ABSTRACT
Membrane treatment facilities function most effectively when the feedwater has a relatively constant quality. Variations in water quality that affect membrane treatment facilities can be classified into two areas: physical and chemical. The physical characteristics of surface water include those properties that can affect membrane operation, such as supply, temperature, and concentrations of potential foulants, such as suspended sediments, algae, or others. Surface water use includes a balance between the public usage of water, the rights of downstream water users, other users of water such as agriculture and industry, and the requirements of the natural system to maintain biological viability. Most freshwater intake systems are unaffected by biological organisms, and plant and animal debris can be excluded from the intake using trash racks or screens. Biological factors are grouped within the physical characteristics because aquatic vegetation or marine organisms tend to act much like sediments in terms of potential fouling of intakes and membranes.
