Borders General Hospital

The hospital’s boiler system consists of three dual fuel (gas/oil) boilers and a waste heat boiler linked to the incinerator. It is critical to the hospital’s operation, supplying steam for space heating, sterile services, laundry and
kitchens. The boiler conditions must meet the requirements of BS2486.

Direct steam injection into autoclaves, laundry and steam ovens in the kitchen limits the condensate return. Softened make-up water mixes with returned condensate in the hotwell where a blended alkaline tannin chemical was added to provide oxygen scavenging. Corrosion inhibitor and sludge conditioner were dosed to each boiler feed. The chemical added high levels of alkalinity. This resulted in very high levels of blowdown, making it difficult to control the Total Dissolved Solids (TDS) and alkalinity in the boiler water in accordance with the standard.

Following a system evaluation by one of their highly qualified chemical specialists, Veolia Water Technologies changed the treatment regime to a neutralised sulphite programme that allowed the alkalinity levels to be reduced. The boilers already had individual feed lines which Veolia recommended to be upgraded from copper to chemical resistant plastic.

• Blowdown reduced by 20%
• Boiler operating cost savings £5,000 per annum
• Chemical handling costs reduced by 25%