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TURBIDIMETERS Turbidity relates to suspended solids in a liquid, but it is NOT a direct measurement of them.Turbidity measures the amount of light that a sample scatters.Measuring low turbidity samples requires proper technique and cleanliness.Turbidity take home messageWhat is Turbidity?Turbidity InstrumentationTurbidity models

Turbidity out lineWhat is Turbidity?A measure of relative water clarityA measure of suspended solidsAn indicator of water quality

Suspended particles may includeSiltClayAlgae and Other MicroorganismsOrganic MatterOther Minute ParticlesWhat is Turbidity?Solids in Water:Support growth of harmful microorganismsReduce effectiveness of chemical disinfectionInterfere with chemical and biological analysisHave poor aestheticsAre unacceptable for most industrial applicationsWhat is Turbidity?Turbidity is NOT:A direct measure of total suspended solids (TSS) concentration Able to identify the type of particlesA spectrophotometric analysisWhat is Not Turbidity?Industrial Water

Drinking Water

Turbidity applications Cooling water - high levels of suspended solids are acceptableHigher pressure boiler - requires extremely low turbidity

Industrial waterRequires low turbiditySolids in drinking waterReduce effectiveness of disinfectionMay support microorganismsPoor aesthetics

Drinking waterTurbidity measurementHistorical progression of turbidity measurementJackson Candle - visual extinctionPhotometer - light transmissionNephelometry - 90o light scatterMeasurement strategies

Photometers Once photometers were developed, light transmission was used to measure turbidity.

Photometer ProblemsLow turbidity (drinking water levels)Transmittance changes too small to measureHigh turbidityLight scattering by many particles interferes with light absorption 15NephelometersUse a 90 design in their optical systemDetector 90o from light sourceResults are reported as Nephelometric Turbidity Units (NTU). Required for EPA reporting

How do Nephelometers Work?Measure the amount of light scattered by a samplePhotometerTransmitted lightNephelometerScattered light

Basic 90o Nephelometer0.5 NTU

LampLensSample Cell90o Detector Why 90 Degrees? Many factors affect light scattering:Particle SizeParticle ShapeRefractive IndexColor of Particles and FluidParticle Concentration Why 90 Degrees? Nephelometers attempt to minimize the effects of these factors (size, shape, color of particles) while maximizing measurement accuracy. Example particle sizeWhy 90 Degrees?

Small ParticlesLarger ParticlesEven Larger ParticlesMeasure light scattering at 90 degrees to minimize the effect of particle size Color of Particles and SolutionColored substances absorb light.If light is absorbed, then less light reaches the detector and the measured turbidity will be lower.

Color of Particles and SolutionCorrect for this with a ratio nephelometer.Additional detector/ by using with IR light source measures amount of light absorbed by sample and performs correction.

Ratio DetectorRatio Nephelometer0.5 NTU

LampLensSample Cell90o DetectorTransmitted Light Detector Measuring TurbidityTurbidity is just plain different than colorimetryNo zero (impossible to measure zero turbidity)Not a comparison measurementRequires calibration on a regular basis

ApplicationsAll Types of Waters (Drinking water, wastewater, process water)Pharmaceutical/bulk drug industry. Pharma/bulk drug industries, which are manufacturing as per USFDA guidelines and those who are exporting their products to USA, need invariably measure Turbidity of their product. Virchow labs , Novarties , Divis , Dr.ReddysApplicationsTurbidity & Color measurement in tea liquor Turbidity is contributed mainly due to insoluble in tea liquor. Since, tea liquor being dark colored liquor, turbidity measurement is not easy job with ordinary turbidity meters. Tea color will interfere with turbidity readings and thus accurate measurement of turbidity is not possible with ordinary turbidity meters Tata Tea, Upasi Tea, Lipton Ice Tea Beverages industries Pepsi, Coke etc.Chlora caustic industries for Brine analysisNRC, Indian Rayen, Mardia, Atul etc. Edible Oils Industries for Wax in ppm estimation Cargill India Ltd.

TURBIDIMETERS MODELS

TURBIDIMETERS LABORATORY MICRO 100 IR / TMICRO 1000 IR/ T Auto Ranging 0 - 1000 NTU Auto Alert Calibration Prompt Simple Calibration Procedures Response Time: 6 seconds Light Source: Quick Connect Tungsten Filament or Infrared Measurement Principle: Nephelometric non-ratio Extended Auto Ranging up to 10,000 NTU Auto Alert Calibration Prompt Multiple Measurement Modes Built-in Diagnostics Ratio (Color Correction) Reusable Calibration Standards Principle of Operation: Nephelometric Resolution: 0.0001 NTU on Lowest Range Response Time: less than 6 seconds Sample Size: 30 ml Light Source: Quick Connect Tungsten Filament or Infrared

TURBIDIMETERS PORTABLE Auto Ranging 0.01 to 1,100 NTU Extended Battery Life Waterproof Completely Self Contained Certification: CE, Designed to meet IP67 & NEMA 4X Display: 4 Digit (7 segment) LCD LIGHT SOURCEWhite Light (Tungsten)Infrared - LED (860nm) Lamp Life 7-10 years with normal useMICRO TPI/TPWLIGHT SOURCE IR Vs. TUNGSTENPOCKET CHLORINE METER

Laboratory Accuracy in the Field Simple Operation Integrated Packaging WaterproofIP-67 at 1m for 30 minutes EPA Approved MethodMeets Standard Method 4500-Cl G.DPDColorimetric Method for measuring residualchlorine. Range: 0 - 10.0 ppm Method: EPA Approved DPD Response Time: 3 seconds Light Source: Longlife LED - 515nm Sample Size: 3 ml Display: 7 Segment Brightvision LCDPOCKET CHLORINE METERTHANK YOU FOR YOUR ATTENTION