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TSS/NTU Converter

Our air water pollution calculator computes tssntuconverter accurately. Enter measurements for results with formulas and error analysis.

Reviewed by Daniel Agrici, Founder & Lead Developer

Reviewed by Daniel Agrici, Founder & Lead Developer

Formula

TSS = a x NTU + b (linear correlation)

TSS and NTU are related through a site-specific linear regression where a is the slope and b is the intercept.

Worked Examples

Example 1: Stream Monitoring

Problem:NTU=50, slope=1.5, intercept=2.0, 1000 mL.

Solution:TSS = 1.5 x 50 + 2 = 77 mg/L Mass = 77 x 1000/1000 = 77 mg

Result:TSS = 77 mg/L

Example 2: Treatment Plant

Problem:NTU=5, slope=1.2, intercept=0.5, 500 mL.

Solution:TSS = 1.2 x 5 + 0.5 = 6.5 mg/L Mass = 6.5 x 500/1000 = 3.25 mg

Result:TSS = 6.5 mg/L

Frequently Asked Questions

What is the difference between TSS and NTU?

TSS (Total Suspended Solids) is a gravimetric measurement of particle mass in water obtained by filtering and weighing the residue. NTU (Nephelometric Turbidity Units) measures how much light is scattered by suspended particles using an optical instrument. TSS gives actual mass concentration while NTU is an optical proxy that can be measured in real-time.

Why convert between TSS and NTU?

NTU can be measured instantly with portable turbidimeters in the field while TSS requires laboratory analysis taking hours to days. Converting NTU to TSS allows real-time estimation of solids loading for treatment plant operations and discharge monitoring. The relationship must be calibrated for each specific water source because particle characteristics affect light scattering differently.

What affects the TSS-NTU correlation?

Particle size, shape, color, and composition all influence how much light is scattered per unit mass of suspended solids. Clay particles scatter more light per milligram than sand grains due to their smaller size and larger surface area. Algae and organic particles may scatter differently than mineral sediments requiring separate calibration curves for different water types.

What is a typical TSS-NTU ratio?

For many surface waters the TSS-to-NTU ratio falls between 1.0 and 2.5 meaning 1 NTU corresponds to 1-2.5 mg/L TSS. Clean waters with fine clay may show ratios near 1.0 while waters with coarser sediments show higher ratios. Wastewater effluent typically has different ratios than natural streams requiring separate site-specific calibrations.

References

Reviewed by Daniel Agrici, Founder & Lead Developer · Editorial policy