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Raw Water Intake Screens (RWIS)

Bespoke screen designs for raw water extraction

The Eliquo Hydrok RWIS has been developed by our Design, Engineering and Manufacturing teams based on their vast experience of screening technologies utilising their years of experience designing and manufacturing CSO screens.

A growing requirement for stricter clean water screening, eel screens and for fish protection for water extraction from reservoirs and rivers for use as drinking water has led Eliquo Hydrok to develop highly flexible and adaptable screen designs that are able to match the consent requirement of different raw water sources.
The Eliquo Hydrok wedge wire screens can be made to fit the consent requirement from 2mm to 10mm or as required and are manufactured in the UK at our own factory, offering a bespoke raw water extraction solution to meet the specified demand of each specific water source.

Eliquo Hydrok offer a complete turn-key solution for the RWIS from bespoke design and manufacturing to installation, including the control centre technology and maintenance programmes.

The RWIS solution complies with the EU Habitats Directive and the Eel Directive for England & Wales.

How it works

All raw water intake screens are prone to clogging with water source debris and aquatic life which needs to be addressed to maintain the operational functionality of the screen. The Eliquo Hydrok wedge wire profiles will match the water consent requirement through regular purging of the screen in order to maintain the correct intake flow to the pipe work.

Eliquo Hydrok have developed an inner purging system that at pre-determined intervals, or manually if needed, backwashes the intake screen through an innovative Progressive Velocity Flow DistributorTM (PVFD) which maintains the flow rate within the intake screen from the source. Developed at the in-house R&D facility and first prototyped in 2009, this patent pending design works like a colander with variable orifice sizes to meet the demand of the flow rate needed. The PVFD sits within the main intake screen and is fed by compressed air to purge the screen as required.

At pre-determined intervals, a controlled, calculated volume of compressed air is used to purge the screen which creates a 2 stage backwash, a dual action screen purging, firstly with the displaced water within the pipe and secondly by high pressure compressed air blowing through the PVFD and removing any accumulated materials. The Eliquo Hydrok design team calculate the compressed air requirement and size it to suit the scheme and location accordingly. If more than one intake screen is required these can be installed in series so that each intake screen is purged in sequence to meet the water consent requirement.


  • Raw water from reservoirs and rivers for supply to Water Treatment Works
  • Water supply to desalination plants
  • Industrial raw water supply


Effective screening of raw water for clean water requirements