Wastewater treatment plant for a paper mill, 2,160 m³/day
Installation supervision and commissioning of a wastewater treatment plant for a tissue paper mill: screening, chemical DAF, biological treatment and sludge dewatering. Treated water meets the limits for discharge to the municipal sewer.
Input data
| Capacity | 2,160 m³/day |
|---|---|
| Peak discharge from the paper machine | 240 m³/h for 6 hours |
| Treated water requirement | municipal sewer discharge limits |
| My role | installation supervision, DAF tuning, chemical dose selection, biology start-up, sampling (service engineer) |
Engineering challenge
Effluent arrives unevenly: the paper machine discharges up to 240 m³/h for 6 hours. The water has to meet the utility limits for discharge to the municipal sewer, and no untreated water may leave the plant.
Solution
Full-cycle treatment: screening, chemical DAF and biology, with automatic monitoring at every stage. The diagram below shows how it works.
Result
| Guaranteed treatment performance | achieved and confirmed during commissioning |
|---|---|
| COD | ≤ 500 mg/L · discharge limit met |
| BOD₅ | ≤ 300 mg/L · discharge limit met |
| Suspended solids | ≤ 300 mg/L · discharge limit met |
| pH | 6–9 discharge limit met |
| Commissioning completed | November 2024 |
The solution step by step: effluent path from the mill to the sewer
- 01
Screening
drum screens
Remove fibre and coarse solids.
- 02
Equalisation
peak up to 240 m³/h
Mixed and aerated tanks absorb the paper machine peak discharge.
- 03
Chemical DAF
KWI Megacell DAF
Coagulant and flocculant, pH correction, solids removal.
- 04
Biological treatment
2 bioreactors
Turbo aerators. Ammonia water and phosphoric acid as nitrogen and phosphorus sources.
- 05
Sludge separation and discharge
second Megacell DAF
Separates activated sludge. Treated water goes to the municipal sewer.
Sludge
Float sludge and excess sludge are dewatered on Polat decanter centrifuges; the centrate returns to equalisation.
Monitoring
COD, pH and dissolved oxygen sensors. Off-spec water is automatically sent back to the emergency equalisation tank.
My role
Installation supervision, DAF tuning, chemical dose selection, taking part in the biological start-up, sampling for analysis, staff training.
On site
