Farmer's Weekly (South Africa)
Communal Farming
It’s affordable, can be set up without any special skills or tools, and could help solve your winter feed problem!
Feeding livestock in winter, when the grass becomes dry and low in nutrition, is a problem for many communal farmers. Fortunately, many communal farming areas nowadays have access to electricity, and this can be used to power a relatively cheap, single-phase extraction pump to irrigate a small cropland or garden.
But where is the water to come from? The answer is to use grey water, the waste water left over from bathing, and washing dishes and clothes. About six years ago, I decided to start using grey water for irrigation, and was surprised by how much grey water we had daily.
Many people are put off by the idea of harvesting grey water, as they think it’s difficult and very expensive to set up. This is not so. You will basically need just three things:
• An extraction pump. This costs about R800, and cabling should cost no more than R200.
• Class-3 black plastic piping of 32mm diameter to attach to exterior PVC grey water plumbing outlets from your home. You should need 50m in total (about R300). • A 2 500ℓ plastic septic tank (between R4 000 and R7 000 depending on the make and where you buy it) placed in a 2m x 2m x 2m hole in the ground in your backyard. If you are fortunate to have heavy clay soil, you may not even need a tank; you can simply dig the hole and it will hold the water without seepage. (If you have spare bricks and mortar, you may prefer to brick the floor and sides of the hole.)
SETTING UP THE SYSTEM
Attach the various pipes to channel water from your home to the hole/ buried tank. Mount the electric pump nearby, with an extraction pipe extending to the bottom of the hole or tank. Add a gauze filter to the end of the pipe to prevent dirt or mud from being sucked up and damaging the pump. Lay a 20mm Class-3 pipe from the pump to the garden or small cropland you wish to irrigate.
Different size pumps deliver different pressures. My pump can turn one irrigation sprinkler on a tripod stand; we move the sprinkler about to wet all areas of the garden. You can also use a hand sprayer or flood-irrigate the garden or crops.
GET EXPERT ADVICE
Small pumps need to be primed before pumping water, so find out from the supplier how this is done on your pump. If not primed properly, the pump will not suck water.
Ask the supplier for advice if you need to operate more than one irrigation sprinkler, but avoid buying a pump so powerful that it drains the water in your hole/tank too quickly.
While buying the pump, it’s a good idea to ask the supplier to help you wire the pump and add a plug to insert into a single-phase wall socket or an extension lead socket.
ALWAYS ENSURE THAT A GREY WATER HOLE IS SECURELY COVERED
Based on these figures, the entire set-up, including buying a septic tank, should cost between R5 300 and R8 300. If you don’t require a tank, the total cost will be only about R1 300. (Note: these costs assume that you will dig the hole yourself.)
If you don’t have the money to buy a pump, you can still dig the hole or bury one or more 200ℓ drums to hold the grey water. You can then manually extract water using a rope-and-bucket system and irrigate with a watering can.
Always make certain that a grey water hole is securely covered to prevent children, livestock or pets from falling into it.
To keep the pipes clean of fat or soap build-up, flush them once a month or so with very hot, clean water; this water won’t be wasted, of course, as it will also be channelled into the hole.
HARVESTING RAINWATER
If you wish to harvest rainwater, consider digging an additional hole (or two) and installing a simple zinc sheet along the outer perimeter, angling it into the hole. Provided the hole is reasonably clean, you can use this water for livestock drinking water, washing clothes and so forth.