Commonly Used Units of Measurement in Water Treatment

1. Units of Length:

Kilometer (km) = 10³ meters

Meter (m) = 10³ millimeters

Millimeter (mm) = 10³ micrometers

Micrometer (μm) = 10³ nanometers

Nanometer (nm) = 10⁻⁹ meters

Nanotechnology is a hot topic in today's high-tech field. Scientists have discovered that at the nanoscale, the composition and properties of matter undergo extraordinary changes compared to their usual state, leading to the emergence of many new materials and processes.

2. Units of weight:

Ton (T) = 10³ kg

Kilogram (Kg) = 10³ g

Glyph (g) = 10³ mg

Million (mg) = 10³ micrograms

Microgram (μg) = 10⁻⁶ g

3. Units of volume:

m³ (m³) = 10³ liters

L (L) = 10³ milliliters

US gallon (G) = 3.78 liters

4. Weight-to-volume ratio (solution concentration):

1 PPm = 1 mg/L 1 PPb = 1 μg/L

5. Units of pressure:

Kilogram-force/cm² (kg/cm²) = 0.1 megapascal (MPa)

6. Conductivity (μs/cm) & Resistance (MΩ·cm)

These values are reciprocals of each other and are units used in methods for determining the purity of water. Water contains cations and anions. Ions are conductive media, and the amount of ions in water can be indicated by measuring its conductivity (resistance).

7. pH Value

pH value represents the negative logarithm of the H+ concentration in water, also known as the hydrogen ion index. pH value indicates the magnitude of the change in acidity or alkalinity of a solution.

Strongly acidic aqueous solution: pH < 5.0

Weakly acidic aqueous solution: pH = 5.0–6.4

Neutral aqueous solution: pH = 6.5–8.0

Weakly alkaline aqueous solution: pH = 8.1–10

Strongly alkaline aqueous solution: pH > 10