Use this engineering calculation for a transparent preliminary estimate or independent arithmetic check when geometry, materials, loads, operating conditions, and units are defined consistently.

Influent Milligrams Per Liter (mg/L)

Required number input.

Effluent Milligrams Per Liter (mg/L)

Required number input.

BOD removal percentage from influent and effluent concentrations sampled on a comparable basis. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Removal Percent (%)

The resulting removal percent returned as a number.

• Activated-sludge ratios and removal estimates depend on sampling basis, biodegradable versus total load, solids inventory, sludge age, temperature, oxygen, settling, recycle streams, and steady-state assumptions. Plant control and discharge compliance require validated process measurements.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check assumptions against drawings, measurements, current material data, and the applicable design code. Apply required load combinations and safety factors, then obtain qualified review and testing for consequential designs.

• Reactor Conversion

  Single-reactant chemical conversion fraction from inlet and outlet molar flow rates on a consistent basis.

• Activated Sludge F/M Ratio

  Activated-sludge food-to-microorganism ratio Q·S0/(V·X) using matching influent substrate and biomass concentration units.

• Compaction Degree

  Dry-density compaction percentage relative to a specified maximum dry density.