Understanding Parts Per Million (PPM) and Its Calculation

In various industries, including water treatment, chemistry, and environmental science, we often need to measure extremely small quantities of a substance within a much larger quantity of another substance. The term Parts Per Million (PPM) is used to express these minuscule concentrations efficiently, making it easier to comprehend measurements instead of using cumbersome decimals or large numbers (e.g., 0.000016 or 1 car in 13,009,920 feet).

What is PPM (Parts Per Million)?

PPM is a unit of measurement that represents one part of a substance per one million parts of another substance. It is commonly used to measure trace amounts of pollutants, chemicals, and minerals in air, water, and other mediums.

One of the most common representations of PPM in liquid solutions is Milligrams per Liter (mg/L) because:

1 mg/L = 1 PPM (since 1 liter of water weighs one million milligrams).

Thus, for water-based solutions:

1 PPM = 1 mg/L
1 mg/kg = 1 PPM (for solid-based calculations)

PPM Derivations and Equivalents

PPM can be defined using molar mass, volume, or weight ratio between the solute (contaminant) and the solution:

Where:

c = mass, volume, or molar concentration of the solute (kg, m³, lbm, ft³, mole)
s = mass, volume, or molar concentration of the solution (kg, m³, lbm, ft³, mole)

Alternative Concentration Units Related to PPM

PPM is not the only unit used for measuring small concentrations. Other similar units include:

Parts Per Billion (PPB): 1 PPB = 1 / 1,000,000,000 (10⁹)
Parts Per Trillion (PPT): 1 PPT = 1 / 1,000,000,000,000 (10¹²)
Parts Per Quadrillion (PPQ): 1 PPQ = 1 / 1,000,000,000,000,000 (10¹⁵)

For higher concentrations, we use weight percent, calculated as:

Where:

mc = mass of the solute (contaminant)
ms = mass of the solution

PPM Equivalents in Percentage

To express PPM in percentage form:

1 PPM = 0.0001%
1000 PPM = 0.1%
10,000 PPM = 1%

Why is PPM Measurement Important?

PPM is a critical unit of measurement in various industries, particularly in water treatment. Understanding and controlling the PPM level of dissolved minerals and gases in water is essential because:

Water is a heat transfer medium, and high contaminant levels can cause scaling and corrosion in equipment.
Each mineral has a solubility limit; exceeding this limit can lead to precipitation (solid formation), affecting water quality.
To prevent corrosion and scaling, precise amounts of treatment chemicals (measured in PPM) are added to water systems.

Thus, monitoring PPM levels ensures effective water treatment and prolongs the life of industrial and commercial water systems.

How is PPM Calculated?

PPM can be determined using:

Mathematical Formula:

Chemical Testing Methods:
- Titration: A laboratory technique where a reagent is added to the sample to determine concentration.
- Colorimetric Analysis: Using color changes to determine the concentration of a particular substance.
- Ion-Selective Electrode (ISE): A sensor-based method that detects the presence of specific ions in a solution.

Conclusion

The use of PPM as a measurement unit is essential in multiple industries, especially water treatment. Understanding how PPM works and how to calculate it helps ensure the effectiveness of water treatment programs and other chemical management processes.

At 3D Aqua, we specialize in providing advanced water and wastewater treatment solutions. As a leading water treatment plant manufacturer in Noida, we are committed to offering high-quality, efficient, and cost-effective solutions. Whether you require a commercial RO plant, industrial RO plant, sewage treatment plant (STP), effluent treatment plant (ETP), or water softener plant, we have the expertise to meet your needs.