www. mteverestbiogasproject.org may, 2013. 12,000 kg of waste left by climbers each year waste is...
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Mt. Everest Biogas Project
www.MtEverestBiogasProject.org
May, 2013
• 12,000 Kg of waste left by climbers each year
• Waste is hiked down to pits near Gorak Shep
The problem with human waste at Sagarmatha is getting worse
There is no room at Gorak Shep for new pits & yak feet sink down in old pits
Porters walk two hours past Gorak Shep to the new pit
The new pit is larger & located in a glacier’s drainage area
This area drains into Khumbu glacier’s watershed eventually polluting the Dudh Koshi
Every year climbers come from around the world to visit Mt Everest
The local people and the mountain
need a real solution to this problem
Engineers from the Mt Everest Biogas Project have developed a feasible
solution
Report of Our Progress: • Modeled Digester
Performance• Heat Loss Problem Analyzed• Preliminary Design Finished• Successful Site Survey
Conducted
Digester Performance Analysis:
• Dr. Paul Harris Biogas Model (University of Adelaide Australia)• Slurry made from 3 parts water : 1 part human waste• 8 m3 Biogas Digester
Results:
• Residence Time of 43 days• At 20°C the digester will make 2.1 m3 Biogas/day• More Biogas will be made at higher digester temps• All the waste will not be destroyed at temps below 20°C
Biogas can be made at low temperatures from only human waste.
12,000 Kg Waste * (4Kg Slurry / kg Waste) = 48,000 Kg slurry to be digested
8,000Kg slurry to fill the 8m^3 digester the first time 40,000Kg slurry left to feed the digester
At 20° C: (7.5 kg / hr) * (24 hr / day) = 180 kg / day can be fed to digester
40,000kg /(180 kg / day) = 222.22 days to feed all waste to digester
We want the digester to be 30° C, but the process will work at 20° C
The Results show that:
We must keep the digester at least 20° C to process all the waste while making biogas
The big problem is the cold ground at Gorak Shep will steal the digester’s heat
How much heat will the digester loose?
Picture of snow & fog at Gorak Shep on May 27th 2013
Our prospective site is behind the rocky hill on the left
Determining Heat Loss of the Digester:
• The digester’s heat loss was investigated with Computer Modeling(U.S. National Energy Laboratories software)
• Weather Data used in the model is from international satellite measurements over many years (TMY2 database)
• The Computer Model was checked by Hand Calculation, with different insulation and different temperatures
ConditionsBeing Modeled
HandCalculation
Computer
Model
Percent Differen
t
InsulationR-50
20°C 112 W 127 W 12%
30°C 167 W 243 W 31%
We used two different methods to determine how much heat is lost from the digester into
the ground
The two methods were very different, but their results are similarWe have chosen the higher number of 243 W to design a strong
solution
• Passive Solar Heating with a building will not work• We are designing for a 30°C internal temp to make more biogas• The operation will still work if the digester temp goes to 20°C
• Insulated Biogas Digester with Pipes in Floor• Insulated Building with Window for Passive
Heat• Insulated Water Tank Heated by PV solar
panels• Pump Moving Hot Water Through Digester
Floor• Drain Pipes to Dispose of the Effluent Outside
To Overcome the Digester's Heat Loss to the Ground Our Design Will Use:
Window
East Wall
Door Water Tank
| Waste Barrel
Digester
| Drainage Into Sand
Heater η= ~100% 9 Panels RequiredPump η= 60% 4.39W < 1 Panel Required
10 Panels Required in Total
Drainage |
| Solar Panels
| Digester & Heating Pipes
Water
Tank
Doors |
Window
Digested Liquid Out
Slurry In Biogas Out
Digesting Slurry Making
Gas
View of building from South West
View of building’s back from North East
Solar Panels
Hot Water Tank
Water Heaters -
Hot Water Pump -
Pipes in Digester Floor to distribute - heat from hot water
Plan View of the Full System Effluent
-Drainage Field
| Solar Panels
Water
Tank
digester
Doors
Window
Storage Barrels |
Effluent Out Mixin
g Station
• Direct heat transfer from solar panels to the water
• Efficient storage of heat energy in water
• Preheating of water to be added to slurry
• On demand heating of the digester
• DC wiring of the heater is more efficient than AC
• Heating element is in the water & not in the slurry
• Robust system components can survive transport to Gorak Shep
and harsh conditions of use, once installed
• Functions during extended periods of little or no solar energy
Benefits of the Proposed System:
-Food waste is available, codigestion with the human waste will increase the gas yield.
-The proposed site is an excellent choice:•The sandy soil will help insulate the digester.
•Risk of accidents by humans, animals or rocks is low •Solar exposure is very g00d
-Water is available and drainage conditions are very good for disposing of the effluent.
-The Tea House owners and waste porters all support this project. They want to form a local committee to keep the program running.
Lessons Learned from Site Survey
Unwanted Food Waste at Gorak Shep Will Increase Gas Yeild
Yaks are fed grass, but also fed food scraps that
have to go somewhere
About 10% of waste in the new pit beyond Gorak Shep was food
waste
By adding kitchen waste there will be even more biogas
produced at 30°C
The Proposed
Site
__________Porters’ Shelter
________ Digester Site
Water and Good Drainage are Available
The local people want to make this project happen
In Conclusion:The Mt. Everest Biogas Project Team has developed a design that can operate in the harsh conditions at Gorak Shep.
• Modeling shows that all the human waste can be destroyed in a year to make biogas, if the digester temperature stays at or above 20°C. We now know food waste will also be available.
• The heat loss has been modeled and verified with hand calculations. There is not a reasonable passive solution,
we must add heat. Sand at the site will increase heat retention.
• By sheltering the digester with a building and heating water to store solar energy as heat, our system can function at or above 20°C, even during periods of little of no sun light.
Thank you for your attention
•The porters at Gorak Shep•The Tea-House owners at Gorak Shep•Local Sherpa from the Khumbu Valley•Sagarmatha Pollution Control Committee•Sagarmatha National Park•Ministry of Tourism•Ministry of the Environment•Biogas Support Program Nepal•Mt Everest Foundation for Sustainable Development•The international climbing community•Engineers in Seattle Washington
We are working on this project with:
• Raising funds to begin the building process• Developing a local Biogas Committee at
Gorak Shep•Applying for permits with the National Park•Applying for permits with the other related
Ministries
Next Steps Forward
Thank you for your attention
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