Dnipro · Ukraine · 2011
AXOR Industry
Chemical wastewater treatment plant for an alkaline zinc plating line, with sludge dewatering.
Site photo (December 2012) — PP reaction tanks, dosing units and service platform
Project page →Technologies / Chemical Treatment
Coagulation & Flocculation: Where It Is Used
Effective solid-liquid separation through chemical destabilization of colloidal particles and floc formation.
Short answer
Coagulation destabilizes colloidal pollutants through charge neutralization by dosing a coagulant (PAC, FeCl₃, Al₂(SO₄)₃); flocculation then combines these particles, with the help of polymer, into large flocs suitable for settling. This two-step process achieves high removal of TSS, turbidity, color, phosphorus and heavy metals; the optimum chemical and dosage are determined by jar testing.
What Are Coagulation & Flocculation?
Coagulation is the process of destabilizing dissolved or colloidal pollutants in wastewater by charge neutralization, achieved by adding chemicals (coagulants). Flocculation is the subsequent step in which these destabilized particles are bound together with the help of a polymer to form large flocs suitable for settling.
Together, this pair of processes achieves high efficiency in the removal of total suspended solids (TSS), turbidity, color, phosphorus and heavy metals.
Working Principle
pH Adjustment
Coagulant Dosing
Rapid Mixing
Polymer Dosing
Slow Mixing
Floc Formation
Sedimentation / DAF
Coagulant Selection
PAC, FeCl₃, Al₂(SO₄)₃ — the most suitable coagulant for the wastewater characteristics is determined by jar testing.
Polymer Dosing
Floc growth with anionic, cationic or non-ionic polymer. Automatic preparation unit included.
Jar Test Support
The optimum chemical and dosage are determined by jar testing in the GESU laboratory.
Areas of Application
Industries
- Textile (color and turbidity removal)
- Metal finishing (heavy metal precipitation)
- Food (oil & grease and TSS removal)
- Pulp & paper
- Chemical and pharmaceutical industry
Removal Efficiency
- TSS: 90-99% removal
- Color: 85-95% removal
- Phosphorus: 90-95% removal
- Heavy metals: 95-99% removal
- COD: 50-70% pre-removal
Typical ranges from the literature and our own field experience — not a commitment. Actual performance depends on the wastewater composition, temperature, flow variation and operating discipline.
About the numbers on this page
The removal percentages, loading values and concentration ranges given on this page are typical values from the literature and from our own field experience; they are not a commitment. Actual performance depends on the composition of your wastewater, on temperature, flow variation and operating discipline. Guarantee values specific to your project are issued in writing with the offer, only after a jar test / pilot study on your own sample.
Proof from the field
16 chemical treatment plants
Sixteen plants we point to when chemical treatment is the question: plating, iron & steel, aviation, glass, electrical, fasteners, plastics and automotive. Years and scope come from our reference list; the photographs are our own site shots.
India
India
Chemical treatment plant.
No photograph in the archive yet
Kocaeli · Türkiye · 2019
EAE Elektrik
Industrial wastewater treatment plant: PP reaction tanks, dosing line and filter press.
Frame from GESU site video (2021) — PP tanks, platform and filter press
Tarsus · Mersin · 2011
Şişecam Düzcam (Trakya Cam)
Chemical and biological WWTP civil and mechanical works, filtration unit, sludge dewatering.
Site photo from our 2014 catalogue — plate settler and pump line
Project page →
Eskişehir · Türkiye · 2017
Alp Havacılık (Alp Aviation)
Industrial wastewater treatment plant and two gas scrubber units.
Site photo — chemical dosing room
Türkiye
Mişa Galvaniz
Galvanizing plant wastewater treatment — from reinforced-concrete basins to equipment, single-source.
Site photo (2024) — reinforced-concrete basin rebar
Sector page →Ankara · Türkiye · 2014
Mitaş Galvaniz
Industrial wastewater treatment plant for a galvanizing works — chemical treatment.
No photograph in the archive yet
Salihli / Manisa · Sakarya · 2019–2022
Norm Cıvata (Norm Holding)
Salihli industrial WWTP (2019) and its revision (2021); Sakarya wastewater treatment plant (2022).
Site photo — joint Norm Coating + GESU banner over the treatment line
Sector page →
Çayırova / Kocaeli · Adana · 2010 · 2018
Çayırova Boru
Kocaeli: chemical treatment system, 120 m³/day industrial WWTP and sludge dewatering. Adana (2018): WWTP, six plating tanks manufactured, scrubber.
Site photo — filter group and GESU-labelled PP tanks
Project page →Kocaeli · Türkiye · 2018
Diler Demir Çelik (Diler Holding)
Industrial wastewater treatment plant.
No photograph in the archive yet
Kütahya · Türkiye · 2011
Martur Automotive
725 m³/day industrial chemical wastewater treatment plant and 900 m³/day reverse osmosis system.
Site photo — chemical treatment line
Project page →
Istanbul · Türkiye · 2010
Fırat Plastik ve Kauçuk
120 m³/day industrial WWTP: chemical treatment plus UF and RO water recovery system, sludge dewatering.
Site photo — recovery line: dosing, filtration, UF
Çorlu / Tekirdağ · Türkiye · 2014
SIO Automotive
Automotive tier supplier: industrial wastewater treatment plant and water recovery plant.
No photograph in the archive yet
Çerkezköy / Tekirdağ · Türkiye · 2022
EJOT — Çerkezköy
Package treatment plant — chemical treatment.
No photograph in the archive yet
Kapaklı OSB / Tekirdağ · Türkiye · 2022
EJOT Tezmak
Wastewater treatment plant: chemical treatment, filter group and water recovery with UF + RO.
Site photo — filter group and GESU plate
Sector page →
Çanakkale · Türkiye · 2021
İÇDAŞ Çanakkale (Etis)
Iron & steel works wastewater treatment plant: HDPE reaction tanks, dosing and filter press.
Site photo — HDPE tanks and filter press
Sector page →The GESU Difference
Jar
Jar Test in Our Own Laboratory
Auto
Automatic Dosing
PP
Tanks of Our Own Manufacture
PLC
Smart Control System
Related Technologies
Treatment technologies GESU engineers and manufactures.
MBR — Membrane Bioreactor
Biological treatment combined with membrane separation; compact footprint, effluent ready for reuse.
SBR — Sequencing Batch Reactor
Fill-react-settle-decant cycles in a single tank; flexible for variable loads.
MBBR — Moving Bed Biofilm Reactor
Carrier media biofilm process; capacity upgrade without enlarging the tank.
Reverse Osmosis (RO)
High-pressure membrane desalination and polishing for water reuse.
Ultrafiltration (UF)
Barrier against suspended solids and colloids; standard pre-treatment before RO.
Sludge Treatment & Dewatering
Thickening, conditioning and dewatering — filter press, belt press, decanter.
Scrubbers & Gas Treatment
Chemical and biological washing towers for odour, acid and alkaline gas control.
DAF — Dissolved Air Flotation
GESU's flagship product: oil, grease and TSS removal, manufactured in-house.
Let's Talk About Your Project
With our 30 years of experience, let's determine the most suitable solution for your project together.
FAQ
Coagulation & Flocculation — Frequently Asked Questions
We have gathered the questions our customers ask most often. If you can't find the answer you are looking for, get in touch with us.
How does coagulation-flocculation work?
Coagulation is the electrical neutralization of colloidal particles in water so that they can come together. The coagulant (PAC, alum, FeCl3) is dosed under rapid mixing (G=600-1000 s⁻¹, 1-3 minutes). Flocculation then follows under slow mixing (G=20-80 s⁻¹, 15-30 minutes), forming large flocs with polymer. The flocs are separated by sedimentation.
In which industries is it used?
Textile (color removal), paper, drinking water, leather, metal (heavy metal precipitation), food, chemicals — it is a fundamental stage in almost all industrial wastewater applications.
What is the energy consumption?
The energy consumption of coagulation-flocculation is typically in the range of 0.02-0.08 kWh/m³ (mixers only). This is a typical design range, not a commitment; the actual figure depends on the mixing volume, the chemical dose and the operating regime.
What are the alternatives?
There are almost no practical alternatives for removing colloidal particles. Membrane filtration is an alternative, but it is far more expensive. The correct chemical selection (PAC vs alum vs FeCl3) is made by jar testing.