OPTIMIZATION OF WATER DESALINATION BRINE DISPOSAL

Abstract

7.1 INTRODUCTION

Although desalination process has provided solution to millions of citizens all over the world to have a fresh cup of water, but major environmental problems are accompanied by this process, one of which is the production of a flow of brine containing the salts removed from the intake water and that needs to be disposed. Several methods have been identified for brine disposal, also several studies have been developed to mitigate negative impacts on the surrounding environment.

Accordingly, this study aims to develop a mathematical model to assist decision makers (Consultant’s or Government authorities) in the selection of an optimum brine disposal method applying applicable, environmentally friendly and cost effective methods, through a user friendly interface that reaches results in a very short time depending on users inputs.

Thus by applying the “Brine disposal decision support system” (BDDSS) model on any existing desalination plant will provide different scenarios for brine disposal. In addition to creating the environmental solution to minimize negative impacts on the surrounding environment for each method and calculate the design criteria for each method. The model will also calculate the estimated budget for each scenario. After taking the environmental and site considerations into account, the model will provide the optimum solution. The optimum solution provided is the one achieving lowest cost and lowest negative environmental impact

7.2 CONCLUSIONS

Generally, the study outcomes can be summarized as follows:

1. The disposal of brine rejected from desalination plants is always accompanied by negative environmental impacts on the surrounding environment.

2. There are several methods developed for brine disposal, the three methods commonly used are (i) sea disposal, (ii) pond disposal, and (iii) deep well injection.

3. The aim of the study is to develop a mathematical model to assist decision makers (Consultant’s or Government authorities) in the selection of an optimum brine disposal method applying applicable, environmentally friendly and cost effective methods

4. The model addresses a wide range of users starting from an owner of a project who needs to know the optimum solution having the minimum cost and complies with the regulations in order to get the necessary approvals, moving forward to a government entity who wants to check the compliance of the desalination plant to the laws and regulations and ensure it followed the right approach to dispose the brine. Finally the model addresses also the consultant who might be hired by the previous users mentioned above to study the different alternatives for brine disposal as per each entities objectives.

5. The model achieve integration of services, as: - The model integrates applicable water disposal solutions, applying environmental mitigation measures and check compliance with the regulatory / and environmentally aspects together - In addition to above, the model also achieve value for money for optimum disposal method, by assisting decision makers reaching the most economic benefits of each disposal method - The model can act as a water expert in providing a robust applicable method for brine disposal alternatives including design details for each disposal method - The model can act as a cost engineer / expert in estimating budget/ costs for all disposal options identified above, assisting decision makers in verifying the value for money for the optimum method to be used - The model also can act as an Environmental expert, to ensure compliance of each disposal model with all relevant laws & regulations.

6. The model’s interface is considered to be a user friendly interface, as it is supported by auto assisting aiding tools that that provide the users with smart illustrations and hints on the screen that guide the users during entering the input data

7. The model structure consist of inputs, formulas and outputs as follows: - Model input is considered to be the first step after gathering data on the desalination plant and the ambient environment surrounding the plant. The user shall input the data in the identified cells respectively where it is classified into categories starting from desalination plant passing by inputs related to each disposal method as per observed and measured - Model formulas, The model utilize formulas use to design the technical solution used for brine disposal, where the formula’s section includes all the required formulas to convert the data inputs to a comprehensive outputs, it includes all the design principles and equations applied for each disposal method - Model outputs is the final step that translate all the inputs mentioned above to a reliable outcomes that asset decision makers in identifying the optimum disposal method, the outputs are illustrated as follows:  Optimum solutions for brine disposal  Valid / Non Valid options / Environmental concern  Cost estimates for each option  Environmental concerns

8. Finally, the model reach the target of applying the model on any desalination plant, after evaluating all the results and outcomes, calculating cost estimates for each disposal method. In addition to evaluating the environmental concerns for each alternatives the results were illustrated, and provides the optimum scenario among the three brine disposal scenarios having the minimum cost and minimum environmental impacts.