2420 Ozone Flashcards
Describe common uses of ozone in the workplace.
- Swimming pool water treatment
- Drinking water disinfection (bottled water)
- To prevent food from spoiling (example ozonated ice)
Other Uses:
- Waste water treatment
- Cooling tower water treatment
- Treatment of storage water, fishing industry
- Purifying feed water in fish farming
- Disinfection (abattoirs, aquariums, hospitals)
- Pulp bleaching
- Medical treatments
- Perfume manufacturing
- Odour and smoke control
- Air purifiers
List health effects associated with overexposure to ozone.
Acute
Minor irritation of eyes & URT (low due to low water solubility)
Irritation of LRT (often described as a dull chest pain)
Headache
Pulmonary edema with higher concentrations
Chronic (either chronic low exposure, or chronic symptoms after a high exposure)
Reduced lung function, possible premature aging of body.
No evidence of carcinogenicity, or fetal-toxicity.
Explain the concept of a lower respiratory tract irritant.
There are fewer nerves in the lower respiratory tract than in the upper. Irritation of the LRT often feels more like a dull ache/pain than the true irritation of the URT.
Ozone is more of a LRT irritant than URT. As such workers may be less aware of symptoms if they are exposed.
Discuss similarities between ozone and chlorine as hazardous materials.
Both gasses, and toxic process gasses.
Both cause severe respiratory damage and can be fatal.
Both oxidizing agents, and can be used for disinfection.
Both can be used for disinfection of things like drinking water, in which case large quantities used.
Both have similar regulations and require similar control systems.
Describe common technologies used to generate and destroy large quantities of ozone in the workplace.
The most common system to use ozone:
- Water content of air decreased in an air dryer.
- Dry air moved into ozone generator (most commonly corona discharge). O2 breaks down and some O3 formed
- Compressor moves O3 through an injector into contact tank
- O3 meets water in contact tank, disinfection process
- Excess O3 released from contact tank into ozone destructor, where it is catalysed into O2
- Water from contact tank passed through de-ozoning filters and ready for use.
What is ozone?
O3.
A gas under normal circumstances, heavier than air.
Extreme pressure/cold required to liquify (not normally done)
Toxic process gas.
It is part of the smell after lightening.
Electricity can separate O2 molecules, allowing them to reform as O3.
Stratospheric ozone is the earth’s ozone layer. (good)
Ground ozone is an industrial pollutant which can cause environmental damage. (bad)
Ozone used in the workplace is good and bad. It has practical (good) uses, and can be harmful in excess or when not controlled (bad).
Discuss differences between ozone and chlorine.
Chlorine is almost never made on-site. It must be transported and stored. Ozone can be made on-site and is not stored in large quantities.
Chlorine is more water soluble than ozone. This makes it more of an upper respiratory tract irritant than ozone.
List 7 properties of ozone.
Gas at normal temperature/pressure
Heavier than air
Pungent odour
Excellent disinfectant
Blue in pure form
Invisible when in air
Highly reactive
What pictograms apply to ozone?
Health hazard
Oxidizer
Environmental Harm
Exclamation Mark (irritant & toxic)
List 4 properties of ozone as a disinfectant.
Used before other disinfection methods in system.
Greater effectiveness than other methods.
No residue in water.
Ineffective against algae at standard concentrations.
List 4 properties of chlorine as a disinfectant.
Used as last disinfection method in system.
Used in many forms as a disinfectant.
Leaves residue in water.
Effective against algae.
Discuss ozone generated from UV radiation.
A small amount of ozone is produced, and is typically used to disinfect small quantities of water.
Discuss ozone produced from corona discharge.
A high voltage of electricity is passed through a point, resulting in the electrical potential breaking down the molecules surrounding the point. Bluish light produced (the corona), and ozone formed.
Dried air is typically used to reduce unwanted products of reaction.
Discuss ozone desctructors.
A device or oven that used a catalytic process to convert ozone gas into harmless oxygen.
This permits for safe venting into the environment.
Discuss de-ozoning filters
Filters that will remove excess ozone in the ambient air or prior to entering target water source.
