Ozone in Drinking Water Treatment: Applications and Design Criteria

How is ozone used in drinking water treatment plants?

Ozone (O₃) is used in drinking water treatment for disinfection, oxidation of contaminants, taste and odor control, and preparation of water for subsequent treatment stages.

Its application is particularly relevant in drinking water treatment plants (DWTPs) dealing with variable raw water quality, algal blooms, natural organic matter, iron and manganese, micropollutants or demanding microbiological requirements.

Depending on the treatment objectives, ozone can be introduced at different points in the process:

• Pre-ozonation: Applied near the beginning of the treatment train to support selected oxidation objectives and, under suitable conditions, improve subsequent treatment.

• Intermediate ozonation: Applied after clarification or other treatment stages to oxidize dissolved compounds and support downstream filtration or biological activated carbon (BAC).

• Primary disinfection: Used to inactivate microorganisms through controlled dissolved ozone concentration and effective contact time.

• Advanced oxidation: Combined with other processes when additional oxidation of selected contaminants is required.

However, ozone treatment performance depends on much more than ozone generator capacity or the applied dose.

Water chemistry, ozone demand, bromide concentration, gas-to-liquid transfer, hydraulic contact time, residual ozone control and downstream treatment all influence the final results.

An engineered drinking water ozonation plant may incorporate feed-gas preparation, ozone generation, cooling, injection and diffusion, contact chambers, off-gas destruction, instrumentation, safety systems and PLC/SCADA automation.

Longking EnTech Europe develops integrated ozonation solutions for drinking water applications, combining ozone generation technology with process engineering and integration into the complete water treatment plant.

This guide examines the main applications of ozone, their technical limitations and the engineering criteria required to design reliable and efficient drinking water treatment systems.

How is ozone generated and used in drinking water treatment?

Ozone (O₃) is a highly reactive molecule composed of three oxygen atoms. Its strong oxidizing properties make it suitable for several drinking water treatment applications, including microbial disinfection, oxidation of selected contaminants and taste and odor control.

Unlike conventional chemical disinfectants that can be delivered and stored, ozone is unstable and is normally generated directly at the water treatment plant.

After generation, ozone-containing gas must be introduced into the water through a suitable injection or diffusion system.

The effectiveness of the process depends on the amount of ozone transferred and the reactions taking place in the water, rather than simply on the nominal capacity of the ozone generator.

How does corona discharge ozone generation work?

The most widely used industrial method for generating ozone is corona discharge, also known as dielectric barrier discharge.

In this process, a controlled electrical discharge converts part of the oxygen molecules (O₂) in the feed gas into ozone (O₃).

The ozone concentration and production capacity depend on factors including feed-gas composition, gas flow, electrical operating conditions, temperature and generator design.

Industrial ozone generators are normally integrated with supporting systems such as:

• Feed-gas supply and preparation.

• Electrical power supply and ozone generation modules.

• Cooling systems.

• Ozone concentration and gas-flow monitoring.

• Automatic production control.

• Gas injection and contact systems.

• Off-gas treatment and safety instrumentation.

Ozone production capacity is commonly expressed in g O₃/h or kg O₃/h, while ozone concentration in the product gas is a separate parameter.

Both are important for evaluating the complete ozonation process.

What is the difference between oxygen-fed and air-fed ozone generators?

Industrial ozone systems can operate with different feed gases, provided that the generator is designed for the selected supply conditions.

The main alternatives include:

• PSA oxygen generation: Oxygen produced on-site using pressure swing adsorption technology.

• Liquid oxygen (LOX): Oxygen supplied from a cryogenic storage system and vaporized before use.

• Treated dry air: Compressed air that has undergone appropriate filtration and drying before entering a compatible ozone generator.

Oxygen-fed systems generally allow higher ozone concentrations in the product gas than dry-air-fed systems.

However, the most appropriate solution depends on the required ozone capacity, gas supply availability, operating costs, energy consumption, maintenance and integration requirements.

Higher ozone concentration does not automatically guarantee better overall treatment efficiency. Gas-to-liquid transfer, contactor design and water chemistry must also be considered.

In every case, feed-gas quality is essential. Excessive moisture or contaminants can affect generator performance and reliability.

Why must ozone be generated and handled under controlled conditions?

Ozone is a powerful oxidizing agent, but it is also hazardous when released into occupied areas at excessive concentrations.

Drinking water ozonation facilities therefore require appropriate engineering measures, which may include:

• Ozone-compatible materials and piping.

• Ambient ozone leak detection.

• Suitable ventilation.

• Automatic shutdown and protective interlocks.

• Monitoring of gas pressure, flow and operating conditions.

• Collection and destruction of ozone-containing off-gas.

• Maintenance and emergency procedures.

Any residual ozone in the off-gas must be managed through an appropriately designed destruction system before discharge.

Ozone generation, injection and destruction equipment must operate as a coordinated installation.

Is ozone generator capacity the same as the ozone dose received by the water?

No.

The ozone generator produces a defined mass of ozone per unit of time, but not all of the ozone generated necessarily dissolves in the water.

Part of the ozone may remain in the gas phase, while dissolved ozone reacts with substances present in the water and progressively decomposes.

Therefore, it is necessary to distinguish between:

• Ozone production: Mass of ozone generated per unit of time.

• Applied ozone dose: Mass of ozone introduced relative to the treated water volume.

• Transferred ozone dose: Ozone transferred from the gas phase into the water.

• Dissolved ozone residual: Ozone concentration remaining in the water at a defined measurement point and time.

For disinfection applications, the dissolved ozone concentration and effective hydraulic contact time are particularly important.

For oxidation applications, ozone demand, reaction kinetics and potential by-product formation must also be evaluated.

Longking EnTech Europe develops ozonation solutions that integrate ozone generation with gas preparation, mass transfer, hydraulic contact, automation and safety systems, according to the treatment objectives and operating conditions of each drinking water plant.

What are the main benefits of ozone in drinking water treatment?

Ozone is used in drinking water treatment because it combines microbial disinfection with the oxidation of selected inorganic and organic contaminants.

Unlike treatment technologies designed for a single objective, ozonation can contribute to several processes within the same drinking water treatment plant, depending on the characteristics of the raw water.

Ozone reacts with water constituents through two main mechanisms:

• Direct oxidation: Molecular ozone (O₃) reacts selectively with susceptible microorganisms and chemical compounds.

• Indirect oxidation: Ozone decomposition generates reactive species, including hydroxyl radicals (•OH), which can oxidize a wider range of organic substances.

The relative importance of these reactions depends on water chemistry, pH, alkalinity, natural organic matter and other constituents that react with ozone or consume hydroxyl radicals.

The main benefits of ozonation must therefore be evaluated against the specific treatment objectives and the complete treatment process.

How effective is ozone for drinking water disinfection?

Ozone is a powerful disinfectant capable of inactivating bacteria, viruses and certain protozoan pathogens.

Its disinfection effectiveness depends on several factors:

• Target microorganisms and required log reduction.

• Dissolved ozone concentration.

• Effective hydraulic contact time.

• Water temperature and pH.

• Initial ozone demand and residual decay.

• Hydraulic mixing and flow distribution within the contactor.

When ozone is used for primary disinfection, performance is commonly evaluated through a concentration–contact time (CT) approach, according to the applicable regulatory methodology.

CT evaluation considers the concentration of dissolved ozone and the effective exposure time, rather than the nominal ozone dose or contact tank volume alone.

A higher ozone generator capacity does not automatically guarantee greater microbial inactivation. The disinfection system must achieve the required exposure under the specified operating conditions.

Another important consideration is that ozone decomposes relatively quickly and does not provide a persistent disinfectant residual throughout the distribution network.

Therefore, drinking water plants commonly combine primary ozone disinfection with a suitable downstream residual disinfection strategy, where required.

How does ozone transform natural organic matter?

Raw water may contain natural organic matter (NOM), including humic substances and other dissolved organic compounds.

Ozone can react with susceptible molecular structures, changing their chemical characteristics and breaking down certain complex molecules.

Depending on water composition and treatment conditions, these reactions may:

• Reduce colour associated with specific organic compounds.

• Transform selected organic contaminants.

• Increase the biodegradability of part of the dissolved organic matter.

• Modify the formation potential of certain downstream disinfection by-products.

• Improve the suitability of the water for subsequent biological treatment.

However, ozone oxidation does not necessarily remove the organic carbon from the water.

Ozonation may transform larger organic molecules into smaller compounds without achieving substantial mineralization.

Some oxidation products are more biodegradable and can subsequently be removed through biological activated carbon (BAC) filtration.

For this reason, ozone followed by BAC filtration is an important treatment combination in advanced drinking water plants.

The ozone dose and downstream treatment must be evaluated together to prevent biodegradable organic matter from remaining in the finished water.

Can ozone remove taste and odor compounds from drinking water?

Taste and odor problems are a frequent concern in drinking water treatment, particularly when surface water sources experience seasonal algal activity.

Two important compounds are:

• Geosmin: Associated with earthy odors.

• 2-Methylisoborneol (MIB): Associated with musty or earthy odors.

These substances can be detected by consumers at very low concentrations, even when the water otherwise meets health-related quality requirements.

Ozone can contribute to the oxidation of geosmin, MIB and other odor-causing compounds.

However, treatment effectiveness varies with the compound, water chemistry, applied ozone exposure and contribution of hydroxyl radical reactions.

Some taste and odor compounds are relatively resistant to direct molecular ozone oxidation.

Consequently, conventional ozonation may not always achieve the required removal on its own.

Depending on the application, complementary processes may include:

• Granular activated carbon (GAC).

• Biological activated carbon (BAC).

• Powdered activated carbon (PAC).

• Advanced oxidation processes, such as ozone combined with hydrogen peroxide (O₃/H₂O₂).

The treatment strategy should be selected using representative raw water data and, where necessary, laboratory or pilot testing.

How does ozone remove iron and manganese from drinking water?

Dissolved iron and manganese can cause discoloration, staining, deposits and operational problems in drinking water systems.

Ozone can oxidize certain dissolved forms of these metals, facilitating their subsequent removal.

For example:

• Iron: Dissolved ferrous iron (Fe²⁺) can be oxidized to ferric forms that precipitate under suitable water chemistry conditions.

• Manganese: Dissolved manganese (Mn²⁺) can be oxidized to higher oxidation states, potentially forming insoluble manganese oxides that can be removed by filtration.

The effectiveness of these reactions depends on pH, alkalinity, dissolved constituents, oxidation conditions and the characteristics of the water.

Ozone performs the oxidation, but the resulting particulate matter must still be removed by an appropriate separation process, such as filtration.

Special attention is required when treating manganese.

Excessive oxidation under certain conditions can favour the formation of soluble permanganate species, potentially causing unwanted pink coloration.

The ozone dose must therefore be carefully controlled rather than increased indiscriminately.

What are the main limitations of ozonation in drinking water treatment?

Although ozone offers several treatment benefits, it also introduces important engineering considerations.

These include:

• Ozone demand: Natural organic matter and other reactive substances consume ozone before the intended treatment objective is achieved.

• Oxidation by-products: Ozonation can produce aldehydes, ketones, organic acids and other transformation products.

• Bromate formation: Bromide-containing waters may form bromate during ozonation, creating a critical drinking water quality concern.

• Lack of persistent residual: Additional disinfection may be required to protect water during storage and distribution.

• Downstream treatment: Oxidized metals and biodegradable organic compounds may require filtration or biological removal.

• Process complexity: Efficient ozonation requires suitable gas generation, mass transfer, hydraulic contact, monitoring and safety systems.

These limitations do not necessarily prevent the use of ozone, but they must be addressed during process selection and engineering.

The main advantage of ozone lies in its ability to support several drinking water treatment objectives within an integrated process—not in replacing every other treatment stage.

A properly engineered ozonation system combines the required oxidation or disinfection performance with appropriate water quality control, downstream treatment and safe operation.

Where should ozone be applied in a drinking water treatment plant?

The location of an ozone treatment stage within a drinking water treatment plant has a significant influence on its effectiveness, operating costs and interaction with other treatment processes.

Ozone can be applied before clarification, between treatment stages or as part of a dedicated disinfection and oxidation process, depending on the water quality and treatment objectives.

The main configurations include:

• Pre-ozonation: Ozone is applied near the beginning of the treatment train, generally before coagulation or clarification. It may support oxidation of selected contaminants, colour reduction and management of certain algae-related problems. However, raw water can have high ozone demand, and the effects on coagulation and cyanobacterial cells must be evaluated.

• Intermediate ozonation: Ozone is typically applied after clarification and before filtration or biological activated carbon (BAC). This arrangement can support oxidation of dissolved compounds and transformation of organic matter into more biodegradable substances.

• Ozone for primary disinfection: Ozone is introduced at a suitable treatment stage where the required dissolved ozone concentration and effective hydraulic contact time can be achieved. Its location depends on the treatment process, rather than being restricted to a single position.

• Ozonation for specific contaminants: A dedicated oxidation stage may target taste and odor compounds, iron and manganese, selected micropollutants or other substances identified through water quality assessment.

These applications are not mutually exclusive. A properly designed ozonation stage may contribute to several treatment objectives, although the required operating conditions may differ.

How is the best ozone application point selected?

The selection should consider the characteristics of the water entering the ozone stage and the processes located downstream.

Important factors include:

• Raw water quality and seasonal variations.

• Primary treatment objectives and required performance.

• Initial ozone demand and residual decay.

• Bromide concentration and bromate formation potential.

• Suspended solids and organic matter characteristics.

• Required disinfection CT, where applicable.

• Existing clarification, filtration and activated carbon systems.

• Available hydraulic contact time and installation space.

• Energy consumption, operating costs and process control requirements.

Applying ozone earlier in the process may provide useful oxidation benefits, but it can also result in higher consumption due to the presence of reactive substances in raw water.

Applying ozone after clarification may reduce some competing ozone demand and facilitate treatment of dissolved contaminants, but it must still be coordinated with downstream filtration, biological treatment and final disinfection.

There is no universally optimal ozone application point for every drinking water treatment plant.

Can one ozonation stage achieve several treatment objectives?

Yes, but the process must be designed around clearly defined priorities.

For example, an intermediate ozonation stage may contribute to the transformation of natural organic matter, oxidation of selected taste and odor compounds and preparation of the water for downstream biological activated carbon treatment.

However, a dose selected for oxidation may not provide the CT required for microbial disinfection.

Likewise, increasing the ozone dose to improve oxidation can increase the risk of bromate formation in bromide-containing waters.

The engineering assessment must therefore identify which objectives can be achieved simultaneously and which require additional treatment or separate process stages.

Longking EnTech Europe evaluates ozone application points as part of the complete drinking water treatment process, considering ozone generation, gas transfer, water chemistry, hydraulic contact, bromate control and integration with downstream treatment.

The following sections examine the two principal process arrangements in greater detail: pre-ozonation and intermediate ozonation combined with biological activated carbon.

What is pre-ozonation in drinking water treatment and when should it be used?

Pre-ozonation is the application of ozone near the beginning of a drinking water treatment process, typically before coagulation, clarification or filtration.

It is mainly considered in drinking water treatment plants using surface water sources with variable organic matter, colour, algae, taste and odor compounds or specific oxidation requirements.

At this stage, the water may contain relatively high concentrations of suspended solids, natural organic matter, microorganisms and other substances that consume ozone.

Pre-ozonation can contribute to several treatment objectives, but its performance depends strongly on raw water quality and its interaction with downstream treatment processes.

The decision to install pre-ozonation should be based on demonstrated process benefits rather than assuming that adding ozone before coagulation will always improve treatment.

How does pre-ozonation affect coagulation and clarification?

Pre-ozonation can modify the chemical structure, molecular characteristics and surface properties of natural organic matter (NOM).

Under certain conditions, these changes may influence particle destabilization, floc formation and the removal of organic matter during subsequent coagulation and clarification.

Potential benefits include:

• Improved removal of selected organic compounds during coagulation.

• Modification of natural organic matter characteristics.

• Improved clarification performance under suitable operating conditions.

• Possible reduction in coagulant demand for certain water compositions.

However, pre-ozonation does not always improve coagulation.

Its effects depend on several factors, including:

• Type and concentration of natural organic matter.

• Applied ozone dose and reaction conditions.

• Raw water pH and alkalinity.

• Type and dosage of coagulant.

• Characteristics of suspended and colloidal particles.

• Subsequent flocculation and clarification conditions.

In some waters, ozone can break down larger organic molecules into smaller, more soluble compounds that are more difficult to remove through conventional coagulation.

Excessive pre-ozonation may therefore reduce clarification performance or increase the demand for downstream treatment.

Laboratory jar tests, ozone demand studies and pilot testing should be used where necessary to determine whether pre-ozonation improves the complete coagulation and clarification process.

Can pre-ozonation help control algae and cyanobacteria?

Surface water sources may experience seasonal algal blooms and increases in cyanobacteria populations.

These events can affect drinking water treatment through increased organic loading, taste and odor compounds, filter clogging and, in some cases, the presence of cyanotoxins.

Ozone can damage or inactivate algal and cyanobacterial cells.

However, cell inactivation is not equivalent to safe removal of the cells or their associated contaminants.

When ozone damages cell membranes, intracellular material may be released into the surrounding water.

This can include:

• Dissolved organic compounds.

• Taste and odor substances, including geosmin and 2-methylisoborneol (MIB).

• Intracellular cyanotoxins produced by certain cyanobacteria.

• Other compounds that may increase downstream treatment demand.

Consequently, pre-ozonation may temporarily increase the concentration of dissolved contaminants if the oxidation exposure is insufficient to degrade the substances released.

Why is cyanotoxin release a critical consideration?

Some cyanobacteria produce toxins that may remain largely inside intact cells until those cells are damaged or break down.

When toxin-producing cyanobacteria are present, pre-ozonation can rupture cells and release previously intracellular toxins into the dissolved phase.

Although ozone can oxidize certain cyanotoxins, its effectiveness depends on the toxin involved, ozone demand, water chemistry and achieved oxidation exposure.

An ozone dose sufficient to damage cells may not be sufficient to destroy the released toxins.

For this reason, pre-ozonation should not be selected as a routine algae-control measure without evaluating the potential release and subsequent treatment of cyanotoxins.

Where cyanotoxins are a concern, the treatment strategy should consider:

• Identification and monitoring of relevant cyanobacteria.

• Measurement of intracellular, extracellular and total cyanotoxins where appropriate.

• Removal of intact cells through suitable clarification, flotation or filtration processes.

• The potential for toxin release during oxidation.

• The effectiveness of downstream activated carbon or other suitable treatment barriers.

• Verification that the complete treatment process achieves the required finished-water quality.

Depending on the water source and bloom conditions, removing intact cyanobacterial cells before oxidation may be preferable to applying ozone directly to the raw water.

The appropriate approach must be established through water-specific risk assessment and process evaluation.

How can pre-ozonation reduce colour and taste and odor compounds?

Natural water colour is frequently associated with organic compounds containing chemical structures that absorb visible light.

Ozone can oxidize some of these structures, reducing apparent colour and modifying the characteristics of dissolved organic matter.

However, colour reduction does not necessarily indicate an equivalent reduction in dissolved organic carbon (DOC).

Ozonation may transform coloured organic molecules into smaller or more biodegradable compounds without removing the corresponding carbon from the water.

Similarly, pre-ozonation may help reduce certain taste and odor compounds, depending on their chemical characteristics and the operating conditions.

For geosmin and MIB, performance can vary significantly with water chemistry, ozone demand and the contribution of hydroxyl radical reactions.

Where dissolved taste and odor compounds cannot be adequately controlled through pre-ozonation alone, additional treatment may be necessary, including powdered activated carbon (PAC), granular activated carbon (GAC), biological activated carbon (BAC) or appropriately designed advanced oxidation processes.

The most effective solution should be selected according to the contaminants present and their concentrations.

What operating risks must be evaluated before installing pre-ozonation?

Pre-ozonation is applied to raw water, where the composition and ozone demand may vary substantially over time.

The engineering assessment should therefore consider:

• Raw water ozone demand: High or variable demand can increase ozone consumption and limit the exposure available for target reactions.

• Cyanobacterial cell damage: Oxidation may release intracellular toxins and odor compounds.

• Coagulation performance: Changes in organic matter can improve or impair subsequent clarification.

• Bromate formation: Bromide-containing waters require assessment of bromate formation potential during ozonation.

• Oxidation by-products: Certain organic compounds may be transformed into aldehydes, organic acids and other reaction products.

• Downstream treatment: Filtration, adsorption or biological treatment may be required to remove or control oxidation products.

• Operational variability: Seasonal changes in water quality may require adjustments to the ozone operating strategy.

The ozone dose should be optimized for the relevant treatment objectives while avoiding unnecessary oxidation exposure.

A higher applied ozone dose is not automatically associated with better overall treatment performance.

When is pre-ozonation the right choice for a drinking water plant?

Pre-ozonation may be appropriate when water quality testing demonstrates that it provides useful oxidation benefits without compromising subsequent treatment or finished-water quality.

Potential applications include selected colour-control objectives, oxidation of particular inorganic compounds, management of certain dissolved contaminants and improvement of downstream treatment under suitable conditions.

However, an intermediate ozonation stage after clarification may be preferable when the main objective involves dissolved organic compounds, taste and odor control or preparation for biological activated carbon treatment.

Longking EnTech Europe evaluates pre-ozonation as part of the complete drinking water treatment process, considering raw water characterization, ozone demand, gas transfer, hydraulic contact, bromate formation potential and integration with clarification and filtration.

The objective is to determine whether applying ozone before conventional treatment provides a measurable technical and operational advantage for the specific water source.

Pre-ozonation should be selected because it improves the complete treatment process—not simply because ozone is an effective oxidant.

How does intermediate ozonation combined with biological activated carbon improve drinking water treatment?

Intermediate ozonation is commonly applied after clarification and before filtration or biological activated carbon (BAC) treatment in advanced drinking water treatment plants.

At this stage, a significant proportion of suspended solids and certain ozone-consuming substances may already have been removed, allowing ozone to act on dissolved organic compounds and other target contaminants.

The combination of ozone and biological activated carbon (O₃–BAC) is particularly relevant when treatment objectives include organic matter transformation, improvement of biological stability, taste and odor control, and oxidation of selected micropollutants.

However, the effectiveness of the process depends on both treatment stages and must be evaluated using the characteristics of the water being treated.

Why is ozone often applied after clarification?

Applying ozone after clarification can offer process advantages compared with pre-ozonation, particularly when the main objective is the treatment of dissolved substances.

Potential benefits include:

• Lower concentrations of suspended solids entering the ozonation stage.

• Reduced competition from certain ozone-consuming constituents.

• More controlled oxidation of selected dissolved organic compounds.

• Improved compatibility with downstream activated carbon or biological filtration.

• Greater flexibility to optimize oxidation and filtration as a combined treatment process.

However, clarified water can still contain substantial dissolved organic matter and other compounds that consume ozone.

The required ozone dose must therefore be determined from representative water quality measurements and the desired treatment objectives.

What is biological activated carbon (BAC) filtration?

Biological activated carbon (BAC) filtration uses granular activated carbon colonized by microorganisms capable of degrading certain biodegradable organic compounds.

Unlike a filtration process based exclusively on physical separation, BAC combines several mechanisms:

• Biodegradation: Microorganisms attached to the carbon medium consume suitable biodegradable organic substances.

• Adsorption: Activated carbon retains certain dissolved organic compounds within its porous structure.

• Particle retention: The filter can retain suspended particles according to its hydraulic and filtration characteristics.

The relative contribution of these mechanisms depends on the characteristics and operating history of the carbon, biological activity, water quality and filtration conditions.

Fresh granular activated carbon may initially provide substantial adsorption capacity, while biological degradation can become increasingly important as the filter develops biological activity.

BAC should not be considered an unlimited adsorption or biodegradation system. Its performance depends on the compounds present and the operating conditions.

How does ozonation improve downstream BAC performance?

Ozone can break down certain complex organic molecules and modify their chemical structure.

Some resulting compounds may be more readily biodegradable than the original substances.

This process can increase parameters such as:

• Biodegradable dissolved organic carbon (BDOC): The fraction of dissolved organic carbon susceptible to biological degradation.

• Assimilable organic carbon (AOC): Organic carbon that can support microbial growth under defined test conditions.

An increase in biodegradable organic matter after ozonation is not necessarily a negative result if a suitably designed biological treatment stage follows.

The BAC filter can subsequently remove part of this biodegradable material, contributing to improved finished-water biological stability.

However, ozone does not automatically remove the carbon it transforms, and BAC does not necessarily remove every oxidation product.

The performance of the complete O₃–BAC treatment train must therefore be verified at the outlet of the biological filtration stage, rather than evaluating only the immediate effects of ozonation.

Can O₃–BAC remove micropollutants from drinking water?

Ozonation can transform selected micropollutants, including certain pesticides, pharmaceutical residues and other organic contaminants.

The extent of oxidation depends on the chemical structure of each compound, the contribution of molecular ozone and hydroxyl radicals, the water matrix and the achieved oxidation exposure.

Downstream BAC filtration may provide additional removal through adsorption or biodegradation.

However, several important limitations must be considered:

• Some micropollutants react rapidly with ozone, while others are comparatively resistant.

• Ozonation can produce transformation products whose properties differ from those of the original compounds.

• Certain transformation products may be biodegradable, but others may persist through biological filtration.

• BAC adsorption capacity depends on the carbon characteristics, operating history and contaminant loading.

• A reduction in the parent contaminant concentration does not necessarily demonstrate complete mineralization or the absence of undesirable transformation products.

Consequently, O₃–BAC should not be presented as a universal solution for removing all micropollutants.

Where specific contaminants or treatment guarantees are involved, laboratory studies, pilot testing and appropriate analytical monitoring may be necessary.

Which design parameters determine O₃–BAC performance?

An integrated ozone–BAC system requires coordinated engineering of both treatment stages.

The main design parameters include:

Ozonation stage

• Water flow and quality variations.

• Dissolved organic carbon (DOC) and ozone demand.

• Target compounds and required oxidation performance.

• Applied and transferred ozone dose.

• Dissolved ozone concentration and contact time.

• Bromide concentration and bromate formation potential.

• Hydraulic mixing and gas-to-liquid mass transfer.

• Residual ozone control before downstream biological treatment.

BAC filtration stage

• Activated carbon characteristics and filter configuration.

• Empty bed contact time (EBCT).

• Hydraulic loading and flow distribution.

• Water temperature and biological activity.

• Biodegradable organic matter loading.

• Filter maturation and biological adaptation.

• Backwashing strategy and head-loss management.

• Carbon replacement or regeneration requirements.

• Finished-water biological stability and microbiological monitoring.

Excessive ozone residual entering the biological filtration stage may negatively affect the microorganisms responsible for biodegradation.

The contact and hydraulic arrangements must therefore ensure suitable conditions for downstream biological activity.

The optimal ozone dose should be determined from the combined performance of ozonation and biological filtration, rather than maximizing oxidation in the ozone contactor alone.

Why is O₃–BAC important for finished-water quality?

One of the principal objectives of O₃–BAC treatment is to limit the concentration of biodegradable organic substances remaining in the finished water.

If ozonation increases biodegradable organic carbon without sufficient downstream removal, the resulting water may have a greater potential to support microbial regrowth during storage or distribution.

Properly designed biological filtration can help reduce this risk by removing part of the biodegradable organic matter before final treatment and distribution.

However, BAC filtration does not replace appropriate final disinfection or distribution-system controls where these are required.

Likewise, BAC filtration should not be assumed to eliminate bromate formed during ozonation. Bromate formation must be addressed primarily through water-specific process assessment and suitable ozonation control measures.

Engineering an integrated ozone–BAC treatment process

Longking EnTech Europe evaluates intermediate ozonation as part of the complete drinking water treatment process.

Depending on the project, this may involve defining ozone production capacity, feed-gas preparation, gas injection, contactor hydraulics, dissolved ozone monitoring, off-gas destruction and integration with downstream activated carbon treatment.

The engineering assessment must also consider variations in raw water quality, bromate formation potential, oxidation by-products and the operating requirements of the biological filtration stage.

The objective is not simply to achieve the highest possible oxidation rate, but to obtain the required finished-water quality through a coordinated and controllable treatment process.

By combining ozone generation technology with process engineering and integration capabilities, Longking EnTech Europe can develop ozonation solutions adapted to advanced drinking water treatment requirements.

How does ozonation affect disinfection by-products in drinking water?

Ozonation can modify the formation of disinfection by-products (DBPs) in drinking water treatment, but its effects depend on the water composition and the complete treatment process.

Disinfection by-products are formed when disinfectants react with naturally occurring or other substances present in water.

Two important groups associated with chlorination are:

• Trihalomethanes (THMs): Compounds formed through reactions involving chlorine or bromine species and suitable organic precursors.

• Haloacetic acids (HAAs): Another group of halogenated organic compounds that can form during chemical disinfection.

Ozone can oxidize some of the organic compounds responsible for subsequent DBP formation, potentially changing both the quantity and characteristics of the by-products generated during final disinfection.

However, ozone also produces its own oxidation by-products, including bromate under certain water chemistry conditions.

The objective is therefore not simply to reduce one group of DBPs, but to control the overall formation of potentially undesirable compounds while maintaining the required microbiological safety.

Can ozonation reduce trihalomethane (THM) formation?

Natural organic matter (NOM) contains compounds that can react with chlorine to form trihalomethanes.

Ozonation modifies the chemical structure of part of this organic matter, potentially reducing the concentration of certain THM precursors.

In suitable drinking water treatment processes, ozone followed by appropriate downstream treatment may help reduce THM formation during subsequent chlorination.

However, the response is not universal.

Depending on the composition of the water and the oxidation conditions, ozonation can:

• Reduce the formation potential of certain THMs.

• Have limited influence on overall THM formation.

• Increase the formation potential of some THM species.

• Change the relative proportions of chlorinated and brominated THMs.

These effects depend on natural organic matter characteristics, bromide concentration, ozone exposure, pH and the conditions of subsequent chlorination.

A reduction in organic colour or UV absorbance after ozonation does not necessarily demonstrate an equivalent reduction in THM formation potential.

Performance must be established through suitable water quality analysis and DBP formation testing.

How does ozone affect haloacetic acid (HAA) formation?

Haloacetic acids are another important group of drinking water disinfection by-products.

Like THMs, their formation depends on the availability of suitable precursors and the operating conditions of the chemical disinfection process.

Ozonation can change the characteristics of organic matter and affect the subsequent formation of HAAs.

However, the response of HAAs to ozonation is not necessarily the same as the response of THMs.

A treatment configuration that reduces THM formation may have a different effect on HAA concentrations or individual HAA species.

The evaluation should therefore consider both compound groups, rather than relying on THM measurements alone.

Where bromide is present, changes in the relative formation of chlorinated and brominated compounds must also be considered.

What oxidation by-products can ozone produce?

Ozone reacts with organic matter through direct molecular oxidation and reactions involving reactive radical species.

These reactions can transform larger organic molecules into smaller compounds, including:

• Aldehydes, such as formaldehyde, acetaldehyde and glyoxal.

• Ketones and related oxygenated compounds.

• Organic and carboxylic acids.

• Other transformation products depending on the substances present in the water.

Some of these compounds are more biodegradable than their precursors.

This is one reason why ozonation is frequently combined with biological activated carbon (BAC) or other suitable downstream treatment processes.

BAC can remove part of the biodegradable organic matter generated during ozonation, helping improve the biological stability of the finished water.

However, not every oxidation product is biodegradable or effectively removed through BAC filtration.

The absence of chlorine addition during ozonation does not mean that ozone treatment is free from oxidation by-products.

Why is bromide important for DBP formation during ozonation?

Bromide (Br⁻) may be naturally present in raw water or introduced through saline intrusion and other water quality influences.

During ozonation, bromide can participate in oxidation reactions that generate reactive bromine species.

These reactions may contribute to the formation of:

• Bromate (BrO₃⁻): An inorganic oxidation by-product of particular concern in drinking water.

• Brominated organic by-products: Compounds that can form when reactive bromine species interact with suitable organic matter.

The presence of bromide can also influence the distribution of THM and HAA species formed during subsequent chlorination.

Consequently, bromide concentration is an important parameter when evaluating the suitability of ozone for drinking water treatment.

Bromate formation is a separate and particularly important engineering concern, requiring specific monitoring and process control.

The following section examines bromate formation mechanisms, relevant operating parameters and potential mitigation strategies in greater detail.

How should ozonation and final chlorination be integrated?

Ozone is commonly used for primary disinfection or oxidation, while chlorine or another suitable secondary disinfectant is applied to maintain microbiological protection during storage and distribution.

Because ozone decomposes relatively quickly, it does not provide the persistent disinfectant residual typically required in drinking water distribution systems.

The integration of ozonation and final chlorination must therefore consider:

• Organic precursor characteristics before and after ozonation.

• Changes in THM and HAA formation potential.

• Bromide concentration and brominated by-product formation.

• Oxidation products and biodegradable organic matter.

• Downstream filtration and BAC performance.

• Final chlorine demand and required disinfectant residual.

• Contact time, temperature and distribution-system conditions.

• Applicable drinking water quality requirements.

The treatment strategy should maintain the required microbial protection while controlling DBP formation throughout the treatment plant and distribution system.

Reducing the chlorine dose without verifying disinfection requirements and the necessary residual should not be considered an acceptable DBP control strategy.

How can a drinking water plant evaluate DBP formation potential?

The effect of ozonation on DBPs should be investigated using representative water samples and operating conditions.

Depending on the project, the evaluation may include:

• Raw water characterization, including dissolved organic carbon (DOC), UV absorbance, bromide and pH.

• Ozone demand and decay testing.

• Measurement of relevant organic oxidation products.

• THM and HAA formation potential tests under defined chlorination conditions.

• Evaluation of bromate formation during ozonation.

• Comparison of water quality before and after biological filtration.

• Finished-water monitoring under representative disinfection and distribution conditions.

Laboratory or pilot-scale studies can help identify whether ozone provides a measurable benefit for the specific water source and determine the operating conditions required.

Balancing oxidation, disinfection and drinking water quality

The selection of an ozone treatment strategy should consider all relevant water quality objectives together.

An ozone dose that improves oxidation of a target contaminant may also alter the formation of downstream chlorination by-products or increase bromate formation potential.

Similarly, reducing ozone exposure to limit undesirable by-products must not compromise required primary disinfection or contaminant oxidation.

Longking EnTech Europe evaluates ozonation systems as part of the complete drinking water treatment process, considering ozone demand, gas transfer, contact hydraulics, water chemistry, bromate control and integration with downstream treatment.

The engineering objective is to achieve the required treatment performance while controlling disinfection and oxidation by-products throughout the complete process.

How can bromate formation be controlled during drinking water ozonation?

Bromate (BrO₃⁻) formation is one of the most important water quality risks associated with ozone treatment in drinking water plants.

When raw water contains bromide (Br⁻), ozonation can convert part of it into bromate through a series of oxidation reactions involving molecular ozone, reactive bromine species and hydroxyl radicals.

Bromide occurs naturally in many water sources, particularly in coastal areas, groundwater affected by saline intrusion and certain surface waters influenced by geological or human activities.

The amount of bromate formed depends on water chemistry, ozone exposure and the operating conditions of the treatment process.

Bromate control must therefore be considered from the earliest stages of ozonation system design, rather than treated as a problem to be corrected after commissioning.

What is the drinking water limit for bromate in Europe?

Under Directive (EU) 2020/2184 on the quality of water intended for human consumption, the parametric value for bromate is:

10 µg/L (0.010 mg/L) of bromate (BrO₃⁻).

This value applies to drinking water quality and must be considered alongside the relevant national legislation and compliance requirements.

The World Health Organization (WHO) also establishes a provisional drinking water guideline value of 0.01 mg/L for bromate.

For an ozonation installation, the engineering objective is to control bromate formation so that the complete drinking water treatment and supply system can meet the applicable requirements.

Where bromate is identified as a relevant risk, an appropriate operating margin below the regulatory limit should be considered to account for water quality variations, process uncertainties and analytical monitoring.

The regulatory value must not be interpreted as an allowable bromate increase across the ozone contactor. Bromate already present in the incoming water and any contribution from other treatment stages must also be considered.

Which factors influence bromate formation during ozonation?

Bromate formation results from several interacting chemical pathways.

The most important influencing factors include:

• Bromide concentration: Higher bromide concentrations generally increase the potential for bromate formation, although the actual conversion depends on the water chemistry.

• Applied ozone dose: Increasing ozone exposure can promote bromate formation, particularly when ozone remains available after the initial water demand has been satisfied.

• Dissolved ozone residual and contact time: Higher residual concentrations and longer exposure may increase the opportunity for bromate-forming reactions.

• Water pH: Higher pH generally favours bromate formation through changes in reactive bromine speciation and ozone decomposition chemistry.

• Temperature: Influences ozone solubility, decay and chemical reaction rates.

• Natural organic matter (NOM): May consume ozone and reactive intermediates, but can also increase the ozone dose needed to achieve the intended treatment objective.

• Alkalinity and carbonate chemistry: Influence hydroxyl radical reactions and other pathways associated with bromate formation.

• Ammonia and other reactive constituents: May modify the formation and transformation of bromine intermediates.

• Gas-to-liquid mass transfer: Affects dissolved ozone concentrations, local exposure conditions and the overall efficiency of the process.

There is no universal bromide concentration below which bromate formation can always be disregarded.

The risk must be evaluated under the actual water chemistry and the expected range of ozonation conditions.

Can bromate formation be reduced by optimizing ozone dose and contact time?

Yes. Optimizing ozone exposure is one of the principal approaches to controlling bromate formation.

The objective is to provide the ozone exposure required for the treatment process while avoiding unnecessary dissolved ozone residuals and excessive contact conditions.

Potential measures include:

• Adjusting ozone production to actual water flow and treatment demand.

• Optimizing the applied dose using ozone demand and decay measurements.

• Avoiding unnecessarily high dissolved ozone residuals.

• Evaluating the ozone application point within the treatment process.

• Improving gas-to-liquid transfer and hydraulic contact.

• Assessing staged ozone application where it offers measurable benefits.

• Implementing suitable monitoring and automatic control strategies.

However, reducing ozone exposure must not compromise the primary treatment objective.

When ozone is used for microbial disinfection, the required concentration–contact time (CT) conditions must still be achieved.

Similarly, when the process is designed to oxidize specific contaminants, reducing the ozone dose may affect the required oxidation performance.

The appropriate design must balance bromate formation, treatment effectiveness and operating costs.

Can pH adjustment, ammonia or hydrogen peroxide help control bromate?

Several chemical strategies have been investigated and applied under specific operating conditions to limit bromate formation.

pH adjustment

Reducing pH during ozonation can decrease bromate formation in many waters.

However, pH adjustment introduces additional chemical consumption and may affect corrosion control, subsequent treatment and finished-water stabilization.

It must therefore be assessed within the complete drinking water treatment process.

Ammonia addition

Under suitable conditions, ammonia can react with certain reactive bromine intermediates and reduce their progression towards bromate.

The effect depends on water chemistry, ozone exposure and ammonia concentration.

Potential impacts on downstream biological treatment, nitrogen species and final disinfection chemistry must also be considered.

Hydrogen peroxide addition

Hydrogen peroxide can modify ozone decomposition and hydroxyl radical chemistry.

Under selected conditions, this may reduce bromate formation.

However, adding hydrogen peroxide does not universally prevent bromate formation.

Its effect varies with the water matrix, operating conditions and treatment objectives. Ozone–hydrogen peroxide processes may also behave differently from conventional ozonation because they increase the contribution of radical oxidation.

The use of ammonia, hydrogen peroxide or other chemical control strategies should therefore be supported by laboratory studies, pilot testing or reliable application-specific evidence.

Can biological activated carbon remove bromate after ozonation?

Bromate control should generally prioritize preventing excessive formation during the ozone treatment stage.

Biological activated carbon (BAC) is commonly used after ozonation to remove biodegradable organic matter and certain oxidation products.

However, conventional BAC filtration must not be assumed to provide reliable bromate removal.

Although bromate reduction may occur under particular biological or treatment conditions, it is not an inherent or guaranteed function of a standard BAC filter.

Once bromate has formed, its removal can be considerably more difficult than preventing its formation.

Where the required bromate limits cannot be achieved through conventional ozonation and appropriate process control, the treatment strategy may need to be reconsidered.

This can involve modifying upstream treatment, evaluating alternative oxidation processes or assessing technologies specifically capable of addressing the remaining bromate.

How should bromate formation be evaluated during ozone system design?

A technically defensible ozonation project should assess bromate risk before defining the final equipment capacity and operating strategy.

The evaluation should include:

• Representative bromide and bromate measurements in the incoming water.

• Seasonal variations in raw water quality.

• pH, temperature, alkalinity and dissolved organic carbon (DOC).

• Ozone demand and decay characteristics.

• Required disinfection or oxidation performance.

• Applied and transferred ozone doses.

• Dissolved ozone residual profiles.

• Hydraulic contact time and flow distribution.

• Bromate formation under representative and unfavourable operating conditions.

• Effects of any proposed bromate mitigation measures.

Where the risk is significant, laboratory and pilot-scale ozone testing can help establish the relationship between ozone exposure, treatment performance and bromate formation.

The resulting information should be incorporated into the system sizing and operating philosophy.

What instrumentation and control strategies help manage bromate risk?

An ozone installation should provide the instrumentation needed to operate within its defined treatment and safety limits.

Depending on the application, relevant measurements may include:

• Water flow rate.

• Gas flow and ozone concentration.

• Applied ozone production.

• Dissolved ozone concentration at selected points.

• Water pH and temperature.

• Relevant indicators of raw water quality.

• Equipment operating status and alarms.

• Periodic analytical measurements of bromide and bromate.

Automatic regulation can adjust ozone production using relevant process measurements and predefined operating limits.

However, online dissolved ozone monitoring does not directly measure bromate formation.

Routine bromate analysis is generally required to verify finished-water quality and confirm that the selected control strategy remains effective.

Control setpoints should be established using actual water quality data and the required treatment performance.

Engineering drinking water ozonation with bromate control in mind

Bromate formation demonstrates why the design of an ozone treatment plant cannot be based solely on generator capacity.

The selection of ozone dose, gas transfer system, hydraulic contactor, monitoring equipment and automatic controls must consider the water chemistry and the applicable drinking water requirements.

Longking EnTech Europe evaluates these parameters when developing ozonation solutions for drinking water treatment, integrating ozone generation with process engineering, hydraulic design, instrumentation and safety systems.

The objective is to achieve the required oxidation or disinfection performance while minimizing bromate formation and maintaining reliable operation within the defined treatment conditions.

Successful drinking water ozonation requires controlling both what ozone removes or transforms and what it may produce during treatment.

What are the key design criteria for an ozone drinking water treatment system?

Designing an industrial ozonation system for drinking water requires a coordinated evaluation of water chemistry, treatment objectives, ozone production, gas-to-liquid transfer, hydraulic contact and operational safety.

The required ozone generator capacity is only one part of the engineering process. A correctly selected generator cannot compensate for inadequate gas transfer, poor hydraulic contact, unsuitable operating conditions or insufficient downstream treatment.

An effective design must establish how much ozone is required, how it will be transferred to the water, how the necessary oxidation or disinfection exposure will be achieved and how the complete installation will operate under changing water quality conditions.

1. Raw water characterization and treatment objectives

The first step is obtaining representative water quality data and defining what the ozonation stage must achieve.

Depending on the application, relevant parameters may include:

• Treatment flow: Minimum, average and maximum design flow, expressed in m³/h.

• Water chemistry: pH, temperature, alkalinity and conductivity.

• Organic matter: Dissolved organic carbon (DOC), total organic carbon (TOC) and UV absorbance at 254 nm (UV254).

• Ozone-consuming compounds: Nitrite, reduced metals and other reactive inorganic or organic substances.

• Bromide and bromate: Essential for evaluating bromate formation potential.

• Suspended solids and turbidity: Particularly relevant when ozone is applied before clarification.

• Specific contaminants: Iron, manganese, geosmin, MIB, pesticides or other target compounds.

• Microbiological requirements: Target pathogens and required inactivation when ozone is used for primary disinfection.

• Downstream treatment: Filtration, biological activated carbon, membranes and final disinfection.

Water quality should be evaluated across representative operating conditions, including seasonal variations and events such as algal blooms.

A system designed using average water quality alone may not be suitable for the most demanding operating conditions.

The project must also distinguish between disinfection, oxidation and preparation for downstream biological treatment, because these objectives can require different ozone exposures.

2. Ozone demand, decay and treatment performance

Before defining the ozone dose, it is necessary to understand how ozone reacts with the water.

Ozone demand describes the consumption of ozone by substances present in the water. After ozone is introduced, part of it reacts rapidly, while the remaining dissolved ozone may continue reacting or decomposing over time.

Laboratory ozone demand and decay studies can help determine:

• Initial ozone consumption.

• Development of measurable dissolved ozone residuals.

• Ozone decay under representative conditions.

• Oxidation performance for selected target compounds.

• Relevant contact times.

• Bromate formation potential.

• Effects on subsequent treatment processes.

These measurements help establish an appropriate ozone exposure rather than selecting an arbitrary dose.

A dose sufficient for iron oxidation, for example, may not provide the required disinfection performance or treatment of more resistant organic compounds.

Similarly, increasing ozone exposure can improve certain oxidation reactions while increasing the risk of undesirable by-products.

The design dose should be established for defined treatment objectives and representative water conditions.

3. How is ozone generator capacity calculated?

Ozone generator capacity is normally expressed as a mass production rate, typically in g O₃/h or kg O₃/h.

For a defined ozone dose and treatment flow, the basic mass-flow relationship is:

Ozone mass rate (g/h) = Water flow (m³/h) × Ozone dose (mg/L)

This relationship is useful for preliminary engineering because 1 mg/L is equivalent to 1 g/m³.

However, the calculation must specify whether the dose represents ozone generated, ozone applied through the gas injection system or ozone actually transferred into the water.

If the target dose is expressed as transferred ozone, the required generator production must also account for the expected gas-to-liquid transfer efficiency.

For preliminary calculations:

Required ozone production (g/h) ≈ Water flow (m³/h) × Target transferred dose (mg/L) ÷ Transfer efficiency

In this expression, transfer efficiency is represented as a fraction between 0 and 1.

The calculation is a preliminary mass balance, not a complete ozonation design. The target transferred dose must already be established from the water treatment requirements, including the relevant ozone demand and reaction conditions.

Final generator selection must additionally consider:

• Maximum and minimum treatment flows.

• Seasonal variation in ozone demand.

• Required production range and turndown capability.

• Product gas ozone concentration.

• Feed-gas conditions.

• Operating and design margins.

• Equipment availability and redundancy.

• Applicable performance guarantees.

Ozone concentration in the product gas and total ozone production capacity are different parameters. A generator producing a higher ozone concentration does not necessarily provide a higher ozone mass flow.

4. Feed-gas selection: PSA oxygen, liquid oxygen or treated dry air

The feed-gas system has a significant influence on ozone production, operating costs and plant reliability.

Industrial ozone generators may use:

• PSA oxygen: Oxygen produced on-site through pressure swing adsorption.

• Liquid oxygen (LOX): Oxygen supplied from an external cryogenic storage system and vaporized before use.

• Treated dry air: Conditioned compressed air supplied to an ozone generator designed for air-fed operation.

Oxygen-fed systems generally provide higher ozone concentrations than dry-air-fed configurations.

The most appropriate alternative depends on the required capacity, electricity consumption, local oxygen supply conditions, maintenance requirements and lifecycle costs.

The evaluation should consider the complete gas supply system, including compressors where applicable, oxygen generation or storage, drying, filtration, pressure regulation and safety equipment.

Feed-gas purity and dryness must remain within the ozone generator's specified operating limits.

The cooling system must be evaluated separately from the feed-gas system. Using treated dry air as the ozone feed gas does not mean that the generator uses air cooling.

The required cooling arrangement and cooling-water specifications depend on the selected equipment.

5. Ozone injection and gas-to-liquid mass transfer

Once ozone has been generated, it must be transferred from the gas phase into the water.

Common ozone injection technologies include:

• Fine-bubble diffuser systems.

• Venturi injectors.

• Sidestream injection and dissolution.

• Static mixers.

• Pressurized gas-to-liquid contact systems.

Each technology has advantages and limitations depending on the available hydraulic conditions and the required treatment performance.

Ozone transfer efficiency depends on several interacting factors, including:

• Ozone concentration in the feed gas.

• Gas and water flow rates.

• Gas-to-liquid ratio.

• Operating pressure and water depth.

• Bubble size and gas distribution.

• Water temperature.

• Mixing conditions.

• Hydraulic arrangement and contactor design.

Poor transfer efficiency increases the ozone production required to achieve a given transferred dose.

It can also increase oxygen consumption, off-gas treatment requirements and overall operating costs.

However, maximizing transfer efficiency alone is not sufficient. The dissolved ozone must also reach the water under suitable mixing and contact conditions to achieve the treatment objective.

The ozone generator, injection system and contactor must therefore be designed together.

6. Ozone contact chambers and effective hydraulic contact time

The contactor is responsible for providing the hydraulic conditions required for gas transfer, oxidation and, where applicable, microbial disinfection.

Important design considerations include:

• Contactor volume and geometry.

• Number and arrangement of contact chambers.

• Water depth and operating levels.

• Baffle design and flow distribution.

• Gas injection and mixing locations.

• Hydraulic short-circuiting and dead zones.

• Maximum and minimum flow conditions.

• Sampling points and instrumentation.

• Maintenance access and suitable construction materials.

For disinfection applications, the performance assessment must consider dissolved ozone concentration and effective contact time.

The nominal hydraulic retention time is calculated from contactor volume and water flow, but nominal retention time is not necessarily equivalent to effective disinfection contact time.

Short-circuiting and non-ideal flow patterns may reduce the exposure received by part of the treated water.

Depending on the applicable methodology, hydraulic performance can be evaluated using tracer studies, appropriately justified baffling assumptions or hydraulic modelling.

Where a T10-based contact time is specified, T10 represents the time associated with 10% cumulative tracer passage through the relevant hydraulic section.

For an ozone disinfection system, the applicable concentration–contact time (CT) methodology must also account for the location of ozone application and the variation of dissolved ozone residual along the contactor.

A large contact tank does not automatically guarantee adequate disinfection performance.

7. Off-gas destruction and operational safety

Not all ozone introduced into the gas transfer system dissolves in the water.

Untransferred ozone may leave the contactor in the off-gas, which must be collected and treated before discharge.

An industrial ozone installation may incorporate:

• Gas-tight contactor covers and ozone-compatible connections.

• Off-gas collection piping.

• Moisture separation and condensate management.

• Catalytic or thermal ozone destruction.

• Monitoring of relevant gas conditions.

• Ambient ozone leak detectors.

• Suitable ventilation systems.

• Automatic shutdown and safety interlocks.

• Emergency procedures and maintenance provisions.

Ozone-containing gas is hazardous and requires appropriate containment and safety systems.

The engineering assessment must also consider risks associated with the oxygen supply and any relevant operating pressure or cryogenic equipment.

Off-gas treatment and safety equipment are integral parts of the ozonation installation, not optional accessories that can be disregarded during preliminary design.

8. Integration with filtration, BAC and final disinfection

Ozonation must be evaluated together with the processes located before and after the ozone stage.

For example:

• Oxidation of dissolved iron or manganese may require subsequent filtration.

• Transformation of organic matter may increase biodegradable organic carbon.

• Biological activated carbon can remove part of the biodegradable compounds produced through ozonation.

• Certain oxidation products may require additional treatment or monitoring.

• Residual ozone may need to decay or be removed before sensitive downstream processes.

• Final chlorination or another suitable disinfection strategy may be required to provide a persistent residual in distribution.

The correct ozone application point depends on the treatment objectives and the characteristics of the complete process.

The effectiveness of ozonation should be evaluated using the quality of the finished water, not only the oxidation achieved immediately after ozone injection.

9. Instrumentation, automatic control and SCADA integration

Drinking water ozonation plants require reliable monitoring and automatic control to respond to changing treatment conditions.

Depending on the application and equipment configuration, relevant operating measurements may include:

• Water flow and temperature.

• Feed-gas flow, pressure and quality.

• Oxygen purity where applicable.

• Ozone production and product gas concentration.

• Dissolved ozone concentration at selected contactor points.

• Cooling-water operating conditions.

• Off-gas system status.

• Ambient ozone concentrations.

• Equipment faults and protective alarms.

• Relevant raw water quality measurements.

The control system may combine feed-forward control, based on parameters such as water flow and selected water quality measurements, with feedback control, using dissolved ozone residuals or other appropriate process signals.

This can help adapt ozone production to operating conditions while maintaining the specified treatment limits.

However, dissolved ozone monitoring does not directly demonstrate bromate compliance or guarantee contaminant removal.

Analytical verification and appropriate operating procedures remain necessary.

Longking ozone systems can incorporate PLC/HMI automation and interfaces for integration with plant SCADA systems, according to project requirements.

The final instrumentation list, communication protocols, control philosophy and safety interlocks must be defined during engineering.

10. Redundancy, energy efficiency and lifecycle costs

Drinking water treatment plants may require high equipment availability and uninterrupted treatment.

Depending on the installation, redundancy may be considered for:

• Ozone generators and power supplies.

• Oxygen generation or supply systems.

• Cooling equipment.

• Injection and recirculation pumps.

• Off-gas destruction systems.

• Essential instrumentation and controls.

The required duty/standby arrangement should be established according to the treatment plant's operating philosophy and applicable availability requirements.

Modular ozone generators can offer operational flexibility, but the capacity remaining during equipment maintenance or failure must be evaluated.

Energy efficiency should also be assessed across the entire installation.

Relevant contributions include:

• Ozone generator electrical consumption.

• Oxygen generation or supply costs.

• Cooling-system electricity and water demand.

• Injection and recirculation pumping.

• Gas compression and pressure losses.

• Off-gas destruction.

• Operation at partial treatment loads.

• Maintenance and component replacement.

The lowest ozone generator electrical consumption does not necessarily correspond to the lowest total operating cost.

A lifecycle comparison should consider the electricity, oxygen, maintenance and other resources required to deliver the specified treatment performance under representative operating conditions.

11. Performance verification and commissioning

Before an ozonation plant enters normal operation, the equipment and complete process must be evaluated against the agreed project requirements.

Verification activities may include:

• Factory Acceptance Testing (FAT) of relevant equipment and control functions.

• Installation inspection and mechanical checks.

• Safety-system and interlock verification.

• Ozone production and gas concentration testing.

• Gas-transfer and hydraulic performance assessment where specified.

• Instrumentation calibration and functional testing.

• Site Acceptance Testing (SAT) and commissioning.

• Water quality and treatment performance verification under agreed conditions.

Functional equipment testing does not automatically demonstrate the required oxidation performance, microbial inactivation or bromate compliance.

Where treatment guarantees apply, the required performance tests, operating conditions and acceptance methodology must be clearly established.

Engineering complete ozone systems for drinking water treatment

Longking EnTech Europe approaches drinking water ozonation as an integrated treatment process rather than an isolated ozone generation package.

Depending on the project scope, the solution can combine ozone generation, feed-gas preparation, cooling, gas injection, hydraulic contact, off-gas destruction, instrumentation and automation.

The engineering process considers the water source, treatment objectives, available infrastructure, operating conditions and downstream processes.

For an initial assessment, the essential starting information includes design flow, raw water characterization, treatment objectives, available hydraulic conditions and relevant regulatory requirements.

Additional laboratory testing, pilot studies or hydraulic evaluations may be required before establishing the final ozone capacity and performance commitments.

The objective is to design an ozonation system that delivers the required treatment performance safely, reliably and efficiently throughout its operational life.

When should advanced oxidation processes (AOPs) be used in drinking water treatment?

Advanced Oxidation Processes (AOPs) are treatment technologies designed to generate highly reactive oxidizing species, particularly hydroxyl radicals (•OH), for the transformation of selected organic contaminants.

They are particularly relevant when conventional treatment or ozonation alone cannot achieve the required reduction of specific dissolved substances.

In drinking water treatment, ozone-based AOPs may be considered for selected pesticides, pharmaceutical residues, taste and odor compounds and other organic micropollutants that are relatively resistant to direct oxidation by molecular ozone.

However, advanced oxidation is not automatically necessary or preferable for every drinking water treatment application.

The appropriate technology depends on the target contaminants, water composition, required removal performance, potential transformation products and lifecycle costs.

What is the difference between conventional ozonation and advanced oxidation?

Conventional ozonation involves two main oxidation mechanisms:

• Direct oxidation by molecular ozone (O₃): Selective reactions with compounds that are susceptible to ozone attack.

• Indirect oxidation through reactive species: Ozone decomposition in water can generate hydroxyl radicals and other reactive intermediates.

Advanced oxidation processes are designed to promote radical-based oxidation when additional treatment of selected compounds is required.

Hydroxyl radicals are highly reactive and can attack a broader range of organic substances than molecular ozone.

However, their effectiveness depends on their ability to react with the target contaminants before being consumed by other constituents in the water.

Natural organic matter, bicarbonate, carbonate and other substances may act as radical scavengers, reducing the oxidation capacity available for the target compounds.

Therefore, increasing hydroxyl radical production does not necessarily result in a proportional increase in contaminant removal.

How does the O₃/H₂O₂ advanced oxidation process work?

The combination of ozone and hydrogen peroxide (O₃/H₂O₂) is commonly known as the peroxone process.

Hydrogen peroxide promotes ozone decomposition through reaction pathways that increase hydroxyl radical production.

This can improve the oxidation of certain organic compounds that react slowly with molecular ozone.

Potential applications include:

• Oxidation of selected pesticides and pharmaceutical residues.

• Treatment of certain taste and odor compounds.

• Transformation of organic micropollutants resistant to direct ozone oxidation.

• Advanced treatment of water containing specific compounds for which radical oxidation has demonstrated benefits.

The effectiveness of O₃/H₂O₂ depends on:

• Ozone dose and dissolved ozone availability.

• Hydrogen peroxide dose and dosing ratio.

• Water pH and temperature.

• Natural organic matter and radical scavenging capacity.

• Target contaminant concentration and reaction kinetics.

• Hydraulic contact conditions and reaction time.

The relationship between ozone and hydrogen peroxide must be optimized for each application.

Excessive hydrogen peroxide addition is not necessarily beneficial, since it may increase chemical consumption and affect the distribution and availability of reactive species.

An important limitation is that O₃/H₂O₂ typically accelerates the decomposition of dissolved ozone.

Consequently, a peroxone process designed for contaminant oxidation cannot automatically be assumed to provide the same dissolved ozone residual or disinfection CT as conventional ozonation.

Where microbial disinfection is also required, the treatment process must be specifically engineered and verified to achieve both objectives.

How does the O₃/UV advanced oxidation process work?

The O₃/UV process combines ozonation with ultraviolet irradiation to promote photochemical reactions and increase radical-based oxidation.

Under suitable conditions, UV radiation can contribute to ozone decomposition and the formation of reactive oxidizing species.

This combination may improve the transformation of selected organic contaminants when conventional ozonation does not provide sufficient treatment.

However, effective O₃/UV treatment requires more than simply installing a conventional UV disinfection unit after an ozone generator.

The process must be designed considering:

• Ozone concentration and its availability in the irradiated water.

• UV wavelength and spectral characteristics.

• UV fluence and irradiation conditions.

• UV transmittance of the water.

• Reactor geometry and hydraulic exposure.

• Target contaminant reaction kinetics.

• Radical scavenging by natural water constituents.

• Potential oxidation by-products.

A UV system designed for microbial disinfection is not automatically suitable or validated for advanced oxidation.

The UV equipment, ozone application and hydraulic arrangement must be evaluated as a coordinated oxidation process.

Can AOPs remove all micropollutants from drinking water?

No. Advanced oxidation can be effective for selected contaminants, but there is no universal removal efficiency applicable to every micropollutant.

Treatment performance depends on the chemical structure of each compound and its reaction rates with molecular ozone, hydroxyl radicals or UV radiation.

Some contaminants are highly susceptible to oxidation, while others are comparatively resistant.

In addition, degradation of the original contaminant does not necessarily mean complete mineralization.

Advanced oxidation can produce intermediate transformation products that remain in the treated water.

These products may have different chemical, biological or toxicological properties from the original substances.

Depending on the application, downstream biological activated carbon (BAC), adsorption or other treatment processes may be necessary.

For projects involving specific micropollutant removal guarantees, the engineering assessment should consider:

• Analysis of the target contaminants.

• Laboratory or pilot-scale oxidation studies.

• Measurement of parent compound removal.

• Evaluation of relevant transformation products.

• Water quality and by-product monitoring.

• Performance of downstream treatment processes.

The objective is to demonstrate the required finished-water quality, not simply the disappearance of the original contaminant.

Do advanced oxidation processes increase the risk of bromate formation?

Bromate formation remains an important consideration when ozone-based AOPs are applied to bromide-containing drinking water.

The interaction between molecular ozone, hydroxyl radicals and reactive bromine species can influence bromate formation.

However, the effect depends on the specific AOP configuration and water chemistry.

For example, adding hydrogen peroxide may reduce bromate formation under certain conditions by modifying ozone decomposition and reactive bromine chemistry.

Under other conditions, the benefit may be limited or bromate formation may increase.

Therefore, O₃/H₂O₂ must not be presented as a universally effective bromate prevention strategy.

Similarly, O₃/UV processes require evaluation of potential bromate formation and other oxidation by-products.

Where bromate is a concern, the treatment design should consider both the required oxidation performance and compliance with the applicable finished-water bromate limit.

Any proposed mitigation strategy should be supported by representative water testing.

How should conventional ozonation and AOPs be compared?

The selection between conventional ozonation and an advanced oxidation process should be based on equivalent treatment objectives.

The comparison should consider:

• Target contaminants and required reduction.

• Water chemistry and ozone demand.

• Conventional ozone oxidation performance.

• Additional oxidation achieved through AOP operation.

• Bromate formation and other transformation products.

• Required downstream treatment.

• Energy consumption and chemical consumption.

• Equipment investment and maintenance costs.

• Instrumentation, safety and operational complexity.

For O₃/H₂O₂, additional costs may include hydrogen peroxide storage, dosing, residual management and associated safety requirements.

For O₃/UV, the evaluation must also consider UV reactor equipment, electrical consumption, lamp maintenance and the effect of water UV transmittance.

The most technically complex solution is not necessarily the most appropriate or economical.

Where conventional ozonation achieves the required treatment performance, an additional advanced oxidation stage may provide limited benefit.

Conversely, where specific contaminants are poorly removed by molecular ozone, AOPs may offer a technically justified alternative.

Engineering ozone-based AOP solutions for drinking water treatment

Longking EnTech Europe combines experience in ozone generation, UV technology and water treatment process engineering to evaluate advanced oxidation alternatives for specific applications.

Depending on the treatment objectives, this may involve assessing conventional ozonation, O₃/H₂O₂ or O₃/UV configurations alongside appropriate downstream treatment.

The engineering process should establish the required oxidation performance, available treatment conditions, equipment configuration, process controls and verification methodology.

For applications involving micropollutants, laboratory testing or pilot studies may be necessary before defining the final process and establishing performance commitments.

The objective is to select an oxidation strategy that achieves the required drinking water quality while controlling energy consumption, chemical use, transformation products and operational risks.

Advanced oxidation should therefore be considered a targeted treatment option within an integrated drinking water process, rather than a universal replacement for conventional ozonation, filtration or disinfection.

How does Longking EnTech Europe engineer integrated ozone treatment systems?

The successful implementation of ozone in a drinking water treatment plant requires much more than selecting an ozone generator.

Longking EnTech Europe combines ozone generation technology, process engineering and system integration to develop ozonation solutions adapted to the treatment objectives and operating conditions of each installation.

Building on its experience in water treatment technologies and the industrial manufacturing capabilities of Longking Group, the company works with water utilities, engineering consultants and EPC contractors on drinking water ozonation projects.

Its approach focuses on coordinating ozone production with the equipment, hydraulic infrastructure, instrumentation and downstream treatment processes required for reliable operation.

From water quality assessment to ozone system selection

The engineering process begins with the characteristics of the water and the treatment performance required.

Depending on the application, the initial evaluation considers:

• Treatment flow and operating variations.

• Raw water characteristics and ozone demand.

• Required disinfection or oxidation performance.

• Bromide concentration and bromate formation potential.

• Available hydraulic infrastructure and contact time.

• Existing treatment processes and downstream filtration.

• Electrical, cooling and utility requirements.

• Applicable technical specifications and operational constraints.

These parameters help determine whether conventional ozonation, an alternative application point or a more advanced treatment configuration should be considered.

Where the available data are insufficient, additional analytical measurements, laboratory testing or pilot studies may be necessary before establishing final design conditions.

Engineering the complete ozone generation and application system

Longking EnTech Europe can develop project-specific solutions integrating the main components of an industrial ozonation installation.

Depending on the agreed scope of supply, these may include:

• Ozone generation: Industrial ozone generators, power supplies and production control.

• Feed-gas systems: PSA oxygen generation, liquid oxygen supply integration or treated dry-air preparation.

• Cooling systems: Equipment and utilities required to maintain the specified operating conditions.

• Ozone injection: Diffusers, Venturi systems or other suitable gas-to-liquid transfer technologies.

• Hydraulic integration: Assessment of contact chambers, mixing conditions and effective contact time.

• Off-gas treatment: Collection and destruction of residual ozone from the gas phase.

• Instrumentation: Measurement of relevant gas, water and equipment operating parameters.

• Automation: PLC/HMI control, operating sequences, alarms and SCADA integration where specified.

• Safety systems: Ozone leak detection, ventilation interfaces and protective interlocks.

The final configuration depends on the required treatment performance, plant infrastructure and contractual scope.

The objective is to ensure that ozone generation, transfer, contact and control operate as a coordinated treatment process.

Integrating ozone with existing drinking water infrastructure

Both new drinking water treatment plants and modernization projects require careful coordination with the surrounding infrastructure.

For a new installation, the ozone system can be considered during the development of the overall treatment process and hydraulic arrangement.

For an existing plant, the assessment must consider available space, contactor geometry, hydraulic capacity, electrical supply, maintenance accessibility and integration with existing automation.

The feasibility of reusing contact chambers, pipelines or other civil structures must be established through project-specific engineering.

Where ozone is combined with clarification, filtration, biological activated carbon or final disinfection, the interface between treatment stages must also be considered.

Automation, commissioning and operational reliability

Reliable ozone treatment requires appropriate monitoring, control and safety provisions.

Longking ozone installations can incorporate automatic production regulation, equipment alarms, process instrumentation and interfaces for integration with the plant's central control system.

Depending on the project, commissioning and acceptance activities may include verification of ozone production, equipment operation, protective interlocks, instrumentation and control sequences.

Where specific water treatment performance guarantees apply, the corresponding verification methodology and acceptance conditions must be established separately.

Operational reliability also depends on appropriate maintenance planning, equipment redundancy where required and access to essential spare parts.

Longking EnTech Europe can provide technical support, commissioning assistance, operator training and maintenance-related services according to the agreed project scope.

A coordinated engineering approach for drinking water ozonation

The main advantage of integrated ozone engineering is the ability to evaluate the treatment installation as a complete system rather than a collection of independent components.

An ozone generator with suitable nominal capacity may still deliver unsatisfactory results if gas transfer, contact hydraulics, process control or downstream treatment are inadequate.

Conversely, appropriate integration can help improve operational consistency and support efficient use of the installed ozone generation capacity.

Longking EnTech Europe's objective is to combine industrial ozone technology with project-specific engineering, helping utilities and EPC contractors develop technically suitable ozonation solutions for drinking water treatment.

The result should be a system designed not only to produce ozone, but to achieve the required treatment objectives safely, reliably and with appropriate lifecycle operating costs.

Why should ozone be integrated into a multi-barrier drinking water treatment strategy?

Ozone is most effective when integrated into a drinking water treatment process in which different technologies address complementary water quality and microbiological risks.

This approach is commonly known as a multi-barrier treatment strategy.

Rather than relying on a single process to achieve every treatment objective, a multi-barrier system combines technologies that remove particles, transform contaminants, inactivate microorganisms and protect finished water during storage and distribution.

Ozonation can provide an important oxidation and disinfection barrier, but it does not replace the functions of coagulation, filtration, adsorption, biological treatment or final residual disinfection.

The treatment stages must be selected and coordinated according to the characteristics of the water source and the required finished-water quality.

How does ozone work with other drinking water treatment barriers?

Different treatment technologies perform complementary functions within the treatment train:

• Coagulation and clarification: Remove suspended particles, colloids and part of the organic matter, potentially reducing the load entering subsequent treatment stages.

• Ozonation: Inactivates selected microorganisms and oxidizes susceptible inorganic and organic compounds, depending on the applied exposure and water chemistry.

• Filtration: Removes suspended particles, including certain oxidized metal precipitates, and supports the required physical water quality.

• Granular activated carbon (GAC): Adsorbs selected organic contaminants according to their characteristics and the available adsorption capacity.

• Biological activated carbon (BAC): Combines adsorption and biological degradation, helping remove part of the biodegradable organic matter generated during ozonation.

• UV disinfection: Provides an additional or alternative microbial inactivation barrier where required by the treatment objectives.

• Final chemical disinfection: Where specified, provides a disinfectant residual to help maintain microbiological protection during storage and distribution.

Not every drinking water treatment plant requires all these technologies.

The treatment configuration must be justified by the specific water quality challenges, applicable regulations, reliability requirements and lifecycle costs.

Why is downstream treatment important after ozonation?

Ozone frequently transforms contaminants rather than removing them completely from the water.

For example, oxidation of dissolved iron or manganese may generate particles that require subsequent filtration.

Similarly, ozonation can convert certain organic substances into smaller and more biodegradable compounds.

A properly designed BAC stage may remove part of these compounds, improving the biological stability of the water before final disinfection.

However, ozone–BAC does not automatically remove every oxidation product, micropollutant or inorganic by-product.

Bromate formation, in particular, must be controlled during ozonation rather than assuming that conventional downstream biological filtration will remove it.

The effectiveness of the complete treatment process must be assessed through appropriate water quality monitoring and performance verification.

Can ozone and UV disinfection be combined in drinking water treatment?

Yes. Ozone and ultraviolet disinfection can be incorporated into the same drinking water treatment plant when their respective functions are technically justified.

Ozone can provide oxidation of selected contaminants and microbial inactivation, while UV offers an additional disinfection mechanism without chemical dosing at the UV stage.

Depending on the process, combining different disinfection barriers may help address specific microbiological requirements.

However, their individual contributions must be evaluated according to the target microorganisms, water quality and applicable performance criteria.

Neither conventional ozone disinfection nor UV disinfection provides a persistent residual suitable for protecting an entire drinking water distribution network.

Where residual protection is required, an appropriate secondary disinfection strategy must be incorporated into the treatment process.

Furthermore, installing separate ozone and UV stages does not automatically create an ozone–UV Advanced Oxidation Process. A dedicated O₃/UV AOP requires specific process engineering and operating conditions.

How can the complete treatment process be monitored and controlled?

A multi-barrier strategy depends not only on equipment selection, but also on maintaining the required performance of each treatment stage.

Depending on the installation, the operational strategy may include:

• Monitoring raw water quality and seasonal changes.

• Controlling ozone production according to flow and treatment demand.

• Measuring dissolved ozone residual and relevant contact conditions.

• Monitoring bromate formation and other applicable water quality parameters.

• Supervising filtration or BAC operating conditions.

• Verifying microbial disinfection performance using the applicable methodology.

• Managing final disinfectant residuals where required.

• Integrating equipment alarms, operating signals and protective interlocks into the plant's SCADA system.

If one treatment stage experiences reduced performance, the plant must have appropriate monitoring and operating procedures to evaluate its effect on downstream barriers and finished-water quality.

The reliability of a multi-barrier process depends on the performance of the complete treatment train, not simply on the number of technologies installed.

Engineering ozone as an effective treatment barrier

Longking EnTech Europe evaluates ozonation within the context of the complete drinking water treatment process.

This involves identifying the role of ozone, selecting an appropriate application point and establishing the required oxidation or disinfection performance.

The engineering assessment also considers gas transfer, hydraulic contact, bromate control, downstream filtration, automation and operational safety.

Where appropriate, ozone can be integrated with other treatment technologies to develop a process adapted to the water source and the treatment objectives.

The goal is not to install more treatment stages, but to combine the necessary barriers so that each contributes effectively to safe, reliable and economically sustainable drinking water production.

Drinking water ozonation: from treatment objectives to integrated engineering

Ozone is a versatile technology for drinking water treatment, with applications in microbial disinfection, taste and odor control, oxidation of iron and manganese, transformation of natural organic matter and treatment of selected organic micropollutants.

However, successful ozonation depends on the design of the complete treatment process, not simply on ozone generator capacity.

An effective installation must combine:

• Water quality assessment: Raw water characteristics, ozone demand, bromide concentration and seasonal variations.

• Treatment objectives: Required disinfection, oxidation performance and finished-water quality.

• Ozone generation: Appropriate production capacity, feed-gas preparation and operating flexibility.

• Gas transfer and hydraulic contact: Efficient ozone dissolution, suitable mixing and effective contact time.

• By-product control: Evaluation of bromate formation and other relevant oxidation products.

• Process integration: Coordination with clarification, filtration, biological activated carbon and final disinfection.

• Automation and safety: Instrumentation, ozone production control, off-gas destruction and protective interlocks.

• Lifecycle operation: Energy consumption, maintenance, equipment availability and long-term operating costs.

The most appropriate ozonation system is the one that achieves the required treatment performance safely and reliably under the actual conditions of the drinking water plant.

Longking EnTech Europe combines industrial ozone generation technology with process engineering and system integration to develop project-specific solutions for drinking water treatment applications.

Whether the project involves a new installation, intermediate ozonation, ozone–BAC treatment or modernization of an existing system, the engineering approach must be adapted to the water source, treatment objectives and available infrastructure.

Planning an ozone treatment project for a drinking water plant?

Longking EnTech Europe works with water utilities, engineering consultants and EPC contractors to evaluate ozone treatment requirements and develop technically appropriate solutions.

For an initial technical assessment, the following information is particularly useful:

• Minimum, average and maximum treatment flow (m³/h).

• Raw water characteristics and available analytical results.

• Required oxidation or disinfection objectives.

• Bromide concentration and relevant water chemistry.

• Existing treatment process and proposed ozone application point.

• Available contact chambers, hydraulic conditions and installation space.

• Preferred oxygen supply arrangement, where defined.

• Applicable project specifications and regulatory requirements.

Our engineering team can use this information to assess potential ozonation configurations, identify additional data requirements and develop a project-specific technical proposal.

Explore Longking's industrial ozone generation technologies or contact our team to discuss your drinking water treatment project.