Water Reuse Project of the Year
San Diego Pure Water, USA
What is it?
A multi-phased $2.9 billion programme to implement 83MGD (314,155m³/d) of advanced water purification capacity in the City of San Diego, ultimately meeting a third of the city’s needs. The overall project will reclaim for beneficial reuse more than 100MGD (378,500m³/d) of wastewater that is currently discharged into the Pacific Ocean. The first phase of the programme was completed in 2015 when a state-of-the-art 1MGD (3,785m³/d) demonstration project at the North City Water Reclamation Plant came online.
Who is responsible?
The City of San Diego and the Water Reliability Coalition are spearheading the programme. MWH and Brown & Caldwell are acting as programme managers, while CDM Smith, MWH, and Trussell Technologies are the project consultants for the North City Demonstration Facility, which features low-pressure membranes from Pall and Toray, RO membranes from Toray and Hydranautics, an H2O Innovation RO system, a Leopold Oxelia filtration system furnished by Xylem, and a Trojan UV system.
What makes it special?
San Diego has historically been dependent on imported water. Despite this, a 1990s plan to reclaim primary effluent for potable reuse purposes met with strong opposition from local citizens, who coined the phrase “toilet-to-tap”. The tenacity of local officials in turning public opinion around is thus all the more remarkable.
The plant uses a multi-barrier approach to destroy pathogens and bacteria, employing UF/MF membrane filtration systems, reverse osmosis, and advanced oxidation through the application of UV disinfection and hydrogen peroxide. As part of its outreach effort, the city’s Public Utilities Department has opened the pilot facility to the public to demonstrate the safety of the water produced.
The pilot plant marks a significant step towards San Diego’s dream of achieving water independence, and will also generate valuable data which could help shape the future implementation of direct potable reuse.
Distinction
Orange County GWRS Expansion, USA
What is it?
A 30MGD (113,600m³/d) expansion of the existing 70MGD (264,950m³/d) Groundwater Replenishment System (GWRS), the world’s largest indirect potable reuse scheme.
Who is responsible?
The Orange County Water District (OCWD) and the Orange County Sanitation District (OCSD) are jointly in charge of the system. Black & Veatch served as the civil and mechanical engineer, while Parsons was the construction manager. Dow Water & Process Solutions supplied its Filmtec reverse osmosis elements, and MF membranes were supplied by Evoqua, while Trojan UV treatment technology was also installed. FEDCO was responsible for the supply of energy recovery devices for the BWRO portion of the project.
What makes it special?
With California in the grip of a catastrophic drought, finding new water sources to reduce the state’s reliance on imported water and the overstretched Colorado River has never been more important. Orange County’s groundwater replenishment scheme does this at an unprecedented scale and at a fraction of the cost of desalination, whilst anticipating future statewide legislation on eliminating ocean discharges of treated wastewater.
The expansion, which came online in 2015, saw the construction of eight new below-grade treatment basins, a new reverse osmosis building, and five additional ultraviolet light (UV) treatment trains. A new equalisation system allows effluent generated during peak flow periods to be scalped and stored nearby for treatment during periods of low flow, enabling the GWRS to operate more efficiently by running at maximum capacity 24/7.
Orange County’s unique level of engagement with the public has turned the GWRS into a living endorsement of how California is pro-actively addressing its water resourcing crisis. The plant’s popular monthly tours are a vital tool in the battle to overcome public resistance by championing the benefits of reuse in their own back yards.
The Global Water Awards 2018 is proudly sponsored by:
