Case study — effluent & heavy metals
Acid pickling effluent to zero discharge at a steel pipe coating plant
Lime-only treatment left iron high and the water unusable. EPSE chemistry took the same stream to over 99.9% heavy metal removal — with the water fully recycled and nothing discharged.
Acid pickling is how a steel pipe plant gets a clean surface before coating — and its effluent is about as hostile as industrial water gets: very low pH, high chlorides, and dissolved iron, zinc and lead. The plant's lime-only treatment could not hold it. Iron stayed high, the water could not be reused, the process generated heavy sludge, and the plant needed a full clean every three months, draining 10 to 20 cubic metres each time.
This is the kind of stream where a supplier's claims need proving, not believing — so the programme was built on evidence at every step: laboratory verification before full-scale implementation, and daily on-site sampling run in parallel against the lime-only treatment it replaced.
The record
Problem, programme, result
Every figure below is client-confirmed.
The problem
Acid pickling effluent, very low pH, high chlorides, dissolved iron, zinc and lead. Lime-only treatment left iron high, limited water reuse, generated heavy sludge, and forced a full plant clean every three months, draining 10 to 20 cubic metres each time.
The programme
EPSE chemistry verified at laboratory scale in Finland (November 2024) before full-scale implementation (June 2025). Daily on-site sampling run in parallel against lime-only treatment. pH control automated to a 9.5 target after operator variability was identified as a treatment quality risk.
The result
Iron consistently below 0.37 mg/L (previously above 0.87 mg/L). Lead and zinc removed where lime removed neither. Overall heavy metal reduction above 99.9%. Plant cleaning down from quarterly to once in eight months, that one precautionary. Fully recycled water, zero discharge. Sludge declassification from hazardous waste under review.
Why it worked
Verified first, automated where it mattered
The chemistry was verified at laboratory scale before a single day of full-scale operation, then proven in parallel against the old treatment with daily sampling. And when operator variability showed up as a treatment quality risk, pH control was automated to a 9.5 target rather than left to routine. That is the difference between installing a chemical and running a programme.
Where to next
The programme behind the numbers
Effluent treatment
The programme behind this result — complex streams to DWS limits, with EPSE heavy metals removal.
View serviceMetal smelters & processing
How the same chemistry serves metal processing sites.
Sector pageHow we work
Assess, engineer, prove, monitor — the method this case followed.
Our methodAn effluent stream your current treatment can't hold?
Send us the analysis, or let us sample it. We verify the chemistry before you commit — the same way this plant did.