Tank Volume
Environmental Engineering · FE Reference Handbook section
Handbook notes for this section
Definitions and conditions exactly as the handbook states them.
- FSi can be neglected if primary sludge is not included on the sludge flow to the digester.
- VOLATILE SOLIDS REDUCTION IN AN AEROBIC DIGESTER AS A FUNCTION
- OF DIGESTER LIQUID TEMPERATURE AND DIGESTER SLUDGE AGE
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.
tank volume required for a target detention time in a storage tank Given flow rate (Q) = 17,300 m^3/day; hydraulic detention time (theta) = 15.2500 day, determine the tank volume (V) in m^3.
Given
Find
tank volume (V), in m^3
Start with the thinking
- The governing relation printed in this handbook section is Tank Volume.
- 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.
- Tank volume for a treatment basin is the product of flow rate and required hydraulic detention time.
Figure 1 — schematic for Tank Volume — solve for tank volume — Tank Volume
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for V:
Step 3 — List the givens: flow rate (Q) = 17,300 m^3/day, hydraulic detention time (theta) = 15.2500 day.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
V = 263825\ \text{m^3}Step 6 — Check: returning V = 263,825 m^3 to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 527,650 — kept a factor of two that cancels in the correct rearrangement.
- 131,913 — dropped that same factor in the other direction.
- 290,208 — rounded an intermediate value before the final step.
Reference: FE Handbook — Tank Volume
tank volume sizing for an equalization basin Given hydraulic detention time (theta) = 3.8000 day; tank volume (V) = 184,669 m^3, determine the flow rate (Q) in m^3/day.
Given
Find
flow rate (Q), in m^3/day
Start with the thinking
- The governing relation printed in this handbook section is Tank Volume.
- Everything except Q is given, so isolate Q 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.
- Tank volume for a treatment basin is the product of flow rate and required hydraulic detention time.
Figure 2 — schematic for Tank Volume — solve for flow rate — Tank Volume (2)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for Q:
Step 3 — List the givens: hydraulic detention time (theta) = 3.8000 day, tank volume (V) = 184,669 m^3.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Q = 48597\ \text{m^3/day}Step 6 — Check: returning Q = 48,597 m^3/day to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 97,194 — kept a factor of two that cancels in the correct rearrangement.
- 24,299 — dropped that same factor in the other direction.
- 53,457 — rounded an intermediate value before the final step.
Reference: FE Handbook — Tank Volume
detention tank volume calculated from plant flow rate Given flow rate (Q) = 17,990 m^3/day; tank volume (V) = 245,191 m^3, determine the hydraulic detention time (theta) in day.
Given
Find
hydraulic detention time (theta), in day
Start with the thinking
- The governing relation printed in this handbook section is Tank Volume.
- Everything except theta is given, so isolate theta 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.
- Tank volume for a treatment basin is the product of flow rate and required hydraulic detention time.
Figure 3 — schematic for Tank Volume — solve for hydraulic detention time — Tank Volume (3)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for theta:
Step 3
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning theta = 13.6293 day to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 27.2586 — kept a factor of two that cancels in the correct rearrangement.
- 6.8146 — dropped that same factor in the other direction.
- 14.9922 — rounded an intermediate value before the final step.
Reference: FE Handbook — Tank Volume
tank volume required for a target detention time in a storage tank Given flow rate (Q) = 12,900 m^3/day; hydraulic detention time (theta) = 0.5500 day, determine the tank volume (V) in m^3.
Given
Find
tank volume (V), in m^3
Start with the thinking
- The governing relation printed in this handbook section is Tank Volume.
- 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.
- Tank volume for a treatment basin is the product of flow rate and required hydraulic detention time.
Figure 4 — schematic for Tank Volume — solve for tank volume (case 2) — Tank Volume (4)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for V:
Step 3 — List the givens: flow rate (Q) = 12,900 m^3/day, hydraulic detention time (theta) = 0.5500 day.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
V = 7095\ \text{m^3}Step 6 — Check: returning V = 7,095 m^3 to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 14,190 — kept a factor of two that cancels in the correct rearrangement.
- 3,548 — dropped that same factor in the other direction.
- 7,805 — rounded an intermediate value before the final step.
Reference: FE Handbook — Tank Volume
tank volume sizing for an equalization basin Given hydraulic detention time (theta) = 3.2500 day; tank volume (V) = 40,693 m^3, determine the flow rate (Q) in m^3/day.
Given
Find
flow rate (Q), in m^3/day
Start with the thinking
- The governing relation printed in this handbook section is Tank Volume.
- Everything except Q is given, so isolate Q 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.
- Tank volume for a treatment basin is the product of flow rate and required hydraulic detention time.
Figure 5 — schematic for Tank Volume — solve for flow rate (case 2) — Tank Volume (5)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for Q:
Step 3 — List the givens: hydraulic detention time (theta) = 3.2500 day, tank volume (V) = 40,693 m^3.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Q = 12521\ \text{m^3/day}Step 6 — Check: returning Q = 12,521 m^3/day to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 25,042 — kept a factor of two that cancels in the correct rearrangement.
- 6,260 — dropped that same factor in the other direction.
- 13,773 — rounded an intermediate value before the final step.
Reference: FE Handbook — Tank Volume
detention tank volume calculated from plant flow rate Given flow rate (Q) = 14,580 m^3/day; tank volume (V) = 192,478 m^3, determine the hydraulic detention time (theta) in day.
Given
Find
hydraulic detention time (theta), in day
Start with the thinking
- The governing relation printed in this handbook section is Tank Volume.
- Everything except theta is given, so isolate theta 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.
- Tank volume for a treatment basin is the product of flow rate and required hydraulic detention time.
Figure 6 — schematic for Tank Volume — solve for hydraulic detention time (case 2) — Tank Volume (6)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for theta:
Step 3
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning theta = 13.2015 day to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 26.4030 — kept a factor of two that cancels in the correct rearrangement.
- 6.6008 — dropped that same factor in the other direction.
- 14.5217 — rounded an intermediate value before the final step.
Reference: FE Handbook — Tank Volume
tank volume required for a target detention time in a storage tank Given flow rate (Q) = 13,270 m^3/day; hydraulic detention time (theta) = 3.4000 day, determine the tank volume (V) in m^3.
Given
Find
tank volume (V), in m^3
Start with the thinking
- The governing relation printed in this handbook section is Tank Volume.
- 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.
- Tank volume for a treatment basin is the product of flow rate and required hydraulic detention time.
Figure 7 — schematic for Tank Volume — solve for tank volume (case 3) — Tank Volume (7)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for V:
Step 3 — List the givens: flow rate (Q) = 13,270 m^3/day, hydraulic detention time (theta) = 3.4000 day.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
V = 45118\ \text{m^3}Step 6 — Check: returning V = 45,118 m^3 to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 90,236 — kept a factor of two that cancels in the correct rearrangement.
- 22,559 — dropped that same factor in the other direction.
- 49,630 — rounded an intermediate value before the final step.
Reference: FE Handbook — Tank Volume
tank volume sizing for an equalization basin Given hydraulic detention time (theta) = 0.7000 day; tank volume (V) = 185,687 m^3, determine the flow rate (Q) in m^3/day.
Given
Find
flow rate (Q), in m^3/day
Start with the thinking
- The governing relation printed in this handbook section is Tank Volume.
- Everything except Q is given, so isolate Q 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.
- Tank volume for a treatment basin is the product of flow rate and required hydraulic detention time.
Figure 8 — schematic for Tank Volume — solve for flow rate (case 3) — Tank Volume (8)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for Q:
Step 3 — List the givens: hydraulic detention time (theta) = 0.7000 day, tank volume (V) = 185,687 m^3.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Q = 265267\ \text{m^3/day}Step 6 — Check: returning Q = 265,267 m^3/day to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 530,534 — kept a factor of two that cancels in the correct rearrangement.
- 132,634 — dropped that same factor in the other direction.
- 291,794 — rounded an intermediate value before the final step.
Reference: FE Handbook — Tank Volume
detention tank volume calculated from plant flow rate Given flow rate (Q) = 9,670 m^3/day; tank volume (V) = 354,469 m^3, determine the hydraulic detention time (theta) in day.
Given
Find
hydraulic detention time (theta), in day
Start with the thinking
- The governing relation printed in this handbook section is Tank Volume.
- Everything except theta is given, so isolate theta 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.
- Tank volume for a treatment basin is the product of flow rate and required hydraulic detention time.
Figure 9 — schematic for Tank Volume — solve for hydraulic detention time (case 3) — Tank Volume (9)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for theta:
Step 3
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning theta = 36.6566 day to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 73.3131 — kept a factor of two that cancels in the correct rearrangement.
- 18.3283 — dropped that same factor in the other direction.
- 40.3222 — rounded an intermediate value before the final step.
Reference: FE Handbook — Tank Volume
tank volume required for a target detention time in a storage tank Given flow rate (Q) = 19,130 m^3/day; hydraulic detention time (theta) = 14.2500 day, determine the tank volume (V) in m^3.
Given
Find
tank volume (V), in m^3
Start with the thinking
- The governing relation printed in this handbook section is Tank Volume.
- 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.
- Tank volume for a treatment basin is the product of flow rate and required hydraulic detention time.
Figure 10 — schematic for Tank Volume — solve for tank volume (case 4) — Tank Volume (10)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for V:
Step 3 — List the givens: flow rate (Q) = 19,130 m^3/day, hydraulic detention time (theta) = 14.2500 day.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
V = 272603\ \text{m^3}Step 6 — Check: returning V = 272,603 m^3 to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 545,205 — kept a factor of two that cancels in the correct rearrangement.
- 136,301 — dropped that same factor in the other direction.
- 299,863 — rounded an intermediate value before the final step.
Reference: FE Handbook — Tank Volume