Just like New: Waste Water Treatment

Waste water is water that has become contaminated through use. It includes household sewage, municipal waste water, industrial effluent, collected rainwater and water that flows off paved surfaces. Waste water treatment is generally conducted in three to four stages in centrally located sewage works. The task of the mechanical first stage is to separate out large components, sand and settleable solids by means of screening, grit chambers, settling tanks or primary clarifiers. The biological second stage brings the remaining readily soluble waste water components into contact with bacteria and other microorganisms. The purpose of the third, chemical purification stage is primarily to remove contaminants such as phosphorus from the waste water. However, to ensure that the water that leaves the sewage works is really clean, a fourth stage is then necessary to remove pathogenic germs and viruses. This is where ultrafiltration technology comes into its own as a means of purifying the waste water without using chemicals.

But it is not only municipal sewage works that use ultrafiltration technology: There is also an increasing tendency for industrial concerns that purify their waste water on site to switch to this treatment technology. The membrane method not only enables the removal of products from complex material streams, but it also allows other useful substances or pure water to be separated out. Recirculation techniques can then be employed to re-insert these materials into the production process to enable them to be reused.

The number of people who have no access to adequate waste water treatment currently stands at 2.9 billion, 80% of whom live in the developing and newly industrialized countries of Asia. The WHO estimates that investments of 180 billion US dollars each year are required if drinking water purification and waste water treatment are to meet worldwide demand. These figures refer solely to increases in capacity and do not include the renovation or modernization activities that will be needed over the coming years, primarily in industrialized countries, in order to adapt sewage works to the latest technologies. The volume of business this will create for ultrafiltration technology is considerable and is set to increase sharply on a global level in the years ahead.

Waste water reference projects