Calculate how quickly a chemical process generates waste — in grams per hour, per minute, or per second. Optionally normalise by reactor volume for a volumetric WGR. Results update live as you type — and every session stays in your browser, never on a server.
The Waste Generation Rate (WGR) measures how quickly a chemical process produces waste — expressed as mass of waste per unit time. Where the E-factor tells you how much waste is produced per gram of product, WGR tells you how fast that waste is being generated. This time dimension makes WGR particularly valuable for batch process optimisation, continuous manufacturing design, and comparing the environmental burden of processes operating at different timescales.
| Symbol | Term | Units |
|---|---|---|
| $\text{WGR}$ | Waste Generation Rate | g/h, g/min, kg/h (user-selected) |
| $m_{\text{waste}}$ | Total mass of all process waste (inputs minus product and recovered materials) | g, kg, or mg |
| $t$ | Total process time (from first reagent addition to product isolation) | h, min, or s |
| Symbol | Term | Units |
|---|---|---|
| $\text{WGR}_V$ | Volumetric Waste Generation Rate — normalises WGR by reactor volume; useful for comparing processes run at different scales | g/h/L, g/min/L |
| $V$ | Reactor (vessel) volume | L |
Volumetric WGR is optional. Enter a reactor volume in Section 04 to activate it. A lower volumetric WGR means the reactor is generating less waste per litre of capacity per unit time — a useful proxy for process intensification.
| Sector | Typical WGR | Key driver |
|---|---|---|
| Bulk / commodity chemicals | < 5 g/h | Continuous, highly optimised, minimal solvent per cycle |
| Fine chemicals | 5–50 g/h | Batch processing, moderate solvent and workup waste |
| Pharmaceuticals (API, batch) | 50–200 g/h | Long reaction times, large solvent volumes, extensive workup |
| Pharmaceuticals (complex, multi-step) | > 200 g/h | Many sequential steps, protecting group chemistry, chiral resolution |
These benchmarks are based on lab-scale (1–10 L) processes. Pilot and production scale will show markedly different WGR values; always compare WGR within the same scale or use volumetric WGR for cross-scale comparisons.
| Metric | Answers the question… | Best for… |
|---|---|---|
| E-factor | How much waste per gram of product? | Comparing reaction efficiency; process selection |
| WGR | How fast is waste being generated? | Equipment sizing; comparing batch vs continuous; real-time monitoring design |
| PMI | What fraction of all inputs ends up as product? | Overall mass efficiency; supply chain analysis |
| Volumetric WGR | How much waste per litre of reactor per hour? | Scale-up decisions; process intensification benchmarking |
Enter all materials that become waste in the process: unreacted reagents, solvents, catalysts, workup and purification materials, and by-products. If a solvent or catalyst is recovered and recycled, enter the recovered mass — it is subtracted from the waste total. Do not enter the desired product here.
| Material name | Category | Mass used (g) | Recovered (g) | Net waste (g) |
|---|
Enter the total process time (from first reagent addition to product isolation). Optionally enter reactor volume to calculate a volumetric WGR — useful for comparing processes run at different scales. Use the mass unit selector to change the unit used across all waste stream masses and the WGR output.
| Material | Category | Mass used | Recovered | Net waste | % of waste | Visual |
|---|---|---|---|---|---|---|
| Enter waste streams and process time above to see breakdown. | ||||||
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Export your WGR calculation as a PDF report or CSV data file. PDF opens in a new tab and uses your browser's print function. CSV downloads directly.
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