World Water Day 2025 focuses on Glacier Preservation, highlighting the close relationship between glaciers, freshwater availability and long-term water security.
As glaciers retreat and hydrological patterns become less predictable, utilities, industries and communities face increasing pressure to use water more efficiently, protect available resources and strengthen the resilience of treatment infrastructure.
This makes water reuse, advanced treatment and reliable multi-barrier systems increasingly important—not as isolated technologies, but as part of a broader strategy to reduce dependence on freshwater resources and improve water-system resilience.
Why Water Resilience Matters
Water security depends not only on the amount of water available, but also on the ability to treat, reuse and manage water reliably under changing conditions.
Around 2.2 billion people lacked safely managed drinking-water services in 2022, according to WHO/UNICEF monitoring, showing that access to reliable and safe water remains a major global challenge.
At the same time, climate variability, population growth, urbanization and industrial demand are placing additional pressure on freshwater resources.
For utilities and industries, improving resilience can therefore involve a combination of:
Reducing unnecessary water consumption
Improving treatment efficiency
Protecting source-water quality
Increasing water reuse where appropriate
Designing treatment systems for variable operating conditions
Strengthening monitoring and process control
Water reuse is especially relevant because it allows treated wastewater to become a managed water resource rather than simply a discharge stream.
Water Reuse Requires a Multi-Barrier Approach
Water reuse is not based on a single treatment technology. It requires a treatment train designed around the intended end use, source-water quality and required risk reduction.
Each treatment barrier should have a clearly defined function, and the complete system must remain effective as flow and influent quality change.
A robust reuse strategy can therefore consider:
Target reclaimed-water quality and intended end use
Microbiological and chemical treatment objectives
Source-water variability
Removal and inactivation barriers
Process redundancy where required
Continuous monitoring and automation
Defined operating limits for each treatment stage
Applicable regulatory and risk-management requirements
The appropriate treatment train may combine physical separation, filtration, oxidation, disinfection and final polishing depending on the project.
The objective is not to add as many technologies as possible, but to create complementary barriers with clearly defined roles and verifiable performance.
Learn more about our municipal water treatment and water reuse solutions.
Where Ozone and UV Add Value in Water Reuse
Advanced water-reuse schemes often require treatment barriers capable of addressing both microbiological risks and residual chemical contaminants.
Ozone and UV can both contribute to this objective, but they perform different functions and should be selected according to the specific treatment goals.
Ozone: Oxidation & Disinfection Support
Ozone is a strong oxidant that can be used to treat selected residual organic and inorganic compounds remaining after conventional wastewater treatment.
Depending on the water quality and operating conditions, ozonation can contribute to:
Oxidation of selected micropollutants
Taste and odour control
Colour reduction
Oxidation of selected inorganic compounds
Microbial inactivation
Preparation of the water for downstream biological or adsorption processes
Its performance depends on the ozone dose, water matrix, ozone demand, transfer efficiency and contact conditions.
Ozone should therefore be evaluated as part of the complete treatment process rather than only from the nominal generator capacity.
UV: A Controlled Disinfection Barrier
UV is primarily used as a disinfection barrier.
Its effectiveness depends on the UV dose delivered under the defined operating conditions, including:
Flow
UV transmittance
Lamp output
Reactor hydraulics
Fouling condition
Validation requirements where applicable
Unlike chemical disinfectants, UV does not rely on maintaining a residual concentration after the reactor.
Complementary Roles
Ozone and UV can be integrated within the same treatment train when the project requires both advanced oxidation and robust microbial control.
A typical treatment concept may use ozone upstream to address oxidation objectives and UV downstream as an additional disinfection barrier.
The value of the combination lies in the fact that the two technologies rely on different treatment mechanisms and different operating parameters.
Advanced Oxidation Processes
In some projects, ozone or UV can also form part of advanced oxidation processes (AOPs) designed to increase the formation of highly reactive oxidizing species.
Examples include:
O₃/H₂O₂
UV/H₂O₂
Other project-specific advanced oxidation combinations
These processes may be relevant where conventional oxidation alone is insufficient for the target compounds.
Design from the Treatment Objective
The correct question is not whether ozone or UV is universally “better”.
The treatment strategy should instead be defined from:
water quality → reuse objective → contaminants of concern → microbial targets → regulatory requirements → plant constraints
This allows ozone, UV and other treatment barriers to be combined only where they provide a clearly defined function.
From Awareness to Implementation
World Water Day helps bring global attention to the importance of protecting freshwater resources, but long-term water resilience ultimately depends on how water is managed, treated and reused in practice.
For utilities, industries and communities, this means translating water-security objectives into treatment strategies capable of responding to real operating conditions.
Effective implementation requires more than selecting individual technologies. It requires understanding:
Water availability and source quality
Current and future treatment requirements
Potential for water reuse
Microbiological and chemical risks
Energy and operational constraints
Regulatory requirements
Monitoring and automation needs
Long-term maintainability
The objective should be to develop treatment systems that are technically justified, operationally robust and appropriate for the intended use of the water.
Longking EnTech Europe: Ozone & UV for Water Treatment
Longking EnTech Europe develops and integrates ozone and UV treatment systems for municipal and industrial water applications.
Our work includes projects involving:
Drinking-water treatment
Municipal wastewater treatment
Water reuse
Industrial process water
Advanced oxidation
Disinfection
Containerized treatment systems
Large-capacity ozone generation
Open-channel and closed-reactor UV systems
Depending on the project, our engineering can cover the integration of ozone generation, oxygen supply, cooling, gas transfer, contact systems, off-gas treatment, UV disinfection, instrumentation, automation and process interfaces.
The appropriate solution is defined from the actual water quality, flow, treatment objective and plant constraints, rather than from a predefined technology package.
Building More Resilient Water Systems
Glacier preservation, water reuse and advanced treatment are different parts of the same broader challenge: improving how limited water resources are protected and managed.
For future water infrastructure, resilience will increasingly depend on the ability to:
protect water sources → treat efficiently → reuse where appropriate → monitor continuously → adapt to changing conditions
Ozone and UV can contribute to this strategy when they are applied as part of a treatment train with a clearly defined technical purpose.
Planning a Water Treatment or Reuse Project?
If your project requires ozone, UV disinfection, advanced oxidation or a multi-barrier water-reuse strategy, Longking EnTech Europe can evaluate the treatment requirements and define the appropriate process approach.
Contact our team with your project data and treatment objectives.