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What Is a UV COD Sensor?

A UV COD sensor uses ultraviolet light absorption spectroscopy to measure the Chemical Oxygen Demand (COD) of water in real time — without any chemical reagents. Organic compounds dissolved in water absorb UV light at specific wavelengths, most significantly at 254 nm. By measuring how much UV energy is absorbed as light passes through the water sample, the sensor calculates an equivalent COD value continuously and instantaneously.

This is fundamentally different from the traditional dichromate digestion method (GB 11914) used in laboratory COD analysis, which requires strong acids, heavy metal catalysts, heating at 150°C for 2 hours, and generates hazardous chemical waste. A UV COD sensor eliminates all of these steps — delivering real-time organic load data with zero chemical consumption and zero secondary pollution.

UV COD vs. Traditional Laboratory COD — Key Differences

Introducing the Kainafu KNF-108A

The KNF-108A is Kainafu's UV absorption COD sensor — designed for continuous, unattended online monitoring of organic pollution load in wastewater, surface water, industrial effluent, and sewage. It simultaneously measures COD, TOC, and turbidity from a single submersible probe, with automatic compensation for turbidity interference — the most common source of error in UV-based COD measurement.

Full Technical Specifications

Key Features

✅ No Reagents — Zero Chemical Cost

The KNF-108A requires no potassium dichromate, no sulfuric acid, no silver sulfate, and no ammonia. Ongoing operating cost is essentially zero beyond periodic maintenance. This also eliminates all hazardous chemical storage, handling, and disposal requirements — significantly simplifying site safety management.

✅ Simultaneous COD + TOC + Turbidity

Three parameters from one probe, one installation, one cable. COD and TOC values are derived from UV absorption at 254 nm; turbidity is measured simultaneously and used to automatically compensate for particulate interference on the UV signal — the most important factor in maintaining COD accuracy in real-world wastewater.

✅ Integrated Self-Cleaning Brush

The split-design cleaning brush is integrated into the sensor body — preventing biological adhesion and particulate fouling on the optical windows without requiring manual cleaning between maintenance visits. This is essential for long-term deployment in wastewater and industrial effluent where biofouling would otherwise rapidly degrade UV measurement accuracy.

✅ 316L Stainless Steel Housing

Food-grade and corrosion-resistant 316L stainless steel protects the sensor in the aggressive chemical environments found in industrial wastewater, sewage, and surface water. Titanium alloy housing is available for particularly corrosive applications.

✅ Continuous 24/7 Monitoring

Water quality monitoring can be conducted online without interruption. The KNF-108A detects COD spikes in real time — giving operators and automated control systems the data needed to respond to pollution events within seconds rather than waiting hours for laboratory results.

Where the KNF-108A Is Used

Wastewater treatment plant influent and effluent — continuous organic load monitoring for process control and discharge compliance verification

Industrial effluent discharge points — real-time COD monitoring at factory outfalls for regulatory compliance and pollution incident detection

River and surface water cross-sections — early warning of upstream industrial discharge events before contaminated water reaches downstream intakes

Sewage drainage network nodes — combined with the KNF-400D drainage monitoring system for manhole deployment

Small water quality monitoring stations — compact size and minimal maintenance requirements make the KNF-108A ideal for unattended remote deployments

Pairing the KNF-108A with Kainafu Monitoring Systems

The KNF-108A integrates directly with Kainafu's complete monitoring ecosystem:

All data uploads to the Kainafu cloud platform (ion.onetestinc.com) — real-time dashboards, threshold alarms via WeChat and APP, historical trend analysis, and compliance report export.

About Kainafu: Shenzhen Kainafu Technology Co., Ltd. is an ISO 9001 and CMA-certified R&D manufacturer of water quality sensors in Shenzhen, China. The KNF-108A is manufactured entirely in-house and available factory direct with full technical support and OEM customization options.

📧 Email: knfeco@knfsensors.com 🌐 Website: www.knfsensors.com

Shenzhen Kainafu Technology Co., Ltd. — Care for Environments and Health.