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