By simple definition, graywater is as any domestic wastewater produced, excluding sewage. One main difference between graywater and sewage (or blackwater) is the organic concentration. Sewage has a much larger organic loading compared to graywater. Kitchen water, though classified as black water because of its content of grease, oils and other organic matter can be treated for reuse if pre separated from sewage.With depletion of fresh water reserves, rethinking your water re-use should be appropriate.
Benefits of Graywater Re-use
Re-use doesn’t diminish our quality of life, however it can provide big benefits.
- Reducing the need for fresh water. This can significantly reduce household water bills, but also has a broader community benefit in reducing demands on public water supply.
- Reducing the amount of wastewater entering sewers or on-site treatment systems. Again, this can benefit the individual household, but also the broader community.
- Gray water is rich in phophorous and nitrogen from soaps beneficial to soil and plants
Where to use Graywater
Treated greywater can be used to irrigate both food and non food producing plants. The nutrients in the greywater (such as phosphorus and nitrogen) provide an excellent food source for these plants. Its however not to be applied on leaves and fruit of edible plants.
Where properly filtered, it can be applied through normal irrigation systems. Its best to apply slightly below or on the soil surface. Leach fields from gray water distribution may also be applied.
- Use when natural precipitation and normal irrigation water are not available
- Control gray-water application and infiltration to prevent standing puddles and surface runoff.
- Apply gray water to soil. Don’t spray on foliage, twigs or stems.Also don’t soak bark or root-collar area.
- Don’t use on root or leaf crops consumed by people or domestic livestock.
- Don’t use on new transplants
- Don’t use on indoor trees or other plants with limited rooting space, in small containers, or plants normally under saturated conditions
- Avoid using micro or regular sprinkler heads that can blow gray-water aerosols downwind
- Always apply gray water at or slightly below the soil surface. Apply over or under mulch, if present