Home composting bins
Practical Action
Particle size, porosity, structure and texture
The ideal particle size is around 2 to 3 inches. In some cases, such as in the composting of
kitchen waste, the raw material may be too dense to permit adequate air flow or may be too moist.
A common solution to this problem is to add a bulking agent (straw, dry leaves) to allow for proper
air flow. Mixing materials of different sizes and textures also helps aeration the compost pile.
(a) Home composting methods
Large scale, commercialised composting facilities (Ex. Windrows, Static piles and Reactor
systems) use sophisticated technologies and equipments to handle the composting process.
Home composting depends on traditional or small scale simplified composting technologies at low
cost. (Ex. simple pit method, heap method, bins, rotating drums). But each method uses the
same scientific principle though it differs in procedures and equipments used. Appropriate/most
suitable home composting systems may differ from place to place depending on, climate
conditions, economic conditions and social factors of the people. In Sri Lanka, space limitation
has been a critical issue for many local authorities that have crippled the implementation of home
composting programmes.
Most common home composting systems in Sri Lanka
1. Heap method
2. Pit method
3. Traditional Jeewakotu and basket methods
4. Rotating drums
5. Composting bin systems
Composting Bin System
Bin composting is the most popular and advance version of home composting system that
overcomes problems experienced in other composting systems. There are different types of bins
available for home composting and generally it varies from 200- 300L in size. These are from
different materials such as cement/concrete, plastic, metal, etc. The bins allow higher stacking of
composting materials and better use of floor space than free-standing piles. Bins can also
eliminate weather problems and reduce problems of odours, and provide better temperature
control. At present, most bins are designed to suit the urban landscape as well.
Plate: Different composting bin designs available in Sri Lanka. Credit: Practical Action South Asia
As mentioned before, composting bins are popular in urban areas with emerging solid waste
disposal problems and therefore, it is important to give proper guidance to the community in
using composting bins. It is identified that some technical and management problems have been
the main constraints in popularising the composting bin among citizens.
The bin design should facilitate the composting process with easy management practices.
Therefore, standard bin design should focus on;
Easy transportation and installation:
Good aeration (sufficient aeration for all parts of the bin - aeration hole diameter - <
1cm)
Drain the excess moisture (porous bottom pad)
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