Control at the source is the key to protect and manage raw water source and prevent it from being polluted, said Johanna Lindgren, Senior Adviser of Swedish Water & Waste Water Association.

"Control at the source, both at the water source and at the waste water plants as well as individual households are very important and effective," said Lingren in an exclusive interview with Xinhua at the ongoing World Water Week in Stockholm.

Accoring to her, in Sweden, the environmental law was issued in 1969 when the Environmental court was established and the Environmental Agency was formed.

Since then, the pollution in the lakes and rivers from industries have been cleaned up. The legislation regulates how much pollution can come from agriculture, industry and waste water treatment plant. And it is the state-owned water companies that manage the water source.

To protect the water source from pollution coming from agricultural pesticides and fertilizers which accounts for one fourth of the pollutants, two thirds of the drinking water plants have established their water protection zones in Sweden.

In the water protection zones which is much bigger than the water body area, farmers are restricted to use certain pesticides or fertilizers.

Farmers who live within the protection zones must build their own small scale waste water treatment facilities with the help of water companies and use less or no pesticides in the fields.

During the process, it involves not only government officials or officials from water utility, but also experts in both agriculture and water issues so that the farmers can understand the rules and implement them while their own interest is also taken into consideration, said Lindgren.

The water companies are very proactive and have the responsibility to provide information and organize meetings to discuss with the farmers living in the zone how they can reduce pesticides and fertilizers, added she.

In Sweden, all the industrial waste water must be treated by their own waste water treatment plants while the households sewage is treated in the state-owned waste water treatment plants. About 95 to 98 percent of the nitrogen, phorspherous and all the COD type of biodegradable pollutants can be removed from the waste water and turned into fertilizer or biogas. This way the water discharged into the lakes or rivers must have been treated.

Lindgred also said that a third way of protecting the water source from pollution is to raise the public awareness in not throwing hazedous particles into the toilet and use less detergent.

"Most of the pollution comes from clothes, and what you eat and drink. In Sweden, many water companies work with information to the people not to use detergent and pharmerceuticals and some pharmerceuticals are worse than others, they just pass through the waste water treatment plant, and to the lakes, " Lindgren warned.

She said Sweden is also working to implement the regulation that the waste water in rural households should also be treated, otherwise, that can cause a lot of algaes too.