Fiber optic online turbidity sensors provide real-time, accurate, and stable measurement of suspended particles in water using 90° scattered light detection.

Working Principle

Fiber optic turbidity sensors operate on the nephelometric principle, where an infrared or visible light beam is emitted into the water sample, and the intensity of light scattered at a 90° angle is measured. The scattered light intensity correlates with the concentration of suspended solids, which is then converted into turbidity units (NTU or FNU) ( ). Some advanced designs use multi-mode glass fibers to deliver and collect light through a single fiber, enhancing sensitivity and reducing noise ( ).

Key Features

• High Accuracy and Stability: Fiber optic sensors provide highly linear responses and can detect turbidity as low as 0.1 NTU, with excellent reproducibility and stability against temperature changes ( ).
• Self-Cleaning Mechanisms: Many models, such as the DSS410 and KWS-900, include automatic cleaning brushes to remove bubbles and fouling, reducing maintenance and ensuring long-term stability ( ).
• Wide Measurement Range: Suitable for low-turbidity drinking water and high-turbidity wastewater, with ranges up to 5000 NTU ( ).
• Resistance to Ambient Light: Fiber-optic design effectively suppresses interference from external light sources, improving measurement reliability ( ).
• Compact and Flexible Installation: Fiber-based sensors can be installed in small pipeworks or submersible setups, making them suitable for distributed monitoring networks ( ).

Applications

Fiber optic turbidity sensors are widely used in:

• Drinking water production: Ensuring filtration efficiency and microbial safety ( ).
• Wastewater treatment: Monitoring effluent quality and process control ( ).
• Environmental monitoring: Real-time assessment of rivers, lakes, and reservoirs ( ).
• Industrial processes: Monitoring circulating water and process streams in chemical, food, and beverage industries ( ).

Advantages

• Real-time, in situ monitoring without the need for sample extraction ( ).
• Long-term stability with minimal maintenance due to anti-fouling and self-cleaning features ( ).
• High sensitivity and linearity, suitable for both low and high turbidity applications ( ).
• Integration with smart water management systems via RS-485 Modbus RTU or other industrial protocols ( ). Fiber optic online turbidity sensors combine precision, durability, and adaptability, making them ideal for continuous water quality monitoring in municipal, industrial, and environmental applications.