Suspended & Dissolved Solids
Colour (Hazen Pt-Co scale)
Specific Gravity (SG)
pH is a quantitative measure of the acidity or basicity of aqueous or other liquid solutions. The term, translates the values of the concentration of the hydrogen ion—which ordinarily ranges between about 1 and 10−14 gram-equivalents per litre—into numbers between 0 and 14. In pure water, which is neutral (neither acidic nor alkaline), the concentration of the hydrogen ion is 10−7 gram-equivalents per litre, which corresponds to a pH of 7. A solution with a pH less than 7 is considered acidic; a solution with a pH greater than 7 is considered basic, or alkaline.
Conductivity (or specific conductance) of an electrolyte solution is a measure of its ability to conduct electricity. The SI unit of conductivity is Siemens per meter (S/m). Conductivity measurements are used routinely in many industrial and environmental applications as a fast, inexpensive and reliable way of measuring the ionic content in a solution. For example, the measurement of product conductivity is a typical way to monitor and continuously trend the performance of water purification systems. Electrolytic conductivity of ultra-high purity water as a function of temperature. In many cases, conductivity is linked directly to the total dissolved solids (T.D.S.). High quality deionized water has a conductivity of about 5.5 µS/m at 25 °C, typical drinking water in the range of 5–50 mS/m, while sea water about 5 S/m (or 5,000,000 µS/m). Conductivity is traditionally determined by connecting the electrolyte in a Wheatstone bridge.
What is the Density of Water? The density of a material is defined as its mass per unit volume. It’s a measurement of how tightly matter is packed together. The density of a substance can be explained as the relationship between the mass of the substance and volume it takes up. The Density of Water can be defined as the weight of the water per its unit volume, which depends on the temperature of the water. Factors Affecting Water Density - There are several factors which can affect the density of a substance. Some factors which affect the density of water is given in the points below. The density of water is around approximately about 1 gram/ cubic centimetre (1 g/cm3). It is temperature-dependent, but this relation is said to be non- linear and also it is unimodal in nature rather than monotonic. When it is cooled from the room temperature, the liquid water tends to become increasingly dense, as with another kind of substances, but approximately at about 4°C, pure water is said to reach its maximum density. As it gets cooled further, it tends to expand and becomes less dense. This kind of unusual negative thermal expansion is related to strong, intermolecular forces, orientation-dependent, or interactions and it is observed in the form of molten silica. Density VS Temperature Water does not have an absolute density as its density varies with temperature. It has a higher density in the liquid state than the solid. Check the Density VS Temperature Graph given below to understand how density changes with temperature.
Hardness in water, or "hard water", refers to specific minerals that consume soap and cause scaling in water heaters and boilers . The more minerals, the harder the water. Soft water refers to the absence of these minerals. The minerals that precipitate with soap are polyvalent cations such as calcium, magnesium, iron, manganese, and zinc. The concentration of calcium and magnesium in natural waters generally far exceeds that of any other polyvalent cation. Therefore, hardness is generally considered to be the concentration of calcium and magnesium in water. Hardness is most commonly measured by titration with an EDTA solution. A titration involves adding small amounts of a solution to a water sample until the sample changes color. You can titrate a sample for total hardness using a buret or hard water test kit. You can also measure calcium hardness separately from magnesium hardness by adjusting the pH and using different indicators.
Salinity is the measure of the number of grams of salts per kilogram of seawater, which is expressed in parts per thousand. Parts per thousand can be defined as how many parts, or grams, of salt there are per thousand parts, or kilogram (1,000 g), of seawater. The symbol for parts per thousand is ‰. The average salinity of seawater is about 35 grams per kilogram (g/kg) of seawater, or 35 ppt. Seawater generally ranges from 33 ppt to 38 ppt. Freshwater lakes, rivers, and streams contain some dissolved matter—1 ppt or less
Specific gravity, is the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for liquids is nearly always measured with respect to water at its densest (at 4 °C or 39.2 °F); for gases, the reference is air at room temperature (20 °C or 68 °F). The term "relative density" is often preferred in scientific usage. If a substance's relative density is less than one then it is less dense than the reference; if greater than 1 then it is denser than the reference. If the relative density is exactly 1 then the densities are equal; that is, equal volumes of the two substances have the same mass. If the reference material is water, then a substance with a relative density (or specific gravity) less than 1 will float in water.
Total dissolved solids (TDS) are a measure of the combined content of all inorganic and organic substances contained in a liquid in molecular, ionized or micro-granular suspended form. Total dissolved solids are normally discussed only for freshwater systems, as salinity includes some of the ions constituting the definition of TDS. Total Suspended Solids (TSS) are solids in water that can be trapped by a filter. TSS can include a wide variety of material, such as silt, decaying plant and animal matter, industrial wastes, and sewage. High concentrations of suspended solids can cause many problems for stream health and aquatic life. In terms of analysis, TSS is that portion of the Total Solids that are retained on a no-ash glass fiber filter disc of approximately 0.45 mm pore size. The wetted and weighed filter disc is placed in a filtering apparatus and a suction is applied. A measured volume of wastewater is passed through the filter. The filter containing the residue is then dried in an oven for one hour at 103 to 105°C. The sample is then cooled and weighed. The difference in weight of the dry filter before and after solids are passed through is the TSS milligrams (mg) of suspended solids per liter (l) of wastewater filtered Suspended Solids Filtering Apparatus This inexpensive TSS test tells much about the wastewater character and can be run in less than two hours with fairly inexpensive equipment. The TSS test indicates whether it is likely that solids suspended in a wastewater can be removed by settling, floating or filtering. In order to remove all solids that were removed in the TSS Test, a filter similar to the TSS Filter paper (0.45 mm) must be used in full scale. TDS are the solids in the filtrate from the TSS test. The liquid which passes through the TSS filter is collected in a weighed dish and evaporated for an hour at 180°C ± 2°C. The dish is then re-weighed with the TDS equaling the difference between the dish weight before and after filling with filtrate and drying, in mg per liter of filtrate.Again, this inexpensive test can be run in less than two hours and will indicate the chemical or biological solids in a wastewater which cannot be removed through settling, floating or filtration.
Suspended & Dissolved Solids
The Platinum-Cobalt Scale (Pt/Co scale or Apha-Hazen Scale ) is a colour scale that was introduced in 1892 by chemist Allen Hazen (1869–1930). The index was developed as a way to evaluate pollution levels in waste water. It has since expanded to a common method of comparison of the intensity of yellow-tinted samples. It is specific to the colour yellow and is based on dilutions of a 500 ppm platinum cobalt solution. The colour produced by one milligram of platinum cobalt dissolved in one litre of water is fixed as one unit of colour in platinum-cobalt scale. The ASTM has detailed description and procedures in ASTM Designation D1209, "Standard Test Method for Colour of Clear Liquids (Platinum-Cobalt Scale).
Colour (Hazen Pt-Co scale)
Turbidity is the measure of relative clarity of a liquid. It is an optical characteristic of water and is a measurement of the amount of light that is scattered by material in the water when a light is shined through the water sample. The higher the intensity of scattered light, the higher the turbidity. Material that causes water to be turbid include clay, silt, very tiny inorganic and organic matter, algae, dissolved coloured organic compounds, and plankton and other microscopic organisms.
The viscosity of a fluid is a measure of its resistance to deformation at a given rate For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water. Viscosity can be conceptualized as quantifying the internal frictional force that arises between adjacent layers of fluid that are in relative motion. For instance, when a fluid is forced through a tube, it flows more quickly near the tube's axis than near its walls. In such a case, experiments show that some stress (such as a pressure difference between the two ends of the tube) is needed to sustain the flow through the tube. This is because a force is required to overcome the friction between the layers of the fluid which are in relative motion: the strength of this force is proportional to the viscosity. A fluid that has no resistance to shear stress is known as an ideal or inviscid fluid. Zero viscosity is observed only at very low temperatures in superfluids. Otherwise, the second law of thermodynamics requires all fluids to have positive viscosity; such fluids are technically said to be viscous or viscid. A fluid with a high viscosity, such as pitch, may appear to be a solid.
Wet chemistry is a form of analytical chemistry that uses classical methods such as observation to analyse materials. It is called wet chemistry since most analysing is done in the liquid phase. Wet chemistry techniques can be used for qualitative chemical measurements, such as changes in color (colourimetry), but often involves more quantitative chemical measurements, using methods such as gravimetry and titrimetery. Some uses for wet chemistry include tests for...