CF200 Band Screens Reduce Maintenance Costs Case Study

Background

Intensive weekly repair tasks that were required at the works when Escalator screens were in operation are now a thing of the past, with preventative maintenance now only required every six months.

Process

Tasman Water Brackett Green CF200 screens, which benefit from a flow pattern that draws effluent through its centre, has eliminated the traditional problem of 'carry over'.

Whereas the former escalator screens generated two skip-full of screenings each week, the CF200 Band Screens have more than doubled this amount.

Wastewater enters the center of the fine screen and flows outwards through a continuously moving band of polyurethane mesh panels to the outside of the screen chamber. Screenings are retained on the inside of the screen panels and then discharged when the panels elevate to deck level where they are cleaned by low pressure water jets.

The jets continuously clean the panels as they pass the discharge point above the debris hopper.

The entire frame is manufactured from stainless steel with heavy duty sections to maximize the life of the equipment.

The low pressure spray bar easily cleans the flat mesh panels at 2 bar discharge pressure. The patented thick panel technology has the highest screening capture ratio available and does not require secondary mechanical cleaning devices.

Performance

A spokesperson for Anglian Water commented that the investment has delivered cost savings of two full man-days per week.

Previously, maintenance included the head works and downstream equipment, with baffles on detritors requiring de-ragging, bar screens needing daily cleaning, and sludge ram pumps and valves requiring unblocking and de-ragging.

The cost saving on man-hours is significant, in addition to reduced spending on cleaning and tankering.

Since the CF200 Band Screens have been installed, the old bar screens on the primary settlement tanks have been removed, with strong satisfaction reported in the results.

Tested at the National Screens Evaluation Facility (NSEF), the CF200 screen achieved an impressive 80% average capture ratio.