Optimization of zinc discharges by coagulation–flocculation chain and compact lamella clarification
This compact coagulation–flocculation + lamella clarification chain secures the treatment of zinc discharges while being integrated into the most constrained spaces. Modular, optimised by jar tests and easy to use, it guarantees water that complies with standards, controlled costs and a scalable supply chain for industrial sites.
Project information
- Viviez (FR-12110)
- 2024
- Keywords
- Flow & Load
Variable zinc effluents
Chain sized for peak loads
- Physico-chemical process
Coag–optimized floc
Assays set by jar tests (pH, reagents)
- Compact clarification
Compact lamella clarifier
High usable area, small footprint
- Performance & Compliance
Standard-compliant zinc discharges
Optimized operating costs and reagents
Project Background
An industrial company had to bring its zinc discharges up to environmental standards, despite strong load variations and very limited available space. The treatments in place were unstable and difficult to manage, with high operating costs. We studied the effluents (zinc, suspended solids, pH, daily variations) and the civil engineering constraints to propose a compact physico-chemical system, which can be integrated without heavy work or prolonged shutdown of the activity.
Objectives
To ensure the precipitation and removal of zinc to continuously achieve the imposed rejection values, while stabilizing operation despite load peaks. To design a modular solution, quickly installable, easy to use on a daily basis and optimized in reagents thanks to jar tests. Finally, to ensure an evolving sector, capable of being strengthened or extended if flow rates or regulatory requirements increase.
Technical solution
Compact physico-chemical chain based on coagulation–flocculation followed by lamella clarification. The jar tests made it possible to precisely calibrate the coagulant/flocculant pair and the pH to guarantee the precipitation of the zinc. In-line, the reactors ensure the formation of dense flocs and then two compact lamella clarifier maximize the sedimentation surface on a reduced footprint, to obtain clarified water that complies with standards.
CNC prefabrication & modularity
The equipment (coagulation-flocculation reactors, lamella clarifier, dosing and instrumentation) is prefabricated in ready-to-connect modules: chassis, main pipes and automation systems assembled in the workshop. This modularity facilitates transport in constrained spaces, reduces on-site assembly time and leaves the door open to future expansions (addition of decanter, reaction reinforcement, complementary treatment options).
On-site implementation
Installation of reaction modules and two lamella clarifier in the available area, connection to inlets/outlets and utilities (electricity, reagents). The low heights and compactness limited civil engineering adaptations and heavy interventions. Commissioning was based on parameters from the jar tests to adjust pump flow rates, reagent dosages and contact times.
Results
The combination of coagulation–flocculation + lamella clarification stabilized the treatment despite load variations. Zinc discharges have been brought within the standards with clear water and rapid sedimentation. Reagent requirements have been optimised thanks to preliminary tests, operating costs have been reduced overall, and the system is now reproducible and scalable in the event of an increase in throughput or regulatory tightening.
Operation & Maintenance
The operation is based on simple routines: pH and turbidity control, possible adjustment of dosages, regular purging of the sludge at the bottom of the clarifier. The main components (dosing pumps, agitators, valves) are accessible for maintenance and standardized for easy replacements. The settings from the jar tests serve as a basis for instructions and limit daily operating drifts.
Key figures
- 2 compact lamellar decanters — high sedimentation surface area for a small footprint
- 1 optimized coagulation–flocculation line — dosages set by jar tests (reagents + pH)
- Modular & plug-and-play die — easy installation in constrained space
- Compliant zinc discharges — stable performance despite effluent variations
Product focus: TOP lamellar decanter (DLH-XXL / DLH-XXXL)
To secure the clarification of zinc-laden effluents in a confined space, we chose a high-capacity HAUT lamella clarifier.
Thanks to its large lamella surface and optimised settling volume, it enables rapid separation of clear water and sludge, even in the event of strong variations in flow or concentration.
Its modular design makes on-site integration easier (limited headroom, confined spaces) and allows future extensions: adding lamella surface, upgrading the treatment line, or creating a second stream.
Access points and adjustment devices are grouped together to simplify draining, visual inspections, and preventive maintenance, while ensuring consistently high performance over time.
- High clarification capacity
- Small footprint
- Suitable for zinc load peaks
- Easy integration in space-constrained
- Simplified operation and maintenance
Steps to collaborate
- Effluent and site diagnosis — flow rates, zinc contents, suspended solids, pH, variations, space and discharge constraints.
- Jar tests & pre-sizing — choice of coagulant/flocculant pair, optimization of pH and dosages, first estimation of the lamellar surface.
- Preliminary project of the sector — process flowsheet, location of reactors and lamella clarifier, definition of options (sludge storage, instrumentation, automation).
- Manufacturing & logistics – preparation of coagulation-flocculation modules, lamella clarifier and dosing skids, organisation of transport according to access.
- Installation & commissioning — connections, fine calibration of flow rates and dosages, verification of settling rates and validation of zinc compliance.
- Monitoring & optimization — support for operations, reactive adjustments if necessary, help with performance monitoring and future developments.
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High lamella clarifier DLH-XXXL
Lamella clarifiers -
High lamella clarifier DLH-XXL
Lamella clarifiers
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