Online Turbidity and Suspended Solids Monitor

What is the Online Turbidity and Suspended Solids Monitor?

A continuous optical monitor that measures turbidity or suspended solids by light scattering or absorption. It is the right choice for filtration control in drinking water plants, clarifier performance checks and sediment monitoring in rivers and outfalls.

Overview

This monitor uses a light source and one or more detectors to quantify particles in water. Nephelometric designs measure light scattered at 90 degrees from a beam at 860 nm and follow ISO 7027 for low-range drinking water, reporting in FNU or NTU. Surface scatter or backscatter probes cover higher ranges, and multi-angle designs compensate for color and bubbles. For suspended solids, the output is calibrated against gravimetric results for the specific water. Flow-through units with a bubble trap suit filter effluent, while immersion probes with wipers handle rivers and sludge. Ranges run from 0–10 NTU with 0.001 resolution to 0–4000 NTU or 0–50 g/L for solids. Signal outputs of 4–20 mA and Modbus make integration into plant control straightforward.

How does it work?

Water monitors combine sensors with a controller and communication unit. Electrochemical sensors measure pH by glass electrode potential, conductivity by electrode cell resistance, and dissolved oxygen by optical luminescence quenching or a membrane-covered amperometric cell. Turbidity uses nephelometric scattering of light at 90 degrees, typically at 860 nm per ISO 7027. Ammonia, nitrate and fluoride use ion-selective electrodes, while COD, total phosphorus and total nitrogen analyzers automate digestion and photometric detection, often with UV absorbance at 254 nm as a proxy for organics. Multiparameter sondes integrate several sensors on one cable. Automatic cleaning with wipers or air blasts limits fouling. Data loggers record readings with time stamps, and telemetry sends results over cellular, satellite or radio links to a central platform with alarms.

What are the key features?

• Nephelometric 860 nm design conforms to ISO 7027 for drinking water turbidity.
• Bubble trap and flow-through cell prevent air bubbles from causing false readings.
• Auto-wiper or ultrasonic cleaning maintains optical window clarity in dirty water.
• Low-range sensors resolve 0.001 NTU for filter breakthrough detection.
• 4–20 mA, relay and Modbus outputs integrate with plant control systems.
• Calibration with formazin or stabilized standards is traceable and repeatable.

What are the technical specifications?

A typical online turbidity and suspended solids monitor configuration offers turbidity range (low) of 0–10 NTU, 0.001 NTU resolution, turbidity range (high) of 0–4000 NTU, accuracy of ±2% of reading or ±0.02 NTU, light source of LED, 860 nm, measurement angle of 90° scatter and response time of ≤ 30 s (T90). Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Online Turbidity and Suspended Solids Monitor is used in drinking water filter effluent, clarifier and sedimentation control, river sediment monitoring and construction site runoff. Across the wider Water Monitoring class, laboratories also deploy it for surface water and river monitoring, wastewater effluent compliance and drinking water source protection.

Which standards and certifications apply?

Relevant standards and methods include ISO 5667-1, ISO 7027-1 (turbidity), ISO 5814 (dissolved oxygen), ISO 10523 (pH), HJ 355, HJ 377 and IEC 61010-1. Certification candidates for this model are CE, ISO 9001 manufacturing and RoHS; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Install sensors where flow is representative and away from dead zones, and ensure cable glands and enclosures meet the stated ingress protection. Calibrate pH with two or three buffers, dissolved oxygen in air-saturated water or at zero, and turbidity with formazin or polymer standards, following the manufacturer schedule. Cleaning intervals depend on biofouling, from weekly in warm eutrophic water to monthly in clean streams. Replace membranes, electrolytes and reagent cartridges on time, and keep maintenance logs. For regulatory use, validate data against laboratory reference results and apply quality flags. Protect telemetry equipment from lightning and confirm cellular coverage before deployment.

How do I select the right Online Turbidity and Suspended Solids Monitor?

Select this monitor for filtration control or sediment tracking where a single optical parameter drives process decisions. A multiparameter sonde adds other parameters but is less sensitive at low NTU. In an RFQ, state the range, whether ISO 7027 compliance is needed, flow-through or immersion format, cleaning method and output signals.

How does it compare with other Water Monitoring variants?

Begin with the parameters required by the permit or the monitoring objective, then the deployment style. Spot checks and river surveys favor handheld meters or multiparameter sondes, while compliance monitoring of effluent needs online analyzers with automatic calibration and sample conditioning. Check measurement range and accuracy against the regulatory limits, for example ammonia nitrogen at 0.05–100 mg/L or COD up to 2000 mg/L. Consider fouling in raw wastewater, which may need ultrasonic or brush cleaning, and sensor life for consumables such as membranes and reagents. For remote locations, evaluate battery or solar power and telemetry. Confirm data protocols and calibration support, and choose IP68 or IP65 enclosures suited to immersion or outdoor cabinets.