12
Oct
2003
Comments Off
Where does the water in your tap come from?

If you are a resident in the Klerksdorp, Orkney, Stilfontein region, you are one of thousands using tap water treated and supplied by Midvaal Water Company. The Company buys water from the Department of Water Affairs and, after treatment, sells it to consumers.

Water is abstracted from the Vaal River approximately 15 km south of Stilfontein. Midvaalʼs installed capacity enables us to treat a volume of 250 000 kL (250 million litres) daily.

An adequate supply of safe water is absolutely necessary to ensure a healthy community. Clean water is still relatively cheap in South Africa when compared internationally. To cater for the demand of water supplied through the Vaal River system, there is a persistent need to transfer it from the Tugela River as well as from Lesotho.

The projects to build dams, lay pipelines and erect water treatment works are capital-intensive, and in order to recover the huge investments required, it is only fair that the user has to pay for this. It is inevitable that water-users pay for the right to obtain clean and safe water for their use, readily available in their taps.

Although water is Natureʼs gift, it has to be processed before it is available for household use. The water cycle entails the abstraction of water from the source and taking it through the treatment systems to reach households and, eventually, end up in the river again -completing the cycle. In order to achieve this complicated task, dams, canals, pipelines, pump stations and purification works have to be built and operated efficiently. This necessitates substantial capital expenditure and its funding appropriately.

Sewage water is not fit for human or animal consumption. For this reason, it needs to be purified. Sewage contains numerous bacteria and impurities. Some of these impurities can be utilised as food by specific groups of bacteria. At a sewage works, oxygen is added to accelerate the growth of these bacteria, thereby enhancing the utilisation of waste materials. The bacteria are then separated from the water and disposed of as sludge. The purified water is disinfected to kill harmful bacteria, after which it can be reintroduced into a stream or dam asthis water should be suitable for reuse.

Pollution

Pollution has a serious effect on the earthʼs fresh water sources. Polluted water is not suitable for recreational use such as swimming or fishing. Polluted water is also unfit for irrigation. Therefore, it has to be treated with expensive processes before it can be used again. Pollution from storm water drainage is difficult to prevent. The most successful approach is to educate the community regarding pollution prevention. In this way, through the combined efforts of all, people can prevent pollution and make a valuable contribution towards preserving scarce and precious water resources.

Industries contribute to the salt load of water sources, and these salinised effluents cause other problems. There is no natural treatment process to desalinise water and to do it physically, is very expensive and unsustainable. To date, the most economical method is evaporation in open dams. Here the salts are concentrated away from the fresh water sources. Over the past decade, significant progress has been made with the development of specialised technology to desalinate water. The cost of drinking water, resulting from the desalination of e.g. sea water is still quite high compared to the cost of tap water. However, the unavailability of fresh water worldwide forces many countries to make use of these technologies, as the only source of water available is often sea water/brackish water.

Agricultural activities can also be responsible for pollution. Fertilisers and pesticides as well as drainage of feed lots, stables and sties, contribute to the pollution level of water in that area.

Water pollution is a threat to our health. Bacteria and viruses in water are responsible for many diseases such as enteric fever, dysentery, cholera, polio and Hepatitis A (yellow jaundice). Toxic substances like heavy metals (lead, mercury, etc.) and pesticides are detrimental to the environment and water fauna, and can also cause chronic illnesses to humans (e.g. cancer, deformities, blindness and organ damage). All should be aware of the dangers of pollution and make a concerted effort to prevent it.

Useful Links

In the interest of promoting awareness of water and associated aspects, we suggest that you also visit the following useful websites for more information:

(You will need a suitable program to view pdf documents. We suggest one of the following: Adobe Acrobat Reader.)

12
Oct
2001
Comments Off
Interesting Facts About Water

Is it possible to drink water that was part of the dinosaur era?

  • Yes, water molecules are recycled in the water cycle

How much water in:

  • the human body – 66%
  • an elephant – 70%
  • a chicken – 75%
  • a tomato – 95%
  • a pineapple – 80%

How much water does the average home use during a year?:

  • 400 000 litres

How much water to process a hamburger?

  • 4 litres

How much to manufacture a new car?

  • 148 000 litres

How much of the earthʼs water is suitable for drinking?

  • 1%