14 Billion Lira Wastewater Master Plan Approved for the Gulf of Izmir
A Thirty-Year Renewal Programme for the Gulf
The Ministry of Environment, Urbanization and Climate Change has officially approved the wastewater infrastructure master plan for the Gulf of Izmir. Covering the 2026-2035 period, the 14 billion lira programme foresees three new advanced treatment plants, 480 kilometres of collector line and 12 new pumping stations in the gulf basin. Groundbreaking for the first phase is scheduled for autumn 2026.
The plan stands out as the most comprehensive wastewater investment to be commissioned at gulf scale since the 1990s. The eastern, northern and southern basins of the gulf have been defined as three separate integrated management areas.
Profile of the Existing Infrastructure
According to Izmir Metropolitan data, total daily wastewater generation around the gulf reaches 1.2 million cubic metres. Existing advanced treatment capacity covers about 78 percent of this volume. Capacity gaps and ageing collector lines have been flagged as the main obstacles to controlling the pollution load reaching the gulf.
The three main weaknesses of the existing infrastructure:
- A significant portion of collector lines dates from the 1970-1990 period
- Combined sewer systems are inadequate for managing stormwater overflows
- Industrial pre-treatment obligations are not synchronised with advanced treatment capacities
Three New Advanced Treatment Plants
Profiles of the three plants in the master plan:
- North Basin Plant: Covering the Aliağa-Foça corridor, 280,000 cubic metres/day capacity, MBR technology
- South Basin Plant: Targeting the Çeşme-Urla corridor, adapted to seasonal tourism load, 220,000 cubic metres/day capacity
- East Basin Expansion: Integration of a fourth stage (micropollutant removal) to the existing plant, additional 150,000 cubic metres/day
Total investment for the three plants is set at 7.8 billion lira. Design criteria include micropollutant removal performance aligned with the EU's revised Wastewater Directive.
Collector Line Renewal
The 480-kilometre collector renewal programme will use trenchless technologies for 65 percent of the existing lines. The approach aims to minimise impact on urban transport and commercial activity. HDPE and GRP pipe will be the preferred materials; a 100-year durability performance has been written into the specification.
Trenchless technologies include cured-in-place pipe (CIPP) rehabilitation and microtunneling methods. Five-year experiences from ISKI and the Ankara Water and Sewerage Authority feed the programme's technical infrastructure as a reference.
Coordination with Industrial Zones
The master plan also redefines the pre-treatment obligations of organised industrial zones in the gulf basin. Under the new framework, a digital coordination platform is being set up between OIZ central wastewater treatment plants and municipal advanced t plants. Industrial discharge parameters will be verified through real-time monitoring infrastructure.
This approach is regarded as the first national model applying the "control at source" principle at an operational level. Sector analysts say the spread of the model to the Marmara, Aegean and Eastern Mediterranean basins is inevitable in the medium term.
Financing Model
Financing structure of the 14 billion lira programme:
- ISKI own resources and Ilbank loan: 7.2 billion lira
- EU IPA fund: 2.8 billion lira
- European Investment Bank loan: 2.4 billion lira
- Ministry of Environment, Urbanization and Climate Change transfer: 1.6 billion lira
EU IPA financing stands out as the largest single-line support under Turkey's Environment Chapter for 2026. The European Investment Bank loan was structured at preferential rates under the Green Deal framework.
Implications for the Sector
The master plan will drive a clear order pipeline for engineering consulting, equipment supply, installation and operations work in the Aegean region during 2026-2032. Membrane manufacturers, trenchless infrastructure specialists, digital monitoring software providers and pre-treatment equipment suppliers stand out among the leading beneficiaries.
Over the next decade, the Gulf of Izmir will become a kind of "open laboratory" for Turkey's advanced wastewater treatment technologies. Micropollutant removal, digital supervision, trenchless rehabilitation and OIZ-municipal coordination are reference applications the sector should follow closely.