Carlsbad Desalination Research Articles

Microbial diversity analysis of two full-scale seawater desalination treatment trains provides insights into detrimental biofilm formation

Detrimental biofilms on RO membranes remain a crucial challenge for seawater desalination. Comparative analysis of 16S rRNA gene amplicon sequencing data revealed differences and commonalities of biofilm communities associated with unit operations in the two largest seawater desalination facilities in the U.S., the Claude "Bud" Lewis Carlsbad Desalination Plant and the Tampa Bay Seater Desalination facility. At both plants, feedwater collected at a single time point was a poor indicator of the RO membrane communities, which showed far greater taxa diversity. The analysis of prefilter cartridges from the Carlsbad plant revealed similarly high taxon diversity as the RO module biofilms, with relevant differences. Algal sequences were enriched on the prefilter cartridges as were sequences representing Bdellovibrionota, which are predatory bacteria. Sequences representing opportunistic Gammaproteobacteria (i.e., Shewanella, Woesia) were present in significantly higher relative abundance on the RO membranes than in the prefilter cartridges, suggesting growth of certain taxa in the RO modules. Untargeted metabolomics distinguished intra- and inter-desalination plant biofilm samples, highlighting the potential value of this tool for biofilm monitoring. These findings underscore the value of omics tools for effective microbial monitoring, to understand biofouling dynamics within RO desalination plants, and to provide insight for the development of ecologically-informed biofilm control measures.

Planning the restoration of membranes in RO desalination using a digital twin

This paper describes the development of a decision support system (DSS) for evaluating membrane restoration strategy. The engine of the DSS is a digital twin (DT), a virtual representation of wear (degradation) and restoration of membrane elements in a reverse osmosis (RO) pressure vessel. The basis of the DT is a mathematical model that describes an RO vessel as a novel multi-component system in which the wear-states of individual elements (components) are quantified and elements can be swapped or replaced. This contrasts with the contemporary presentation in the literature of a membrane system as a single system. We estimate the parameters of the model using statistical methods. We describe our approach in the context of a case study on the Carlsbad Desalination Plant in California, which suffers from biofouling due to seasonal algae blooms. Our results show a good fit between the observed and the modelled wear-states. Competing policies are compared based on risk, cost, downtime, and number of stoppages. Projections indicate that a significant cost-saving can be achieved while not compromising the integrity of plant.

Stand-Alone Direct Current Power Network Based on Photovoltaics and Lithium-Ion Batteries for Reverse Osmosis Desalination Plant

Plummeting reserves and increasing demand of freshwater resources have culminated into a global water crisis. Desalination is a potential solution to mitigate the freshwater shortage. However, the process of desalination is expensive and energy-intensive. Due to the water-energy-climate nexus, there is an urgent need to provide sustainable low-cost electrical power for desalination that has the lowest impact on climate and related ecosystem challenges. For a large-scale reverse osmosis desalination plant, we have proposed the design and analysis of a photovoltaics and battery-based stand-alone direct current power network. The design methodology focusses on appropriate sizing, optimum tilt and temperature compensation techniques based on 10 years of irradiation data for the Carlsbad Desalination Plant in California, USA. A decision-tree approach is employed for ensuring hourly load-generation balance. The power flow analysis evaluates self-sufficient generation even during cloud cover contingencies. The primary goal of the proposed system is to maximize the utilization of generated photovoltaic power and battery energy storage with minimal conversions and transmission losses. The direct current based topology includes high-voltage transmission, on-the-spot local inversion, situational awareness and cyber security features. Lastly, economic feasibility of the proposed system is carried out for a plant lifetime of 30 years. The variable effect of utility-scale battery storage costs for 16–18 h of operation is studied. Our results show that the proposed design will provide low electricity costs ranging from 3.79 to 6.43 ¢/kWh depending on the debt rate. Without employing the concept of baseload electric power, photovoltaics and battery-based direct current power networks for large-scale desalination plants can achieve tremendous energy savings and cost reduction with negligible carbon footprint, thereby providing affordable water for all.

Carlsbad Desalination Plant Staff Shelter in Place to Produce Safe Water During COVID‐19 Pandemic

In the semiarid San Diego region, significant efforts have been under way to enhance water supply diversification for several years. Most of the region's potable water is imported from Northern California and the Colorado River, with the notable exception of the Claude “Bud” Lewis Carlsbad Desalination Plant.

Biological and Physical Effects of Brine Discharge from the Carlsbad Desalination Plant and Implications for Future Desalination Plant Constructions

Seawater reverse osmosis (SWRO) desalination is increasingly used as a technology for addressing shortages of freshwater supply and desalination plants are in operation or being planned world-wide and specifically in California, USA. However, the effects of continuous discharge of high-salinity brine into coastal environments are ill-constrained and in California are an issue of public debate. We collected in situ measurements of water chemistry and biological indicators in coastal waters (up to ~2 km from shore) before and after the newly constructed Carlsbad Desalination Plant (Carlsbad, CA, USA) began operations. A bottom water salinity anomaly indicates that the spatial footprint of the brine discharge plume extended about 600 m offshore with salinity up to 2.7 units above ambient (33.2). This exceeds the maximum salinity permitted for this location based on the California Ocean Plan (2015 Amendment to Water Quality Control Plan). However, no significant changes in the assessed biological indicators (benthic macrofauna, BOPA-index, brittle-star survival and growth) were observed at the discharge site. A model of mean ocean wave potential was used as an indicator of coastal mixing at Carlsbad Beach and at other locations in southern and central CA where desalination facilities are proposed. Our results indicated that to minimize environmental impacts discharge should target waters where a long history of anthropogenic activity has already compromised the natural setting. To ensure adequate mixing of the discharge brine desalination plants should be constructed at high-energy sites with sandy substrates, and discharge through diffusor systems.

Financialising urban water infrastructure: Extracting local value, distributing value globally

Since the insertion of urban infrastructure into the risk-taking world of financialisation, techniques for capturing added value from underlying revenue streams, from securitisation and derivatives to the structuring of bond and equity returns, have come to the fore. A value model, based on extraction through interest and dividends paid, as well as multiple fees, in our view, has benefited investors and financial intermediaries alike. Through the example of Carlsbad desalination plant in San Diego, California, the paper sets out to show how a piece of drinking water infrastructure was translated as a value asset to match the needs of institutional investors in the USA and beyond. The geography of value capture and its distribution globally is shown to be not simply financially innovative, but also spatially innovative and perhaps best understood through its topological spaces.

Tapping into the Pacific

In its first year of operations, the 54 mgd Claude “Bud” Lewis Carlsbad Desalination Plant, in Carlsbad, California, has greatly boosted the volume and reliability of San Diego’s local water supplies. At a time when much of California must contend with drought and the prospect of diminishing water supplies, the San Diego region enjoys the comfort of knowing that a portion of its water supply is droughtproof.

“Salty” conversation

Thiel replies: When thinking about potential toxicity, which Neal Reid mentions, it’s key to remember that almost all the material in the brine originated in the ocean. Nevertheless, ensuring environmentally friendly disposal continues to be an active area of research, and modern outfalls are very effective at dispersing the brine flow so as to minimize local increases in the concentration of salts and other dissolved compounds. A study for the Carlsbad desalination project in California concluded that properly designed outfalls have “impacts that extend only a few tens of meters from the discharge.”11. S. Jenkins et al., Management of Brine Discharges to Coastal Waters: Recommendations of a Science Advisory Panel, tech. rep. 694, Southern California Coastal Water Research Project (March 2012), p. ii. The Carlsbad plant also mixes the reverse-osmosis brine with seawater used for cooling a colocated power plant prior to discharge, which reduces its salinity before it hits the ocean. And as for the comparison to nuclear waste, let’s not forget that the diffusion time for the salt in the disposed brine is orders of magnitude less than the half-life of radioactive waste!To answer Jonathan Allen’s concern, the kWhe values given for the evaporative systems are exergetic values of the heat input. That approach uses the Carnot efficiency between the desalination system’s top temperature, which often reaches 70 °C, and an ambient temperature of 25 °C to convert between heat and work. The cost of the thermal energy input itself may be less than for electricity, but the costs associated with constructing, for example, a solar-thermal collector or a heat exchanger required to use waste heat can be significant. Lower energy consumption may not imply lower cost, but reverse osmosis is far and away the dominant choice of recent installed desalination capacity.Desalination powered by renewable energy is a topic of great interest to many in the desalination community—myself included!REFERENCESSection:ChooseTop of pageREFERENCES <<CITING ARTICLES1. S. Jenkins et al., Management of Brine Discharges to Coastal Waters: Recommendations of a Science Advisory Panel, tech. rep. 694, Southern California Coastal Water Research Project (March 2012), p. ii. Google Scholar© 2015 American Institute of Physics.

CoorsTek forms membrane sciences group - combining hydrogen and oxygen transport membrane technologies

Detrimental biofilms on RO membranes remain a crucial challenge for seawater desalination. Comparative analysis of 16S rRNA gene amplicon sequencing data revealed differences and commonalities of biofilm communities associated with unit operations in the two largest seawater desalination facilities in the U.S., the Claude "Bud" Lewis Carlsbad Desalination Plant and the Tampa Bay Seater Desalination facility. At both plants, feedwater collected at a single time point was a poor indicator of the RO membrane communities, which showed far greater taxa diversity. The analysis of prefilter cartridges from the Carlsbad plant revealed similarly high taxon diversity as the RO module biofilms, with relevant differences. Algal sequences were enriched on the prefilter cartridges as were sequences representing Bdellovibrionota, which are predatory bacteria. Sequences representing opportunistic Gammaproteobacteria (i.e., Shewanella, Woesia) were present in significantly higher relative abundance on the RO membranes than in the prefilter cartridges, suggesting growth of certain taxa in the RO modules. Untargeted metabolomics distinguished intra- and inter-desalination plant biofilm samples, highlighting the potential value of this tool for biofilm monitoring. These findings underscore the value of omics tools for effective microbial monitoring, to understand biofouling dynamics within RO desalination plants, and to provide insight for the development of ecologically-informed biofilm control measures.

IAEA's DEEP in Carlsbad: co-producing energy and water in Southern California

The joint production of energy and desalinated water is examined in the context of the construction of a Reverse Osmosis (RO) plant at the site of the (fossil-fired) Encina Power Station in Carlsbad, California. The first part of the paper reproduces cost estimates of water at the Carlsbad Desalination Project. The second part of the paper reproduces these cost estimates using the International Atomic Energy Agency's Desalination Economic Evaluation Program (DEEP). The paper shows that the cost of desalinating water with nuclear power is cheaper than at fossil-fired plants, given the high cost of fossil fuel. Further, the estimated costs of producing electricity and water with gas reactors and gas turbines are lower than light water reactors with steam turbines. The paper concludes by suggesting that the next step in nuclear desalination in the USA would be to construct an RO plant at an existing light water reactor.