Wastewater Project of the Year
Digha and Kankarbagh Integrated Wastewater, India
What is it?
An integrated wastewater programme, consisting of 150,000m3/d combined wastewater treatment capacity at two sites and a 450km sewerage network serving the Digha (100,000m3/d) and Kankarbagh (50,000m3/d) zones of Patna city, Bihar.
Who is involved?
VA Tech Wabag delivered the project as lead EPC contractor, and will operate for 15 years. The facility was tendered by the Bihar Urban Infrastructure Development Corporation (BUIDCO), as part of the Indian government’s Namami Gange river cleanup programme. Artelia was project management consultant.
What makes it special?
- The integrated approach creates a tailored wastewater service that directly guarantees safe sanitation for around half a million residents in one of India’s most densely populated urban regions, and marking a huge step towards BUIDCO’s target of universal wastewater treatment coverage.
- As one of the largest single contracts awarded under the Namami Gange programme, the project marks a new scale of action for reducing the uncontrolled discharge of sewage into the holy river. Arresting pollution at source, it dramatically improves water quality, public health, and the surrounding ecosystem all at the same time.
- The complex contracting process combining directly financed design-build-operate (sewerage) and independently financed hybrid annuity model (sewage treatment) delicately balanced risk between contractor and client, while opening new sources of finance for one of the world’s most capital-heavy environmental efforts.
The NICE Project, Spain
What is it?
A multi-site programme deploying and testing nature-based solutions and their integration into the urban water cycle.
Who is involved?
Aqualia was responsible for the design and construction of key installations, in partnership with a string of research and academic institutions across the wider programme. The programme was backed by the EU through its Horizon 2020 research and innovation funding scheme.
What makes it special?
- In 2025, Aqualia completed works on a series of key pilot-scale installations at sites across Spain, in Talavera, Algeciras and Benalmádena municipalities. The successful deployment of focused, multi-stage urban wetland schemes require minimal footprint and zero energy consumption to effectively filter wastewater from urban sites, in contrast to the energy-heavy established model for urban treatment.
- Localised nature-based treatment elements can act as water storage facilities as well as water treatment elements; a key situation when urban areas are more exposed than ever to flooding and storm surges in increasingly unreliable climactic conditions.
- The project is starting to take effect outside Europe: pilots in Cairo (Egypt) and Pereira (Colombia), show that nature-based solutions are not a luxury for wealthier European cities but a genuine part of the environmental struggle.
Okhla Sewage Treatment Plant, India
What is it?
A 564,000m3/d wastewater treatment plant in Okhla, Delhi, replacing four smaller plants on the site and serving up to 4 million people across south and central parts of the mega-city.
Who is involved?
The project was delivered and will be operated by Suez under an 11-year design-build operate contract. Key equipment suppliers included Sulzer and KSB (pumps), Aqua Aerobics (disc filters), Xylem (UV), Siemens (gas engines), Schneider Electric (SCADA), Endress+Hauser and Hach (instrumentation). The client was the Delhi Jal Board.
What makes it special?
- As one of the largest single-phase wastewater treatment plants in Asia, the project sets a new benchmark for scale and impact both in terms of utility service coverage and the reduction of the pollutant load entering the overtaxed Yamuna river.
- The project integrated advanced sludge management into the wastewater process to an extent never seen in India so far. The installation of an advanced heat recovery system led to an 80% reduction in the operating cost of the anaerobic digestion process, while biogas generated can provide for up to 55% of the energy burden of the entire site.
- Completion of the plant allowed for the go-ahead of one of India’s largest ever circularity programmes: while sludge facilities produce Class A sludge for safe reuse, 180,000m3/d of recycled water is made available for non-potable reuse networks, reducing dependence on freshwater infrastructure.
Ringsend WWTP Upgrade, Ireland
What is it?
A €550 million upgrade to the Ringsend wastewater treatment plant in Dublin, and the largest wastewater treatment project ever undertaken in Ireland. The upgrade meets the needs of the city’s growing population, safeguards the water quality of Dublin Bay, and makes the plant compliant with EU standards on urban wastewater treatment.
Who is involved?
Design and engineering was delivered by a joint venture comprising Haskoning, TJ O’Connor and Egis, while Veolia acted as EPC contractor. Haskoning provided its Nereda biological treatment and Ephyra digestion technology, while further equipment came from Xylem (diffusers), Cambi (thermal hydrolysis), Ostara (resource recovery) and Hach (instrumentation). The client is national utility Uisce Éireann.
What makes it special?
- The phased upgrade marks a huge expansion to a plant already operating well over peak capacity: the plant now serves the needs of up to 2.4 million population equivalent from both domestic and commercial/industrial sources, treating more than 40% of Ireland’s wastewater in one of the biggest national infrastructure turnarounds the country has ever seen.
- As well as a capacity revolution, the project represents a revolution in self-sustaining wastewater processing. Recoverable nutrients like struvite are extracted from biosolids, while the sludge handling means that up to half of energy consumed by the plant is now generated internally from biogas.
- Innovation in vertical and retrofit engineering solutions meant that the highly-complex project was delivered on a congested site with barely any room for expansion, while full operations were maintained at the existing plant throughout the eight-year upgrade process.
Thames Tideway Tunnel, UK
What is it?
The largest individual water infrastructure programme ever undertaken in the UK; a £4.6 billion, 25km-long tunnel running under central London, intercepting tens of millions of tonnes of sewage that had previously been discharged untreated into the Thames.
Who is involved?
Jacobs acted as programme manager for the Tideway project vehicle, while Amey was lead systems integrator. Construction was led by BAM Nuttall/Morgan Sindall/Balfour Beatty (west section), Ferrovial Agroman/Laing O’Rourke (central) and Costain/Vinci Construction/Bachy Soletanch (east).
What makes it special?
- The most radical modernisation to date on London’s 150-year-old sewer system, the Tunnel is the keystone of a master plan reducing untreated discharges into the River Thames by 95%, virtually eliminating the harmful effects of river sewage pollution in the urban Thames.
- Against a background of a growing PR disaster over river sewage in the UK, the tunnel’s 1.6 million m3 storage capability protects against overflows, cleaning up one of London’s greatest natural assets and promising to future-proof a clean Thames for the next century and beyond.
- At a time when the UK’s unique private water utility structure was coming under unprecedented pressure, the programme leveraged a first-of-its-kind business delivery model, with independent infrastructure delivery keeping the risk profile low, while the vehicle issued the UK’s first “blue project bond” to support innovative and low-cost financing.