Llanfyrnach Sewage Treatment Works required an Inlet Screen to screen all sewage and limit the flow to treatment to 2.65 l/sec. The existing Inlet area was at the top of the site with no vehicular access and an unreliable wash water system, where flows needed to be raised by a metre to allow the site to operate on a gravity basis.

Haigh installed a 490 ACE screener with an inlet box to process all of the incoming flows and storm returns, with manual grit removal and a LS305 Lisep/Lipactor station on top of a gantry, discharging into a Haigh Carriskip at ground level. 

An automated downstream flow control and flume arrangement were then mounted directly onto the downstream side of the prefabricated inlet, incorporating a weir arrangement to limit the F.F.T. to 2.65 l/sec, and direct the remainder of the flow to storm. A simplex control panel was also provided to control the screening system, while lighting columns were installed on the gantry for operator safety during dark periods. Given the restricted access to the site, the Haigh Environmental team was able to split the gantry and the equipment into three sections for ease of installation, which took less than three days.

The site saw a reduction in operating costs and no additional dilution of inflow to the main works, thanks to the ACE Screener system’s zero wash water requirement. The 64% screenings capture ratio significantly improved the process efficiency of the main works, with screenings pumped to the most suitable discharge point at a remote distance from the channels. This ACE Screener design has allowed for quick and easy maintenance in-situ, despite the small site size.