In Sri Lanka, home composting is promoted in many municipalities as a simple and low-cost solution to emerging waste disposal problems in the present day society. In this process, valuable compost is produced using the organic components of household waste that we dispose of as being spent, useless, worthless, or in excess to our needs.

Different types of home composting units/bins are available in the market, which are manufactured from plastic, metal or concrete rings. Concrete bins have been identified as the most cost-effective and environmentally friendly solution, when compared to other designs. Production of concrete bins has been limited to a few fabricators in the capital city Colombo but there is a huge gap in the dissemination of this knowledge to the other small-scale fabricators in other parts of Sri Lanka. Therefore, this technical brief is intended to disseminate the technology of concrete composting bin fabrication.

Main component of 3-ring concrete compost bin

Plate-01. Credit: Practical Action South Asia

Moulds for the manufacturing process[edit | edit source]

During the bin fabricating process, each component of the bin is moulded separately in concrete. Moulds can be prepared using metal sheets or, preferably, fibreglass. Separate moulds are required for:

  • Basement
  • Bottom ring
  • Middle ring
  • Top ring
  • Top cover
  • Covering lid
  • Compost removing doors

Materials required for fabrication one concrete bin

Description Amount/rate Cost (Rs) as prices on 1/06/2005
Cement (rapid hardening cement 30.0 kg (cost-18000.00/mould) 300
Iron (1/4" rods) 1.25 Kg 112.50
Metals (3/4") 1.5 cu ft 60.00
Sand 1.25 cu ft 50.00
Paints 3 bins/person/day 60.00
Labour Assuming 100 bins are produced from 1 mould 275.00
Cost for mould 180.00
Total 1037.50

Fabrictaiong Process

A) Preparation of the concrete mixture

Material Ratios
Sand 4 pans (screened through 1/2" mesh)
Metal 3 pans (size 3/4")
Cement 30 Kg

Materials above should be well mixed and then gradually add water to have a free-flowing concrete mixture. A good finish can be expected by adding 1 pan of quarry dust.

B) Bottom pad

  1. Get the bottom pad mould (1" width iron ring that is bolted by one side) and place it on a polythene sheet laid on levelled ground (Plate-02).
  2. Pour concrete mixture into the mould (half –fill).
Plate-02. Credit: Practical Action South Asia
Plate-03. Credit: Practical Action South Asia
  1. Place iron rings (¼") as in diagram (three rings) Plate-03.
  2. Fill the mould with concrete mixture covering the iron rings completely.
  3. Level the surface using a straight pole and remove the excess concrete from the mould (maintain thickness 1").
  4. Locate 4-5 PVC pipe pieces (½ " diameter and 2" long each) to make the pad porous (Plate -04).
Plate-04. Credit: Practical Action South Asia

C) Bottom, middle and top rings (depend on the design)

  1. Get three separate moulds for top middle and bottom rings (correctly fix all components of each mould using bolt and nuts).

Before fixing the ring parts of the mould, some burnt oil (oil from petrol vehicles is preferable) can be applied to the inner side of the mould. It makes it easier to remove the blocks form the mould.

  1. Locate the moulds on levelled ground (Plate 05 and 06).
Plate-05 and 06. Credit: Practical Action South Asia
  1. Get the concrete mixture and pour it in to the moulds to fill 1-1.5" from the bottom (Plate -07).
  2. Insert first iron ring between inner and outer moulds – should not touch the walls of the moulds
  3. Fixed the plugs for aeration holes in all bins (Plate-09)
  4. Add concrete mixture gradually and spread it uniformly with a stick (Plate -08)
Plate-07 and 08. Credit: Practical Action South Asia
Plate-09. Credit: Practical Action South Asia

For middle and top rings

  1. Once the mould is filled up to 1-1.5" from the top level-place 2nd iron ring as first ring (Plate10).
  2. Fill the concrete mixture up to the top level of the moulds and levelled using a trowel
  3. After 30 minutes, fix the strip to the mould and add some mortar to make the inner interlocking grove (only for middle ring) and levelled (Plate-11).
Plate-10 and 11. Credit: Practical Action South Asia

For bottom ring

  1. Stop the filling the mould once the level of the concrete is close to 4" form the top.
  2. Insert the 2nd iron ring and add 1" thick concrete layer on it.
  3. Insert 3 sockets with equal spacing to leave the space for compost removing doors (Plate-12).

10. Fill the space between the sockets and insert iron rods from the sides of each door (6 rods 15" long and ¼" diameter) (Plate-13).
11. Cover the iron rods level the surface.

Plate-12 and 13. Credit: Practical Action South Asia

c) Top cover

  1. Place the mould on levelled ground.
  2. Apply some oil inside the mould (Plate -14)
  3. Fill the mould with concrete (¾ " from bottom).
  4. Place two iron rings (¼") (Plate-15).
  5. Fill with concrete up to the top level of the mould (1.5") leaving the space for the door (Plate-16).
Plate-14 and 15. Credit: Practical Action South Asia
Plate-16. Credit: Practical Action South Asia

d) Top lid and compost removing doors

  1. Place the mould on levelled ground.
  2. Apply some used oil in side the mould (Plate-17).
  3. Fill the mould with concrete (half).
Plate-17 and 18. Credit: Practical Action South Asia
  1. Place iron rods as shown in the diagrams (Plate-18).
  2. Fill with concrete up to the top level of the mould and levelled well.

e) Remove the moulds
If rapid hardening cement was used, the mould can be removed after 24 hours. Special care should be taken to remove the moulds from the concrete rings. Inner mould should remove first to minimise possible damage.

  1. Remove bolts and nuts in the flange of the inner mould and loosen it from the mould with a little knocking (Plate-19).
  2. Remove the inner mould with little curling (slide upwards) (Plate-20).
Plate-19 and 20. Credit: Practical Action South Asia
  1. Remove the nuts in outer mould and separate it carefully from the ring (Plate – 21).
Plate-21. Credit: Practical Action South Asia
  • The plugs that were used for aeration holes need to be removed in 3-4 hours. It is a little bit difficult to remove them after hardening.
  • Other components of the bins are easy to separate. A little knocking may be required to loosen the concrete blocks from the moulds.
  • These blocks are suitable to use after two weeks of maturating. (It is better to spray some water during the curing period.)

F) Painting
Painting can be done after the initial maturation period (2 weeks). Any colour can be used but dark colours are preferable to absorb more heat from the environment. Green is commonly used due to its association with environmentally friendliness.

Plate-22. Credit: Practical Action South Asia

Concrete compost bin manufacturers and mould producers[edit | edit source]

Bin Manufacturers:

Lakna Concrete Works No.125, Hiripitiya, Pannipitiya Tele: 011-4305792/ 071-4058045 Reg. No. WF 4104

Ruhunu Concrete Works K.K.D.Koratuwa Rd Polhena Tel:0412229262/077457133

M.G. Saman Ravindra No.171, Bandaranayakapura Malkaduwawa Kurunegala.

P.M. Prematilaka Silva No.2/234 "Senani" Thuduwa, Hungama

Bin Mould Producers[edit | edit source]

Lakna fibre works No.125, Hiripitiya, Pannipitiya Tel: 011-4305792/ 071-4058045

Prasantha Kumara Mel "Melsiri" Ullala Kamburupitiya Tel: 0773285516

Who to contact[edit | edit source]

Project Manager – Solid Waste Management or the Resource Desk at

Practical Action South Asia
No 5, Lionel Edirisinghe Mw, Colombo 5, Sri Lanka
Tel: +94 (11) 2829412 Fax: +94 (11) 2856188
E-mail: Web:

For specific training details please contact the Project Officer at Practical Action:
Hambantota (Tel: 047- 4379339 E-mail:
Ampara (Tel: 063-2224932 E-mail:

Discussion[View | Edit]

Tagging this page as needing to have contact details checked, and if necessary updated Joeturner 13:33, 7 February 2013 (PST)

We haven't yet looked at the issue of how we handle contact details. Perhaps as a general rule they could be left in, each with a small tag saying not checked, or last checked on (date)... Those tags would be implemented with a template or templates, for ease and consistency. --Chriswaterguy 18:05, 7 February 2013 (PST)
If I may be so bold as to suggest policy: information which contains outdated contact details is useless. Even if the source is originally from outside of appropedia, nobody can use the details if the contacts are wrong. Hence I believe they should be a) checked and b) updated. Joeturner 00:31, 8 February 2013 (PST)
Cookies help us deliver our services. By using our services, you agree to our use of cookies.