Success Story

Design and detailled engineering for the plant in Oradea, Romania

Compania de Apa S. A. Oradea, Romania
Design and detailled Engineering, civil engineering, delivery and installation of electrical and mechanical equipment

Design and build of a turnkey wastewater treatment plant

Oradea is located in the eastern part of the Great Hungarian Plain on the banks of the river Crişul Repede (aka Sebes-Körös). The city center is 13 km away from the Hungarian border. The foothills of the Apuseni mountains end at the north eastern area of the city. The Oradea WWTP was designed for 210,000 inhabitants with a dry weather flow for the entire plant of 190,000 m³ per day.
Primary clarification is designed with max. 345,600 m³ per day whereas the difference after primary clarification is discharged into the river via bypass.
The WWTP was financed through a loan from the EBRD (European Bank for Reconstruction and Development) and ISPA funds (Instrument for Structural Policies for Pre-Accession).

PWT Solution

Mechanical treatment includes coarse and fine screens with screenings press, grit chamber, aerated grease removal and primary sedimentation tank.

Biological treatment includes aeration tanks and final sedimentation tanks.

Sludge treatment includes static excess sludge thickeners with centrifuge, digesters, sludge storage tank and de-watering centrifuges.

Biogas forming in the digesters is stored in gas tanks and is used to heat the digesters and the administration building with the help of a combined heat and power plant (CHP). The CHP generates approx. 720 kW of power.


Processing stages

Coarse and fine screens with screenings press
Grit chambers
Aerated grease chambers
(Diameters: 2 tanks Ø 45 m, 1 tank Ø 40 m,
1 tank Ø 30 m)
4 coarse screens
4 fine screens
6 grit chambers
3 grease chambers
4 tanks

Activated sludge tanks

(Depth: 4 m, width: 48 m, length: 95 m)
(Tank volume: 18,000 m³/tank)
2 double tanks

Final sedimentation tanks

Diameter: Ø 45 m
Tank volume: 5,500 m³ / tank
4 tanks

Static excess sludge thickener

Tanks volume: 1,100 m³ / tank
2 tanks


Sludge thickener

Centrifuges for excess sludge
Capacity: 30 m³/h per centrifuge
2 centrifuges

Sludge digesters

Digester volume: 4,000 m³ / digester
3 sludge digesters

Sludge dewatering

Centrifuge for digested sludge
Capacity: 30 m³/h pro centrifuge
1 centrifuge

Gas tanks

Tank volume: 1,000 m³ / tank
2 gas tanks

Heat and power generation (CHP)

Electrical capacity: 360 kW each
Thermal capacity: 416 kW each
2 heat and power generation plants
1 gas flare
1 desulphurization unit

Plant size
250.000 PE
Population equivalent:
Raw water intake
190.000 m3/d
Peak dry weather flow Qt
345.600 m3/d
Peak flow
103.700 m3/d
Average flow
15.080 kg/d
BOD5 load
103.700 m3/d
Quantity of wastewater
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