DAF/UF pretreatment stems Kuwait red tide

Pentair X-Flow reported on 8 November 2012 that the combination of dissolved air flotation (DAF) and pressurized inside-out ultrafiltration (UF) pretreatment at the Shuwaikh Seawater Reverse Osmosis (SWRO) Desalination Plant has proved efficient at treating seawater with high turbidity and can reliably operate during red tides.

Located near Shuwaikh port, the plant was built in 2010 for the Kuwaiti Ministry of Electricity & Water in order to provide additional potable water for its communities. With a UF permeate capacity of 350,000 m³/d and RO output of 94,700 m³/d, the plant supplies drinking water for more than 450,000 residents in Kuwait City.

The plant design paid special attention to pretreatment as the seawater in the area is highly saline, rich in organic components and known for occasional red tides, which can last for 10 days. This resulted in a combination of DAF and Pentair X-Flow‘s Seaguard 40 UF membrane modules and skids.

Together, DAF and UF efficiently remove high concentrations of suspended solids and small-sized colloidal particulates. The RO feed water has a consistent silt density index value of less than 3.0 at all times.

Even during a red tide event, the combined DAF and UF pretreatment proved successful in removing the increased number of particles caused by the abnormal algae growth with turbidity levels of up to 31 NTU. Only small operational adjustments were needed to be taken to guarantee optimum pretreatment for the RO system.

This helps prevent reduced production or plant shutdown and helps ensure a reliable supply of potable water to the city of Kuwait. Doosan Heavy Industries & Construction designed and built the plant.