Course: BFM 203 Water Treatment and Control

Lecture

Physical Characteristics

Physcial Characteristics

The physical characteristics of water relate to the sensory qualities of water for domestic use. The following paragraphs outline these physical characteristics.

Turbidity refers to the presence of suspended material in water that causes cloudiness. These materials include clay, silt, finely divided organic material, plankton, and other organic material. Above 5 NTU (Nephelometric Turbidity Units) is usually visible and objectionable to users. This suspended material may harbor bacteria and create high chlorine demand. Finished water is normally between 0.05 and 0.3 NTU.

Color may be affected by dissolved organic material from decaying vegetation and certain inorganic matter. Algal blooms, aquatic microorganisms, iron, manganese, and other materials can cause discoloration. Color may indicate more than an aesthetic problem. Treatment facilities may use sequestering agents if color from iron and manganese are a significant nuisance.

Temperature may affect perception of taste and odor. Desirable drinking water is cool without temperature fluctuation. 50 - 60 F is generally pleasing; greater than 86 F is not acceptable. Deeper aquifers are generally warmer; some ground water reaches the surface at temperatures greater than 100 F. The same wells may have other adverse characteristics such as odor and high salinity. Blending with cooler water of better quality may be necessary.

Taste is related to the dissolved mineral characteristics of local geology. Algal growths can also impart a distinctive taste.

Odor may be caused by algal growths in water supply. These growths create an unpleasant odor. Some groundwater has hydrogen sulfide which produces a rotten egg odor.

Use the following "Quiz Me" activity to self check your understanding of the physical characteristics of water.

Turbidity – the presence of suspended material in water that causes cloudiness

Color – affected by dissolved organic OR inorganic matter.

Temperature – may affect perception of taste and odor

Taste – related to dissolved mineral characteristics, algal growth, or treatment methods.

Odor – caused by algal growth, hydrogen sulfide in the groundwater, or treatment methods.