What is Class A water

Class A water means that organic, inorganic and biological impurities have been removed, leaving you with clear, good quality water.  It looks just like the water from your tap: clear and with no odour.  However, purified grey water should never be drunk.

	Target (Australia & California)	Perpetual Water – Home® results
E.coli	10 cfu/L	√ 0cuf/L
BOD5	<20mg/L	<2mg/L
Suspended solids	<30mg/L	<2mg/L
Virus	<1	0
Protozoa (per 50L)	<1	0
pH	6.5 – 8.5	6.5 – 8.0
Turbidity	TBA	0.7
Residual chlorine	<2mg/L after 30 mins	0.5 – 2mg/L after 30 mins

Garden-ready water

This table gives an overview of the results achieved by the GardenAngel.  It has been extensively tested with a range of different detergents.  This water is to be used for sub
-surface irrigation and should never be drunk.

	Untreated laundry grey water (typical)	GardenAngel Results
pH (measure of alkalinity or acidity)	8.5 - 10.5	6.0 - 7.0
Turbidity Cloudiness of water)	50 - 120 ntu*	<2 ntu
SAR Sodium absorption ratio	6 – 10	1 - 3
Phosphates	25mg/L	<1 mg/L

pH levels

pH is a parameter that indicates whether the water is alkaline or acidic. Laundry detergents specifically raise the pH of water to assist stain removal, making grey water from the laundry highly alkaline, with common pH levels between 8 and 10.
Addition of highly alkaline laundry wastewater to soil can increase the soil pH which can affect plant growth. The availability of nutrients required for plant growth is dependent on soil pH. As such, important nutrients will not be available for plants if the soils pH  is wrong.
The Garden Angel reduces the pH of grey water to between 6 – 7 which is neutral and will not change the pH of the soil. 

GardenAngel Phosphorus Reduction

Phosphorus is an important nutrient for plant growth. Many Australian native plants are intolerant to high concentrations of phosphorous. It is a key ingredient in most garden fertilisers so using raw grey water from the laundry will initially encourage growth of a nice green lawn or garden.  As the Phosphorus level in the soil increases, the plants will suffer. Phosphorus that cannot be absorbed by plants can run off into waterways causing contamination of ground water which can lead to algal blooms.

Most laundry powders contain a high level of Phosphorus, generally as phosphates, which can damage plants and the environment through untreated grey water use.  In Australia there are two phosphorus ratings for laundry detergents:

• NP – no added phosphorus
• P – Less than 7.8g P/wash (a voluntary rating system)
  

Concentrations of phosphorus in raw grey water range from 5mg/L for NP detergent to 53mg/L for P detergents.

The GardenAngel is suitable for use with laundry detergents even if they have a high concentration of phosphorus.  The Garden Angel can reduce phosphorus in grey water by up to 99.8%

Sodium Adsorption Ratio (SAR)

This is the ratio of sodium salts to magnesium and calcium salts in water. Laundry detergents often contain high levels of sodium salts which soften the wash water, assist in cleaning and act as fillers for the detergents. High sodium concentrations (salinity) in irrigation water can reduce the plants’ ability to take up water from the soil and affect plant growth. Over time salinity can build up in soil, degrading the structure of the soil which reduces the amount of water that can be retained.

An SAR value below 3 means salts are balanced and the grey water will don’t damage the soil.  SAR values of above 3 can cause permanent damage to soil, making it hydrophobic (won’t absorb water).  Raw grey water from the laundry can have a SAR of between 6 and 10.  The GardenAngel reduces the SAR to between 1 and 3. 

Turbidity

Turbidity is a measurement of water clarity or cloudiness caused by the amount of solid particles suspended in water.  Raw grey water from the washing machine is highly turbid (cloudy) as it can contain detergent residue as well as dirt that is removed from the clothing.  If not properly filtered, particles in grey water can clog up sub-surface dripper systems.  The GardenAngel conditions and filters the water so it flows easily through dripper systems. 

TIP: The longer the water is left in the tank before distributing, the clearer the water will be and the longer the filter will last.