Water Treatment With 'The No-Moving Parts Method'

It has been said, "running water purifies itself." This adage is only true however in the ideal application where suspended particles are large enough in diameter to settle out on their own, or where a nearly infinitesimal amount of purification must be obtained over a nearly infinite length of flow. Unfortunately, in most wastewater applications neither of these ideal situations occur. It is therefore necessary to find the most suitable method to purify water to the degree that must be obtained. Motionless mixers used in conjunction with control instrumentation provide a way in which wastewater can be treated on a continuous basis.

There are a number of effective wastewater treatment processes. For example, zeolites or cation exchange resins are used for the removal of heavy metal cations. Cation exchange resins can deionize wastewater by using a mixed-bed ion exchange process or using a weakly or strongly basis anion exchange subsequent to cation exchange. Activated carbon absorption beds are effective in removing chloride or fluoride ions from wastewater where the concentration is high. Carbon is best utilized in its granular form, which facilitates its reuse. Reverse osmosis is also an effective method of wastewater treatment that combines a high-pressure pump and a semi permanent membrane to filter dissolved salts. Each of these various treatment systems has certain strengths and weaknesses, which make them suitable for removal of many, but not all, ions and colloidal particles in solution.

For large systems, or systems where ion contamination is in excess of 600-700 rpm, they become economically undesirable and cannot match the flexibility of inline treatment offered by motionless mixers. Colloidal particles, that is particles with a diameter on the order of one to five hundred milli -microns, are too small to settle out of wastewater by gravity.