Wastewater treatment is an area where simple, natural solutions are often not just cheaper, but more effective, than complicated technological ones. As fresh clean water becomes scarcer, recycling wastewater makes more and more sense.
Domestic wastewater can be divided into two main categories. Blackwater is water that contains human waste, that is, from toilets; while greywater comes from all the other sources in the house: showers, baths, washing machines, dishwashers and the kitchen sink.
Ecological greywater treatment is actually very straightforward: you just need to let nature do the work. Provided you aren’t using toxic chemicals such as chlorine-based bleach, greywater can be safely applied to the topsoil, ideally near plants that can benefit from the water and nutrients. Naturally occurring, beneficial soil bacteria will then quickly break down the contaminants.
So the main challenge in greywater recycling simply is how to get the greywater to the soil as effectively as possible. This is normally quite easy, as long as you keep a few things in mind:
- Greywater should be kept separate from blackwater, which requires much more intensive treatment.
- Greywater should be kept away from places that people frequent (e.g. lawns) or vegetables that people will eat raw. Placing the end of the pipe in a pit covered with woodchip is one way of doing this.
- Greywater is not suitable for passing through pumps, sprinkler or drip irrigation systems, or gravel beds, all of which will block rapidly. Nor should it be stored in tanks where it will become stagnant and smelly. It’s best to simply send the greywater directly to the soil by gravity flow.
- Where possible, use biodegradable cleaning products and avoid toxic chemicals like chlorine-based bleach.