Wastewater treatment system upgrade to the King Edward VII Memorial Hospital

The King Edward VII Memorial Hospital on the beautiful island of Bermuda will benefit from an exciting expansion program which includes 90 new single occupancy en suite patient rooms, a day surgery unit, ambulatory care facilities, diagnostic imaging services and a new emergency room. Due to this extensive development there is a need to include an upgrade to the existing sewage treatment system (off mains drainage) as part of the project.

Challenge

Due to the size and position of the hospital the system had to achieve the very high standard of discharge to 10mg/l suspended solids, 10mg/l Biological Oxygen Demand and 10mg/l Total Kjeldahl Nitrogen with a flow of 460m3 per day, and the population equivalent was increased to 1755.

Solution

The sewage treatment solution had to achieve strict consent standards and the design needed to maximise the available space - an underground chamber beneath the car park.

The final sewage treatment solution included eight SAF units, each 6.2m long. A flow splitter separates the stream from the primary treatment into two, with each stream then passing through four specialist SAF units. A lamella plate separator would be used for final clarification, and a Microscreen with a 40 micron filter cloth for final polishing of the effluent prior to discharge.