Veolia upgrades water treatment facility at Sasol Synfuels refinery

Veolia Water Solutions & Technologies has upgraded the water treatment facility at the Sasol Synfuels refinery in Secunda, South Africa.

The upgrade will increase the plant’s production capacity with the addition of a fourth water treatment train.

The treatment plant will also generate more condensate and polished water for re-use, while reducing the synthetic fuel plant’s overall environmental footprint.

Veolia Water Solutions & Technologies South Africa general manager Chris Braybrooke said the water treatment plant’s production capacity will be increased to nearly 600m3/h of condensate and 330m3/h of polished water, with the addition of a fourth train in 2011.

"Proper planning in the design phase enabled easy execution of the upgrade as the engineers allowed for sufficient space to accommodate any future equipment to be installed," Braybrooke said.

Known as Project Landlord, the facility consists of two Multiflo clarifiers, three trains of water treatment consisting of submerged membrane installations, ion exchange softeners, reverse osmosis and a mixed bed demineralisation system.

Initially deployed in 2005, Project Landlord’s work included desalinating blow down water from the Synfuels utility cooling towers and re-incorporating it into the plant’s processes, reducing overall process waste.

As part of the treatment process, the blow down water undergoes initial fine screening and cold lime softening.

The water is then directed into the submerged ultrafiltration membranes, where hydrostatic pressure forces the water against a semi-permeable membrane and suspended solutes of high molecular weight are trapped.

The water is then treated with ion exchange softeners, to reduce the residual hardness, before going through spiral reverse osmosis, and this removes the majority of dissolved solids from the water.

The mixed bed de-mineralisation process will deliver the final purification.

Figure Caption: The upgraded water treatment plant will generate more condensate and polished water for re-use.