NORRES‘s Pre-PUR® ventilation membrane is characterised by the use of Pre-PUR® raw materials which provide many benefits. NORRES Pre-PUR® is unplasticised thereby preventing embrittlement of the material. At the same time, the high-quality Pre-PUR® used is chemically, hydrolytically and thermally stable thanks to the raw material used. This material is longer lasting than other plastics and rubber compounds and provides very high mechanical resistance while maintaining flexibility. NORRES ventilation technology is used in many areas of industrial wastewater treatment. These include permanent intermittent aeration, the mixing of aeration tanks, or the ventilation of reservoir and storage containers, as well as aquaculture or the renaturation of lakes and rivers.