Water saving technology adopted – Black Water (Sewage) Treatment
The Hilton Sewage treatment plant is a Sequential Batch-Reactor (SBR) designed to treat the hotel effluent with a maximum capacity of 120 m3/day.
The process starts from a collection tank, in which all the sewage is received. The sewage is then pumped using grinder pumps to 3 primary tanks in series where the effluent is successively decanted removing any large solid waste and sludge. The water then passes to the aeration tank, where plastic honeycomb structures provide for a large surface area on which bacteria can grow and digest the sewage. The bacteria is aerated by a number of diffusers and an air blower regulated by a dissolved oxygen meter, ensuring that the oxygen level is maintained constant. The water then flows through a final settlement tank which removes any remaining suspended solids, followed by a glass bead filter for finer filtration.
The filtered treated effluent is then dosed with chlorine for disinfection purposes and stored. This is then used in irrigation and toilet flushing.
The process is stable, mainly requiring a filter backwash daily and de-sludging of the tanks approximately every 6 weeks. Cost per m3 averages at €0.9.
Approximate unit footprint – 200 m2
Cost of produced water – €0.90
Approximate treatment plant cost – €120,000
How satisfied is the hotel with the technology?
Commenting on the plant, Ing Joseph Restall, Chief Engineer Hilton Malta, stated “Hilton is satisfied with the technology and is in fact planning on further investing in it by adding a polishing plant to make the water suitable for more sensitive plants and flowers”
Visit the Hilton's website here.