Turbidity Definition - What is it?

Turbidity is the optical property that causes light to be scattered and absorbed rather than transmitted in straight lines through the sample.
Standard Methods for Examination of Water and Wastewater

Turbidity is the clarity of the sample sample.

Turbidity Applications
MUNICIPAL Water Treatment Plants Wastewater Treatment Plants INDUSTRIAL Metals and Mining Chemical Processing Pulp and Paper Power Food and Beverage g Pharmaceuticals Refining

Why Measure Turbidity in Drinking Water?

Plant Goal: Provide a Source of Safe and Reliable Drinking Water to Their Community Community. Harmful Microorganisms Are Removed by a Combination of Filtration and Disinfection Turbidity Measures the Adequacy of the Filtration Process Why Measure Turbidity? Monitor M it and d Improve I Plant Pl t Effi Efficiency i Detect Filter Breakthrough Meet Regulatory and Governmental Requirements

Turbidity - Two Approved Methods

Two Design Methods For Reporting Turbidity: United States Environmental Protection Agency (USEPA 180.1) 180 1) International Standards (ISO 7027) Turbidity Measuring Method Must Meet EPA or ISO Requirements for Water Testing Comparison of USEPA 180.1 and ISO 7027 Method
Item Light Source Wavelength Characteristics EPA 180.1 Tungsten Lamp 400-600 nm Long Warm Up Time More sensitive to Smaller Particles Color Interferences ISO 7027 LED or Other Filtered Source 860 30 nm Low Stray Light Less Sensitive to Smaller Particles Low Color Interferences

Units of Measure - Turbidity

Different Units
NTU: Nephelometric Turbidity Units FTU: Formazin Turbidity Units FNU: Formazin Nephelometric Units These Units, NTU, FTU, and FNU are Equivalent

Formazin is the Polymer Suspension Used to Calibrate Turbidity Sensors Turbidity is Determined in a Nephelometric Instrument, g that is Scattered at 90 from the and Measures the Light Light Source

Total Suspended Solids - Definition and Units

Definition:
A Measure of the Total Mass of Particles in a Sample

Determination of TSS:
Filtering a Volume of Sample and Weighing the Mass of the Dried Residue Retained on the Filter

The TSS V Th Value l i is C Calculated l l t dF From th the T Turbidity bidit Measurement Turbidity and TSS Relationship Must be Determined by the User Available Units: ppm ppm, mg/L or no units displayed

Turbidity versus Total Suspended Solids

Turbidity is not the same as total suspended solids (TSS)

Both Turbidity and TSS Are Defined by the Method Used to Measure Them TSS is a Gravimetric Measurement; it Depends on the Total Mass of Filterable Material in the Sample Turbidity is an Optical Measurement; it Depends on the Number of Particles in the Sample and Their Shape and Size

TSS is still 100 mg/L. For 100 mg of solid particles in 1 L TSS is 100 mg/L. g Turbidity has a certain value Turbidity is different: since there are more particles and smaller in size.

Cut each particle in half

Effects on Turbidity
Turbidity Depends on: Number of Particles Per Volume Size Si of fP Particles ti l Wavelength of Light Used for Measurement Color of Particles Shape of Particles Refractive Index of Particles Presence of Air Bubbles

Development of Turbidimeter
First Turbidimeter: The Quality of Wine of Beer Was Determined by Holding the Glass up to a Light Source and Look for Small Particles.

Pattern of Particle Scattering

Small Particles Medium Particles

Size: Smaller Thank 1/10 the Wavelength of Light Description: Symmetric

Size: Approximately 1/4 the Wavelength of Light Description: Scattering Concentrated in Forward Direction

Large Particles

Basic Nephelometer
Light Source Light Scattered y Particles by

Transmitted Light Scattered Light at 90

Detector Turbidity is the measure of the amount of light scattered by particles in a sample. A beam of light passes through a sample containing suspended particles. The particles interact with the light and scatter the light. A detector at 90 measures the intensity of the scattered light.

Turbidity Sensor - EPA 180 180. .1 Method

Collimator Particles Transmitted Light Scattered Light g at 90 Light Source Optical Filter Detector

EPA Method 180.1 requires: 1. Tungsten Lamp Light Source with Filament Temperature Between 2200 - 2700 K 3. Detector Response Between 400 and 600 nm 4. Scattered Light be Measured at 90 30 5. Total Path Length Through Sample Less Than 10 cm

Turbidity Sensor - ISO 7027 Method

Particles Transmitted Light Light Source Scattered Light g at 90

ISO Method 7027 requires: 1. The Wavelength of the light to be 860 nm 30 nm 2. The Measuring angle to be 90 2.5 3. Light Source Using a Laser, LED, or Tungsten Filament Lamp with Filter

Detector

Turbidity Measuring System

Complete System Single or Dual Sensor Input Debubbler/Measuring Chamber USEPA Method 180.1 or ISO Method ISO 7027 0 - XXX NTU Range Resolution X.XXX NTU Ideal for ??? Level Turbidity Analyzer Suitable for Wastewater / Discharge / Industrial / P Process W Water t Applications A li ti

Online Turbidimeter

Turbidity Sensor

Debubbler/Measurement Chamber

Calibration Methods
Three Turbidity Calibration Methods: 1 User 1. U P Prepared dS Solution l ti 2. Commercially Available Standard Solution 3. Comparison with a Referee Turbidity Instrument Note: The USEPA Does Not Recommend Calibrating an On-line Turbidity meter by Comparison with a Bench Meter Dry Calibration Standard Available for Checking the Performance

Total Suspended Solids Calibration Method: Enter an Equation into the Analyzer to Convert Turbidity to a TSS Reading

Installation

Turbidity Sensor

Debubbler/Measurement Chamber

Sampling Methods
Not Recommended
Sample Line Sample Line Sample Line

Not Recommended Good BEST METHOD!

Process (water) Sediment

Process (water) Sediment

Process (water) Sediment

Process (water) Sediment

Process Pipe

Process Pipe

Process Pipe

Process Pipe

Cooling Water Systems

Quantity of analyzers depends on whether h th the th water t used d is i in a closed circuit or from a once-through natural source

Turbidity

Raw Make Make-up Water System

Polymer y Addition
Turbidity monitors the coagulants/polymers present

Chlorine Addition

River Water Or Ground Water

T
T

Cl

Sludge Blowoff

To Cooling System Clearwell

Cl ifi Clarifier

Media Filters
Turbidity monitors for particulate breakthrough

Coagulation and Flocculation

Ferric Chl id Chloride Tank

Caust c Caustic Tank

Clarifier
T

Industrial Waste Water

pH

Clean Water

further t t treatment t

Flocculants are used to remove suspended solids from water. Optimum removal depends on pH. Turbidity is used to control addition of the flocculent

slime
to landfill

Following the Water in Steam Power Generation

Overview
Efficiency reductions and equipment failures due to corrosion and deposition cost the power industry billions of dollars every year. Good water chemistry can help to mitigate some of these effects and is best achieved with online liquid analysis and control.

Applications
Demineralization (Make-up Water) Condensate Returns Boiler Water & Steam Treatment Cooling Water Systems Scrubbers Waste Treatment

Measurements
Conductivity, Cation Conducitivity, pH & ORP, Dissolved Oxygen, Chlorine, Ozone, Turbidity, Silica, Sodium, Phosphate, Hydrazine

Turbidity - Drinking Water Applications

Plant Intake Settling basin Filter e wastewater as e a e bac backwash as Filter bed effluent (individual and combined)

Drinking Water Regulations - USEPA

Two USEPA Rules to Monitor Turbidity for Drinking Water Treatment Plants 1 Plants Serving >10 1. >10,000 000 People Combined Filter Effluent (CFE) Water Turbidity: <0.3 NTU 95% of Measurements Taken Each Month Never Exceed 1 NTU Filter Individual Filter Effluent (IFE) Water Turbidity: < 0.5 NTU 1 2 3 Never Exceed 1.0 NTU
Readings: Continuous and Recorded Every 15 Minutes IFE Water Source: Surface or Ground Water Filtration: Conventional and Direct Rule: Interim Enhanced Surface Water Treatment Rule (IESWTR) Compliance: Jan 1, 1 2002 Report Violations to the State Keep Records for Three Years IFE IFE CFE

Drinking Water Regulations - USEPA

Second Rule .. 2. Plants Serving <10,000 people Turbidity Requirements for the Small Plants (<10,000 people) Will be the Same as Th Those for f the th Big Bi Plants Pl t (>10,000 (>10 000 people) l ) Rule: Long Term 1 Enhanced Surface Water Treatment Rule (LT1ESWTR) C Compliance: li J Jan 14, 14 2005

Drinking Water Regulations - International

Regulations for Turbidity Requirements for Drinking Water Treatment Plants Outside the USA These Plants Have Either ... Adopted the USEPA Standards, Developed Their Own O Regulations, or Follow the World Health Organization (WHO) Recommendations of 1 NTU

Questions?