As California grapples with the multifaceted challenges of a changing climate, the state finds itself at a critical juncture, facing a convergence of environmental, demographic, and climatic challenges that are reshaping its landscape and testing the resilience of its communities. Amid these challenges, water desalination is emerging as a promising solution to the state’s enduring drought and water supply issues. This process, which involves removing salts and minerals from seawater or brackish water, offers a dependable source of potable water without further straining traditional freshwater resources. If done with proper planning and collaboration across the public and private sectors, then desalination technology has the potential to redefine our relationship with one of our most precious resources.
The growing crisis of water scarcity
California’s struggle with water scarcity is a reflection of a broader global crisis. The state’s dependence on the Colorado River, a vital lifeline for Southern California, is under threat as the river suffers from reduced flows due to prolonged droughts and decades of overallocation — a situation exacerbated by climate change.
Additionally, California’s continued population growth is pressuring the state’s already stretched water resources. This growing demand extends beyond residential needs to the agricultural sector, which consumes a substantial amount of water and is now confronting the repercussions of an unstable water supply. The uncertainty introduced to agriculture, a cornerstone of California’s economy, could have far-reaching effects on food production and economic stability across the country.
Moreover, climate change is leading to more frequent and severe droughts in California, diminishing water availability from traditional sources like snowpack and surface water. The Sierra Nevada snowpack, a critical water reserve, is dwindling as rising temperatures cause more precipitation to fall as rain rather than snow, resulting in a pace of runoff that state reservoirs cannot match.
This phenomenon, coupled with the prospect of more extreme weather patterns — termed “climate whiplash”— where prolonged droughts are followed by intense rainfall, poses a significant challenge to water management processes and infrastructure. This whiplash considerably disrupts ecosystems that rely on regular water flow regimes, threatening biodiversity and the health of aquatic habitats.
Exploring the potential of desalination
hese compounding environmental pressures necessitate immediate action and establish a clear need for a new and improved approach to generating new water supplies.
Desalination is not a one-size-fits-all solution; it is a nuanced approach with its own set of challenges and opportunities. It should be viewed as a component of the water supply portfolio, not a fix-all. Seawater desalination, particularly through reverse osmosis (RO), is a critical technology for addressing global water scarcity, especially in coastal regions. RO is a process used to remove the salt from seawater, and it involves several complex and energy-intensive steps due to the high salinity levels of seawater (typically around 35,000 parts per million of dissolved salts).
This high salinity water must undergo extensive pretreatment to prevent clogging and damage from contaminants like dirt or debris. Although effective, seawater desalination is energy-intensive and can pose environmental concerns due to the discharge of saline brine and chemical pollutants into the marine environment.
On the other hand, brackish water desalination deals with water that has more salinity than freshwater but less than seawater, making it easier and less costly to treat. The recovery rates for brackish water treatment are higher, resulting in lower concentrate volumes. However, the disposal of concentrate from brackish water desalination can be challenging and sometimes requires pipelines or other supporting infrastructure to manage it properly.
This can be mitigated with the correct technology. Take, for example, the Antioch Brackish Water Desalination Project, which leverages existing infrastructure to not only lower the project’s capital costs but also speed up implementation. This factor contributes to the project’s viability and attractiveness, demonstrating that brackish water desalination can significantly bolster local water supplies. However, while beneficial, brackish water desalination alone cannot fully meet California’s extensive water demands.
For ideal desalination efficiency, reversal of climate change impacts, and building up potable water supplies, both seawater and brackish water must be considered. The Keppel Marina East Desalination Plant (KMEDP) in Singapore took a unique approach to desalination technology, showcasing dual-mode operations that enhance the efficiency and sustainability of water treatment facilities. KMEDP’s dual-mode functionality allows it to switch between treating seawater and brackish water based on availability, conserving energy and reducing operational costs. The plant achieves this through advanced engineering solutions, including a two-pass RO system, energy recovery devices, and direct coupling techniques. This dual-mode functionality allows for optimal desalination efficiency and could be a model for areas like California, which could benefit from adopting similar facilities that can switch between seawater and brackish water sources.
Policy, advancement, and the argument for desalination
To truly harness the potential of desalination, California needs to streamline the current permitting process, as the current system is protracted and acts as a deterrent to the development of new projects.
Establishing clear, measurable criteria that, if met, guarantee project approval could significantly expedite the process. Additionally, providing financial incentives such as grants or appropriations could encourage the development of both brackish and seawater desalination projects. Further incentives for “green” solutions that incorporate renewable energy or other environmentally friendly practices could also be beneficial. These policies would not only accelerate the deployment of desalination technologies but also ensure they contribute both to California’s water scarcity issues and sustainability goals.
Furthermore, recent technological advancements in desalination are poised to mitigate both cost and environmental concerns. AECOM has been pioneering the integration of renewable energy sources, such as solar or hydro, into the desalination process. This approach can diminish the carbon footprint and lower operational expenses. A prime example is the Sydney Desalination Plant, which operates solely on renewable wind energy, significantly cutting emissions and costs.
Moreover, innovations in the recovery of valuable elements like chlorine and lithium from desalination byproducts promise to further improve desalination facilities’ sustainability and economic feasibility. Additionally, the adoption of digital technologies, including augmented reality (AR), is revolutionizing water resource management. For instance, at the Kaohsiung Linhai Wastewater Treatment Plant, AECOM has employed AR for process control optimization, leading to decreased operational expenses, chemical use, and environmental impact.
Desalination is on the verge of playing a pivotal role in addressing water scarcity, but further refinement is needed in areas such as dual-mode functionality and operational cost reduction. Improving these aspects can significantly enhance the efficiency and viability of desalination technologies. Successful outcomes in water management require not just technological solutions but also a comprehensive approach that includes stakeholder engagement, environmental considerations, and long-term sustainability planning. These efforts, along with continued innovation supported by favorable policies and incentives, are crucial for propelling desalination technology forward, encouraging investment in desalination infrastructure, and ultimately will contribute to securing a sustainable water future for all.
