What is the TSS sensor?
A TSS sensor measures the concentration of suspended solids in water, typically reported in mg/L, enabling operators to monitor treatment efficiency and environmental impact.
What Total Suspended Solids (TSS) are and why they're monitored
TSS refers to solid particles that are suspended in water rather than dissolved. Common constituents include silt, clay, organic matter, and microorganisms. High TSS can reduce light penetration, hinder aquatic life, clog pipes and filters, and complicate drinking-water treatment. Monitoring TSS supports regulatory compliance, guides treatment adjustments, and helps detect pollution events.
How a TSS sensor works
Gravimetric, filtration-based TSS sensors
These devices automate the classic lab method: a known water volume is filtered, the filter is dried and weighed, and the difference in weight yields TSS. Inline systems integrate a microbalance and automated filter exchange, delivering a direct mg/L reading but requiring routine filter maintenance and periodic recalibration.
Optical or turbidity-based TSS sensing
Many online sensors infer TSS from light interactions with suspended particles. Turbidity or nephelometric measurements are calibrated against lab TSS determinations to estimate mg/L. These sensors offer continuous data and low maintenance but can drift if particle composition changes or color and temperature affect measurements.
Hybrid approaches
Some systems blend optical sensing with periodic gravimetric verification to improve accuracy, providing real-time estimates with periodic confirmation to correct drift.
Below are common approaches used in the field and factors to consider when selecting a TSS sensor:
- Gravimetric in-line TSS sensors (filtration-based) – collect a known water volume, filter, dry, and weigh to obtain direct TSS in mg/L.
- Optical/ultrasonic turbidity-based sensors – infer TSS from light scattering, typically giving NTU or mg/L via site-specific calibration.
- Hybrid or automated systems – combine optical sensing with periodic gravimetric checks for accuracy and reliability.
These approaches reflect a spectrum from direct mass measurement to proxy-based estimation, enabling operators to balance accuracy, maintenance, and cost according to site needs.
Applications and typical deployments
Online TSS sensors are common in municipal wastewater plants, drinking-water treatment facilities, stormwater monitoring, environmental monitoring of rivers and lakes, and industrial processes where solids management is important.
Maintenance, calibration, and data integration
Regular calibration against laboratory TSS measurements is crucial. Optical sensors require periodic cleaning to reduce fouling, and many modern units are IoT-enabled with remote diagnostics, self-cleaning features, and anti-fouling designs. Temperature compensation and calibration are essential, and data from TSS sensors are typically integrated into SCADA, data historians, or cloud dashboards for real-time decision-making.
Conclusion
A TSS sensor provides a practical, real-time window into suspended solids in water, supporting process control, environmental protection, and regulatory compliance. Choosing the right technology depends on site conditions, required accuracy, and maintenance capacity, with ongoing calibration ensuring reliable readings.
Summary
In essence, a TSS sensor measures total suspended solids in water, either directly by filtration and mass measurement or indirectly through optical proxies calibrated to TSS. It is a key tool for water-quality management and treatment optimization. Site conditions, accuracy needs, and maintenance capabilities drive the best sensor choice, with ongoing calibration and maintenance ensuring trustworthy data.
