There are many ways to work with water to gain information about a selected sample, with a lot of options for equipment. Laboratory balances can be a great option to measure different properties with many different methods possible. To view our range of balances suitable for waste water analysis, click here.
Analytical balances for waste water analysis
Balances provide quantitative measurements, so they can help with measurements such as volume, mass and density. Analytical balances are commonly used with wastewater testing and should have a minimum readability of 0.1mg. These balances are used in a few different procedures which include:
- Gravimetric – through knowing the mass of a pure compound containing the ion, an impure sample is then compared against it. The mass is measured, then the sample (also known as analyte) is dissolved and mixed with a precipitating agent. It then goes through various filtering and heating until the final product is acquired. The pure compound mass is then measured against the impure sample product to determine the content percentage found in the sample.
- Colorimetric – the balance is used to measure out the solutions and reagents needed for this method. Colorimetric analysis involves adding reagents that give specific colours for certain properties.
- Titration – a reagent is gradually added to the sample until the analyte has been quantitatively consumed. With titration methods, the analytical balance is used to weigh out the solutions and reagents being used in the method.
Wastewater analysis will also include measuring the concentration of samples. This is measured using the formula:
There are two ways to express concentration:
- Normailty – this is where the gram equivalent weight is measured per litre of the solution. It is dependent on an equivalence factor. Because of this, it is not always the preferred expression.
- Molarity – This is the number of moles of your dissolved material in 1 litre of solution. One mol is classified as 6.02214076 x 1023 particles of a substance (also known as Avogadro’s constant). To work out molarity, you divide the number of moles by the volume of the solution (typically 1L).
Moisture balances for waste water analysis
Another option that can be used in the analysis of wastewater is a moisture balance. They measure the moisture content through weighing the water content of your sample. These balances work by weighing the starting sample, heating the sample to remove any moisture, then weighing the final product. Any weight difference between the starting sample and the final product is the water weight. For a more in depth understanding of how a moisture balance works, click here.
Moisture balances can assist in the steps required for samples that need drying before being weighed and worked with. It is much easier to control the temperature needed and can help the final product to be cooled down much quicker if the samples needs transferring to an analytical balance. Cooling is an important step as analytical balances are very sensitive and the results may be effected if the sample is not room temperature.