Effluent Colour ADMI Removal, Compliance Margin & Chemical Cost

The formula

This is the expression the tool evaluates. Every term is named underneath, with the unit it must be supplied in.

How the result is derived

Step by step, from the values you type to the figure on screen.

1. The 9 inputs are read from the form on every keystroke: Effluent Flow, Inlet Colour, Outlet Colour, Discharge Limit, ADMI to Pt-Co Factor, Coagulant Dose, Coagulant Price, Decolourising Agent Dose and Decolourising Agent Price.
2. Each value is checked against the accepted range in the input table below. A value outside its range stops the calculation rather than producing a misleading figure — the results blank out and a message appears.
3. The validated values are substituted into the expression above, which resolves Colour Removal together with every supporting figure in one pass — no value is carried over from a previous entry.
4. The supporting outputs — Margin to the Discharge Limit, Removal the Limit Demands, Chemical Cost, ADMI Removed per mg/L Dosed, Coagulant, Decolourising Agent, Chemical Cost and Outlet Colour in Pt-Co — come from the same pass, so they always describe the same case as the headline figure.
5. Results are rounded for display only. The full-precision value is used throughout the chain, so reading a rounded intermediate figure back into the tool by hand can shift the last digit.

What each input means

Where to read each value on the floor, the unit it must be in, and the range the tool accepts.

What the tool returns

The headline figure and every supporting value it is built from.

Worked example

Substituting

The decolourising agent is 12% of the dose by mass and 48% of the cost, which is where any optimisation should start. And note the two removal figures: 86% achieved against 78% required is real margin, so there is room to trim the expensive half of the dose - the specific removal figure is what tells you when trimming has gone too far.

How to use it

1. Work through the input groups in order — Colour Readings and Chemical Dosing. The defaults are a realistic case, so you can change one value at a time and watch what moves.
2. There is no calculate button. Every figure recalculates as you type or drag, which is what makes this usable for a what-if sweep rather than a single answer.
3. Read Colour Removal in the dark results panel — that is the headline figure, expressed in %.
4. Check the supporting rows underneath (Margin to the Discharge Limit, Removal the Limit Demands, Chemical Cost, ADMI Removed per mg/L Dosed, Coagulant, Decolourising Agent, Chemical Cost and Outlet Colour in Pt-Co) before acting on the headline — they are where an implausible input usually shows itself first.
5. Reset to defaults returns every field to the reference case, which is the quickest way to check whether a surprising result came from the tool or from an input you had changed earlier.

Where this is used

• Process planning — establishing Colour Removal before a trial is booked, so machine time and material in Sustainability, ETP & Utilities are committed against a calculated figure rather than an estimate.
• Costing and quotation — Colour Removal is an input to the cost sheet, and quoting from a worked number rather than a remembered one is what keeps a margin intact.
• Troubleshooting — when the floor result drifts from plan, entering the measured values (starting with Effluent Flow) shows how much of the gap in Colour Removal each variable explains.
• Teaching and study — the accepted ranges bracket normal Sustainability, ETP & Utilities practice, so moving one variable at a time shows the shape of the relationship rather than a single answer.

Reading the result

Typical bands and what each one is telling you.

Assumptions and limits

• ADMI is reported on a 1 cm path length at a stated pH; colour is pH-sensitive for many dye classes, so a reading taken before neutralisation is not comparable with one after it. The specific removal figure is a simple ratio and will fall as dose rises because colour removal saturates - it is a tracking metric, not a linear coefficient to extrapolate. Coagulant dose also generates sludge, which is a separate cost and is not included here. The ADMI to Pt-Co factor is site and shade specific and the two scales are not interchangeable; where a permit names one, measure that one rather than converting.
• Every input is bounded to the range normal practice occupies (Effluent Flow 10 to 50000 m3/d, Inlet Colour 50 to 20000 ADMI and Outlet Colour 1 to 20000 ADMI, and so on for the rest). Those bounds are guard rails against typing errors, not a claim that the formula fails one unit outside them.
• The calculation is deterministic: the same inputs always give the same result. It carries no allowance for machine condition, operator skill, ambient conditions or lot-to-lot material variation unless an input above explicitly represents one.
• Nothing is sent anywhere. The maths runs in your browser, so the numbers you type never leave the page.

Standards and further reading

• ADMI 3-wavelength method, Standard Methods for the Examination of Water and Wastewater 2120 F.
• APHA platinum-cobalt visual method, Standard Methods 2120 B, for the Pt-Co scale.
• ISO 7887 - Water quality, examination and determination of colour.
• ZDHC Wastewater Guidelines, which set colour among the conventional parameters.

Questions people ask