Navigation

System Operation

Wastewater is pumped to the wastewater treatment plant from collection sumps at different points in Scott Base.

• The wastewater first passes through an automatic brush screen, which removes large solids. The solids pass through a chute and are collected in a sealed bag for transport back to New Zealand for disposal.
• The screened wastewater drops down into an aerated balance tank. The aerated and homogenized wastewater is then pumped to a pre-clarifier at a controlled rate to ensure even loading of the biological stage.
• Settleable fine solids are settled out in the pre-clarifier and pumped to a sludge holding tank.
• The clarified wastewater enters the fixed bed chambers by gravity. In summer all the chambers are used while in winter only the smaller chamber is used.
• Effluent from the fixed bed chambers overflows to the final clarifier where the secondary sludge is settled out and pumped to the sludge holding tank.
• The clarified and biologically treated effluent overflows through the UV-disinfection unit to the treated water tank from which it can be reused for toilet flushing or else discharged to the ocean through the outfall pipe.
• The solids in the sludge holding tank are aerobically digested and acquire very good dewatering characteristics.
• The sludge dewatering cycle is performed automatically by feeding the sludge mixed with the polymer to the centrifuge. The resultant de-watered sludg "cake" is collected in the solids drum while the filtrate is returned to the sludge holding tank.

The treatment scheme is designed in such a way that all major equipment has 100% redundancy and can be by-passed for maintenance and repairs.