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Wastewater Solids Inventory Calculator

Estimated solids kilograms = working liquid volume in m³ × representative concentration in mg/L × 0.001.

224 / WASTEWATER SOLIDS INVENTORY

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Starting values are illustrative. Use your own costs, rates and assumptions.

INPUT GROUP 01

Entered quantities and model assumptions

Illustrative defaults are examples. Replace them with matching measurements, reviewed properties and actual quote terms.

Check the assumptions before acting on a result.

Read the method and example

YOUR CALCULATION

Convert a representative solids concentration and working liquid volume to mass.

Estimated solids inventory · kg

3,000

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Saving is optional and stays on this device. Unsaved edits are not kept when you leave. CSV includes every input and the current results.

Illustrative inputs loaded. Replace them with your own assumptions.

How the wastewater solids inventory calculator works

Estimated solids kilograms = working liquid volume in m³ × representative concentration in mg/L × 0.001. The factor combines 1,000 litres per m³ and 1,000,000 mg per kg. Zero volume or concentration gives zero estimated constituent mass.

Use one consistent solids definition and sampling boundary, such as TSS, MLSS or MLVSS as appropriate to the intended inventory. The tool does not establish representative sampling, a process-control target, treatment performance, solids age or discharge compliance. Liquid volume is not itself total solids mass.

Quantities use the stated units and finite bounded inputs. Whole purchases round up under the documented model; cost components round half-up to cents before totals are summed. Undefined ratios stay unavailable. π and logarithms use normal numeric precision. Display rounding does not alter the entered assumptions.

Worked example

1,000 m³ at 3,000 mg/L corresponds to 3,000 kg solids on the stated basis. Changing concentration to 2,000 mg/L gives 2,000 kg.

Sources and assumptions

The source material explains the underlying calculation or pricing structure. Entered prices, costs, schedules and scenario choices are your assumptions; this tool does not obtain supplier quotes or predict actual results.

  • Wastewater Mass Loading

    Estimate a daily constituent mass rate from representative liquid flow and mg/L concentration. Extend the same constant conditions over an entered period.

  • Treatment Concentration & Mass Removal

    Concentration reduction percent = (inlet − outlet concentration) ÷ inlet concentration × 100.

  • Solution Dilution Arithmetic

    On matching compatible mass-per-volume or molar concentration bases, stock concentration × stock volume = target concentration × final solution volume.

  • Sludge Retention Time Scenario

    Nominal solids retention time in days = solids inventory in kilograms ÷ (external wasted solids + external effluent solids in kg/day).

Calculation methods, testing and sources · Practical calculation guides