The Pool & Hot Tub Alliance announced this week that a supplement to the ANSI/APSP/ICC/NPC-12 2016...
The Pool & Hot Tub Alliance has awarded the 2019 Dr. R. Neil Lowry Grant to the Pueblo Department...
The Texas legislature has passed HB 2858, which allows municipalities in the state to require...
Ozone has become one of the pillars of pool and spa sanitizing. Today, ozone generators are commonly plumbed into circulation lines as a valuable assist to the sanitizer. These devices generate and inject ozone gas (O3) into swimming pool or spa water. They consist of two basic components, an ozone generator and an ozone management system. Commercial and residential systems differ in some respects, as detailed here:
This component consists of an electrical enclosure which includes a compressor, oxygen concentrator, high-voltage power supply, corona discharge ozone-producing cell and ancillary items that control all these sub-components. Ambient air is drawn into the oxygen concentrator, which removes moisture, nitrogen, trace gases and contaminants. This clean and dry oxygen is then drawn into the ozone producing cell and some of it (2 to 10 percent) is converted into ozone gas.
This component consists of a booster pump (on very small systems, booster pumps are not required), a venturi injector assembly, undissolved ozone degas tank, undissolved ozone destruct device and an oxidation reduction potential (ORP) monitor/controller. The ozone management system maintains appropriate ozone levels in the water regulated with the ORP monitor/controller. These components operate in unison and are installed on a pool or spa as a side-stream of the main filtration system. Ozone is introduced to the water after filtration (and heating), and before the chlorine feeder. The side stream flow is normally 15 to 25 percent of the main flow, depending on the size and type of vessel. The system size is proportional to the water volume, water temperature and organic load.
For systems using corona discharge (CD), the ozone generator consists of an electrical enclosure which includes a high-voltage power supply, ozone-producing cell and ancillary items that control these components. Ambient air is drawn into the ozone generator and some of it is converted into ozone gas. Corona discharge generation typically produces more ozone than ultraviolet generation.
RELATED: Ozone and UV Systems Allow Pool Owners to Approach No-chlorine Systems
For systems using ultraviolet radiation, the ozone generator consists of an electrical power supply and an ozone-producing ultraviolet lamp (185 nm wavelength). Ambient air is drawn into the ozone generator and some of it is converted into ozone gas.
This component consists of some means of injecting the ozone into the water. Ozone is typically introduced to the water after filtration (and heating) and before the chlorine feeder.
Once the ozone has been dissolved in the water, an oxidation reaction occurs upon any collision between an ozone molecule and an oxidizable substance. Organic contaminants are destroyed and many dissolved metals become insoluble.
Ozone is capable of killing all known microorganisms (including cryptosporidium and giardia), destroying organic contaminants that may create chloramines and breaking down existing chloramines. This oxidation occurs immediately at the ozone gas injection point and continues in the return lines. A small residual (~0.1 ppm) of dissolved ozone may enter the pool, providing further oxidation.
An ozone-generating system is considered a pesticidal device under US EPA Federal Insecticide, Fungicide, and Rodenticide Act, and has an EPA Establishment number.
Commercial ozone generating systems are tested and listed under NSF/ANSI Standard 50, Equipment for Swimming Pools, Spas, Hot Tubs and Other Recreational Water Facilities. The device must meet the requirements of NSF 50, Disinfection Efficacy, and is intended for supplemental treatment (Annex H.1) or secondary disinfection (Annex H.1 and Annex H.4) depending on which test criteria are chosen. For either listing, the system should be used with an EPA registered sanitizer to impart residual concentrations in accordance with state or local regulations.
Ozone-generating systems do not leave a substantial ozone residual in the pool or spa. All ozone generating systems must be used in conjunction with an EPA registered sanitizer.
RELATED: Ozone Mixing Key to Disinfection
A. Commercial Pools and Spas
Ozone is appropriate for use in conjunction with chlorine but is not recommended for use in conjunction with bromine in commercial spas. Also, corona discharge-generated ozone should not be used with a biguanide system because the ozone produced may destroy some of the PHMB.
B. Residential Pools
Ozone is appropriate for use in conjunction with chlorine but is not recommended for use with bromine in residential pools because of the potential to produce bromate. UV generated ozone systems can be used with biguanide in residential pools.
C. Residential Spas
Due to low levels of ozone produced from residential spa equipment, ozone is appropriate for use with bromine and all EPA registered sanitizers.
Gaseous ozone is harmful to breathe. The Occupational Safety and Health Administration Permissible Exposure Limit (PEL) is currently 0.1 ppm over an eight-hour time weighted average. No OSHA regulations apply to aqueous ozone; it is not anticipated to be harmful to humans at the concentrations used.
Ozone gas is introduced into the water under vacuum. If a line is breached, the system loses vacuum and the ozone generator immediately stops producing ozone gas.
Please consult the manufacturer's instructions regarding safe use and operation of their ozone generation system.
Many of us may have had the unfortunate experience of adding soda ash "wrong" to pool water, resulting in a pool that looks like it is filled with milk. In fact, we refer to it as "milking" a pool. Why does that happen?
When we decide, for example, to raise the pH of a pool from 7.2 to 7.6, we calculate how much soda ash is required for that size pool to achieve a 0.4 pH unit increase. A solution of soda ash (sodium carbonate) has a pH of above 11, so when added to pool water the pH...
The Pool & Hot Tub Alliance announced this week that a supplement to the ANSI/APSP/ICC/NPC-12 2016 Standard for the Plastering of Swimming Pools and Spas was approved by the American National Standards Institute on May 10. The new supplement impacts the way that industry professionals plaster pools and spas.
"We are excited that our PHTA Standard Writing Committee for the Plastering of Pools and Spas was able to address plastering applications in cold temperatures and further...
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The Pool & Hot Tub Alliance has awarded the 2019 Dr. R. Neil Lowry Grant to the Pueblo Department of Public Health and Environment at the National Environmental Health Association’s 2019 Annual Education Conference & Exhibition awards ceremony in Nashville, Tenn.
Given in the memory of Dr. Robert Neil Lowry, a...