Constructing a biogas eco-system The use of biogas in Yan'an

Constructing a biogas eco-system

The use of biogas in Yan'an,

Shan Xi Province of China

Context

the need for proper sanitation in certain infrastructure challenged areas.

concern when discussing the general awarness towards the phenomenon

the locals in the envisaged areas do not have the means for expensive radical solutions

Yan'an region - Chinese case study

Starting point

Bill Gates funding for proper waterless sanitation.

solar energy based.

costs ?

effectiveness in rain season countries ?

real parameters of implementing ?

The Chinese initiative

Pros:

time test

cheaper alternative

energy producing waste

smooth implementing

large part of the population can benefit

The Chinese initiative

Cons:

- dependent on water supply but also applicable to latrine type facilities.

- Costs relatively high but subsidized by the state.

How it actually works

Basic principle: Collecting human (and animal, if available) excreta and other biodegradable waste into a digester in order to produce biogas.

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Sticky Note

Pig waste, combined with human excrement from a toilet can be fed into a biogas plant. Bacteria in the plant decompose this waste matter under anaerobic conditions. The decomposition produces biogas, which consists of 60-70% methane and 30-35% carbon dioxide, and a semi-solid residue.The biogas is piped into the house and connected to a two-ring stove for cooking, a lamp for lighting and a water-heater for showers.These plants provide clean fuel for cooking and lighting which replaces wood and coal, and they also improve sanitation and hygiene. Thesolid residue from the plants is also a valuable fertiliser.

Biogas impacts

Specific:

The gas is used for electricity and cooking.

The solid residue is used as organic fertilizer (and organic pesticide). This lessens soil pollution

discharged water may be reused.

Additional environment relevant facts:

Preserve the wood resource.

preservation of ground water.

Improved air quality

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Sticky Note

direct avoidance of CO2 from coal and unsustainable wood use

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Sticky Note

It prevents effluent form seeping into ground water and reduces the level of pathogenic bacteria.

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Sticky Note

direct avoidance of CO2 from coal and unsustainable wood use, and also the reduction in methane emission from pig manure

Yan'an case

The Shaanxi Mothers' Environmental Protection Volunteer Association.

The plants produce biogas from pig and human

waste.(+ rain water collection cellars)

1,294 biogas plants in rural farming households since 1999.

Costs: 440-560USD (divided among locals,

government and NGO)

A household saves 4.5 t/year fuel wood.

Challenges:

The extensive use of wood and coal led to rapid economic growth - environmental damage.

soil erosion is widespread

springtime flow in the rivers has diminished to a fraction.

Erosion leads to dust storms and poor outdoor air quality.

the use of wood and coal is polluting.

Solution

Government solution: Farmers are paid to plant trees and encouraged to use biogas.

NGO solution http://www.youtube.com/watch?v=ZMreH1YUs90

Documents

Constructing a biogas eco-system The use of biogas in Yan'an