Lenntech is a supplier of water treatment plants. The company promotes the Wet Cross-flow System units (WCS-units) on an and international scale. The system treats process water from ceramic plants in such a way that it can be reused in the ceramic production process.

The filtration process

In average the brick industry uses 60 m3/hour of process water. The main use of this water is for cleaning the moulds of the mould chain. The capacity of the required installation is calculated in close co-operation with the experts of the supplier of the press. The capacity depends on the number of moulds in the chain of the press.
The sand, clay and water are rapidly separated in one stage in the single tank of the WCs-unit. Sand / clay are gather at the bottom of the tank and this mixture is pumped by means of a tube-pump into an open-air sedimentation tank. Through the overflow of the WCS-unit the water flows free falling into the clean water basin. In this basin a pump is placed which pumps the water to the press. Where it can be used for rinsing, cleaning or for regulating the moisture content of the clay mixture. The latter application shows that we are dealing with very clean water!
The sand and clay are reused as well.
To improve the sedimentation of the sand and clay a little poly-electrolyte (0.1 % solution: 1 litre poly for 1000 litre in order to treat ± 400,000 litre of process water) is added and a lamella separator is used. The poly increases the density and the separator enhances the sedimentation.
The process of the total installation is in principle controlled by one pump. The type of pump used is capable to transport up to 60 % of dry matter, sand, clay. The water level in the dirty water tank is measured with a dryly-mounted sensor. When the water level reaches a certain level the pump is switched on. A PLC controls the entire process. When the pump starts the rest of the unit is automatically switched on as well. The energy consumption of the entire installation is about 8.5 kilowatt.

Mr. P.F.H. Collard, managing director of Facade Beek bv, The Netherlands stated:
"Several modification were necessary. Energetically these were carried out. After that the unit operates successfully and is nearly maintenance free and easy to operate."
In 1997 at Facade Beek a production plant for hand form bricks a 40 m3 installation was installed.
With the WCS-unit a large amount of water is saved, which not only brings financial savings. Next to the ceramic industry WET penetrates the glass industry and other industrial areas as well.

A compact unit, rapid erection and little maintenance

Strict environmental rules come in force in case of renovation and or changes in the existing production. In that case investment in a water treatment plant is good decision, which has a favourable pay back time. The compact WCS-unit (necessary surface area 2.5 x 3.85 m) absorbs little space and is easily transported all over the world and can be installed in a short time. The project manager from WET stays in close contact with the client in the period between the initial contact and the installation of the unit in the plant. In order train the operators and make sure that the unit is functioning well. The construction of the WCS-unit by the client ensures a fast supply.
A touch-screen improves the operation; therefore, it is possible to operate the unit after a short period of training. It is also possible to change a number of set points in order to optimise the unit for the specific process conditions. Since every client uses different types of raw materials the 'standard' installation is build up in such a way that extra adaptations can easily be made.