 4 Collagen hydrolysed Inhibition

Microbial degradation of hair Intact hair Hair degradation 5 6 (Mag. X400, 5.0kV) 7 (Mag. X600, 5.0kV) (Mag. X1.0K, 5.0kV)

Composting parameters Compost achieved self-buffering at pH 7.0 and 8.0 Average temperature maintained @ 49C Thermal destruction of pathogens @ > 55C

Composting parameters Supports microbial activity Must be balanced to allow oxygen transfer. Excessive: anaerobic process Average moisture: 55% RH

Structural modification Control: 15 days Treated: 15 days 9 8 (Mag. X800, 5.0kV) (Mag. X800, 5.0kV) 10 11 60 days (Mag. X600, 5.0kV) 60 days (Mag. X600, 5.0kV)

Final products 13 12 14 15 Control: 120 days Treated: 120 days (Mag. X300, 5.0kV) (Mag. X600, 5.0kV) 14 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)

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