Home composting bins
Practical Action
B) Design modification in concrete bin
Design modifications were done with considering the scientific requirement of the
composting process and practical problems experienced by the users.
Concrete bin widely used in Sri Lanka
Bin with modifications
When bin designs were identified at the beginning, it did not include aeration holes in the bottom
ring. Aeration is a critical factor for composting process and as a result, delayed composting and
bad odour problems were identified.
The bin modified by Practical Action includes the following features:
To improve the aeration, the modified bin was designed with more aeration holes. 70-100
holes were included in each ring and the diameter of these holes was less than 1cm (this
minimise pest entering).
Previous bin designs included only one door of 10”x3.5” for compost removing purposes.
As people encountered difficulties in compost removing, the new bin was designed with
three compost removing doors of 10”x3.5”.
Some designs included a bottom pad which enabled the bin to stand steadily and prevent
rats entering. But, it was not porous enough to drain excess moisture. Therefore, the new
design included a permeable pad with 5-10 holes of ½” size to enable draining of excess
water. Further, it facilitates entering of soil micro organism to the composting process.
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