A Case for Water Reuse
Recycling water both in acceptance of concept and in practice has steadily increased in recent years. Various factors such as diminishing water supplies, extreme drought, seawater intrusion, population increase, and others have created an urgency for municipalities and industries to explore alternate water supply options. Thankfully, there are innovative solutions, such as membrane systems, that can help facilities looking for reliable water reuse treatment technologies.
Water reuse applications include:
- Direct Potable Reuse (DPR), where purified wastewater is introduced directly into a potable water supply distribution system or into the raw water supply immediately upstream of the water treatment plant.
- Indirect Potable Reuse (IPR), where environmental buffers, such as a lake or groundwater aquifer, are used to blend the reuse water before the potable water treatment plant.
- Non-potable applications, including agricultural irrigation, recreational use at golf courses or community parks, and industrial process water.
These applications have been implemented in communities across the U.S. in a variety of ways, providing key benefits for long-term water sustainability.
How Filtration Treatment Options Can be Used for Water Reuse
Membrane filtration technology has become a widely accepted treatment for water reuse applications as it can produce reliable, consistent, high quality water safe for human consumption. Membrane filtration technology provides pathogen removal, one of the primary treatment goals for water reuse. Membranes typically require fewer unit processes compared to a multi-barrier approach and can be highly automated to require little operator involvement on a day-to-day basis.
WesTech’s AltaPac™ packaged ultrafiltration system comes as a fully functional, self-contained unit that can include all the components and controls necessary for a complete and operable water treatment system.
Microfiltration (MF) and ultrafiltration (UF) membranes are used to remove suspended solids, turbidity, and bacteria from secondary wastewater or industrial process water sources. MF/UF is an absolute barrier technology, where hollow fibers with nominal pore sizes from 0.01 – 0.1 micron are used to remove contaminants. The fibers are potted in a housing, called a module, and the modules are integrated with required components and controls for a fully functioning system.
WesTech has supplied low pressure membrane filtration systems for over 18 years. Our membrane filtration product team has supplied or are under contract for more than 100 facilities in North America, ranging from 10 gpm to 10 MGD.
Nanofiltration (NF) and Reverse Osmosis (RO) are used in advanced water reuse applications where high quality permeate is required with low levels of dissolved solids and hardness. For the RO process, high pressure is used to counter natural osmotic pressure and the dissolved contaminants are rejected.
A reverse osmosis element is comprised of a flat sheet membrane that is spiral wound around a center product tube. Water flows in a crossflow direction across the membrane, and clean permeate flows through the center tube. The concentrated reject remains on the outside and is sent to waste. Similar to ultrafiltration, the RO elements are integrated with other required components and controls for an operational system.
Whether for potable water applications or industrial processes, water reuse can help organizations save money and maintain consistent production without having to go to outside sources for additional water.
Microfiltration, ultrafiltration, and reverse osmosis are playing a vital role in developing water reuse best practices and conserving this scarce resource. Their efficiency and ease of use make them a number one choice in water reuse.