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Mt. Everest Biogas Project. May , 2013 . www. MtEverestBiogasProject .org. 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.
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Mt. Everest Biogas Project May, 2013 www.MtEverestBiogasProject.org
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 Timeof 43 days • At 20°C the digester will make 2.1 m3Biogas/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.
We want the digester to be 30° C, but the process will work at 20° C 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
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
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 similar We 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
To Overcome the Digester's Heat Loss to the Ground Our Design Will Use: • 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
Wi ndow East Wall Water Tank Door | Waste Barrel | Drainage Into Sand Digester
Heater η= ~100% 9 Panels Required Pump η= 60% 4.39W < 1 Panel Required 10 Panels Required in Total Doors | Drainage | Window Water Tank | Solar Panels | Digester & Heating Pipes
Slurry In Digested Liquid Out Biogas Out Digesting Slurry Making Gas
Water Heaters - Hot Water Tank Hot Water Pump - Solar Panels Pipes in Digester Floor to distribute - heat from hot water
Window Effluent Out digester Mixing Station Storage Barrels | Water Tank | Solar Panels Doors Plan View of the Full System Effluent -Drainage Field
Benefits of the Proposed System: • 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
Lessons Learned from Site Survey -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.
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
________ Digester Site __________Porters’ Shelter
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
We are working on this project with: •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
Next Steps Forward • 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