Concentrate Management Toolbox and Selected Case Studies

Project ID: 5239
Principal Investigator: Saied Delagah
Research Topic: Desalination and Water Treatment
Priority Area Assignments: 2015 (Advanced Water Treatment), 2016 (Advanced Water Treatment)
Funded Fiscal Years: 2015, 2016 and 2017
Keywords: concentrate management, ntmwd, emwd, sustainability, environmental impact, cost, energy efficiency

Research Question

In this study, we propose to develop a toolbox of concentrate management methods that is evaluated within the context of two case studies: North Texas Municipal Water District (NTMWD), TX and Eastern Municipal Water District (EMWD), CA. The aim of the effort is to reduce the overall cost of in-land brackish desalination by reducing concentrate volumes and management costs.

The following research questions will be addressed during the development of the concentrate management methods toolbox:

1. What methods are available to treat, manage, and reduce the volume of concentrate generated by inland desalination of brackish water? The following are examples of the types of methods to be considered:
* Concentrate minimization by increasing primary RO recovery (pretreatment, RO operational improvements, membrane selection, etc.)
* Concentrate treatment technologies
* Concentrate disposal methods

2. How can different concentrate management methods be compared? Which criteria should be used to compare different methods, and how might these criteria differ by state?

The following research questions will be answered during the case studies for NTMWD and EMWD:

1. What factors are affecting concentrate management at the two case study sites?

2. How can the criteria identified above be applied to assess the factors which determine the most suitable concentrate management technique for each inland desalination application?

3. Based on the results of the criteria evaluation, what strategies are best suited to reduce and manage concentrate generated from the NTMWD and EMWD desalination plants?

Need and Benefit

Brackish water desalination plants are being installed across the country in an effort to diversify water supply portfolios and improve overall supply reliability, particularly during droughts. According to the International Desalination Association, the United States is ranked as having the second largest total desalination capacity of any country in the world with desalination plants in more than 40 states. In this project we will work with water districts in both Texas and California to address inland concentrate management needs. Texas has a total of 46 desalination plants in operation with an installed capacity of about 123 MGD, the majority of which employ RO. California has brackish and seawater desalination with an installed capacity of approximately 250 MGD. Wider adoption of inland brackish desalination remains constrained by technological, financial, environmental, and regulatory issues associated with concentrate management.

Regarding concentrate management technologies, a wide variety of methods exist that have already been commercialized, and many water purveyors are often overwhelmed when considering which technology is the best for their situation. Due to the large number of technologies available for treating concentrate, there is an increased interest by commercial entities looking to sell technology to solve concentrate issues. All new and expanding desalination facilities must spend time and resources evaluating these technologies, which drives up the high cost of implementation even further. By developing a Concentrate Management Toolbox that inventories existing technologies and identifies practical and economical strategies to optimize concentrate management, water planners can more rapidly assess concentrate management options and lower costs of implementation.

Thousands of documents have been published regarding concentrate management. These documents range from technology development studies to regional assessments, and review documents. In this project we do not propose to duplicate any of the work previously published, rather we intend to leverage Reclamation's unique perspective, technical expertise, stakeholder relationships, and past funding experiences, to provide a more practical assessment of concentrate management.

In terms of new technologies, researchers and consultants have published reports documenting the success of these projects. However, as we have found from past funding experience, what the researchers consider successful may not be suitable for a water district interested in implementing the technology. Additionally, what may work on a smaller scale, may not be practical on a large scale. A good example of this is the large salt requirement needed to operate the ZDD technology. During the Toolbox development tasks of this project we will conduct a critical assessment of technology suitability and assess the commercial readiness of emerging technologies. This has not been done before by an entirely unbiased group.

The main class of documents in the literature regarding concentrate are those which summarize concentrate management methods (WRF 05-009-01 and WRF 02-006a-01, USBR 123, USBR 155,). Again these documents typically lack assessments based on pilot testing and often times are specific to one type of technology or method. WRF 07-02-1 provides background in concentrate. In WRF 02-006d-01, guidelines are presented for selecting a concentrate management practice. The guidelines presented in this work will be considered as a first step in Case Studies and our 2 case studies will be evaluated within this context. If the guidelines are insufficient, then steps will be taken to modify them to meet our needs. Additionally, WRF-02-006d-01, includes general technologies such as RO and EDR, but does not consider the technologies undergoing commercialization such a the ZDD and AquaSel. Our effort will identify how these technologies can be considered within the framewo

Contributing Partners

Contact the Principal Investigator for information about partners.

Research Products

The final study products will include:

• Final Report containing comprehensive concentrate management tools and methodologies
• Concentrate mgmt. solutions for the case studies at NTMWD and EMWD
• Presentations at various professional conferences


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Last Updated: 4/4/17