AWWA ACE65281

This powerpoint presentation outlines the concentrate management process of zero liquid discharge (ZLD). Topics outlined include: established ZLD technologies; energy required for water phase changes; energy required for desalination; evaporation ponds can be expensive; technical approach; sparingly soluble salts; processes evaluated for concentrate treatment; summary of precipitation; effect of seeding; Fluidized Bed Crystallizer (Crystalactor); advantages of crystallization; water sources tested; research approach; Fluidized Bed Crystallizer vs. Chemical Softening; Barium was removed in proportion to calcium removal; high pH required for silica removal; Silica removed with precipitation of Mg(OH)₂; Silica effectively removed with alum or sodium aluminate; comparison of costs and energy consumption; treatment cost $/kgal concentrate recovered; energy reduction; and, comparison of energy consumption by process.