Over the last eight years, ozone has made a prominent place for itself in the garment processing industry all over the world. Widely used as a bleaching agent, Ozone is a powerful within the denim industries that give denim garments a unique and distinctive look and feel from other traditional processing without reducing strength.
Though it changes the color of the Indigo dye, ozone eliminates tinting from the reverse of the denims as also from the sewing thread, pocket fabric, labels, zippers, buttons etc. giving the garment a cleaner look.
Normally jeans are rinsed with large amounts of water to get rid of the excess indigo from the garment, and chemicals are applied to fade the jean and clean up indigo bleeds on the pocket linings. When a jean is ‘ozonized’ however, those processes are drastically reduced, if not eliminated. The ozone acts as a bleach to disinfect the garment, kill bacteria and clean up the indigo, dramatically lowering water consumption and greatly lowering energy and chemical usage.
Ozone is generated via corona discharge in an ozone generator and fed into the bleaching machine as a gas. The bleaching machine is a tumbler where ozone gas is introduced and removed after processing. The process time is 15 to 20 minutes per batch. During this time; tumbling action slowly turns over the garments for even exposure to the gas circulating in the entire tumbler. Later, with the help of the exhaust pipe the gas in the tumbler is flushed into an ozone decomposing system.
Koos Manufacturing applies ozone technology to its denim manufacturing as a dry process that essentially produces a cleaner finish to the jean, in a much quicker time frame and uses no water during its cycle. Koos expects to reduce its consumption of water, chemicals and dirty energy by approximately 25% annually, helping to save the world one jean at a time.
A $45-million rebuild of the Holmedale water treatment plant in near Brantford, ON Canada is currently underway with an estimated completion date sometime in the summer of 2011.
The rebuild will involve replacing the water filter beds, replacing a high-lift pumping station and adding an ultraviolet disinfecting feature as a backup to the existing chlorination process.
An ozonation process will also be added in which ozone is used to pretreat organic material in the water. Ozone is increasingly being used for pretreatment of water for applications such as organic removal.
Skien Municipality in southern Norway is rebuilding Steinsvika Water Treatment Plant into an ozonation/biofiltration process. Steinsvika WTP will have a max production capacity of 1650 m3/h (39 600 m3/day) and a normal production of 650 – 1250 m3/h (15 600 – 30 000 m3/day). The plant will be in full operation by the end of February 2010.
The raw water of the plant is taken from the lake Norsjø. The main issue for the treatment process is removal of Natural Organic Matter (NOM) that gives color to the water and to ensure good hygienic barriers.
The NOM removal will be done by adding ozone at the inlet of the plant. The ozone breaks up the large NOM molecules into smaller molecules that are easily biodegradable. It also kills any micro organisms that might be in the water and increases the UV transmission of the water, so that the UV disinfection will be more effective. In the biofilters bacteria will use the organic molecules produced in the ozonation process as “food”. As a final step the water is disinfected, first by UV light and finally with chlorination.
Ozone biofiltration is used around the world to remove organic matter not only for elimination of color, but also to reduce the formation of chlorinated organics that might result fromt eh reaction of chlorine with teh NOM.
The city of Springfield will receive $16.2 million to replace the Spring Branch trunk sewer line on the northwest side of town and replace an outdated ozone generator used to disinfect water at the Southwest Wastewater Treatment Plant, according to Steve Meyer, assistant director of public works.
Meyer said $3 million of the $16.2 million will be federal stimulus funds and the remaining $13.2 million will be a 20-year loan from the state’s revolving fund.
At the Southwest Wastewater Treatment Plant, money from the stimulus funds and state loan will be spent on a 24-month project to build a new ozone generator, expanding the facility’s capacity to disinfect up to 100 million gallons of treated water each day. Currently, the facility is limited to 60 million gallons, Meyer said.
“It’s a significant increase in what we can disinfect and treat,” Meyer said. “It will help up with our wet water flows and our peak flows.”