It is said that the next wars will not be fought over oil, but rather over a far more precious resource, water. Changing weather patterns have caused enormous droughts in some parts of the world, Australia is one example, but regional examples abound, for instance California has experienced water restrictions in the past, as have many other parts of the United States. This has lead many homes in drought prone areas to install greywater treatment systems.
One of the first casualties of water restrictions are gardens. As a first step authorities usually restrict watering to certain times and amounts. If the drought worsens watering gardens is usually banned outright. Greywater is water that has been used for bathing, washing dishes or doing laundry and can consist of up to 80% of the water used by a household. Water from some portable and basement dehumidifiers are also classified as greywater. By installing greywater treatment systems households allow for greywater recycling. Once the greywater has been treated it can be used for gardening purposes, or for other tasks like washing the car. Recycled greywater is generally not suitable for human consumption. Dwindling levels of fresh water have also caused authorities in some parts of the world to investigate the use of greywater for large scale irrigation.
Although plants and greywater make a great combination care should be taken to ensure that the water can be classified as grey. With higher levels of contamination, such as large concentrations of household or industrial solvents, water becomes ‘dark grey’ and may not be suitable for use in gardens where these high concentrations of contaminants can poison plants. In this case specialized processes must be employed to remove or reduce the amount of contaminants in the water. One of the ways to remove contaminants, especially biological ones is through the use of greywater treatment chemicals. One of the most widely used of these being chlorine, however chemical treatment is falling out of favor due to its potential impact on the environment. Newer techniques like using treatment chemicals to cause coagulation of the contaminants, using settlement tanks are increasingly gaining favor.
Greywater usage is becoming more and more popular as strains on the natural ecosystems of the world become more and more apparent. For countries such as those found in sub Saharan Africa and the Middle East the use of greywater is not simply a good idea, it is essential for their continued development. Although there is almost no legislation governing the installation of greywater treatment systems some states will not permit greywater systems to be installed in newly built houses.
There are an estimated eight million greywater installations in the United States, with 22 million users and to date there is no evidence that anyone has gotten ill or suffered any harm through the use of greywater treatment systems. On a practical note, greywater recycling is not only good for the environment but can reduce the expense associated with fresh water. As noted previously up to 80% of the water used in the household can be reused as greywater so the saving can be considerable.