SANITATION STUDIES OF A REVERSE OSMOSIS UNIT USED FOR CONCENTRATION OF MAPLE SAP

Abstract

Sanitation studies of an industrial-scale reverse osmosis unit used for the concentration of maple sap are discussed. Bacterial plate counts of the concentrate and permeate effluent streams declined steadily during the initial 10–12 hr of operation, followed by respective increases in count from 2.8 × 104 per ml (12 hr) to 2.0 × 105 per ml (36 hr) and from 3.3 × 103 per ml (12 hr) to 2.4 × 104 per ml (36 hr). Membrane modules were maintained in good sanitary condition in the reverse osmosis unit pressure vessels for as long as one month when the modules were kept in contact with an acidified chlorine dioxide sanitizer.