Post on 12-Apr-2017
The Design & Build of a Biodigester ToiletDesign Project 1587
James Bass, Nishanth Cheruvu, Natasha Rayan, Charlie Savory, Kieren Sheehan
The Design & Build of a Biodigester Toilet
University of Adelaide Natasha Rayan 2
• Problem Background• Significance• Scope• Technical Background• Design• Testing & Operation• Current Progress• Future Work• Design Improvements
Natasha Rayan
Nishanth Cheruvu
Charlie Savory
James Bass
Kieren Sheehan
Problem Background
• 2.6 billion people lack access to facilities (WHO 2014)
• 2 million deaths per year (WHO 2014) • Some health implications– Cholera– Diarrhoea– Fluorosis– Hepatitis A– Schistosomiasis– Typhoid
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Sanitation
University of Adelaide Natasha Rayan
Problem Background
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(SSMV 2007)
(The Safe Toilet Blog 2010)
Definitions of Sanitation
University of Adelaide Natasha Rayan
Problem Background
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Definitions of Sanitation
Shared Sanitation:
“sanitation facility that hygienically separates human excreta from human contact and is shared between two or more households, including public toilets.”
(WHO 2014)
University of Adelaide Natasha Rayan
Problem Background
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The Proportion of the population using improved sanitation (WHO 2010)
Access to Sanitation
University of Adelaide Natasha Rayan
Problem Background
• Over 3 billion people rely on burning solid fuels (WHO 2014)
• 4 million deaths per year (GACC 2010) • Solid Fuels
– Coal– Wood– Wheat– Straw– Manure
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Energy Usage & Indoor Air Pollution
University of Adelaide Natasha Rayan
Problem Background
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(UCR Today 2012)
Social Implications
University of Adelaide Natasha Rayan
Problem Background
• Modern Fuels– Ethanol– LPG– Kerosene– Biogas
• Fewer harmful emissions• More efficient• Higher temperatures
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Alternative Energy
University of Adelaide Natasha Rayan
Problem Background
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Indication of household solid fuel use globally (GACC 2007)
Solid Fuel Usage
University of Adelaide Natasha Rayan
Problem Background
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The Proportion of the population using improved sanitation (WHO 2010)
Access to Sanitation
University of Adelaide Natasha Rayan
Problem Background
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Indication of household solid fuel use globally (GACC 2007)
Biomass Usage
University of Adelaide Natasha Rayan
Scope
• Design and build a WHO defined “shared sanitation” facility for waste collection
• Employ anaerobic digestion as a waste management strategy
• Ensure portability
• Comply with relevant Australian Standards
• Demonstrate a viable use for the biogas
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Objectives
University of Adelaide Natasha Rayan
Technical Background
• Human waste is harmful• Pathogens
– Viruses, bacteria and parasites spread disease
• Requires treatment
University of Adelaide Charlie Savory 14
Waste Management
• Aerobic: The breakdown of organic matter in the presence of oxygen– Major product CO2
• Anaerobic: The breakdown of organic matter in the absence of oxygen– Major product biogas (CH4 and CO2)
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DigestionTechnical Background
University of Adelaide Charlie Savory
Technical Background
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(Amon et al. 2005)
Biogas
Technical Factors- Temperature- Retention Time- Volatile Solids %- C/N Ratio
Gas Component
Concentration Range
Mean Value
Methane 45-75% 60%
Carbon Dioxide 25-53% 35%
Water Vapour 0-10% 3%
Nitrogen 0.01-5% 1%
Oxygen 0.01-2% 0.3%
Hydrogen 0-1% <1%
Ammonia 0.01-2.5mg/m3 0.7%
University of Adelaide Charlie Savory
Technical Background
• Thermophilic: 49°C – 57°C– 10 day retention time– More common in developed industrial countries
• Mesophilic: 30°C – 38°C– 30-40 day retention time– More applicable to developing countries
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Temperature & Retention Time
University of Adelaide Charlie Savory
Technical Background
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Indication of household solid fuel use globally (GACC 2007)
Biomass Usage
University of Adelaide Charlie Savory
Technical Background
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(Salam et al. 2005)
Biogas Output
Feedstock Biogas Yield (L/kg)
Daily Production
(kg/day)
Daily Biogas Production
(L/day)
Human 30 0.6 18
Cow 25 12 300
Chicken 100 0.1 10
Pig 25 2 50
University of Adelaide Charlie Savory
Technical Background
• Biodigester– Sealed container in which anaerobic digestion process
takes place
• Existing designs– Fixed dome– Floating drum– Plug flow
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Existing Designs
University of Adelaide Charlie Savory
Technical Background
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(SNV 2009) (Energypedia 2009)
Fixed Dome Biodigester
University of Adelaide Charlie Savory
Technical Background
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(SNV 2009) (Energypedia 2009)
Floating Drum Biodigester
University of Adelaide Charlie Savory
Technical Background
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(SNV 2009) (Maximiliano Ortega 2008)
Plug-Flow Biodigester
University of Adelaide Charlie Savory
Technical Background
• Prefabricated, portable biodigesters versus brick/concrete based biodigesters
(Cardo 2013) (Solar Cities 2010)
Emerging Designs
23University of Adelaide Charlie Savory
Technical Background
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(Coffee et al. 2009)
• Design fits the scope of 2014 project
• Several issues with design and testing
Combined Systems
University of Adelaide Charlie Savory
Design
Isolate human waste from the user of the toiletUse the waste collected to produce biogasAffordable for low income communitiesSimple to assemble and disassembleEntirely portableSimple to use and maintain by the end users
University of Adelaide Nishanth Cheruvu 26
Criteria
Design
27
Conceptual
• 4 conceptual designs• Differed in several
important ways– Digestion stages– Biodigester mechanism
• Shared common aspects– Simplicity– Effectiveness
Concept Design 1
University of Adelaide Nishanth Cheruvu
Design
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Common Aspects
Crushed BricksOutletGas Collection
University of Adelaide Nishanth Cheruvu
Concept Design 1
Design
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Preliminary Design
University of Adelaide Nishanth Cheruvu
Design
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Preliminary Design
University of Adelaide Nishanth Cheruvu
Design
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Preliminary Design
University of Adelaide Nishanth Cheruvu
Toilet Location
Design
32
Preliminary Design
University of Adelaide Nishanth Cheruvu
Design
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Preliminary Design
University of Adelaide Nishanth Cheruvu
Inflatable Membrane
Design
34
Detailed Design
University of Adelaide Nishanth Cheruvu
Design
35
Digestion Tanks• 1000L polyethylene tanks• Lightweight• Easy to modify
Detailed Design
University of Adelaide Nishanth Cheruvu
Design
36
Detailed Design
Piping• 100mm PVC for waste inlet• 20mm Blue-Line Poly for gas flows• 50mm Suction Pipe for tank connections
University of Adelaide Nishanth Cheruvu
Design
37
Detailed Design
Bioballs• Form a biofilm• Avoid clogging of effluent at the outlet
University of Adelaide Nishanth Cheruvu
(Drsfostersmith 2014)
Design
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Costing
Subsystem Final Cost
Biodigester Tanks (x2) $400
Gas Membrane (x1) $196
Parts and Fittings $282
Toilet $0
Entire System $878
University of Adelaide Nishanth Cheruvu
Testing & Operation
University of Adelaide James Bass 39
.
Location
• Needed– Easy access to feedstock– Security– Willing land owner
• Urrbrae High School– Farm abundant with animal waste– Locked greenhouses and gates– Active biogas program
Testing & Operation
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Sourcing Feedstock
•Human waste difficult to source•Pig waste
• Easy access•Known biogas producer
University of Adelaide James Bass
Testing & Operation
• Fire and Explosion– Flame traps designed– Explosive zoning (AS 60079.10)– Warning signs
• Exposure to Pathogens– PPE use mandatory– Standard operating procedure
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Major Risks
University of Adelaide James Bass
Testing & Operation
• Urrbrae Greenhouse– Removed the need for insulation– Provided extra security
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Thermal conditions
University of Adelaide James Bass
Testing & Operation
• Tested for leaks before addition of feedstock• During construction, digestion process was
started in four 76L drums– Added to system once construction and safety testing
was completed
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System Start-up
University of Adelaide James Bass
Testing & Operation
• Continuous process to replicate shared toilet use• 245L total feedstock added twice per week
– Equivalent to 2.75L solid and 67L liquid added daily
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Operating Procedure
University of Adelaide James Bass
Testing & Operation
• Greenhouse temperature• Feedstock pH
– Indicative of system health
• Feedstock temperature• Gas composition• Flame test• Biogas volume
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Process & Data
University of Adelaide James Bass
Current Progress
University of Adelaide Kieren Sheehan 46
Construction
• Constructed entirely by project team• Issues with gas leaks• Two weeks to complete
Current Progress
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Prototype
• Completed and filled 11th September
• No toilet– To be installed
University of Adelaide Kieren Sheehan
Current Progress
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Preliminary Results
• No flammable gas produced• Biogas production expected in 2 weeks• Tested for CH4 & CO2
University of Adelaide Kieren Sheehan
Future Work
• Provided by Caroma• Construct wooden support
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Toilet
University of Adelaide Kieren Sheehan
Future Work
• If successful – Urrbrae will continue to run digester
• Otherwise– Digested waste disposed appropriately– Parts recycled
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Post Treatment
University of Adelaide Kieren Sheehan
Design Improvements
• Greenhouse provides warm environment• Include insulation
– Add insulating material– Tanks underground
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Improved Insulation
University of Adelaide Kieren Sheehan
Design Improvements
• Inflatable membrane– Cheap– Effective– Portable– Easily damaged
• Floating drum– Provides constant gas
pressure
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Improved Gas Collection System
University of Adelaide Kieren Sheehan
Design Improvements
• Cooker• Heater• Lamp• Generator
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Practical Application of Biogas
University of Adelaide Kieren Sheehan
Design Improvements
• Privacy• Access to toilet• Support user and toilet
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Toilet Housing
University of Adelaide Kieren Sheehan
Design Improvements
• Layer of scum forms on surface• Breaks up scum layer• Accelerates gas production
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Stirrer
University of Adelaide Kieren Sheehan
Summary
• Poor sanitation kills 2 million annually (WHO 2014)
• Solid fuel use kills 4 million annually (GACC 2010)• Biodigester toilet may address both issues
• Saving 6 million lives every year• Designed and testing prototype system
56University of Adelaide Kieren Sheehan
Thanks
• Dr Cristian Birzer• Dr Paul Medwell• Neil Harris & Urrbrae Agricultural High School• Mike Hatch• Paul Stewart & Mitre 10 Malvern• Caroma• Lynair Logistics
57University of Adelaide Kieren Sheehan
References• Amon, T., Amon, B., Kryvoruchko, V., Zollitsch, W., Mayer, K. and Gruber, L. (2007). Biogas production from maize
and dairy cattle manure—influence of biomass composition on the methane yield. Agriculture, Ecosystems \& Environment, 118(1), pp.173--182.
• Cleancookstoves.org, (2010). Data & Statistics. [online] Available at: http://www.cleancookstoves.org/resources/data-and-statistics/ [Accessed 23 Sep. 2014].
• Culhane, T. (2014). SOLAR CITIES. [online] Solarcities.blogspot.com.au. Available at: http://solarcities.blogspot.com.au/ [Accessed 16 Sep. 2014].
• Drsfostersmith.com, (2014). [online] Available at: http://www.drsfostersmith.com/images/Categoryimages/larger/lg_26378_35703D.jpg [Accessed 18 Sep. 2014].
• Hymans, G. (2013). China Non-Stop: Good manners in China: what could change?. [online] Chinanon-stop.com. Available at: http://www.chinanon-stop.com/2013/07/good-manners-in-china-what-could-change.html [Accessed 16 Sep. 2014].
• Junfeng, L., Runqing, H., Yanqin, S., Jingli, S., Bhattacharya, S. and Abdul Salam, P. (2005). Assessment of sustainable energy potential of non-plantation biomass resources in China. Biomass and Bioenergy, 29(3), pp.167--177.
• Junfeng, L., Runqing, H., Yanqin, S., Jingli, S., Bhattacharya, S. and Abdul Salam, P. (2005). Assessment of sustainable energy potential of non-plantation biomass resources in China. Biomass and Bioenergy, 29(3), pp.167--177.
• Ortega, M., Agriculture, I. and Society, F. (2009). Installation of a low cost polyethylene biodigester.• Snvworld.org, (2009). Biogas. [online] Available at: http://www.snvworld.org/en/biogas [Accessed 23 Sep. 2014].• Sswm.info, (2014). Overhung Latrine | SSWM. [online] Available at: http://www.sswm.
info/category/implementation-tools/wastewater-treatment/hardware/user-interface/overhung-latrine [Accessed 16 Sep. 2014].
• Teune, B. (n.d.). Sector Development for Domestic Biodigesters: Experiences of SNV, Dutch Development Organisation. p.125.
• UCR Today, (2012). Woman & Child Cooking. [image] Available at: http://ucrtoday.ucr.edu/6664 [Accessed 10 Sep. 2014].
• Who.int, (2014). WHO | Household air pollution and health. [online] Available at: http://www.who.int/mediacentre/factsheets/fs292/en/ [Accessed 23 Sep. 2014].
• World Health Organisation, (2014). Progress on drinking water and sanitation Joint Monitoring Programme update 2014. Geneva: WHO, pp.3-4.
University of Adelaide 58