Membrane fouling, scaling, and controls

One of the hmitations of membrane processes for hquid separations is severe loss of productivity due to concentration polarisation and fouhng as discussed in Chapter 1. The drop in flux can be as much as 80% in a few minutes or may take days. The loss of productivity is substantial vis-a-vis membrane permeabdity measured with water. Sources of membrane fording and scahng are detailed in Table 2.4. Common pre-treatment processes discussed in this chapter are summarised in Tables 2.2 and 5.1. 

Mineral salts Form mineral scales when their solubility is exceeded 

Colloids Electrically charged SDI and zeta potential determine fouling 

Organic acids Humic and fiilvic acids cause severe fouling 

Severe penneate flux decline Loose, sparse, thin fouling layer 

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