Steplight recently conducted a sustainability workshop on greywater for Liverpool City Council. Marta Lett shares some key points on the topic here…
What is greywater?
Greywater is wastewater from household areas including showers, baths, basins, sinks, washing machines and dishwashers. Reusing greywater can save up to 50,000 litres of drinking water per household per year. Reusing greywater has health implications for ourselves and the environment. Following a few simple steps will keep your families safe and your garden soils healthy.
Do’s and don’ts of greywater use
- Wash your hands after watering with greywater
- Use garden-friendly cleaning products that are biodegradable and low in sodium and phosphorous
- Pipe greywater underground or under mulch to water your garden
- Irrigate your ornamentals and orchards, making sure greywater is not in direct contact with fruit
- Regularly check your greywater system is working properly
- Divert greywater to the sewer during wet periods
- Stop using greywater if someone in the household is sick
- Don’t use greywater that has disinfectants and bleaches in it
- Don’t store untreated greywater for more than 24 hours
- Don’t use greywater to water vegetables and herbs that are to be eaten raw or partly cooked
- Don’t use greywater sourced from washing nappies or soiled clothes
- Don’t use greywater from kitchens, unless it has been treated
- Don’t let greywater leave your property
- Don’t use greywater that is still hot as it will kill beneficial organisms in the soil
- Don’t spray or hose greywater.
What you put in water has an environmental effect on where the wastewater ends up (such as backyards). The chemicals in greywater can alter the condition of soils by changing their chemical composition and structure. This includes changing soil pH and the ability of plants to absorb moisture and nutrients from the soil. Soil pH testing kits and soil conditioners are available from any plant nurseries.
Choose laundry detergents that are low in sodium and phosphorous. Liquid laundry detergents tend to have lower sodium content than powdered laundry detergents. Lanfax Labs have done extensive testing of laundry detergent brands and types to determine levels of sodium and phosphorous content.
- Avoid all hard soaps due to high salt content
- Avoid products containing zinc
- Choose products with low sodium and low phosphorous content
- Choose body washes in preference to hard soaps, as there are no problems with soil pH being altered
- Sodium level in most shampoos and conditioners is low
- Hair conditioners tend to produce a low pH in soils and shampoos tend to produce a slightly higher pH in soils. As these are usually used together they are unlikely to alter soil pH.
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