AQUATIC SOLUBLE UNREACTIVE PHOSPHORUS - CONCENTRATION BY ULTRAFILTRATION AND REVERSE-OSMOSIS MEMBRANES

Ultrafiltration (UF) and reverse osmosis (RO) membranes were used to c oncrete and molecular size fractionate soluble unreactive phosphorus ( SUP) present in lake water. Qualitative behavior of the UF and RO memb ranes with SUP was examined using the model SUP compounds: highly poly merized DNA, degraded DNA, inositol hexaphosphate and orthophosphate. To concentrate and molecular size fractionate SUP in lake water, UF an d RO membranes were placed in series and the larger pore sized membran e preceding the smaller pore sized membrane. Six different membrane se quence configurations were examined. The percent SUP recovery of twent y lake water samples collected over a year ranged from 16 to 100%. The present SUP recovery was examined as a function of the membrane seque nce used, volume concentration factor, the initial SUP concentration w as the only major factor for SUP recovery. Calculated permeation facto rs for each sample illustrate that seasonal changes in the SUP composi tion may be occurring.