Turbidity—the cloudiness of water caused by suspended particles—is a critical indicator of water quality. Online turbidity monitors and sensors provide real-time data to ensure compliance with environmental regulations, optimize treatment processes, and protect equipment. This guide explains how these systems work, key international standards (ISO, EPA), and their applications in industries ranging from drinking water to wastewater management.
Turbidity sensors measure light散射 (scattering) or absorption caused by particles like silt, algae, or pollutants. Two primary technologies dominate the market:
1. Optical Turbidity Sensors
- Principle:
- Nephelometric (90°散射): A light beam is projected into water, and a detector measures scattered light at a 90° angle. Complies with ISO 7027 and EPA Method 180.1.
- Backscatter (140°散射): Detects light reflected backward, ideal for high-turbidity samples (e.g., wastewater).
- Applications: Drinking water plants, low-to-medium turbidity environments.
2. Immersible Probe Sensors
- Principle: Submersible sensors use laser or LED light sources to measure turbidity directly in pipelines or tanks.
- Compliance: Meets ASTM D6698 for real-time monitoring.
- Applications: Industrial wastewater, stormwater, and raw sewage.
Standard | Scope | Application |
ISO 7027 | Nephelometric method (0–1,000 NTU) | Drinking water, environmental labs |
EPA Method 180.1 | Compliance monitoring for U.S. utilities | Municipal water treatment |
ASTM D6698 | Calibration of online turbidity systems | Industrial processes |
EN ISO 15839 | Sensor performance testing | EU water quality frameworks |
1. Drinking Water Treatment
- Compliance: Ensure turbidity <0.3 NTU (WHO) to prevent pathogen survival.
- Sensor Example: ERUN-SZ4-B6 Water quality online turbidity monitor.
2. Wastewater Management
- Optimization: Monitor clarifiers and filter backwash efficiency.
3. Industrial Processes
- Pharmaceuticals: Maintain ultra-low turbidity (<1 NTU) for purified water.
- Food & Beverage: Prevent sediment in brewing or bottling lines.
4. Environmental Monitoring
- Stormwater: Detect sediment runoff from construction sites.
- Rivers/Lakes: Track erosion or algal blooms in real time.
1. Range:
- Low Turbidity (0–100 NTU):** Laser-based sensors.
- High Turbidity (0–10,000 NTU):** Backscatter sensors.
2. Accuracy:±2% of reading for ISO-compliant systems.
3. Certifications: Look for ISO 7027, EPA 180.1, or CE marks.
4. Durability: IP68-rated housings for submersion; anti-fouling wipers.
5. Outputs: 4–20 mA, Modbus, or cloud connectivity for SCADA integration.
Installation Tips
- Mount sensors in representative flow zones (avoid air bubbles or stagnant areas).
- Use flow cells for pressurized pipelines .
Turbidity online monitors and sensors are indispensable for safeguarding water quality across industries. By selecting ISO 7027 or EPA 180.1-compliant devices, maintaining rigorous calibration, and leveraging smart technologies, operators can achieve regulatory compliance, reduce costs, and protect critical infrastructure.
