Because many natural water sources provide water with a quality not meeting potable water criteria, treatment is required. Simple natural filtration has been discovered and used for centuries and even millennium, and conventional treatment processes were optimized and advanced for many years. As an alternative to the conventional water treatment processes, membrane technologies were developed in early 1960s by launching reverse osmosis (RO) membranes at the University of California in Los Angeles. This was the time of a new era in treatment, the time when membrane technologies started. RO technology started advancing fast, becoming commercial in early 1970s to desalinate sea/ocean and brackish/undergroundwater (Frenkel, 2009). In 1980s, low-pressure membranes were introduced to the market to treat surface water, competing with conventional filtration processes, and they were applied to the treatment of wastewater by introducing the membrane bioreactor technology.
This chapter provides information on low- and high-pressure membranes, configuration, and applications showing simple basic information required to plan and design a membrane plant or facility, either with low- or high-pressure membranes. This chapter helps to identify differences and details when dealing with membranes for those who just started to be involved, while it could be a guideline for those who have advanced skills in membrane technologies and processes.