Blue Spring Corporation Serving World-wide Since 1980
CLOSED LOOP AIR SCRUBBING WITH PrecipRO TM
Air scrubbers, also known as fume scrubbers, are commonly used in the industry for cleaning the air laden with polluting gases or mist containing toxic chemicals. For example, in an electroplating shop using hexavalent chromium process, fine mist containing hexavalent chrome is emitted just above the plating tank. This air must be ducted way from the operating area, since hexavalent chrome is known to be highly carcinogenic. The air is passed through a Fume Scrubber before it is discharged to the environment.
Air scrubbers are also commonly used in power-generation industry, to remove sulfur dioxide, oxides of nitrogen and other acidic gases which are detrimental to the environment.
An Air Scrubber is a counter-current gas-liquid contact device in which the air is blown from bottom to top and it receives a spray of water. The droplets of water absorb the undesirable gases thus, becoming polluted waste water.
A Cooling Tower is a similar air-water contact device in which the water is purposefully adulterated with certain chemicals to stabilize its pH and for preventing the growth of algae and bacteria. This water then must be discharged occasionally because it gets concentrated with salts of sodium, calcium, magnesium and iron, and because the added chemicals loose their effectiveness.
The biggest problem encountered in the operation of the air-water contact devices are buildup of scales of calcium, magnesium and ion, and growth of algae and microbial matter in the water. The other major problem in case of polluted air is how to dispose of the waste water from the device, which now contains the air-borne pollutants.
Blue Spring waste water recycling system can be used to separate the polluting chemicals from the waste water and to reduce its volume before it is discharged to the environment, or hauled away. This can be done without addition of the anti-scalant chemicals or disinfectants. Doing so has considerable economic advantages, in addition to the environmental advantages.
SCRUBBING THE AIR SCRUBBER
In the conventional scrubber or cooling tower configuration, the waste water is collected in a sump which is located at the bottom of the scrubber. This waste water is continuously re-circulated in the scrubber by means of a pump. A portion of this waste water is periodically bled to the sewer. The portion to be removed depends on amount of TDS built up in the water. Building too much TDS will build up scales inside the scrubber, which will deteriorate its perfor
mance. The discharge to the sewer contains the pollutants from the air being scrubbed, the additive chemicals, and the organic matter generated in the water.
Because the Blue Spring PrecipROTM system continuously removes the organic matter and micro-organisms from the water, they never build up. It is not necessary to add those poisonous chemicals to prevent such build up.
Because the Blue Spring PrecipROTM system continuously removes ions of metals, scales do not form inside the scrubber or cooling tower.
Because the Blue Spring PrecipROTM system is a closed loop water recycling system, there is no loss of water (other than normal losses by evaporation and final sludge). Consequently, a larger portion of the waste water may be removed, purified, and recycled. Spray water is of higher quality.
A distinct advantage of the PrecipROTM system is that it removes the highly toxic contaminants from the scrubbing system and treats them. As the result, the final liquid sludge does not contain the original toxic pollutants. Typically, the final liquid sludge will contain salts such as sodium chloride, sodium sulfate, and sodium nitrate. A small amount of cake will be the second by-product which will contain oxides and hydroxides of metals.
Following are the advantages of equipping Air Scrubbers and Cooling Towers with the Blue Spring PrecipRO waste water recycling system:
No chemical addition is necessary to prevent build up of scales, algae and bacteria. Reduced operating costs. Better for the environment,
Water can be re-circulated for longer time. Reduced water consumption, reduced water costs.
Spray water is cleaner. Improved air-water contact efficiency. Better scrubber/cooling tower performance
Contaminants are removed from the final liquid sludge. No environmental issues.
Blue Spring Corporation can supply you with complete system which includes process layout, equipment package and installation assistance. Blue Spring PrecipROTM process operating license is available for a fee.
