MEASURING TOTAL SUSPENDED SOLIDS

(TSS)VACUUM FILTRATION & IMHOFF CONES

Image Source: oos.soest.hawaii.edu

TURBIDITY

• Turbidity: measure of relative sample clarity• Increases with TSS (or SPM)

• Soil particles, algae, plankton, microbes, other debris• Size range of 0.004 mm (clay) to 1.0 mm (sand)

• Affects how much light is scattered• Increased turbidity = Increased scattering of light

• Can affect water color

TURBIDITY

• Can be natural:• Rainfall and Runoff• Hurricanes and Flooding• Water currents • River deltas• Natural soil erosion &

deposition• Decaying plants & animals• Animal activity (e.g., bottom

feeding fish)• Algal blooms

Image Sources: noaa.gov; wired.com; tcmud.org; commons.wikimedia.org

TURBIDITY

• Can be anthropogenic:• Dredging• Boat activities• Outfalls• Expedited soil erosion

Image Sources: pugetsoundkeeper.org; cfcc.edu/martech; dredgeresearchcollaborative.org

MEASURING TURBIDITY: SECCHI DISK• IN SLOW-MOVING AND/OR DEEP WATERS:

• Secchi disk: Measures light attenuation

Image Sources: geoscientific.com; ecy.wa.gov

MEASURING TURBIDITY: NEPHELOMETER

• IN FAST-MOVING AND/OR SHALLOW WATERS:• Nephelometer (Turbidimeter): Measures scattered light

• Nephelometric Turbidity Units (NTUs)

Image Sources: etslabs.com; hach.com

TURBIDITY: NC WATERS

• Average NTUs:• Marine: Approximately 25 NTUs• Fresh: Approximately 50 NTUs• Trout Waters: Approximately 10 NTUs

Image Sources: waterontheweb.org

TURBIDITY &

FISH

MEASURING TSS IN THE LABMillipore Vacuum Filtration & Imhoff Cones

Image Sources: medicalexpo.com; maxlabor.com.br

MILLIPORE VACUUM FILTRATION

Before Filtration After Filtration

• Measures all suspended particulate larger than 0.45 μm

Image Source: emdmillipore.com

IMHOFF CONES

• Measures settleable solids • in one liter of sample water

• Often used by: • Waste water treatment facilities• Aquaculture facilities• Agriculture (irrigation runoff)

Image Source: bioaqua.vn

    Sample   #

    Filter    #

    Tare         Gross         Net     Corrected   Net    

Liters    Filtered    

TSS    [mg/L]   

1

2

3

Blank 1 4

Blank 2 5

Blank 3 6

Avg. blank change

Blank Correction

Example Data Table: One Water Sample

CFR 1

CFR 3

66.5 mg66.8 mg66.7 mg

85.6 mg86.9 mg86.0 mg

CFR 2

66.3 mg66.0 mg

0.1000 L0.1000 L0.0800 L

(mg) (mg)

65.9 mg66.2 mg

CALCULATION

SPM in mg/L = W2 – W1 ± X V

Variables: W2 = GROSS WEIGHT (in mg)W1 = TARE WEIGHT (in mg)X = BLANK CORRECTION (in mg) (+ or - as appropriate)V = VOLUME (in Liters)

Note: W2 – W1 ± X is the CORRECTED NET!