Adsorption System Design Tool

Comparative Analysis: Hydraulics, Physics & Standards

Design Parameters

Material Density

g/cm³
g/cm³ (Envelope)
g/cm³ (Bed)
g/cm³ (Envelope)

GAC (Reference)

Hydraulic Loading (HLR) --
Contact Time (EBCT) --
Bed Porosity --
Interstitial Velocity --
Wetted Density --
Standard performance. Sinks readily.

Biochar (Test)

Hydraulic Loading (HLR) --
Contact Time (EBCT) --
Bed Porosity --
Interstitial Velocity --
Wetted Density --

Lab Data Analysis

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Methodology, Formulas & Sources

Hydraulic Calculations

1. Empty Bed Contact Time (EBCT)

$$EBCT = \frac{V_{bed}}{Q}$$ The time water spends in the contactor if it were empty.
Standard (ASCE): Typically 10–25 minutes.

2. Hydraulic Loading Rate (HLR)

$$HLR = \frac{Q}{A_{surface}}$$ The velocity of flow approaching the bed.
Standard (ASCE): Typically 5–25 m/h.

3. Interstitial Velocity (\(V_{int}\))

$$V_{int} = \frac{HLR}{\epsilon_{bed}}$$ The actual speed of water through the pores. Biochar's high porosity slows this down, aiding adsorption.

Physics & Standards

Density & Porosity

Bed Porosity (\(\epsilon_{bed}\)): \(1 - (\rho_{bulk} / \rho_{particle})\)

Wetted Density: Estimates buoyancy.
\(\rho_{wet} = \rho_{part} + ((1 - \rho_{part}/1.6) \times 1.0)\)

Design Source (ASCE GAC)

"General design considerations... include Design flow rate... Empty bed contact time (EBCT)... Surface loading rate... and Backwashing requirements."

Source: American Society of Civil Engineers GAC.pdf (Chapter 14, p. 14.10)

Backwashing Hazard

"Difference in particle density between GAC and sand... about 1.4 and 2.65 g/cm³... redesign is necessary."

Source: ASCE GAC.pdf (p. 14.14). Note: Your Biochar is ~0.5 g/cm³, far lighter than standard GAC.