Understanding UV Disinfection: How ETS-UV Works

When it comes to reliable secondary (or supplemental) disinfection for aquatic and industrial water systems, ultraviolet (UV) technology stands out as one of the most effective and maintenance-friendly options. This blog post explains how UV disinfection works, the specific advantages of the ETS-UV system line, and what aquatic facility / water-treatment operators need to know for successful integration and operation.

Why UV Disinfection?

Traditional disinfection methods for pool and spa water—and for industrial or municipal reuse streams—often rely on chemical agents such as chlorine, bromine, ozone, or peracetic acid. While these methods remain vital, they also carry drawbacks: chemical by-product formation, the necessity of residual disinfectant monitoring, corrosion or air‐quality issues in indoor natatoriums, and sometimes limitations in inactivating chlorine-resistant pathogens (e.g., some protozoa). UV disinfection addresses many of these concerns.

Key advantages of UV disinfection include:

It is a physical, chemical-free process, meaning no added chemicals remain in the water in the form of residuals.
It is broadly effective against many microorganisms—including bacteria, viruses, protozoa—and does so relatively rapidly. (health.wa.gov.au)
It does not significantly alter taste, odor or pH of the water, making it well‐suited for aquatic environments.
It can reduce formation of disinfection by-products (DBPs) and improve air‐quality in indoor pools by helping to reduce chloramine concentrations. For example, Ultra Aqua describes UV as “a chemical-free sustainable solution … inactivating bacteria, viruses and protozoa.”

Given these benefits, UV is increasingly specified for commercial pools, spas, splash-pads, aquatic facilities, industrial processing water and municipal reuse systems.

The Science Behind UV Disinfection

Wavelength and Mechanism

UV disinfection operates by exposing microorganisms in water to ultraviolet light—typically in the UV-C range (200 nm to 280 nm) or related medium/high pressure lamp wavelengths. When properly delivered, UV light disrupts the nucleic acids (DNA or RNA) of microorganisms, preventing reproduction or metabolic activity.

Specifically:

UV photons are absorbed by cellular DNA/RNA → this leads to formation of pyrimidine dimers (e.g., thymine dimers) or other photoproducts that distort the genetic structure.
With sufficient exposure (a function of intensity × time, often referred to as UV “dose” or fluence), the microorganism becomes unable to replicate and is effectively inactivated.
Water disinfection is achieved not by removal of the organism but by rendering it non‐viable.

UV Dose, Water Quality and Limitations

One critical concept is UV dose (also known as fluence). Dose is typically expressed in millijoules per square centimetre (mJ/cm²) or similar units. The delivered dose depends on three key variables:

UV intensity (irradiance) from the lamp(s)
Exposure time (dependent on water flow and reactor design)
Water clarity and UV transmittance (because particles, turbidity and dissolved matter attenuate UV light)

Some important operational considerations for UV systems:

If the flow rate is too high, water may pass through the reactor too quickly and receive an insufficient dose.
If the water has low UV transmittance (UVT) or contains iron/manganese or suspended solids, the UV dose can be significantly reduced. Pre-filtration or treatment may be required.
UV systems provide disinfection at a point in the flow system. They do not provide a chemical residual downstream; therefore, downstream re-contamination (bio-films, piping surfaces) must be managed.

Public health guidance reinforces this: UV systems must be properly sized, validated and integrated with adequate pre-treatment and monitoring to ensure reliability.

How ETS-UV™ Systems Work

The ETS-UV line from Neptune Benson is built specifically for high-performance aquatic, industrial and municipal water systems. The key features and design advantages of ETS-UV systems include:

Product Overview

According to the manufacturer, the ETS-UV product family “provides disinfection solutions for the municipal, industrial and recreational water markets. While these systems are used for disinfection, they are also used for organic and inorganic contaminants, including chlorine, ozone and Total Organic Carbon (TOC).” (Xylem)

Some of the notable aspects:

Medium-pressure or amalgam lamp options capable of high UV output and high flow rates.
Flexible chamber design with relatively small footprint, horizontal or vertical orientation installs, and retrofit compatibility.
Built-in monitoring, UV sensors, wiper systems (for quartz sleeve cleaning) and data logging capability—important for continuous reliability in aquatic facilities.

Typical Flow & Application Scope

ETS-UV reactors are used in:

Recreational aquatic facilities: indoor/outdoor pools, spas, spray-pads, therapy pools.
Industrial process water, cooling towers, food & beverage, aquaculture and municipal reuse.
Retrofit or upgrade projects where existing chemical systems or older UV systems are being leveraged for improved performance, lower chemical usage and better air quality in natatoriums.

The ETS-UV Disinfection Workflow

At a high level, the process of ETS-UV disinfection in a commercial pool or water system is as follows:

Pre-treatment – Water is filtered (to remove particles, turbidity, iron/manganese) and chemical parameters (pH, UVT) are monitored. This ensures the UV reactor receives clean water for optimal UV dose delivery.
UV Reactor Inlet – Water enters the ETS-UV chamber, typically passing the UV lamps behind quartz sleeves.
Exposure – As water flows through, it is exposed to UV-C (or relevant medium-pressure UV) light. The chamber and lamp layout are designed to deliver the required dose even at the rated flow.
Monitoring & Control – On-board sensors monitor UV intensity, lamp performance, fouling of sleeves, logs data. Some models automatically adjust lamp power or trigger alarms if dose falls below setpoint.
Outlet & Integration – Disinfected water leaves the reactor. It then flows to the next stage of circulation, and – if needed – a chemical residual (chlorine or bromine) may be maintained downstream.
Maintenance & Service – Operators perform scheduled lamp or sleeve replacement, cleaning wipers, verifying sensor calibration and verifying UV performance.

Why ETS-UV for Aquatics & Water Treatment

Reduced Chemical Load: By inactivating pathogens and reducing chloramines (common in indoor pools), ETS-UV helps reduce the dependence on high residual chemical concentrations and improves indoor air quality.
Compact & Flexible Installation: For mechanical rooms in aquatic centres, ETS-UV systems offer a smaller footprint and horizontal/vertical orientation flexibility—making upgrades and replacements smoother.
Validated Performance: Neptune Benson / ETS-UV systems are backed by industry credentials and certifications (e.g., NSF/ANSI listings).
Applicability Across Markets: From leisure pools to industrial reuse, the ETS-UV line supports high-flow, high-demand systems—making it a one-stop solution for aquatic facilities and industrial water professionals alike.

Key Design & Operational Considerations

To achieve the full benefits of UV disinfection with an ETS-UV system, facility managers and service teams should pay attention to the following critical factors:

1. Water Quality & UV Transmittance (UVT)

Even the best UV reactor can’t compensate for poor water quality. If the water entering the unit has low UVT (i.e., high absorption or scattering of UV light due to iron, manganese, organic matter, turbidity), the delivered dose will drop. Pre-filtration (sand, media, cartridge) and monitoring UVT are essential.

2. Flow Rate & Hydraulic Design

Ensure the reactor is sized for the actual flow profile (including peak flow spikes) of the pool or system. If the flow exceeds design, the water may transit too rapidly, reducing exposure and causing under-dosing. Conversely, very low flows may cause fouling or stagnation.

3. Maintenance of Lamps & Quartz Sleeves

UV lamps degrade over time (they “solarise” and output intensities drop). Quartz sleeves must be kept clean (fouling reduces UV penetration). Many ETS-UV units incorporate automatic wipers, but a preventive maintenance schedule is still required. Some guidance notes show lamp effectiveness drops significantly when maintenance is deferred.

4. Monitoring, Alarms & Integration

Because UV systems do not leave a residual chemical disinfectant downstream, it is critical that sensors and alarm systems are in place to alert if UV intensity falls below threshold. Integration with the pool control system or plant SCADA ensures accountability and reliability. ETS-UV designs support such features.

5. Downstream Disinfection Strategy

Remember: UV treatment is a point-disinfection method—water can become re-contaminated downstream in piping and pool circuits. For recreational aquatic facilities, a low residual chemical disinfectant may still be required downstream for biofilm control, piping sanitation and code compliance.

6. Lifecycle Cost & Return on Investment

While the capital cost of a UV reactor may be higher than a simple chemical feed system, the lifecycle savings from reduced chemical usage, fewer by-product issues, improved occupant/air quality, and lower liability can make UV systems cost-effective—especially in high-usage commercial aquatic facilities or reuse applications.

Typical Applications in Aquatic Facilities

Here are a few real-world scenarios where ETS-UV systems make a meaningful difference:

Indoor competitive pools & natatoriums: By reducing chloramine levels, UV systems help improve air-quality at the air/water interface, reduce surface corrosion, improve bather comfort, and may extend the life of mechanical room equipment. (See the sponsorship of USA Swimming by Neptune Benson, which cites improved air/water quality in elite venues.)
Spray parks / wading pools: In these shallow, high-turnover water bodies, UV systems provide secondary disinfection quickly and without adding additional chemical residuals.
Commercial/municipal water reuse & industrial process water: For high-flow, high-demand systems, ETS-UV systems allow robust disinfection without generating new chemical residuals or significantly altering the water chemistry. (Xylem)
Retrofitting aging UV or chemical systems: Mechanical rooms with limited space can benefit from the compact footprint of ETS-UV units, often installing horizontal or vertical in tight areas.

Why “Understanding UV Disinfection” Matters for Orca Pacific Customers

As a provider of pool and spa systems, water-treatment solutions and servicing (and as a distributor of Neptune Benson equipment), Orca Pacific is well-positioned to guide customers through selection, installation, commissioning and lifecycle service of UV systems. Understanding UV disinfection in depth allows you to:

Educate your facility clients about why UV might be a better long-term investment in certain applications (e.g., indoor air quality, high bather load, chemical reduction).
Specify correctly — ensuring the right model, flow rating, chamber orientation, and integration features.
Service proactively — advising customers of maintenance intervals, data logs, lamp life forecasting, and performance monitoring.
Leverage differentiated value — illustrating how ETS-UV systems align with sustainability goals, regulatory compliance (e.g., fewer DBPs), and operational cost savings.

For readers who want to dive deeper into specific models or sizing, we recommend reviewing the ETS-UV product overview page [link below] and contacting your Orca Pacific support engineer for a tailored analysis.

Next Steps & Product/Resource Links

Explore the full ETS-UV product family on Neptune Benson’s website: ETS-UV Systems (Xylem)
Browse typical parts and replacement kits available via Orca Pacific: Neptune Benson Equipment & Parts (orcauv.com)
For a more applied perspective in aquatic settings, see the article on closed-vessel UV systems for reuse: “Neptune Benson’s Closed-Vessel System Uses UV Technology for Wastewater Reuse” (TPO Magazine)
For understanding the broader UV disinfection mechanics and water-quality implications, see the EPA fact sheet on UV disinfection of drinking water.

Summary

In summary: UV disinfection is a robust, chemical-free method of inactivating water-borne microorganisms, and when executed correctly it offers significant benefits for aquatic facilities, spas, reuse systems and industrial water installations. The ETS-UV system line from Neptune Benson is engineered to meet these demands—providing high output, proven validation, and flexibility for both retrofit and new-build projects.

For any facility considering how to improve water and air quality, lower chemical load, meet sustainability goals and deliver a healthier bather experience, understanding how UV disinfection works—and how to integrate a system like ETS-UV—is a key competitive and operational advantage.

If you’d like assistance with sizing, installation best‐practices or service planning for ETS-UV systems, reach out to the Orca Pacific team. We’re ready to help ensure you get the right UV solution for your facility.