What percentage of bacteria can primary sedimentation remove from soil, water, and wastewater?

Primary sedimentation in the treatment of water and wastewater is an essential process that involves the settling of solids under the influence of gravity. During this process, a significant percentage of bacteria can be removed from the water.

The removal efficiency of bacteria during primary sedimentation can vary depending on factors such as the type of waste being treated, the design of the treatment system, and the duration of the sedimentation process. Studies indicate that primary sedimentation generally achieves a removal efficiency that can range substantially.

The correct understanding is that primary sedimentation can effectively remove bacteria within a broad spectrum, including 30% to 90%. Therefore, the range of 50 to 90 percent mentioned in one choice, along with the specific mention of 80 percent in another, are all valid figures within the observed removal rates. Thus, since multiple answers can be valid, the statement that encompasses all these figures is justified in claiming that all of the options provided could represent potential removal percentages achieved in practice.

This comprehension underscores the varying efficiencies of primary sedimentation based on operational conditions and strengthens the understanding that environmental health professionals must consider multiple variables influencing wastewater treatment efficacy.