HOW DO I TREAT GREY WATER?

Grey water can be treated in a number of ways – some more effective than others. Gerhard Cronje explains how:

• Filters are essential because waste products such as hair, fats and soaps can damage pumps. Filters can be expensive, but you must choose wisely – cheap products and those with a too small filtration area will not cope and will need to be cleaned more often, which is not a pleasant task. • Ultraviolet lights can be installed in tanks to kill germs. • More advanced grey water systems put oxygen back into the water. Aeration also improves the colour of the water, making it clearer. Aeration can be done in one of three ways:

By adding hydrogen peroxide (H₂O₂). However, this is potentially dangerous as it could explode.

Other systems introduce ozone (O₂) to the water, but it is a strong oxidiser that erodes pipes and other surfaces.

A fine bubble disc diffuser breaks down air into fine bubbles, mixing it with the de-oxygenated grey water.

Bad odours can be reduced by adding blue toilet deodorisers to the cistern, using a chlorine floater (like those used in pools) inside your grey water tank, or a chlorine pump (about R9 000). But remember: if you use chlorine, the grey water cannot be used in the garden; it is only suitable for toilet flushing. >>