Harmful agal bloom-related water quality monitoring for desalination design and operation.

Abstract

Characterization of the raw seawater at plant intakes and monitoring to detect poor water quality events including harmful algal blooms (HABs) is critical throughout the lifetime of a desalination plant. HABs can result in a substantial increase in the organic and solids load in the seawater feed to be treated at a desalination plant. This may result in an increase in the clogging of granular media filters and accelerated particulate and/or (bio)fouling of pretreatment and reverse osmosis membranes (see Chapter 2). Other feedwater quality changes may be observed during or following a HAB event, such as a reduction in dissolved oxygen levels and continued high concentration of organics due to decomposition of algal matter by bacteria when the algal bloom degrades. Seawater in areas that are prone to algal blooms or silt inflow etc. may require additional pretreatment if events are frequent and/or of long duration (Chapter 9).