New waste water treatment at AluK

waste water treatment

PCA has provided a new and comprehensive waste water treatment installation for the AluK plant located in Chepstow (Wales). Aluk is an international designer and engineer of high quality and performance driven aluminum window, door and curtain walling systems for both commercial and private purposes. The new water treatment plant was necessary because of the addition of a lacquering line with chemical pretreatment within the company.

When working with aluminum, pre-treatment of the profiles is of main importance to ensure the quality of the powder coating applied in the next phase. Our installation processes the waste water produced by this pretreatment phase, in which the aluminum profiles are degreased, stained and passivated. In addition, we process the waste water from the flash anodization. This is a further treatment of the aluminum profiles which ensures that the paint coating will bond very well through an oxide layer.

traitement des eaux

Part of the installation PCA has built at AluK provides the pre-treatment line of demineralized water (< 10 µS). 12m3 of demin water is produced in a closed circuit by means of an ion exchanger. This system ensures that the water can be reused, resulting in very little waste water being produced by this process. We only have to deal with a limited waste stream during the regeneration of the ion exchanger.

The subsequent anodization process is also provided with demineralized water, this time through reverse osmosis (RO). We opted for reverse osmosis because we were unable to work in a closed circuit for this process. With this RO, 2000 liters of water per hour is pumped through a semipermeable membrane at high speed. This technique seperates on ion level and ensures continuous production of demin water.


We chose for a physico-chemical purification to treat the waste water released from the above processes. Successive steps of coagulation, neutralization and flocculation precipitate the contaminants in the waste water, thereby obtaining a sludge fraction. A large decantation tank then causes the sludge to settle and thus be separated from the purified water.

In the next step of the purification process, the sludge is dewatered by using a chamber filter press with a volume of 1000 liters. The sludge is compressed between plates with filter cloths at a pressure of 15 bar.

As a final part of the installation, a break tank has been installed which provides the complete pre-treatment line of urban and rain water.

The result is a fully automated and sustainable waste water treatment plant which is capable of purifying 9m3/h of waste water through the above applications. The full water management of AluK was developed, installed and launched by PCA’s internal team, ensuring the right water quality for each step.