Grey Water Recycling

 In Grey Water Recycling, WC waste is separated from the remaining waste water. The first is disposed of in a septic tank in the ground, whereas the second is used to water the trees and plants. This system is a form known as Landscape Direct. This is the simplest form of grey water recycling. The grey water is distributed to the ground, to water the vegetation. This system follows the same principle used by nature. Nature’s rivers and streams contain clean pure water that has been treated by the system of beneficial bacteria breaking down the harmful content into water soluble plant food (on which plants thrive), leaving pure clean water.

What is Grey water?

Any wastewater generated in the home except toilet water.

What is the simplest form of grey water recycling?

An outside shower. The water drains to the ground, watering the plants. In countries like Cyprus an outside shower can be used in the spring, summer and autumn months.

Why use grey water?

• Saving fresh water.

• Less wastewater to septic tanks and treatment plants.

• More effective purification. (Top soil is a purification engine many times more powerful than engineered treatment plants or septic systems which discharge wastewater deep into the subsoil).

• Reduced use of energy and chemicals.

• Rich plant growth.

• Ground water recharge.

• Reclamation of nutrients which would otherwise be wasted in wastewater disposal.

• Cost savings.

• Environmentally good.

Is grey water recycling permitted?

Most forms of grey water recycling are permitted in many countries including Cyprus.

Are cleaning products damaging to plants?

Products designed to open clogged drains of clean porcelain without scrubbing must not be used in grey water or be replaced with alternative products or boiling water and elbow grease.

Are soaps damaging to plants?

Most hand and dish soaps and shampoos don’t damage plants at low residential concentrations. Laundry detergents on the other hand need to be selected carefully. Powdered detergents and soaps include “filler” ingredients (not essential to clothes cleaning), which are usually some compound of sodium which is harmful to plants. Liquid detergents contain water as the filler thus less sodium. Use soaps and detergents which are free from Sodium, Chlorine and Boron.

To minimise impact on plants take these measures in descending order of importance:

• Avoid washing more often, or using more cleaner than needed.

• Avoid using cleaners that contain Boron (Borax).

• Avoid using chlorine bleach or bleach containing Sodium Perborate. Do not use detergents “with bleach”.

• Avoid detergents that advertise whitening, softening or enzymatic powers.

• Use cleaners that contain little or no Sodium.

• Use plant and soil biocompatible cleaners.

What about urine and salt?

Urine can find its way to the grey water system if one pees in the shower. Urine is full of plant nutrients, primarily nitrogen but also potassium and phosphate. The bad news is that it also contains sodium. It is half as salty as sea water. In a year, a human being disposes of 3 kg of salt through urine. If the soil is not clay, and rainfall is high then urine would more likely be a long term benefit than a liability to the plants. With clay soil and low rainfall however it is best to exclude urine as much as possible from the grey water system.

Health considerations

There is no known case of grey water causing harm to humans but in any case the following should be observed

• Grey water when left to stand becomes black waste water in a few days. Do not allow grey water to collect and stand for long periods of time. Grey water should go in the ground as soon as possible.

• Grey water can be used to water fruit trees if applied under mulch (not on the foliage). Do not apply grey water to lawns or to fruits and vegetables that are eaten raw (e.g. strawberries, lettuce and carrots)

• Use gloves and wash hands after cleaning grey water filters and pipes.

• Do not allow grey water to run into streams and rivers of clean water. Grey water should be absorbed and cleaned by the ground top soil.

Ground preparation around trees

Prepare the watering basin around a tree as shown in the following diagrams.