Ozone Technology Glossary

50 key terms in ozone and water treatment technology — sourced from WHO, US EPA, BIS, and international standards bodies.

A

Advanced Oxidation Process (AOP): A water treatment process that generates highly reactive hydroxyl radicals (·OH) through combinations of ozone, UV light, and hydrogen peroxide to degrade recalcitrant organic compounds.— US EPA, 2006
Applied Dose: The mass of ozone transferred to water per unit volume, expressed in mg/L or g/m³. Equal to the ozone generator output divided by the water flow rate, adjusted for transfer efficiency.— WHO GDWQ 4th Ed.
Aquaculture Disinfection: Use of ozone or UV at low doses (0.1–0.5 mg/L) in recirculating aquaculture systems (RAS) to control bacterial gill disease and reduce total viable count in fish culture water.— FAO Fisheries Technical Paper No. 534

B

BOD (Biochemical Oxygen Demand): The amount of dissolved oxygen consumed by biological processes in water over 5 days (BOD₅) at 20°C. A key indicator of organic pollution load regulated under CPCB discharge standards (BIS IS 2490).— BIS IS 3025 Part 44
Bromate: An oxidation byproduct formed when ozone reacts with naturally occurring bromide ions in water. Regulated at 10 µg/L under WHO GDWQ (4th ed.) and BIS IS 10500:2012. Must be monitored when applying ozone to water with bromide > 50 µg/L.— WHO GDWQ 4th Ed., 2017

C

COD (Chemical Oxygen Demand): The amount of oxygen required to chemically oxidise all organic and inorganic compounds in water. Measured by dichromate oxidation. Higher than BOD; CPCB Schedule VI sets COD limits for discharge to inland waters.— BIS IS 3025 Part 58
Corona Discharge: The most efficient commercial method for generating ozone by passing dry air or oxygen through a high-voltage electrical discharge between two electrodes separated by a dielectric. Produces 1–14% ozone by weight.— US EPA 832-F-99-063
CPCB (Central Pollution Control Board): India's statutory authority under the Water (Prevention and Control of Pollution) Act, 1974. Sets discharge standards (Schedule VI) for industrial and municipal effluents to inland surface waters, public sewers, and coastal waters.— MoEFCC, Government of India
CT Value: The product of disinfectant concentration (C, in mg/L) and contact time (T, in minutes) required to achieve a specific log inactivation of a target pathogen. Used in US EPA Surface Water Treatment Rule to award disinfection log credits.— US EPA SWTR, 1989

D

DBP (Disinfection Byproduct): Chemical compounds formed when disinfectants react with natural organic matter (NOM) in water. Chlorination produces THMs and HAAs; ozonation produces bromate and aldehydes. All are regulated in drinking water standards.— WHO GDWQ 4th Ed.
Dielectric Barrier Discharge: A type of corona discharge used in modern ozone generators where one or both electrodes are covered with a dielectric material (glass, ceramic, or silica), producing more uniform plasma and reducing arc formation.— Ozone industry standard terminology
Dissolved Ozone: Ozone dissolved in water, measured in mg/L using electrochemical or colorimetric methods. Residual dissolved ozone at 0.02–0.4 mg/L is maintained in water distribution loops and food processing wash tanks to provide ongoing disinfection.— WHO GDWQ 4th Ed.

E

ETP (Effluent Treatment Plant): A facility designed to treat industrial wastewater before discharge to comply with CPCB/SPCB standards. Ozone is used in ETPs for colour removal, COD reduction, and treatment of non-biodegradable compounds.— CPCB, India

F

FSSAI: Food Safety and Standards Authority of India. The statutory body under the Food Safety and Standards Act, 2006 that sets food processing hygiene and safety standards in India, including permitted sanitising agents for food contact applications.— Ministry of Health & Family Welfare, India

G

Geosmin: A bicyclic sesquiterpene (C₁₂H₂₂O) produced by cyanobacteria and actinomycetes in surface water sources, causing earthy/musty taste and odour detectable at < 10 ng/L. Effectively removed by ozone at doses of 1–3 mg/L.— WHO GDWQ 4th Ed.
GRAS (Generally Recognized as Safe): A US FDA designation indicating that a substance is considered safe for its intended use in food under conditions of current good manufacturing practice. Ozone received GRAS status for direct food contact in 2001 (21 CFR Part 173.368).— US FDA, 2001

H

HAA (Haloacetic Acid): A class of disinfection byproducts formed when chlorine reacts with natural organic matter. Includes monochloroacetic acid (MCAA), dichloroacetic acid (DCAA), and trichloroacetic acid (TCAA). Regulated at 60 µg/L (HAA5) under US EPA DBPR.— US EPA Disinfectants and Disinfection Byproducts Rule
HACCP (Hazard Analysis and Critical Control Points): A systematic preventive approach to food safety that identifies, evaluates, and controls significant hazards. Required under EU Regulation (EC) 852/2004 and recommended by Codex Alimentarius for food processors using ozone sanitation.— Codex Alimentarius CAC/RCP 1-1969 Rev. 4 (2003)
Hydroxyl Radical (·OH): A highly reactive oxidising species generated during ozone decomposition in water (Haber-Weiss reaction) and during AOP processes. With a reduction potential of +2.80 V, hydroxyl radicals non-selectively oxidise virtually all organic compounds.— WHO Technical Report Series No. 1019, 2021

I

Injection System (Venturi): A device that uses the Venturi effect (pressure differential) to draw ozone gas into a water stream and dissolve it under pressure. Achieves transfer efficiencies of 80–95% in properly designed installations.— US EPA 832-F-99-063
ISO 9001:2015: International standard for quality management systems published by the International Organization for Standardization. Certification demonstrates that a manufacturer's processes consistently meet customer and regulatory requirements.— ISO, 2015
ISO 12100: International standard for safety of machinery — general principles for design, risk assessment, and risk reduction. Required for CE marking of industrial machinery including ozone generators sold in EU markets.— ISO, 2010

L

Log Reduction: A logarithmic (base-10) measure of pathogen inactivation. 1-log = 90% kill, 2-log = 99%, 3-log = 99.9%, 4-log = 99.99%. WHO and EPA specify required log reductions for drinking water treatment based on source water pathogen loading.— WHO GDWQ 4th Ed.

M

MIB (2-Methylisoborneol): A bicyclic monoterpenoid (C₁₁H₂₀O) produced by cyanobacteria and actinomycetes causing musty taste and odour in water at concentrations as low as 7 ng/L. Removed by ozone at doses of 2–5 mg/L.— WHO GDWQ 4th Ed.
MLSS (Mixed Liquor Suspended Solids): The concentration of total suspended solids in the aeration tank of an activated sludge process, typically 2,000–4,000 mg/L. Ozone can be used for sludge reduction by partial ozonation of return activated sludge.— US EPA, Biosolids Technology Fact Sheet
MSME: Micro, Small, and Medium Enterprises — a category of business under the MSME Development Act, 2006 (India). UDYAM registration provides MSME classification and access to government schemes. Ozone India Technology is UDYAM-registered (UP-29-0072870).— MoMSME, Government of India

N

NOM (Natural Organic Matter): A complex mixture of organic compounds (humic and fulvic acids, proteins, carbohydrates) derived from decomposing plant and animal matter in source water. NOM exerts ozone demand and can generate aldehydes as ozonation byproducts.— US EPA, ICR Technical Support Document

O

Ozone (O₃): An allotropic form of oxygen consisting of three oxygen atoms. An unstable, pale blue gas with a pungent odour and a standard reduction potential of +2.07 V. Generated on-site by electrical discharge (corona) or UV irradiation of air or pure oxygen.— WHO GDWQ 4th Ed.
Ozone Demand: The amount of ozone consumed by reactions with water constituents (NOM, inorganics, pathogens) before a residual is established. Ozone dose must exceed demand to produce a measurable dissolved ozone residual.— US EPA 832-F-99-063
Ozone Destructor: A device that catalytically or thermally converts off-gas ozone back to oxygen before venting to prevent worker exposure above the OSHA PEL of 0.1 ppm (8-hr TWA). Required on all ozone contact chambers and storage vessels.— OSHA 29 CFR 1910.1000
Ozone Half-Life: The time for ozone concentration in water to decay to 50% of its initial value. Highly temperature- and pH-dependent: approximately 20–30 minutes at 20°C, pH 7; significantly shorter at higher temperatures and alkaline pH.— WHO GDWQ 4th Ed.
Ozone Yield: The mass of ozone produced per unit of electrical energy consumed, expressed in g/kWh. Typical values: 60–120 g/kWh (air-fed), 80–200 g/kWh (O₂-fed). Higher yield reduces operating cost.— Ozone industry standard
Oxygen Concentrator: A pressure swing adsorption (PSA) device that concentrates oxygen from ambient air to 90–95% purity for use as ozone generator feed gas. Improves ozone yield by 3–4× compared to air-fed operation.— US EPA 832-F-99-063

P

PAC (Powder Activated Carbon): Finely divided activated carbon added to water to adsorb taste, odour compounds, micropollutants, and ozonation byproducts (aldehydes). Often used in combination with ozone treatment in advanced water treatment.— WHO GDWQ 4th Ed.
Pathogen: A microorganism capable of causing disease. In water treatment, key pathogens include *Giardia lamblia*, *Cryptosporidium parvum*, enteric viruses (Adenovirus, Norovirus), and bacteria (*E. coli*, *Salmonella*, *Campylobacter*).— WHO GDWQ 4th Ed.
PPM / PPB: Parts per million (mg/L) and parts per billion (µg/L) — concentration units used for dissolved ozone, disinfection byproducts, and trace contaminants in water. 1 ppm = 1 mg/L; 1 ppb = 1 µg/L.— Standard analytical chemistry terminology

R

RoHS (Restriction of Hazardous Substances): EU Directive 2011/65/EU restricting the use of specific hazardous materials (lead, mercury, cadmium, etc.) in electrical and electronic equipment. CE-marked ozone generators must comply with RoHS.— EU Directive 2011/65/EU
Residual Disinfectant: The concentration of disinfectant remaining in water after the initial demand is satisfied. Chlorine can maintain a distribution system residual; ozone decays rapidly and is typically supplemented by chloramine for distribution system protection.— WHO GDWQ 4th Ed.

S

STP (Sewage Treatment Plant): A facility for removing solids, organic matter, nutrients, and pathogens from municipal wastewater. Ozone is applied at the tertiary stage for final disinfection and colour/odour removal before discharge or reuse.— CPCB, India

T

THM (Trihalomethane): A class of volatile organic compounds (chloroform, bromodichloromethane, etc.) formed when chlorine reacts with NOM. Regulated at 80 µg/L (TTHM) under US EPA DBPR and 0.1 mg/L under BIS IS 10500:2012. Ozone significantly reduces THM formation potential.— BIS IS 10500:2012; US EPA DBPR
TOC (Total Organic Carbon): Total concentration of carbon in organic compounds in water, measured by catalytic combustion or UV/persulfate oxidation. An indicator of NOM content and ozone demand. Higher TOC = higher ozone dose required.— US EPA Method 415.3
Transfer Efficiency: The fraction of ozone generated that is actually dissolved into the water (expressed as %). Depends on contact method, pressure, bubble size, and water characteristics. Venturi injectors: 85–95%; coarse bubble diffusers: 60–75%.— US EPA 832-F-99-063
TSS (Total Suspended Solids): The dry weight of particles retained by a standard filter per unit volume of water, expressed in mg/L. CPCB discharge standards limit TSS in treated effluent. High TSS attenuates UV dose and increases ozone demand.— BIS IS 3025 Part 17

U

UVT (UV Transmittance): The fraction of UV light at 254 nm transmitted through a 1 cm water sample, expressed as a percentage. Used to calculate UV dose delivered by UV disinfection systems. Low UVT (turbidity, colour, organics) requires more lamp intensity.— US EPA UV Guidance Manual, 2006
UV Fluence: The product of UV irradiance (mW/cm²) and exposure time (seconds), expressed in mJ/cm². The key parameter for UV disinfection efficacy. Also called UV dose. Required fluence varies by pathogen and target log inactivation.— US EPA UV Guidance Manual, EPA 815-R-06-007
UDYAM: India's online MSME registration system launched by the Ministry of MSME in July 2020, replacing the Udyog Aadhaar. Registration provides government recognition of MSME status and access to priority sector lending and government procurement preferences.— MoMSME, Government of India, 2020
USP <1231>: United States Pharmacopeia chapter on Water for Pharmaceutical Purposes. Specifies quality requirements for Purified Water (PW) and Water for Injection (WFI) and endorses ozone as an acceptable continuous sanitisation method for distribution loops.— USP 42, Chapter <1231>

V

Venturi Injector: A flow device that creates a vacuum by forcing fluid through a narrowing (throat) to draw ozone gas into the water stream for dissolution. Widely used in industrial ozone systems for efficient gas–liquid mass transfer.— US EPA 832-F-99-063

W

WFI (Water for Injection): Highly purified water used in pharmaceutical manufacturing for parenteral drug preparation and equipment cleaning. Defined in USP <1231> and PhEur 0169. Ozone is used for continuous biofilm control in WFI distribution loops.— USP <1231>; PhEur 0169
WHO GDWQ: WHO Guidelines for Drinking-Water Quality — the international reference standard for safe drinking water, currently in its 4th edition (2017 and online updates). Provides guideline values for microbiological and chemical parameters and endorses ozone and UV as primary disinfectants.— WHO, 2017 (4th edition)

Z

ZLD (Zero Liquid Discharge): A wastewater management strategy where no liquid effluent leaves the site, typically achieved through evaporation, crystallisation, and recycling of all treated water. Ozone pre-treatment reduces the organic and colour load before ZLD membrane systems.— CPCB, India; EU BREF documents