STEP BY STEP GUIDE TO USE THE OHORIZON WOODEN MOLD
Cut the 8' X 4' plywood, using Ohorizon's Instruction Manual
Follow Ohorizon's Wood Mold Instruction Manual to combine the pieces of plywood into the different mold parts.
Assemble the mold:
To prepare for pouring concrete. Apply oil to the mold to increase durability and prevent the concrete from sticking.Linseed oil or cooking oil can be used as a release agent. Another alternative is 30% candles melted into diesel, applied with a rag.
Mix and Pour Concrete:
Fill the mold with concrete: Leave to stand overnight.
Pull the centre pieces out from the mold, leaving a hollow centre.
Loosen the bolts to remove the outer pieces:
Remove filter from mold:
Fill this new filter body with water and allow it to cure for a further 7 days before installing.
Where can I find additional Information?
The OHorizons Wood Mold Construction Manual contains technical information on creating the Wood Mold, using the Wood Mold, and proper filter installation. For additional assistance on problem solving with the Wood Mold, creating diffusers, sourcing sand and gravel, and more please see the OHorizons Wood Mold Appendix, which can also be found on our website. For more information on educating the user, follow-up procedures, and more please contact OHorizons. We have many additional materials that may be helpful in planning and implementing your project. If we don't have the specific resource you need, we can help you locate additional resources elsewhere.
You can always contact OHorizons via the Contact form on our website (www.ohorizons.org)
Or you can email us directly at email@example.com
Stage F: Make the Diffuser
The purpose of the diffuser is to protect the top of the sand from moving around when you pour the water into the filter. This protects the biolayer. The diffuser also makes sure the water drips onto the sand evenly across the top of the sand. This way all of the sand can be used to treat the water. You can build a diffuser out of many materials. Use a material that you can find locally and that someone local has the skills to work with.
· Sheet metal (galvanized)
· Acrylic sheet
Diffuser boxes work better than diffuser plates. Diffuser boxes have to be made out of galvanized sheet metal. CAWST recommends making diffuser boxes.
- Holes should be 3 mm (1/8") in diameter. You can use a 3 mm (1/8") nail to make the holes. Larger holes will cause disturbance of the surface of the sand. Smaller holes will restrict the flow through the filter, possibly causing the flow rate to drop
- Holes should be spaced out by 2.5 cm (1") in a grid pattern.
- The diffuser should fit tightly inside the filter, and there should not be any gaps between the diffuser and the concrete walls. A gap allows water to travel along the walls of the filter, rather than being distributed evenly through the holes of the diffuser plate. A tight fit also keeps the diffuser from floating.
- The diffuser should be easy to remove.
Be careful working with sharp edges, especially when using sheet metal. Use gloves.
Stage G: Make the Lid
The purpose of the lid is to stop anything from getting inside the filter. You can build a lid out of many materials. Use a material that you can find locally and that someone local has the skills to work with.
· Sheet metal (galvanized)
· Simple wood
· Carved wood
· Ceramic tiles
· The lid should cover the entire top of the filter.
· It should not be easily knocked off the filter.
· It should be easy to take off and put on again.
· Some lids have handles, some do not. If there is no handle, people can store items on top of the filter lid.
· On wooden lids, the handle should be attached to the lid with at least 2 nails going into the lid at different directions, so that the handle does not pull out when you lift the lid.
· Wood lids should be painted with an oil-based paint to stop mould from growing inside the lid.
Download Handout #10 - BioSand Wooden Mold
SOWING SEEDS OF SUCCESS - MORINGA CURRICULUM