Singapore Public Utilities Board invests S$453 million into R&D for future water sustainability
PUB is at the forefront of national water R&D initiatives. It also invests in the development of new, innovative technologies across the water loop to sustainably increase future water resources and enhance the efficiency of water treatment processes and operations. The long-term targets it has established particularly focus on reducing the amount of energy used in desalination by more than two-thirds. This will increase NEWater recovery to 90% at low-energy levels and make used water treatment fully energy self-sufficient while also halving sludge generation. PUB has also identified a few promising innovations and technologies which will contribute towards achieving these objectives.
While seawater and used-water streams offer a potentially inexhaustible supply of water, producing potable water which varies with the type of source water used presents certain challenges. Current desalination energy requirements and NEWater recovery rates present the biggest obstacles to their sustainable use. These sources require between five and 17 times more energy to produce while the conventional treatment of rainwater requires much less energy. Additionally, producing treated used water – before it is channelled to NEWater production – generates sludge that is expensive to dispose of.
To meet future water demands with today's technologies, PUB's energy footprint will quadruple from the current 1,000GWh/year to 4,000GWh/year. The amount of sludge generated will double from today’s 300,000 tonnes/year to over 600,000 tonnes/year by 2060. These figures present a future that is unsustainable and can only be overcome by leveraging technological innovations.
Since 2002, PUB along with research associates and the National Research Foundation, have invested S$453 million in over 600 water R&D projects in collaboration with partners from 27 countries. These projects are situated at various positions along the technology readiness spectrum. Some projects are still in the basic research phases or are lab-scale prototypes, pilot studies, and demonstration plants; others have already been approved for full-scale deployment and commercialisation.
Mr Harry Seah, PUB's Assistant Chief Executive (Future Systems and Technology), stated the growing reliance on desalination and water reuse requires that technological advancements continue to meet increasing water demands to maintain sustainability. "PUB is pushing the frontier of water technology to tackle the pressing challenges in energy and sludge management efficiency and is on track to meet its long-term targets. The key to this is collaboration with the local and global research community to develop real, applicable solutions to keep water supply secure and affordable," he added.
R&D Targets and Key Projects
For nearly twenty years, PUB has worked with water industry partners and various universities and institutions to accelerate the development of new technologies to be tested and implemented in its facilities. Currently, the PUB is focusing R&D efforts on increasing water resources while reducing energy usage and sludge generation.
Thus, PUB has identified certain targets to propel the next stage of innovation:
1. Low Energy Desalination: Desalinated water is Singapore's fourth national tap and is its most energy-intensive source. It currently meets up to 30% of the water demand and is expected to meet 30% of future demand in 2060. PUB's aims to reduce the energy consumed by the desalination process by more than half (i.e., from 3.5kWh/m3 to 1.5kWh/m3) in the short-term and eventually to 1kWh/m3, as a system, in the long-term. Seawater Reverse Osmosis, the current desalination method, pushes seawater through membranes which filter out salts and impurities. PUB is demonstrating Electro-deionisation technology at its R&D Facility in Tuas and testing Biomimetic Membranes. These are new, more efficient methods, inspired by science and nature, of low-energy water desalination.
2. Increasing NEWater Recovery at Low Energy: Currently, NEWater meets up to 40% of water demand and will meet up to 55% of future demand in 2060. NEWater is generated by putting treated used water through an efficient 3-stage process of microfiltration, reverse osmosis (RO) and ultraviolet disinfection. PUB's short-term target is to increase the NEWater recovery rate from the current 75% to 90% at the same energy consumption of 0.4kWh/m3 for its energy-intensive RO treatment stage. The long-term target is a 90% NEWater recovery at less than half the energy consumption rate for RO treatment. The Flow Reversal Technology demonstrated at the Kranji NEWater Factory and the Electrodialysis reversal-reverse osmosis (EDR-RO) system piloted at the Ulu Pandan Water Reclamation Plant could potentially reach PUB's long-term sustainability target.
3. Energy Self-Sufficiency and Sludge Reduction in Used Water Treatment: PUB is actively testing technologies to identify those that have the potential to make the used water treatment process energy self-sufficient, producing as much energy as it uses. PUB has set the target for its water reclamation plants to move from the current 25% energy self-sufficiency to 75% in the short-term, and ultimately to 100% energy self-sufficiency in the long-term. Seeing as energy self-sufficiency and sludge management are inextricably linked, PUB also aims to reduce the amount of sludge generated by the used water treatment process by more than 50% in the long-term by harnessing the biogas generation potential of sludge. Allowing for double the amount of used water to be treated in the long-term at today’s sludge footprint. The Ulu Pandan Wastewater Treatment Demonstration Plant validated an innovative combination of energy-efficient technologies for used water treatment. Sludge reduction and enhanced biogas production were demonstrated by a Thermal Hydrolysis Process (THP) at the Jurong Water Reclamation Plant. These technologies will be implemented at Tuas Water Reclamation Plant, a highlight of the Deep Tunnel Sewerage System Phase 2.
These technologies are currently being showcased at the TechXchange and Water Innovation Pavilion at the Singapore International Water Week 2018 (8 – 12 July 2018).
The TechXchange and the Water Innovation Pavilion feature local and international companies with revolutionary technologies. The Innovation Pavilion demonstrates how these technologies work and highlights how some of these technologies were adopted by PUB.