Rapid Mix and Flocculator Design
Environmental Engineering · FE Reference Handbook section
Core formulas for this FE topic
Definitions, applicability, units, assumptions and worked examples for each relation.
Worked exam-style examples
The four ways this section is written on the real exam — thoughts first, then equations, then substitution.
rapid mix and flocculator design velocity gradient for coagulation Given power input (P) = 19,090 W; dynamic viscosity (mu) = 0.0011 Pa*s; basin volume (V) = 1,460 m^3, determine the velocity gradient (G) in 1/s.
Given
Find
velocity gradient (G), in 1/s
Start with the thinking
- The governing relation printed in this handbook section is Rapid Mix and Flocculator Design.
- Everything except G is given, so isolate G symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Rapid mix and flocculator design uses the velocity gradient G to set power input for a coagulation-flocculation basin.
Figure 1 — schematic for Rapid Mix and Flocculator Design — solve for velocity gradient — Rapid Mix and Flocculator Design
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for G:
Step 3 — List the givens: power input (P) = 19,090 W, dynamic viscosity (mu) = 0.0011 Pa*s, basin volume (V) = 1,460 m^3.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning G = 109.5 1/s to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 219.1 — kept a factor of two that cancels in the correct rearrangement.
- 54.7625 — dropped that same factor in the other direction.
- 120.5 — rounded an intermediate value before the final step.
Reference: FE Handbook — Rapid Mix and Flocculator Design
rapid mix basin design power input for a water treatment plant Given dynamic viscosity (mu) = 0.0011 Pa*s; basin volume (V) = 895.0 m^3; velocity gradient (G) = 917.0 1/s, determine the power input (P) in W.
Given
Find
power input (P), in W
Start with the thinking
- The governing relation printed in this handbook section is Rapid Mix and Flocculator Design.
- Everything except P is given, so isolate P symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Rapid mix and flocculator design uses the velocity gradient G to set power input for a coagulation-flocculation basin.
Figure 2 — schematic for Rapid Mix and Flocculator Design — solve for power input — Rapid Mix and Flocculator Design (2)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for P:
Step 3 — List the givens: dynamic viscosity (mu) = 0.0011 Pa*s, basin volume (V) = 895.0 m^3, velocity gradient (G) = 917.0 1/s.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning P = 850,433 W to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 1,700,866 — kept a factor of two that cancels in the correct rearrangement.
- 425,217 — dropped that same factor in the other direction.
- 935,476 — rounded an intermediate value before the final step.
Reference: FE Handbook — Rapid Mix and Flocculator Design
flocculator design velocity gradient and power requirement Given power input (P) = 6,150 W; dynamic viscosity (mu) = 0.0017 Pa*s; velocity gradient (G) = 247.0 1/s, determine the basin volume (V) in m^3.
Given
Find
basin volume (V), in m^3
Start with the thinking
- The governing relation printed in this handbook section is Rapid Mix and Flocculator Design.
- Everything except V is given, so isolate V symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Rapid mix and flocculator design uses the velocity gradient G to set power input for a coagulation-flocculation basin.
Figure 3 — schematic for Rapid Mix and Flocculator Design — solve for basin volume — Rapid Mix and Flocculator Design (3)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for V:
Step 3 — List the givens: power input (P) = 6,150 W, dynamic viscosity (mu) = 0.0017 Pa*s, velocity gradient (G) = 247.0 1/s.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
V = 60.3622\ \text{m^3}Step 6 — Check: returning V = 60.3622 m^3 to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 120.7 — kept a factor of two that cancels in the correct rearrangement.
- 30.1811 — dropped that same factor in the other direction.
- 66.3984 — rounded an intermediate value before the final step.
Reference: FE Handbook — Rapid Mix and Flocculator Design
rapid mix and flocculator design velocity gradient for coagulation Given power input (P) = 4,900 W; dynamic viscosity (mu) = 0.0018 Pa*s; basin volume (V) = 1,858 m^3, determine the velocity gradient (G) in 1/s.
Given
Find
velocity gradient (G), in 1/s
Start with the thinking
- The governing relation printed in this handbook section is Rapid Mix and Flocculator Design.
- Everything except G is given, so isolate G symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Rapid mix and flocculator design uses the velocity gradient G to set power input for a coagulation-flocculation basin.
Figure 4 — schematic for Rapid Mix and Flocculator Design — solve for velocity gradient (case 2) — Rapid Mix and Flocculator Design (4)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for G:
Step 3 — List the givens: power input (P) = 4,900 W, dynamic viscosity (mu) = 0.0018 Pa*s, basin volume (V) = 1,858 m^3.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning G = 38.7096 1/s to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 77.4192 — kept a factor of two that cancels in the correct rearrangement.
- 19.3548 — dropped that same factor in the other direction.
- 42.5806 — rounded an intermediate value before the final step.
Reference: FE Handbook — Rapid Mix and Flocculator Design
rapid mix basin design power input for a water treatment plant Given dynamic viscosity (mu) = 0.0017 Pa*s; basin volume (V) = 491.0 m^3; velocity gradient (G) = 53.0000 1/s, determine the power input (P) in W.
Given
Find
power input (P), in W
Start with the thinking
- The governing relation printed in this handbook section is Rapid Mix and Flocculator Design.
- Everything except P is given, so isolate P symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Rapid mix and flocculator design uses the velocity gradient G to set power input for a coagulation-flocculation basin.
Figure 5 — schematic for Rapid Mix and Flocculator Design — solve for power input (case 2) — Rapid Mix and Flocculator Design (5)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for P:
Step 3 — List the givens: dynamic viscosity (mu) = 0.0017 Pa*s, basin volume (V) = 491.0 m^3, velocity gradient (G) = 53.0000 1/s.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning P = 2,331 W to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 4,662 — kept a factor of two that cancels in the correct rearrangement.
- 1,165 — dropped that same factor in the other direction.
- 2,564 — rounded an intermediate value before the final step.
Reference: FE Handbook — Rapid Mix and Flocculator Design
flocculator design velocity gradient and power requirement Given power input (P) = 17,610 W; dynamic viscosity (mu) = 0.0012 Pa*s; velocity gradient (G) = 454.0 1/s, determine the basin volume (V) in m^3.
Given
Find
basin volume (V), in m^3
Start with the thinking
- The governing relation printed in this handbook section is Rapid Mix and Flocculator Design.
- Everything except V is given, so isolate V symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Rapid mix and flocculator design uses the velocity gradient G to set power input for a coagulation-flocculation basin.
Figure 6 — schematic for Rapid Mix and Flocculator Design — solve for basin volume (case 2) — Rapid Mix and Flocculator Design (6)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for V:
Step 3 — List the givens: power input (P) = 17,610 W, dynamic viscosity (mu) = 0.0012 Pa*s, velocity gradient (G) = 454.0 1/s.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
V = 72.4045\ \text{m^3}Step 6 — Check: returning V = 72.4045 m^3 to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 144.8 — kept a factor of two that cancels in the correct rearrangement.
- 36.2023 — dropped that same factor in the other direction.
- 79.6450 — rounded an intermediate value before the final step.
Reference: FE Handbook — Rapid Mix and Flocculator Design
rapid mix and flocculator design velocity gradient for coagulation Given power input (P) = 11,380 W; dynamic viscosity (mu) = 0.0018 Pa*s; basin volume (V) = 1,055 m^3, determine the velocity gradient (G) in 1/s.
Given
Find
velocity gradient (G), in 1/s
Start with the thinking
- The governing relation printed in this handbook section is Rapid Mix and Flocculator Design.
- Everything except G is given, so isolate G symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Rapid mix and flocculator design uses the velocity gradient G to set power input for a coagulation-flocculation basin.
Figure 7 — schematic for Rapid Mix and Flocculator Design — solve for velocity gradient (case 3) — Rapid Mix and Flocculator Design (7)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for G:
Step 3 — List the givens: power input (P) = 11,380 W, dynamic viscosity (mu) = 0.0018 Pa*s, basin volume (V) = 1,055 m^3.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning G = 77.6280 1/s to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 155.3 — kept a factor of two that cancels in the correct rearrangement.
- 38.8140 — dropped that same factor in the other direction.
- 85.3908 — rounded an intermediate value before the final step.
Reference: FE Handbook — Rapid Mix and Flocculator Design
rapid mix basin design power input for a water treatment plant Given dynamic viscosity (mu) = 0.0012 Pa*s; basin volume (V) = 269.0 m^3; velocity gradient (G) = 863.0 1/s, determine the power input (P) in W.
Given
Find
power input (P), in W
Start with the thinking
- The governing relation printed in this handbook section is Rapid Mix and Flocculator Design.
- Everything except P is given, so isolate P symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Rapid mix and flocculator design uses the velocity gradient G to set power input for a coagulation-flocculation basin.
Figure 8 — schematic for Rapid Mix and Flocculator Design — solve for power input (case 3) — Rapid Mix and Flocculator Design (8)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for P:
Step 3 — List the givens: dynamic viscosity (mu) = 0.0012 Pa*s, basin volume (V) = 269.0 m^3, velocity gradient (G) = 863.0 1/s.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning P = 234,401 W to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 468,802 — kept a factor of two that cancels in the correct rearrangement.
- 117,201 — dropped that same factor in the other direction.
- 257,841 — rounded an intermediate value before the final step.
Reference: FE Handbook — Rapid Mix and Flocculator Design
flocculator design velocity gradient and power requirement Given power input (P) = 16,330 W; dynamic viscosity (mu) = 0.0009 Pa*s; velocity gradient (G) = 488.0 1/s, determine the basin volume (V) in m^3.
Given
Find
basin volume (V), in m^3
Start with the thinking
- The governing relation printed in this handbook section is Rapid Mix and Flocculator Design.
- Everything except V is given, so isolate V symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Rapid mix and flocculator design uses the velocity gradient G to set power input for a coagulation-flocculation basin.
Figure 9 — schematic for Rapid Mix and Flocculator Design — solve for basin volume (case 3) — Rapid Mix and Flocculator Design (9)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for V:
Step 3 — List the givens: power input (P) = 16,330 W, dynamic viscosity (mu) = 0.0009 Pa*s, velocity gradient (G) = 488.0 1/s.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
V = 73.7333\ \text{m^3}Step 6 — Check: returning V = 73.7333 m^3 to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 147.5 — kept a factor of two that cancels in the correct rearrangement.
- 36.8666 — dropped that same factor in the other direction.
- 81.1066 — rounded an intermediate value before the final step.
Reference: FE Handbook — Rapid Mix and Flocculator Design
rapid mix and flocculator design velocity gradient for coagulation Given power input (P) = 3,890 W; dynamic viscosity (mu) = 0.0017 Pa*s; basin volume (V) = 767.0 m^3, determine the velocity gradient (G) in 1/s.
Given
Find
velocity gradient (G), in 1/s
Start with the thinking
- The governing relation printed in this handbook section is Rapid Mix and Flocculator Design.
- Everything except G is given, so isolate G symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Rapid mix and flocculator design uses the velocity gradient G to set power input for a coagulation-flocculation basin.
Figure 10 — schematic for Rapid Mix and Flocculator Design — solve for velocity gradient (case 4) — Rapid Mix and Flocculator Design (10)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for G:
Step 3 — List the givens: power input (P) = 3,890 W, dynamic viscosity (mu) = 0.0017 Pa*s, basin volume (V) = 767.0 m^3.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning G = 54.6201 1/s to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 109.2 — kept a factor of two that cancels in the correct rearrangement.
- 27.3101 — dropped that same factor in the other direction.
- 60.0821 — rounded an intermediate value before the final step.
Reference: FE Handbook — Rapid Mix and Flocculator Design