1. Title, Journal and Authors

 

Title: Overview of systems engineering approaches for a large-scale seawater desalination plant with a reverse osmosis network

 

Journal: Desalination

 

Authors: Young M. Kima,b, Seung J. Kima,b, Yong S. Kima,b, Sangho Leec, In S. Kima,b, Joon Ha Kima,b*

 

2. Summary

 

1. Introduction

It is essential to prepare for the water shortage crisis that may arise from the unpredictable effects of global warming. The use of seawater to solve the water shortage problem is inevitable, and recent global industry outlook has shown that the global desalination industry is rapidly expanding since 2005, which is just the beginning of the desalination market expansion.

 

Researchers have tried to develop Multi-Stage Flash (MSF), Multi-Effect Distillation (MED), Electro-Dialysis (ED), and Reverse Osmosis (RO) processes to solve the water shortage problem. Currently, research is being conducted on the development of a process capable of reducing costs and operating environment-friendly rather than improving performance. Consideration of total water production cost, the land scarcity of a nation, and environment-friendly operation, the reverse osmosis process is expected to become the most economical technology.

These days, the following studies are being actively conducted

 

1. Pressure driven membrane pretreatment process

2. Development of material to prevent contamination of reverse osmosis system
and corrosion of distillation process

3. Hybrid seawater desalination process using reverse osmosis-thermal

4. Converting the energy used in the desalination process to alternative energy
sources.

 

2. Systems investigation

In this paper, the approach and considerations for each system were considered to solve the problem of the Sea Water Reverse Osmosis (SWRO) desalination plant. The models used to predict system characteristics are also described.

 

The UF pretreatment process is more efficient than the conventional pretreatment process.

In the RO membrane process, fouling/scaling can reduce the permeate flow rate, leading to an increase in operating costs. In order to solve this problem, cleaning must be performed, and the optimum cleaning speed enables an optimal estimation of the operating cost of the RO membrane process.

Also, the cleaning principle is as follows.

Silica colloids > Adsorbed organic compounds > Particulate matter > Microorganisms > Metal oxides

In order to increase the permeate recovery rate, the influent through the RO inlet membrane must have a high water quality. As a result, low power consumption can reduce SWRO plant operating costs.

In addition, the high salinity effluent from the SWRO desalination plant and the chemicals used for pretreatment and cleaning can contaminate the marine environment, so methods for treating it must be studied. Here are some disposal options.

1. Discharge into deep aquifers that cannot be used

2. Utilization of evaporation ponds and zero discharge.

3. Connection to wastewater treatment plant

4. Blending with treated waste water and use same discharged outfall, etc.

 

3. System design models & system optimization

In order to optimize the system, seawater quality information, site conditions and area, and environmental impact must be investigated. The author expressed the total cost as an important objective function that should be included in the optimization of the seawater desalination system, and the total cost was divided into the capital cost and O&M (Operation cost & Maintenance cost). The optimization model used thereafter was briefly described. Examples for optimizing total cost have also been described in detail.

 

4. Future implications

Lastly, the author proposed a technical study of four processes (pre-treatment process, RO membrane process, energy saving process, and post-treatment process) from the viewpoint of economical and improved process performance of water production. In the pretreatment process a more effective operational design and more sophisticated automation and control will result in lower costs of water production. And better understanding of the mechanism of water transfer and salt rejection in RO membranes at the molecular level will lead to a new era of membrane technologies.

 

3. Originality and Creativity

 

4. Application to research

 

5. Contact

Yeong Gyu Gu / Intern student

Environmental Systems Engineering Lab.

School of Earth Sciences and Environmental Engineering

Gwangju Institute of Science and Technology

1 Oryong-dong Buk-gu Gwangju, 500-712, Korea

 

Phone : +82-10-6589-6653

E-mail : kududrb1@naver.com