Water Quality Instruments PDF

FISHERIES TECHNOLOGY AND INSTRUMENTATION (FIS2223) By DR. MUHAMAD NAIMULLAH Faculty of Fisheries and Food Sciences Email: [email protected] CHAPTER 6 WATER QUALITY INSTRUMENTS Understand the Water Quality Analysis Understand the Colorimetry...

FISHERIES TECHNOLOGY AND INSTRUMENTATION (FIS2223) By DR. MUHAMAD NAIMULLAH Faculty of Fisheries and Food Sciences Email: [email protected] CHAPTER 6 WATER QUALITY INSTRUMENTS Understand the Water Quality Analysis Understand the Colorimetry & Spectrophotometry  TABLE OF CONTENTS 1 2 3 Colorimetry Water Measuring & Quality Water Spectropho Analysis Clarity tometry  01 Water Quality Analysis  Physical Factors including suspended materials (called suspended solids) and dissolved substances (dissolved solids) Water Chemical Quality Factors including concentrations of ions, Analysis pollutants, etc… Biological Factors including presence of organisms, plankton, macro invertebrates, fish, nutrients, etc…  Physical Factors TSS – Total Suspended Solids can be measured by taking the amount of solid separated from a water sample. Measurement in mg/L https://www.youtube.com/watch?v=_fKGM040wvI  TSS – Total Suspended Solids WHAT ARE THEY? TSS are solid materials, including organic and inorganic, that are suspended in the water. These would include silt, plankton and industrial wastes. WHY TEST FOR THEM? High concentrations of suspended solids can lower water quality by absorbing light. Waters then become warmer and lessen the ability of the water to hold oxygen necessary for aquatic life. Suspended solids also affect life in other ways. They can clog fish gills, reduce growth rates, decrease resistance to disease, and prevent egg and larval development. WHERE DO THEY COME FROM? Suspended solids can result from erosion from urban runoff and agricultural land, industrial wastes, bank erosion, bottom feeders (such as carp), algae growth or wastewater discharges.  Physical Factors TDS – Total dissolved solids can be measured through evaporation and measured in mg/L https://www.youtube.com/watch?v=BGlzYEMjcq0  TDS – Total dissolved solids WHAT ARE THEY? “Dissolved solids" refer to any minerals, salts, metals, cations or anions dissolved in water. This includes anything present in water other than the pure water (H₂0) molecule and suspended solids. WHY TEST FOR THEM? High levels of TDS are caused by the presence of potassium, chlorides and sodium. These ions have little or no short-term effects, but toxic ions (lead arsenic, cadmium, nitrate and others) may also be dissolved in the water. The EPA Secondary Regulations advise a maximum contamination level (MCL) of 500mg/liter (500 parts per million (ppm)) for TDS. WHERE DO THEY COME FROM? Organic sources such as leaves, silt, plankton, and industrial waste and sewage. Other sources come from runoff from urban areas, road salts used on street during the winter, and fertilizers and pesticides used on lawns and farms. Inorganic materials such as rocks and air that may contain calcium bicarbonate, nitrogen, iron phosphorous, sulfur, and other minerals.  02 Measuring Water Clarity  Turbidity Turbidity is a measure of the degree to which the water loses its transparency due to the presence of suspended particulates. A turbidity measurement could be used to provide an estimation of the TSS (Total Suspended Solids) Phytoplankton Waste discharge 1 2 Causes of Resuspended sediments Sediments from erosion 3 Turbidity 4 from the bottom Algae growth 5 6 Urban runoff  Ways to Measure Turbidity Turbidity is measured in Nephelometric Turbidity Unit (NTU): The instrument used for measuring it is called nephelometer, colorimeter or turbidimeter, which measures the intensity of light scattered at 90 degrees as a beam of light passes through a water sample. In lakes or bays, turbidity is measured with a secchi disk. https://www.youtube.com/watch?v=J2M4McUmU1s  Ways to Measure Turbidity https://www.youtube.com/watch?v=fOY2qHfBW0w  03 Colorimetry & Spectrophotom etry  The Difference Between Colorimeter and Spectrophotometer Colorimeters are considered to be less sensitive instruments in comparison to spectrophotometers. Spectrophotometers are more expensive than colorimeters. Spectrophotometers are comparatively heavier than colorimeters. Colorimeter works with the only light in the visible part of the electromagnetic spectrum. However, a spectrophotometer works with infrared and ultraviolet light as well as visible light. In colorimeters, data is displayed on a digital or analogue output. While in spectrophotometers, data is produced and recorded via computer software.  Colorimetry & Spectrophotometry Colorimetry The technique used to measure the absorbance of light. Quantifies color by measuring the three primary color components of light https://www.youtube.com/watch?v=yTabfxvMdCM  Colorimetry & Spectrophotometry Spectrophotometry Spectrophotometer is the instruments used to measure the amount of light that passes through the sample. Measures the actual color within the human visible light wavelength. https://www.youtube.com/watch?v=pxC6F7bK8CU  Principle of Light Visible Light is a part of the electromagnetic spectrum with a range of 350 – 720 nanometers (nm)  Chemical Factors: pH pH (potential of hydrogen) is a scale of acidity from 0 to 14. It tells how acidic or alkaline a substance is. More acidic solutions, have lower pH. More alkaline solutions, have higher pH. Substances that aren't acidic or alkaline (that is, neutral solutions) usually have a pH of 7 Measuring pH Using a meter “Calibrate the probe and meter according to the manufacturer’s directions. Use of two buffers (pH 7 and 10) for calibration is recommended.”  Other Factors: Gases dissolved in water Water can hold gases, but the amount Gases can be measured in mg/L as well or ppm (for depends on the temperature of the water. both carbon dioxide and oxygen) Gases can be tested using meters (including the YSI series of meters) Gases could also be measured using test kits which include titration reactions  Gases could mean… Increased CO₂ and decreased O₂ could mean a decrease in phytoplankton or process called “eutrophication” How about the opposite – a plankton bloom? There could be seasonal variations with higher O₂ in the winter and less CO₂ Measuring Nutrients (Kits and Colorimeter) Nitrogen – Nitrates and Total Nitrate-Nitrogen* Phosphorus – Usually Phosphates* Sulfur – Usually in the form of Sulfates Iron – Sometimes considered a trace nutrient (in the oceans) *May include some hazardous reagents We will measure these using the colorimeter with values in mg/L or ppm  Salinity: a measure of dissolved ions Salinity is a measure of the dissolved cations and anions in water bodies. It can be chlorides, sodium, etc… Salinity is measured in parts salt per thousand parts water (PPT) Since salt is comprised of ions, conductivity could be measured to determine salinity (most accurate method)  Hydrometer The Hydrometer is an accurate way to determine salinity if done correctly. It measures the specific gravity of water which is then converted to salinity according to temperature. https://www.youtube.com/watch?v=8dDaWxzVWEY  Refractometer It works well with good light, but should be used in indirect sunlight.  Conductivity: Meter Measuring the conductivity is an accurate way to determine salinity. Conductivity of ions is measured using the following two units. Freshwater = micro https://www.youtube.com/watch?v=V2V0FAAgXIg Siemens (µS) Saltwater = milli Siemens (mS) Professional Plus (Pro Plus) Multiparameter Instrument  THANK YOU Does anyone have any questions? Dr. Muhamad Naimullah [email protected]