Design parameters and operation of small, and medium size municipal reverse osmosis North America

Abstract

The design, construction and operation of 1,000 to 250,000 gallon per day reverse osmosis systems requires a different approach than larger multi-million gallon per day systems. Smaller modular units are based on actual proven installations. The units are pre-engineexed, and factory tested in their entirety. The unit concept of reverse osmosis design allows for more reliable systems, easily and quickly installed, with a minimum of operation and maintenance attention. Small and medium size reverse osmosis systems have been running for many years. A seawater single pass reverse osmosis system has been producing potable water for over 18 months with little operator attention and maintenance. Construction and operation of small and medium size municipal reverse osmosis systems present some unique areas of consideration which differentiates these units from much larger installations. By small and medium we mean from 1000 gallons to 250,000 gallons per day capacities. The ultimate objectives of any water treating system is to obtain the quality and quantity of water desired with a minimum of operating effort and maintenance. In general, where dissolved solids are to be removed from a feedwater source, reverse osmosis is presently recognized as the most efficient method available. Large reverse osmosis systems are usually engineered on an individual basis to meet the users needs and, include on-site analysis of the raw feedwater and climate conditions. In addition, engineering consultants as well as the ultimate customers preferences need to be considered. Large quantities of time are consumed in the initial engineering, preparation of drawings and design changes. Equipment housing facilities need to be designed around the type of system selected and engineered separately. Large amounts of time are used in the construction of the system components. Membrane racks are erected individually with membranes shipped separately. Large amounts of piping needs to be cut and installed on-site. High pressure pumps, membrane cleaning systems, electrical controls and pretreatment equipment are separately built, shipped individually, and assembled on location.