First, second… third! After Vodice and Zagreb, WTE Wassertechnik GmbH has secured the contract for another wastewater treatment plant in Croatia in an international competition! Over the next three and a half years, WTE will comprehensively modernise and expand the existing main wastewater treatment plant in the city of Split.

The contract was signed at the headquarter of the client, Vodovod i kanalizacija Split d.o.o., on 19 November. Daniel Barišić from WTE’s Zagreb branch signed the contract on behalf of WTE.

As part of the contract, the Stupe wastewater treatment plant will be expanded to include a biological treatment stage to enable year-round carbon elimination and – with rising wastewater temperatures – partial nitrogen elimination. WTE is also constructing a completely new sludge line with thermal sludge drying. Wastewater treatment on the Adriatic coast is thus being raised to a new standard.

WTE will act as consortium leader for the client Vodovod i kanalizacija Split d.o.o. for the planning, construction and one-year trial operation of the wastewater treatment plant. It is located around four kilometres east of the city centre and will have a capacity of 275,000 PE or 60,000 m3/d for the wastewater line and 400,000 PE for the sludge line. Due to the large capacity, all sludge from the surrounding area will be transported to Stupe for centralised treatment.

Specifically, depending on the season, the plant will treat around 60 to 100 million litres of wastewater per day to high quality standards. This will significantly improve the ecological condition of the Adriatic Sea between the Croatian islands and the mainland in the vicinity of the submarine discharge.

Impressions of the current ‘Stupe’ wastewater treatment plant in Split.

The project data at a glance:

• Subject: Reconstruction and expansion of the Stupe wastewater treatment plant
• Contracting authority: Vodovod i kanalizacija Split d.o.o.
• Consortial and construction partner: HERING d.d., Bosnia and Herzegovina
• Publication of the tender: 03.02.2022
• Submission: 19.09.2023
• Capacity of the wastewater line: 275,000 PE or 60,000 m³/d
• Capacity of the sludge line: 400,000 PE
• Technology: mechanical/biological wastewater treatment with C elimination and N elimination at T > 20 °C
  Sewage sludge treatment by means of thickening, anaerobic stabilisation, dewatering and thermal drying
• Planning / construction / trial operation / handover: 10 / 18 / 12 / 3 months
• Co-financed by the EU Cohesion Fund

The contract is part of a project to ‘improve the water and communal infrastructure of the Split-Solin agglomeration’ and is one of the largest contracts in Croatia.

An exciting new project for WTE, with which we are further expanding our commitment in Croatia and actively promoting environmental protection in the region.