On September 5th, Evides Industriewater officially commissioned its new pre-treatment installation of the Botlek DemiWaterPlant, in the port of Rotterdam.

The installation is equipped with the innovative spiral wound AiRO membrane system. Unique about the AiRo membrane system is its cleaning with air, reducing the use of energy and chemicals and prolonging the lifetime.

Supply to surrounding industries
The deminwater plant has a capacity to produce 1.400 m3 from surface water, serving over 15 surrounding industrial sites in the Dutch harbor.

First full scale AiRO installation
Markus Flick, general manager of Evides Industriewater: “We made use of our extensive knowledge on desalination of different water sources. We used the latest technologies, such as the AiRO concept. This concept was used at the DWP for the first time on a full-scale base."

The AiRO water treatment technology is an invention of the Dutch water supply company Vitens, further developed by KWR Watercycle Research Institute, tested by KWR and Evides Industry Water and now first successfully engineered, build and introduced by Logisticon Water Treatment

The AiRO concept was awarded in 2012 with the Design Honour Award by IWA Europe & West Asia.

Increased use of spiral wound membranes
Spiral wound membrane processes, like reverse osmosis (RO) and nanofiltration (NF), are increasingly used in water treatment for the production of drinking water, process water for industrial use and for waste water re-use.

One of the largest problems using membrane processes, however, is biological membrane fouling. This results in loss of performance (capacity/ quality) and increasing the total cost of ownership.

Biofouling only in first membrane
Often only the first membrane in a system is fouled due to biological growth on the membrane surface as a result of nutrients in the feed water. Most pre treatment such as sand filters or micro/ ultra filtration membranes do not take away all these nutrients and thus results in bio growth on the membrane surface of the RO or NF.

If this RO/NF membrane is positioned in a (horizontal) membrane pressure vessel together with more membranes (up to 7) this membrane can only be cleaned by cleaning all other membranes with chemicals in the same time.

The innovative AiRO process uses air/water cleaning in a separate frame with vertically positioned membrane elements to control membrane fouling. By making a separate skid with only one membrane in a vessel upfront a membrane system, only this first membrane has to be cleaned.

Air bubbles in feed water
By using the sheer forces of air bubbles in the feed water, the membrane surface is cleaned and biofouling is removed/ growth is stabilised without or with a minimum of cleaning chemicals.

This is only done with a low frequency when biofouling occurs. As special designed air inlet system provides an equal distribution of air and water during cleaning.

More information
Evides Industriewater (development and plant operator)
Rotterdam, the Netherlands
+31 10 293 5172

Kiwa Water Research (development of membranes)
Nieuwegein, the Netherlands
+31 30 606 95 11

Groot-Ammers, the Netherlands
+31 184 608260