With sedimentation detention times of 10-30 days, what level of bacteria and virus removal can be expected?

With sedimentation detention times of 10-30 days, what level of bacteria and virus removal can be expected?

• A. 50-70 percent
• B. 70-80 percent
• C. 80-90 percent
• D. 90-100 percent

Answer: (C)

Sedimentation is a critical process in water treatment where particles, including bacteria and viruses, settle out of the water over time. A detention time of 10-30 days allows for effective removal of microorganisms. During this period, gravity helps separate denser particles, including colloidal and suspended solids that may carry bacteria and viruses. Research indicates that with sufficient sedimentation time, a significant proportion of these pathogens can be effectively removed from the water. The expected removal level of 80-90 percent reflects the efficacy of sedimentation in reducing microbial loads. This range aligns with findings in environmental health literature which suggest that longer detention times contribute to higher removal efficiencies, particularly for pathogenic organisms. Detention times exceeding 10 days significantly increase the likelihood of achieving this level of removal as the water continues to clarify. Given this context, the choice indicating an 80-90 percent removal rate is substantiated by the principles of sedimentation in water treatment, highlighting its effectiveness in pathogen removal processes.

Sedimentation is a critical process in water treatment where particles, including bacteria and viruses, settle out of the water over time. A detention time of 10-30 days allows for effective removal of microorganisms.

During this period, gravity helps separate denser particles, including colloidal and suspended solids that may carry bacteria and viruses. Research indicates that with sufficient sedimentation time, a significant proportion of these pathogens can be effectively removed from the water.

The expected removal level of 80-90 percent reflects the efficacy of sedimentation in reducing microbial loads. This range aligns with findings in environmental health literature which suggest that longer detention times contribute to higher removal efficiencies, particularly for pathogenic organisms. Detention times exceeding 10 days significantly increase the likelihood of achieving this level of removal as the water continues to clarify.

Given this context, the choice indicating an 80-90 percent removal rate is substantiated by the principles of sedimentation in water treatment, highlighting its effectiveness in pathogen removal processes.