Grey water is the solution to the problems relating to demand and supply management of water not only in South Africa, but worldwide.
- Supply management of water is water supplied by the municipality to your doorstep. The supply of water is severely stressed in South Africa. In simple terms, we do not have any more places to put any more dams, in any more rivers.
Grey water is defined as water from baths, showers, hand basins and clothes washing machines or the laundry. Any water from any other source ( toilet water, and from kitchen and bidet’s) is considered black water, and must be allowed to proceed to the sewer, and be treated by some sort of sewerage treatment works.
Grey water is the biggest contributor to wastage of water and though knowledge of this very useful source is growing generally, this knowledge is still woeful.A best 33% of water consumed in the home is normally thrown away, and at worst perhaps 50%. It is preposterous that any municipality allows this precious source of good water to be thrown away. Grey water is very useful for two purposes, re-used for toilet flushing or for irrigation purposes.
There are several rules for the re-use of grey water and these are:
1. Thou shalt not store grey water: This is the first law and may not be changed: the problem is that grey water has temperature and food value for anaerobic bacteria to breed and produce methane and hydrogen sulphide, the stuff that smells so badly. Any talk of a “tank” into which grey water is fed and used for any purpose whatsoever is simply not possible. Any “tank” will build up sludge, and this is quite unacceptable.
2. Do not let grey water pool: sending water to flood irrigate gardens on a regular basis means that a bacteria will clog the soil, preventing penetration of water into the soil, that needs to be overcome by some sort of cultivation.
3. Grey water must be sprayed under very low pressure that does not exceed 6 metres head at the sprinkler. This will prevent any atomizing of the sprayed water particles. Grey water contains bacteria of many types, and the particles of water must land on the soil, and not float down wind to be breathed in downwind. Spraying means that the likelihood of polluting groundwater is eliminated. Grey water is dirty water and may not be fed into any irrigation system; this includes drip irrigation, because all irrigation systems require clean water and high pressure.
4. Perhaps the most important aspect to the re-use of grey water for irrigation purposes is what to use for washing powders. The use of any phosphate rich washing powder will poison your soil over the long term. There are phosphate free washing powders on the market, and these must be used.
If irrigated: moist soil teems with good bacteria, and will digest the food value of grey water in hours. The byproduct of this digestion process is food (fertilizer) for plants to grow, and water. That is your garden will grow fine without the need for any additional inorganic fertilizer whatsoever.
Grey water may also be used for toilet flushing purposes. With this aspect the grey water is stored in multiples of small pump chambers (not tanks), and pumped directly into the toilet pan. The resultant saving is nearly as good as that of the re-use of grey water for irrigation purposes.
Failure to use grey water for either purposes means that toilet water as well as the grey water is transported (mostly pumped) in the same pipeline to sewerage treatment works. There are 26 sewerage treatment works in and around the Greater Cape Town area and not one of these are able to cope with the volume of water reaching the treatment works. Cape Town is more than 6 billion Rand behind in building new and upgrading existing sewerage treatment works. This means that even if the pipelines taking this effluent could cope with this volume, all of these treatment works are spilling raw untreated sewerage effluent that they cannot process into rivers, canals estuaries and directly into the sea. The toxic state in all the estuaries has only those not re-using grey water and these sewerage treatment works to blame. This is only because of the water aspect in the effluent volume of combined black and grey water. If everyone should remove their grey water from the sewers, and minimize their toilet flushing with a Water Rhapsody Multi-Flush, the volume of water reaching the treatment works would be reduced by 90%. This action alone would mean that these treatment works would be able to cope with the sewerage effluent reaching the treatment works.
Cape Town is not unique in the sewerage problem. South Africa as a country is 66 billion Rand behind in their capital spending for sewerage treatment!
The department of Water and Environmental Affairs and municipalities are unwilling or unable to help, but you can make a difference by re-using grey water and minimising toilet flushing to allow the treatment works to cope. For a full product range see Water Rhapsody Conservation systems.
