October 24, 2011 - The recent 2011 Water Environment Federation Technical Exhibition and Conference (WEFTEC) was attended by over 17,000 professionals in the water and wastewater treatment industry. Held in Los Angeles, California more than 900 companies exhibited the latest technologies in process technology for liquid-solids separation. Many technical papers were presented by industry experts in this vital field.
Unique among the new technologies presented, the WWETCO FlexFilter™ from WesTech Engineering of Salt Lake City drew considerable interest. The patented process is useful in the treatment of storm water, an issue of increasing importance to communities as the EPA steps up enforcement of process regulations specific to high flow events at wastewater treatment plants across the United States.
Comprised of hundreds, thousands or millions, based upon plant flow, the filter media are chemically inert compressible synthetic spheres. As untreated water is introduced into the FlexFilter basin, angled flexible bladders which contain the media bed flex inward. As the head pressure increases with the rising water, compression upon the bottom of the media bed becomes greater than that exerted on the upper media bed allowing a porosity gradient to form within the media.
The water then flows over weirs and into the media. Larger particles are captured in the upper portion of the media bed and as the water flows down through the more tightly compressed media, smaller particles are removed. Retention time within the media is approximately five minutes. No motors or pumps are required to this point; the process is achieved solely through hydrostatic pressure. This saves in plant energy costs.
The surface area on each ball and within the media bed is considerable, resulting in the growth of microorganisms within the media bed. This growth allows for biological process to be achieved as the water passes through the filter. Phosphorus removal denitrification, and other process objectives can thereby be achieved.
An automated upflow air –water backwash is initiated when the flow rate indicates that the media bed is requiring cleaning. This blower is the only part of the process which requires electrical power. The media then is flushed to it’s original clean condition, ready for the next filtration cycle. The compressible media is projected to require replacement only after twenty years of continuous use.