Treatment of mining effluent using lamella clarifier technology
Mining effluent contaminated with heavy metals such as uranium, iridium, iron and sulphate had to be removed before the mine effluent could be discharged. Lamella settling, together with physico-chemical treatment upstream, enabled these contaminants to be separated. water.
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How can metals from mine effluent be treated?
With the tightening of standards, the mining industry has to treat its effluents contaminated with heavy metals. Our customer wanted to implement a treatment system capable of significantly reducing these levels. The aim of the project was to achieve a heavy metal removal rate of over 90%, while complying with the constraints of variable flow rates and the physico-chemical conditions of the effluent.
The requirements for this treatment are listed below:
- Flow rates from 1 to 13 m3/h, with a model based on 20 m3/h.
- The coagulation and flocculation process is also available upstream.
- Installation inside a building, away from direct sunlight.
- pH range from 8 to 9.
- Temperature range 5 to 30 degrees.
- Storage reservoir upstream of lamella clarifier.
- Sludge removal by pumping required.
- No or little floating sludge.
What is the purpose of jar testing in water treatment?
Jar tests were recommended to accurately assess the effectiveness of the coagulation-flocculation process. These tests make it possible to determine the optimum doses of coagulants and flocculants to maximise the agglomeration of particles and heavy metals present in the effluent. By simulating real treatment conditions, jar tests provide an overview of the performance of the process and the final quality of the treated water. The results obtained are essential in deciding whether to integrate a lamella clarifier, confirming that this technology can achieve the objectives of reducing contaminants.
Clariflocculation: the most suitable method for treating metals
To meet this mining effluent treatment challenge, the solution adopted is based on the use of a lamellar decanter, combined with an upstream coagulation and flocculation process. This system effectively separates the fine particles and heavy metals present in the contaminated water. Thanks to its compact, modular design, the 1h2o3 lamellar clarifier offers a large settling surface in a small space, optimising the separation of solids and even the recovery of floating sludge. Coupled with prior chemical treatment, the coagulation-flocculation process promotes the aggregation of fine particles, increasing their sedimentability and enabling contaminants to be eliminated quickly and efficiently.
Metal removal efficiencies of over 95%.
Analyses carried out after installation of the lamellar decanter showed a reduction of more than 95% in the heavy metals present in the effluent, confirming that the process meets the treatment objectives set. This configuration enables metal residues to be treated effectively, even in the presence of fluctuating flow rates, ensuring stable performance adapted to the constraints of the site. The other significant advantage is the operating cost, which is very low compared with other technologies such as membranes or ion exchange resins.
To carry out this project, 1h2o3 produced :
The project included:
- Lamella clarifier design
- Design adapted to site constraints
- Manufacture and integration of electromechanical equipments
- Delivery on the project site
This integrated approach has ensured a coherent, operational solution that meets the project’s technical and environmental requirements.
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Monobloc lamella clarifier DLM-L
Lamella clarifiers
Year of production
2020
