Solutions Details

Home solutions

Concentrated Yellow Dye Liquor Taken to a Colourless Supernatant in Two Steps

2026-08-26

LAB JAR TEST RECORD · CONCENTRATED DYE LIQUOR

Concentrated Yellow Dye Liquor Taken to a Colourless Supernatant in Two Steps

An alkaline yellow dye liquor at pH above 8. Only two reagents were needed — 25 kg/t of compound decolorant followed by 15 g/t anionic PAM. After 2–3 minutes the supernatant was transparent and colourless, the cleanest result in this series.

Industry

Dye production effluent

Raw Water

pH above 8

Programme

Compound decolorant + APAM

Result

Transparent, colourless

Raw yellow dye liquor (left) beside two treated beakers. The colour has transferred into the settled floc bed, leaving the water phase clear.

01 — The Challenge

What makes this effluent difficult

This sample is a different problem from a dilute rinse water. It is a concentrated liquor, and that changes what the treatment has to achieve:

Concentration drives reagent demand

Reagent consumption tracks the mass of colour present, not the volume of water. A concentrated liquor consumes reagent in proportion — here, kilograms per tonne.

Alkaline start

At pH above 8 the charge behaviour of both the colour bodies and the reagents shifts. A programme tuned at neutral pH will not transfer unchanged.

Yellow shows every imperfection

Pale shades are unforgiving. Residual haze or fine carry-over that would pass unnoticed in a dark effluent is plainly visible here.

Two-reagent programmes leave no margin

With only two dosing points, each has to be right. There is no third reagent to compensate for an error in the first.

The objective was set higher than usual for this sample: not merely lighter, but colourless.

02 — The Programme

The dosing programme, step by step

Two moves. A compound decolorant does the chemical work; a small polymer dose makes the result separable.

Step	Action	Dosage / Setpoint	Why It Matters
1	Dose compound decolorant	25 kg/t	Breaks the colour through several mechanisms at once. A compound formulation is used here rather than a single-mechanism decolorant because the liquor is concentrated and alkaline.
2	Dose anionic PAM	15 g/t	Agglomerates the fine particles into large, dense flocs and strengthens solid–liquid separation.

Why a compound decolorant? A single-mechanism product relies on charge neutralisation alone. A compound formulation combines several mechanisms, which is what allows a concentrated, alkaline liquor to be taken all the way to colourless rather than merely lighter.

Why 15 g/t of polymer here? Five times the polymer used on the black effluent in our companion case — because this programme generates a far larger volume of floc. The polymer dose has to match the solids produced, not the colour removed.

03 — Observations

What happened at each stage

Raw sample

Concentrated yellow-amber liquor, alkaline at pH above 8.

After compound decolorant

The colour breaks and transfers out of solution as the chromophores are destabilised.

After anionic PAM

Fine particles agglomerate into large, dense flocs.

After 2–3 min settling

A thick pale floc bed collects at the base of the beaker and the supernatant above it is transparent and colourless.

Reproducibility note: this is a bench-scale jar test on one sample. Every effluent differs. Confirm the dosage on your own water before scaling up.

04 — The Result

Transparent and colourless — the cleanest result in the series

Two dosing steps and 2–3 minutes of settling produced a transparent, colourless supernatant with the colour fully transferred into a dense floc bed. Total chemical input: 25 kg/t compound decolorant plus 15 g/t anionic PAM. Of the eight samples in this laboratory series, this was the only one to reach a genuinely colourless finish.

Colourless, not merely lighter

The outcome most dye effluents fail to reach. No residual tint in the water phase.

Only two dosing points

The simplest programme in this series. Fewer control points, less that can go wrong.

No pH adjustment required

The programme worked on the raw alkaline liquor as received — no acid or caustic step.

Dense, well-defined floc bed

Sharp separation between the settled solids and the water phase, which helps downstream dewatering.

05 — Scale-Up

From jar test to full-scale dosing

1 kg/t = 1,000 ppm · 1 g/t = 1 ppm · 1 tonne of wastewater = 1 m³

Treated Flow	Compound Decolorant @ 25 kg/t	Anionic PAM @ 15 g/t
10 m³ / day	250 kg / day	150 g / day
50 m³ / day	1250 kg / day	750 g / day
100 m³ / day	2500 kg / day	1.5 kg / day
500 m³ / day	12500 kg / day	7.5 kg / day

Prepare PAM as a dilute solution Anionic PAM powder is normally made up to a 0.1–0.2 % working solution and allowed to dissolve fully before dosing. Dosing dry powder gives poor results and blocks lines.

Treat these as a starting point These quantities are arithmetic conversions of one jar test. Use them to size a trial and plan storage, not as a guaranteed design dosage.

06 — Applications

Where this programme applies

The same logic transfers to other strongly coloured industrial effluents. The chemistry is the same; the dosage and the decolorant grade change with the water.

Dye & pigment manufacturing

Textile dyeing & printing

Fine-chemical intermediates

Concentrated dye mother liquor

Ink & pigment dispersions

Paper dyeing

07 — FAQ

Questions we are asked most

Is 25 kg/t not an extremely high dosage?

It is high, and it reflects a concentrated liquor rather than a dilute rinse stream. Where feasible, segregating and treating a concentrated liquor separately is more economical than diluting it into the main flow and then treating a much larger volume.

Could a cheaper decolorant reach the same result?

It may lighten the liquor, but reaching genuinely colourless is what the compound formulation is for. If your target is a colour limit rather than a visual standard, a jar test on your own water will settle which grade is justified.

Why is no pH correction needed when other programmes require one?

The compound decolorant used here tolerates the alkaline condition of this liquor. That is specific to this water — do not assume it transfers to a different effluent without testing.

What happens if I underdose?

You get a lighter liquor rather than a colourless one, and the residual colour will not clear no matter how much polymer follows. The decolorant sets the ceiling on what is achievable; the polymer only makes it separable.

How much sludge does this produce?

The floc bed is visibly substantial — expect meaningful sludge volume at this dosage. Sludge yield was not quantified in this test; factor dewatering into your budget.

Can you test my yellow effluent?

Yes. Send a sample and your target discharge standard and we will run the same procedure and report the dosage.

Free Laboratory Service

Send us your wastewater — we will run the jar test

Tell us your industry, daily flow and target discharge standard. Our laboratory will run a bench-scale trial on your own sample and report the exact chemical and dosage.

Request a free jar test

Products referenced in this case

Product	Role in This Case	Dosage
Compound Water Decoloring Agent	Multi-mechanism colour breaking	25 kg/t
Anionic Polyacrylamide (APAM)	Floc agglomeration and settling	15 g/t

The results described in this document were obtained from a bench-scale jar test on a single customer sample under laboratory conditions. Actual performance depends on the characteristics of each effluent. We recommend a jar test on your own wastewater before finalising a dosing programme.

Solutions Details

Home solutions

Concentrated Yellow Dye Liquor Taken to a Colourless Supernatant in Two Steps

LAB JAR TEST RECORD · CONCENTRATED DYE LIQUOR

Concentrated Yellow Dye Liquor Taken to a Colourless Supernatant in Two Steps

Industry

Dye production effluent

Raw Water

pH above 8

Programme

Compound decolorant + APAM

Result

Transparent, colourless

Raw yellow dye liquor (left) beside two treated beakers. The colour has transferred into the settled floc bed, leaving the water phase clear.

01 — The Challenge

What makes this effluent difficult

This sample is a different problem from a dilute rinse water. It is a concentrated liquor, and that changes what the treatment has to achieve:

Concentration drives reagent demand

Reagent consumption tracks the mass of colour present, not the volume of water. A concentrated liquor consumes reagent in proportion — here, kilograms per tonne.

Alkaline start

At pH above 8 the charge behaviour of both the colour bodies and the reagents shifts. A programme tuned at neutral pH will not transfer unchanged.

Yellow shows every imperfection

Pale shades are unforgiving. Residual haze or fine carry-over that would pass unnoticed in a dark effluent is plainly visible here.

Two-reagent programmes leave no margin

With only two dosing points, each has to be right. There is no third reagent to compensate for an error in the first.

The objective was set higher than usual for this sample: not merely lighter, but colourless.

02 — The Programme

The dosing programme, step by step

Two moves. A compound decolorant does the chemical work; a small polymer dose makes the result separable.

Step	Action	Dosage / Setpoint	Why It Matters
1	Dose compound decolorant	25 kg/t	Breaks the colour through several mechanisms at once. A compound formulation is used here rather than a single-mechanism decolorant because the liquor is concentrated and alkaline.
2	Dose anionic PAM	15 g/t	Agglomerates the fine particles into large, dense flocs and strengthens solid–liquid separation.

03 — Observations

What happened at each stage

Raw sample

Concentrated yellow-amber liquor, alkaline at pH above 8.

After compound decolorant

The colour breaks and transfers out of solution as the chromophores are destabilised.

After anionic PAM

Fine particles agglomerate into large, dense flocs.

After 2–3 min settling

A thick pale floc bed collects at the base of the beaker and the supernatant above it is transparent and colourless.

Reproducibility note: this is a bench-scale jar test on one sample. Every effluent differs. Confirm the dosage on your own water before scaling up.

04 — The Result

Transparent and colourless — the cleanest result in the series

Colourless, not merely lighter

The outcome most dye effluents fail to reach. No residual tint in the water phase.

Only two dosing points

The simplest programme in this series. Fewer control points, less that can go wrong.

No pH adjustment required

The programme worked on the raw alkaline liquor as received — no acid or caustic step.

Dense, well-defined floc bed

Sharp separation between the settled solids and the water phase, which helps downstream dewatering.

05 — Scale-Up

From jar test to full-scale dosing

1 kg/t = 1,000 ppm · 1 g/t = 1 ppm · 1 tonne of wastewater = 1 m³

Treated Flow	Compound Decolorant @ 25 kg/t	Anionic PAM @ 15 g/t
10 m³ / day	250 kg / day	150 g / day
50 m³ / day	1250 kg / day	750 g / day
100 m³ / day	2500 kg / day	1.5 kg / day
500 m³ / day	12500 kg / day	7.5 kg / day

Treat these as a starting point These quantities are arithmetic conversions of one jar test. Use them to size a trial and plan storage, not as a guaranteed design dosage.

06 — Applications

Where this programme applies

The same logic transfers to other strongly coloured industrial effluents. The chemistry is the same; the dosage and the decolorant grade change with the water.

Dye & pigment manufacturing

Textile dyeing & printing

Fine-chemical intermediates

Concentrated dye mother liquor

Ink & pigment dispersions

Paper dyeing

07 — FAQ

Questions we are asked most

Is 25 kg/t not an extremely high dosage?

Could a cheaper decolorant reach the same result?

Why is no pH correction needed when other programmes require one?

The compound decolorant used here tolerates the alkaline condition of this liquor. That is specific to this water — do not assume it transfers to a different effluent without testing.

What happens if I underdose?

How much sludge does this produce?

The floc bed is visibly substantial — expect meaningful sludge volume at this dosage. Sludge yield was not quantified in this test; factor dewatering into your budget.

Can you test my yellow effluent?

Yes. Send a sample and your target discharge standard and we will run the same procedure and report the dosage.

Free Laboratory Service

Send us your wastewater — we will run the jar test

Tell us your industry, daily flow and target discharge standard. Our laboratory will run a bench-scale trial on your own sample and report the exact chemical and dosage.

Request a free jar test

Products referenced in this case

Product	Role in This Case	Dosage
Compound Water Decoloring Agent	Multi-mechanism colour breaking	25 kg/t
Anionic Polyacrylamide (APAM)	Floc agglomeration and settling	15 g/t

Water Purifying Chemicals

Water Decoloring Agent

Anionic Polyacrylamide

Cationic Polyacrylamide

Polyaluminium Chloride

Quaternary Ammonium Polymer

Nonionic Polyacrylamide

Color Removal Chemical

Drilling Mud Additives

Dicyandiamide Formaldehyde Resin

Polyelectrolyte Flocculant

Ferric Sulphate

Color Fixing Agent

Coagulant And Flocculant

Plant Based Deodorant

Anti Foaming Chemicals

Chemical Demulsifier

Water Purifying Chemicals

Water Decoloring Agent

Anionic Polyacrylamide

Cationic Polyacrylamide

Polyaluminium Chloride

Quaternary Ammonium Polymer

Nonionic Polyacrylamide

Color Removal Chemical

Drilling Mud Additives

Dicyandiamide Formaldehyde Resin

Polyelectrolyte Flocculant

Ferric Sulphate

Color Fixing Agent

Coagulant And Flocculant

Plant Based Deodorant

Anti Foaming Chemicals

Chemical Demulsifier

Solutions Details

Concentrated Yellow Dye Liquor Taken to a Colourless Supernatant in Two Steps

Concentrated Yellow Dye Liquor Taken to a Colourless Supernatant in Two Steps

Concentrated Yellow Dye Liquor Taken to a Colourless Supernatant in Two Steps

What makes this effluent difficult

Concentration drives reagent demand

Alkaline start

Yellow shows every imperfection

Two-reagent programmes leave no margin

The dosing programme, step by step

What happened at each stage

Raw sample

After compound decolorant

After anionic PAM

After 2–3 min settling

Transparent and colourless — the cleanest result in the series

Colourless, not merely lighter

Only two dosing points

No pH adjustment required

Dense, well-defined floc bed

From jar test to full-scale dosing

Where this programme applies

Questions we are asked most

Is 25 kg/t not an extremely high dosage?

Could a cheaper decolorant reach the same result?

Why is no pH correction needed when other programmes require one?

What happens if I underdose?

How much sludge does this produce?

Can you test my yellow effluent?

Send us your wastewater — we will run the jar test

Products referenced in this case

Concentrated Yellow Dye Liquor Taken to a Colourless Supernatant in Two Steps

Concentrated Yellow Dye Liquor Taken to a Colourless Supernatant in Two Steps

Concentrated Yellow Dye Liquor Taken to a Colourless Supernatant in Two Steps

What makes this effluent difficult

Concentration drives reagent demand

Alkaline start

Yellow shows every imperfection

Two-reagent programmes leave no margin

The dosing programme, step by step

What happened at each stage

Raw sample

After compound decolorant

After anionic PAM

After 2–3 min settling

Transparent and colourless — the cleanest result in the series