Charfield STW Case Study: Inlet Screen Replacement Project

Project Profile

Installed on site was an old 20mm bar screen discharging into a launder feeding a macerator and licep unit. All the equipment installed were at the end of their asset life and were constantly failing. The inlet screen was also allowing rag to bypass it due to its age.
 

HUBER Technology Supplied

• HUBER Micro Strainer ROTAMAT® Ro9/700/6 without washwater or compaction, throughput 150 l/s peak flow/700/6  without washwater or compaction, throughput 150 l/s peak flow
• HUBER Screenings Wash Press WAP®/L size 2 screenings handling unit
• Control Panels
• HUBER Launder Channel HLC
   

Objective

After an initial site visit, the Wessex Water delivery team gave us a challenge to fit a screen without the normal requirement for washwater ruling out travelling fine screens - HUBER EscaMax® screens. The pumped flow to the screen would peak at 150l/s, which meant that a HUBER Micro Strainer ROTAMAT® Ro9 combined screen would be working on its upper limit. 

The inlet screen channel was 700mm wide and 900mm deep and was too far away to get a skip local to the screen. We then looked at a screen discharging into a launder feeding a HUBER WAP®/L size 2 compactor. We were also challenged due to a lack of washwater on site.
 

Solution

We modified our combined screen (HUBER Micro Strainer ROTAMAT® Ro9) so that it ran without washwater and no compaction, it was essentially a conveyor to elevate the screens into a small washpactor (Washpress WAP®/L). This Inlet screen was one of the first Ro9’s without the washwater feature to be supplied into the UK for the Wessex Water inlet screen replacement projects. This innovative idea of discharging from the Ro9 into a launder was a success and is currently working extremely well.

The lack of wash water for the launder resulted in an additional modification - Wessex Water fitting a submersible pump in a chamber upfront of the screen, this chamber had a 6mm perforated plate upfront to prevent large rag blocking the pump. The pump starter was included in our control panel and was linked to the screen start.  

Adrian Heneghan, Area Manager for HUBER Technology said “This was a considerable challenge for all involved and the end result was a great success. The communication between the client and the contractor was crucial. This type of installation could be used on sites where wash water is limited.”