Conventional ozone treatment involves large complicated equipment, high costs, and low efficiency
Conventional ozone treatment requires large and complicated equipment
that is expensive and inefficient due to large amounts of low concentration
ozone gas being blown into wastewater in sizable concrete tanks. Ozone
gas and target substances react slowly over time.
Porous ceramics diffuser tubes/plates are used for ozone bubbling, but the ozone gas of several millimeters to several centimeters size rises too quickly, and a large amount of unreacted ozone gas is released from the water. Unreacted ozone gas (waste ozone gas) is harmful, so ‘waste ozone decomposing equipment’ is absolutely necessary.
OHR ozone treatment is a highly efficient and low cost method
Both ozone gas and liquids are broken down into microparticles
Micro-nano size ozone bubbles generated by the OHR MIXER stay in
water for a long time, and contact/react with the target substance
in the wastewater. The OHR bubbles contact area is so much larger
than conventional coarse bubbles.
Bubbles generated by the OHR MIXER resembling pure white clouds in the photo on the right are ozone microbubbles. Ozone bubbles of 0.5–30 microns stay for a long time due to low buoyancy. Furthermore, transparent ozone nano bubbles are generated in large quantities by the OHR MIXER. A water treatment engineering company evaluated the OHR gas-liquid reaction method, and found that 70% of the injected gas was dissolved (=nano sized bubbles) and the remaining 30% turned into mostly microbubbles and a few coarse bubbles.
Direct reaction method
At the point of passing through the OHR MIXER, both ozone and wastewater are broken down into microparticles. Then they powerfully collide/react with each other by centrifugal and centripetal forces. In other words, ozone gas and the target substances in wastewater directly contact/react in the OHR MIXER pipe. Hence, the OHR method is the ‘Direct reaction method’.
The conventional method is an ‘indirect reaction method’. Firstly, coarse ozone bubbles are supposed to be dissolved into the wastewater, and then by chance the dissolved ozone gas contacts/reacts with the target substances.
Small and simple equipment
The OHR ozone treatment method does not require waste ozone decomposing equipment. In addition, small amounts of high concentration ozone gas are used, so the ozonizer used is much smaller than the conventional ozone treatment method.
Paper mill T uses the ‘OHR ozone micro-nano bubble treatment method’ for discoloration of 5,000m3/day of colored wastewater, and the treatment equipment has been operating consistently for over more than 10 years. The equipment uses 1) no ozone gas bubbling tank, 2) no waste ozone decomposing equipment, 3) a smaller ozonizer than the conventional ozone treatment method. Therefore the introduction costs of the equipment were $2 million, one third of the conventional method ($6 million). OHR is a highly effective ozone treatment method at a fraction of the cost of conventional methods.
In addition, regular cleaning and replacement of clogged diffuser pipes/plates is necessary for conventional methods. The OHR method does not require an ozone bubbling tank, and OHR MIXER is maintenance-free. Only the pump needs regular maintenance.
Waste ozone decomposing equipment is unnecessary with the OHR method
The waste ozone decomposing equipment is intended to promote the self-decomposition of harmful ozone gas through
the tank filled with activated carbon or catalyst to make it harmless. Large amounts of waste ozone gas are produced in the
conventional ozone treatment facility, so this equipment must be installed. As the scale of ozone treatment increases,
the waste ozone treatment facility will also increase. Also, as the filled activated carbon or catalyst gradually decreases or
deteriorates, periodic replenishment/replacement becomes necessary.
With OHR ozone treatment, it is also possible not to use waste ozone decomposing equipment. For details, please contact us.
Dioxins can be decomposed with ozone alone
In the conventional method, it is said that dioxins can not be decomposed unless the AOP is used
It is said that dioxins cannot be decomposed by ozone alone, so it needs to be treated by AOP* (Advanced Oxidation Process). However, the test conducted by Company Y in Japan has demonstrated that OHR ozone treatment can decompose dioxins with ozone alone. (The test carried out was thorough. The analysis costs alone were $100,000.) Please contact us for more details.
*The AOP (Advanced Oxidation Process) is a treatment method of combining ozone with hydrogen peroxide or ultraviolet rays to generate hydroxyl radical, which is an active oxygen and has the strongest oxidation power.
New effluent international standard! What is ‘WET’?
WET (Whole Effluent Toxicity) is not a chemical analysis method such as BOD or COD
but a method to directly evaluate the effects on the environment of aquatic organisms
such as killifish, algae and water fleas.
BOD and COD are indirect ways of measuring the impurity levels of wastewater by oxidative decomposition using microorganisms or oxidizing chemical agents, but only a part of the substances identified by oxidative decomposition can be measured. For example, it is known that potassium permanganate, an oxidizing agent used in the analysis of COD in Japan, can detect only 40–70% of all organic matter contained in wastewater. Undecomposed persistent trace substances, that are not identified, are released from wastewater emission sources (e.g. factories, sewage plants, etc.) into the environment. It is evident that they cause a significant negative impact on life and the natural environment.
Therefore, new standards to evaluate the effects of treated water on life and the natural environment are needed; not an indirect evaluation standard such as BOD or COD, but a direct evaluation based on actually keeping aquatic organisms in treated water (evaluation by bioassay). This new effluent regulation has already been introduced in the US, Canada, UK, France, Denmark, South Korea, and other countries, although the name and methods differ. Similar regulations will be introduced in Japan shortly.
Even treated water shown in the box below may contravene the WET regulations when the water has an adverse effect on aquatic organisms.
- The followings may contravene the WET regulations
- Treated water that passes the current effluent standard (BOD, COD, etc.).
- Treated water including substances that are difficult to identify, and unknown substances and non-regulated substances.
- Treated water including trace chemicals.
- Treated water that has an adverse effect on life caused by multiple reactions of some chemical substances.
Ozone treatment can decompose approx 90% of undecomposed substances in the treated water, and is an accepted effective treatment method that is WET compliant.