Powder handling equipment improves filtration at desalination plant

The 2787 square-metre Tampa Bay Seawater Desalination Plant in Florida produces up to 94.6 million litres of drinking water per day, making it the largest seawater desalination plant in North America. Since March 2007, the plant has desalinated over 13.6 billion litres of drinking water from the Tampa Bay.
In 2005, however, the plant was shut down, as it could not meet expected operational sustainability. Tampa Bay Water, the government agency responsible for the plant, assigned remediation work to American Water and Acciona Agua, through their operating partnership American Water-Pridesa, a group that has designed and built more than 50 desalination plants worldwide.
Among the firm’s many improvements is the addition of Precoat Filtration using a bulk handling system for diatomaceous earth. This has proven to be instrumental in re-establishing the plant as a major source of drinking water for the Tampa Bay region.

Reverse osmosis converts seawater
Desalination plants rely on reverse osmosis, which uses high pressure to force water through semi-permeable membranes that remove salt from seawater. To ensure efficient reverse osmosis, seawater must be pretreated to remove particulates.
During remediation at the Tampa plant, American Water Acciona Agua improved pretreatment by adding coagulation and flocculation, improving the operation of the existing sand filters and installing a diatomaceous earth filtration system to eliminate microscopic materials from the water prior to reverse osmosis, reports Nacho Lopez, construction manager of the Tampa project.
 

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