Problem

A large electrolyzer manufacturer operates a state‑of‑the‑art electrolyze manufacturing facility at Herøya in Norway, producing components for green hydrogen production. Multiple electrochemical baths and extensive rinsing operations generate several distinct liquid waste streams, including nickel‑contaminated rinse water, Z‑bath and SU‑bath concentrates, and acidic and alkaline pre‑treatment streams.

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Discharge limits for nickel were tightened to an annual total of 300 g, corresponding to an average concentration of 4 µg/L for four‑line operation. The existing chemical‑mechanical precipitation system with chamber filter press could not meet these requirements, produced large quantities of wet sludge with high disposal costs and did not provide water quality suitable for reuse.

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The wastewater treatment bottleneck threatened the company’s expansion plans and operational efficiency. High external disposal costs, inability to reuse treated water, and complex manual operations made the existing solution economically and operationally unsustainable for scaled production.

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Solution

The delivered treatment plant consists of two integrated main systems designed for safe, efficient operation and water reuse. 

Rinse water is treated by a multi‑stage membrane filtration line with buffer tank (TK-01), ultrafiltration (UF), nanofiltration (NF), ion exchange polishing and a vacuum evaporator (DMVP500) for the concentrate. High‑concentration Z‑bath and SU‑bath streams are handled in a separate buffer tank (TK-02) and 4‑stage vacuum evaporator (DMVP250) tailored to the acidic, high‑nickel environment. Additional buffer and storage tanks secure sufficient equalization capacity for acidic, alkaline and concentrated streams, while an integrated control system with remote monitoring ensures stable, automated operation. 
 

The modular design allows straightforward expansion from two to four production lines and further capacity upgrades.

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Result

The new system increases treatment capacity from 46.8 m³/day to 187.2 m³/day while reliably meeting the 4 µg/L nickel discharge limit. 
 

Nickel removal efficiency exceeds 99%, and final waste volumes are reduced by more than 90%, transforming high volumes of chemical sludge into a small, manageable concentrate.

Treated water reaches reuse‑ready quality, enabling process-water recycling and significantly lowering municipal water consumption and disposal costs. By replacing chemical‑ mechanical precipitation with physical separation technologies, the electrolyzer manufactorer achieves higher performance, simplified operation, and a robust platform for future production expansion.