Seawater quality and biofouling

Question

Hello, I want to know which Source Quality Parameter is the best characteristic for the reverse osmosis biofouling potential of seawater ?

Nikolay Voutchkov · Answer

Hi Judith: In my opinion, the best water quality parameter indicating the biofouling capacity of source water is total organic carbon (TOC). If the TOC concentration of source water is below 1.5 mg/L, usually this water will have very low fouling effect on RO membranes. For example, in most seas/oceans under normal conditions seawater TOC concetration is usually below 0.5 mg/L. Durung heavy rains and algal blooms TOC often exceeds levels of 2 mg/L and heavy biofouling is obesrved on the RO membranes. If the biofouling is casued by algal blooms, than another parameter that can be used as a surrogate indication of the biofouling potnetial of the source water is the algal content of the source water. Usually, if algal concentration exceeds 2,000 cells/mL, the amount of lagae is large enough to relase orgnaics triggering RO biofouling. Another similar indicator is the content of algae measured as chlorophyll-a - if the source water content exceeds 1 micrograms per liter, this water will have very high biofouling propensity.