Views: 0 Author: Site Editor Publish Time: 2025-08-11 Origin: Site
A turbidity sensor is an essential tool for measuring the cloudiness or haziness of water caused by suspended particles such as silt, algae, and organic matter. By detecting how light scatters through a water sample, a turbidity sensor provides an accurate reading of water clarity, typically expressed in NTU (Nephelometric Turbidity Units) or FNU (Formazin Nephelometric Units).
Most turbidity sensors use optical methods.
They shine light (often an LED or laser) into the water.
A photodetector measures how much light is scattered at a certain angle (commonly 90° for nephelometric sensors).
The results are expressed in NTU (Nephelometric Turbidity Units) or FNU (Formazin Nephelometric Units).
When selecting the right turbidity sensor, you mainly consider:
| Factor | Why It Matters |
|---|---|
| Measurement range (NTU) | Needed to match your application — drinking water monitoring might need 0–40 NTU; wastewater could be >1000 NTU. |
| Accuracy & resolution | Critical for quality control and regulatory compliance. |
| Light source type | Infrared (IR) for ISO 7027 compliance; white light for EPA Method 180.1. |
| Output signal | Analog (4–20 mA), digital (RS485/Modbus), SDI-12 for easy integration into IoT systems. |
| Environment suitability | Waterproof rating (IP68), temperature tolerance, anti-fouling design. |
| Installation type | Immersion probe, flow-through cell, or in-line pipe mounting. |
Turbidity sensors are widely used in water quality monitoring and process control:
Drinking Water Treatment
Monitor sediment removal efficiency.
Ensure clarity meets WHO or EPA standards (<1 NTU for treated water).
Wastewater Treatment
Check settling tank performance.
Control sludge discharge and filtration systems.
Environmental Monitoring
Measure river, lake, or reservoir turbidity for ecological health.
Track sediment levels after heavy rains or construction.
Industrial Processes
In beverage production (beer, juice) to ensure product clarity.
In paper/pulp industry to monitor suspended solids in process water.
Aquaculture
Maintain optimal water clarity for fish/shrimp health.
Here’s a comparison table of typical turbidity sensor types and representative models (covering drinking water, wastewater, and industrial uses).
| Model Example | Measurement Range | Accuracy | Light Source | Output Signal | Installation | Typical Applications |
|---|---|---|---|---|---|---|
| YSI EXO Turbidity Sensor | 0–4000 FNU | ±2% of reading or ±0.3 FNU | Near-IR LED (ISO 7027) | SDI-12 / RS232 | Submersible probe | Environmental monitoring, rivers, lakes |
| Hach 2100Q Portable | 0–1000 NTU | ±2% of reading plus stray light correction | Tungsten lamp (EPA 180.1) | Handheld readout | Portable | Drinking water testing, field inspections |
| OTT ecoLog 500 with Turbidity Probe | 0–1000 FNU | ±2% of reading | IR LED (ISO 7027) | SDI-12 / RS485 | Submersible | Groundwater, stormwater monitoring |
| Endress+Hauser Turbimax CUS52D | 0–4000 FNU | ±2% of reading | IR LED (ISO 7027) | 4–20 mA / Modbus | In-line or flow-through cell | Drinking water plants, filter monitoring |
| In-Situ Aqua TROLL 500 with Turbidity | 0–4000 FNU | ±2% of reading | IR LED | Modbus / SDI-12 | Submersible probe | Remote IoT water quality stations |
| HF Scientific MTOL+ Online Turbidimeter | 0–1000 NTU | ±2% of reading | White light (EPA 180.1) | 4–20 mA / Modbus | Online process | Municipal water treatment, industrial process water |
| YSI ProDSS with Turbidity Sensor | 0–1000 FNU | ±2% of reading | IR LED | Handheld / USB | Portable | Field testing, aquaculture |
Drinking water (compliance testing) → EPA 180.1 white light or ISO 7027 IR sensors, high accuracy, 0–40 NTU range.
Wastewater → Higher range (>1000 NTU), rugged, anti-fouling coating, 4–20 mA or Modbus output.
Environmental monitoring → Submersible, low power, SDI-12/RS485 for remote logging.
Industrial → In-line or flow-through design, stable under varying temperature/pressure.
Turbidity sensors are widely used in drinking water treatment plants to ensure compliance with safety standards, in wastewater treatment to optimize sediment removal, and in environmental monitoring to track changes in rivers, lakes, and reservoirs. Industrial processes, such as food and beverage production, also rely on them to maintain product clarity. Interestingly, turbidity measurement technology is even found in modern appliances—turbidity sensor dishwasher systems automatically adjust water usage and cycle times based on the water turbidity sensor readings, improving efficiency and saving resources.
