The Mt. Everest Biogas Project will design and implement a sustainable solution to the environmental impact of human waste in the Sagarmatha National Park, below Mt. Everest base camp.
The issue of environmentally disposing of human waste created by mountain tourism is neither new nor unique to the Mt. Everest region. What is unique about this project is that it will adapt existing biogas digester technology that has been successfully implemented throughout Nepal, China, India and other developing countries, but at lower elevations and warmer climates. To bring this technology to the extreme conditions of the upper Himalayas, this project will combine the basic design of a Nepalese biogas digester with a low technology, off the shelf heating design that will allow the biogas digester to operate in a colder environment.
The solution uses off-the-shelf low technology systems that are available in Nepal and recognizes the extreme environment, remote location, and lack of infrastructure in the remote villages in the vicinity of Mt. Everest, The proposed solution will provide direct and indirect benefits to the people of the Khumbu valley in the form of a clean burning renewable energy source (methane gas), an odorless nutrient rich fertilizer and local employment during construction and long-term operation
The Mt. Everest Biogas Project, when implemented, will eliminate the annual dumping of 26,000 pounds (12,000 kilograms) of solid human waste at the teahouse village of Gorak Shep. Additional environmental benefits of this project are reduced reliance on burning wood or yak dung for heating and the resultant respiratory and ocular health risks; reduced deforestation of the areas limited wood resources; and a reduced risk of water contamination by fecal coli form.
If the design is implemented successfully at Gorak Shep, it could be replicated in other high altitude locations within Nepal or other developing countries.
Two major challenges that the project has had to overcome.
- The remote and high elevation location of Gorak Shep
- Maintaining the internal temperature of the digester
We are building our first biogas digester at Gorak Shep, a remote community in Nepal, on the trail to Mt. Everest base camp. It is reached only by a 5-6 day strenuous hike from the closest village at lower elevation. All supplies, food, and fuel must be carried on yaks or porters. There are no electrical, sanitation and water supply systems. To make things worse, all human waste from the Everest, Pomori, Lhotse, and Nupste base camps is dumped here in open pits. These pits slowly leech into the environment and contaminate local water supplies.
Because of the very remote location of our site, all materials must be carried in by yaks or porters. There is no means to bring in heavy equipment for the construction, so all digging will be by hand. Locally available materials and labor will be used whenever possible.
Heating for the biogas reactor is a major issue since the average ambient air and ground temperatures are below freezing most of the year. The slurry temperature inside the reactor needs to be maintained around 30°C for optimum gas production. As the temperature lowers, the gas production rate drops significantly. Near freezing temperature, no gas will be produced. Although some heat from the slurry is lost to the air, the majority of the heat loss is actually through the walls of the reactor, to the surrounding earth. This is a significant loss, and must be overcome to sustain the production of methane.Possible methods to mitigate heat loss include a greenhouse, compost heaping, solar heating, inlet heating, insulation, and a double-walled reactor. A greenhouse can provide a warm environment to elevate the ambient air and, for approximately a meter, ground temperatures, and to warm or thaw stored water and waste products. The greenhouse can also provide an environment for crop growth. To further minimize heat losses, the greenhouse roof can be equipped with a night curtain.
A Typical Biogas Plant
Any proposed solution must meet the requirement for implementation at Gorak Shep and to reduce risk and cost to the program must be off the shelf, low technology, available in Nepal and very rugged to endure the 5-6 day transportation to Gork Shep.
The Mt. Everest Biogas Project design team has iterated several design concepts for meeting the active heating requirements of the biogas system. A design concept was presented to the Gorak Shep teahouse owners and BSP-Nepal in June 2013. Based on their inputs, the design was modified and released in April of 2015 in a document titled “Basis of Design” (http://mteverestbiogasproject.org/basis-of-design-document/) which was subsequently vetted by the outside Seattle technical community. The design features an 3.2 kW solar array ; a 48 volt battery array for storing energy when there is no solar energy: a DC resistence coil inserted inside the digester and a well insulated masonary building built over the digester. The Seattle team of engineers believes this design will meet the extreme temperature conditions of Gorak Shep and is relatively straightforward.