Knowledge and Perception of Brine Waste Management Policies in the Desalination Industry, Malaysia

The global scarcity of fresh water has led to the increased implementation of desalination plants to meet the rising demand for water in human consumption, industrial processes, and agriculture [1]. Seawater desalination involves removing salt and contaminants from seawater to produce freshwater, though it has some disadvantages. One primary by-product of this process is hypersaline effluent, also known as brine, which contains high concentrations of salts, nutrients, heavy metals, organic pollutants, and microbial contaminants [2].

Desalination plants typically produce about 1.5 litres of brine per litre of freshwater, affecting ocean chemistry and health due to altered physicochemical properties [3, 4]. Brine disposal harms marine ecosystems and biodiversity, increasing salinity, temperature, and harmful chemicals [5]. The presence of toxic substances like metals and pesticides in brine makes its disposal an environmental threat [6].

Improper brine disposal affects both marine and land environments. It can contaminate aquifers, degrade soil quality, and pose health risks due to high salinity levels. Even minor salinity shifts (1–2 ppt) can harm communities. Better understanding and management of brine are crucial for environmental sustainability [7].

It can be presumed that seawater desalination is gaining attraction in Malaysia, with many plants proposed or in the planning stage [8]. Desalination plants are planned for Johor, Pulau Pinang, and Labuan, and one existing plant has been constructed in Bachok, Kelantan, Malaysia. Additionally, MPDT Capital Berhad, under a joint venture with Johor Special Water (JSW), has established the largest desalination plant in this part of the region. The seawater desalination plant, with a capacity of 250 MLD, will supply demineralized water to the Pengerang Integrated Petroleum Complex (PIPC) located in Pengerang [9]. MPDT also plans to build a seawater desalination plant in Pulau Pinang, supplying 250 MLD of water to state utility Penang Water Supply Corporation (PBAPP) [10-12].

The proposed desalination plant project aims to address water shortages, but the environmental impact of brine byproduct requires further investigation. Limited studies in Malaysia highlight gaps and opportunities during pre and post-construction stages. Previous research did not clearly address the environmental impact of brine effluent in Malaysian policies. This study examines awareness and perception of desalination plant policies before and after construction and the environmental impact of brine waste on ecosystems. Findings will address gaps in Malaysia's regulatory framework and propose new policy recommendations, comparing practices from other countries. According to Abdul Ghani et al. [13], the increasing public awareness about desalination plants may pose challenges for stakeholders. Nonetheless, it is possible to mitigate the adverse environmental impacts of desalination through the promotion of environmental consciousness and comprehensive preliminary planning. Enhanced awareness among the public and policymakers regarding the environmental issues associated with brine disposal could lead to the development of new environmental regulations in Malaysia.

Based on expert feedback, seven questions were modified, and two were removed from the revised questionnaire. Questions that appeared unclear or confusing were omitted. Part A of the distributed questionnaire includes the respondent's name, years of experience, education level, and organization.

Table 2 shows demographics of 100 respondents: 60 from government agencies like DOE and SPAN, 28 from private companies such as Dubai desalination firms and CarbonWorks, and the rest from universities including Universiti Teknologi Malaysia and Universiti Malaysia Terengganu.

Table 2. Demographic data of respondent

In this study, twenty (20) experts were selected from a pool of 100 respondents, representing diverse fields of expertise and varying years of experience. These experts, chosen for the next phase of analysis, possess over 15 years of experience in critical areas such as the desalination process, environmental impact assessment (EIA), environmental engineering, chemical engineering, mechanical engineering, civil engineering, and waste management. The careful selection of these experts is crucial for the Fuzzy Delphi study, as the study's validity hinges on the panel members' expertise. This selection process ensures that the study's findings are grounded in the knowledge and experience of seasoned professionals in their respective fields.

3.1 Fuzzy Delphi Method (FDM) for parameter’s limit for brine disposal

The symbols P1, P2, P3, and P4 denote the temperature limit, pH limit, salinity impact zone, and salinity limit, respectively. Table 3 shows the threshold value, d, for regulation and guidelines for brine disposal.

According to Table 3, the ‘d’ value for P1 is 0.263, P2 is 0.227, P3 is 0.223, and P4 is 0.199. All the threshold values are less than 0.3, indicating that all experts accept the suggested solutions. The panel's agreement indicates that the chosen parameters are linked to the theoretical framework, as these factors impact environmental ecosystems when considering brine effluent.

Table 3. The threshold value, d, for regulation and guidelines for brine disposal

Table 4 presents the percentage of parameters for the limit of brine disposal. For P1, 15 experts achieved d values less than or equal to 0.2, resulting in a 75% agreement among experts. For P2, 16 experts had d values below 0.2, amounting to 80% expert unanimity. Similarly, P3 also saw 16 experts with d values under 0.2, leading to an 80% consensus. In the case of P4, 17 experts reported d values smaller than 0.2, indicating 85% expert agreement. Consequently, all parameter limits are accepted by the experts as the consensus exceeds 75%.

Table 4. Percentage (%) of parameters limit of brine disposal

Table 5 presents a defuzzified process for determining the fuzzy score. As indicated by the table, the fuzzy scores are as follows: P1 is 0.770, P2 is 0.790, P3 is 0.792, and P4 is 0.803. P4 achieves the highest score, suggesting that the most effective actions recommended within these four proposals should be implemented to enhance the Environmental Quality Act 1974 (Act 127) and mitigate the environmental impact of brine effluent disposal on marine ecosystems.

Table 5. Defuzzified process for determining the fuzzy score

Tables 4 and 5 explain the correlation between the consensus of 75% and the fuzzy scores for different parameters (P1, P2, P3, and P4), which reflect the complexity and uncertainty associated with brine waste management. These fuzzy scores indicate the importance of incorporating these factors into policies or guidelines for both the pre-construction and post-construction phases of desalination plants due to brine waste management considerations [24].

Table 6 provides summaries of the parameter’s limit of brine disposal regulations and guidelines. Here, all the solutions offered adhere to the criterion provided by the FDM. This result also revealed that P4 received the top rating based on the fuzzy score. P2 and P3 have the same rank, and P1 has the fourth-ranking score. Undoubtedly, all the proposed guidelines are acceptable to all the experts who participated. However, P4 is the most efficient after considering the proposed guidelines in the questionnaire form. In agreement with Khan and Al-Ghouti [25], the expert acknowledges that the salinity limits (P4) play a crucial role in brine disposal management. The high saline content in brine poses severe threats to aquatic organisms. Furthermore, elevated salinity levels in land application can harm groundwater, potentially leading to aquifer pollution.

Table 6. Summaries of the FDM for parameter’s limit of brine disposal

3.2 Fuzzy Delphi Method (FDM) for brine management practice

There are three brine management practices for this section: (1) The construction of a desalination plant should be included in the prescribed activities of Schedule 1 (S1) or Schedule 2 (S2) under the Guidelines of Environmental Impact Assessment (EIA); (2) Regulations on brine waste disposal under the Environmental Quality Act of 1974 (S3) should be implemented. Table 7 shows the threshold value for brine management practices.

Table 7. The threshold value ‘d’ for brine management practice

Table 7 showed that all of the threshold values are less than 0.3, suggesting that all experts agree upon all of the assertions in this section. The table showed the expert consensus of questions relating to brine management practice. The average d value for the statement that the construction of a desalination plant should be listed in the prescribed activities of Schedule 1 (S1) is 0.184. In contrast, the idea of the construction of a desalination plant should be listed in the prescribed activities of Schedule 2 (S2) as 0.216. Malaysia should regulate brine waste disposal in the Environmental Quality Act 1974 (S3) is 0.224. Since this threshold value fell below 0.3, all statements in this section were permitted for further investigation because they satisfied the first requirement.

Table 8 shows the percentage of brine management practice. According to the table, for S1, 19 experts have d values less than or equal to 0.2, resulting in a 95% agreement among experts. For S2, there are only 13 experts with d values smaller than 0.2; the proportion of expert unanimity is 65%. Similarly, for S3, there are only 12 experts with d values smaller than 0.2, leading to a 60% expert consensus. Therefore, only the S1 proposal meets the criteria for acceptance by the experts, while S2 and S3 do not achieve the required level of expert consensus.

Table 8. Getting a 75% consensus for brine management practices

Table 9. Defuzzified for brine management practice

According to Table 9, the fuzzy score for S1 is 0.803, S2 is 0.743 and S3 is 0.725. As a result, only the S1 practice meets the required agreement threshold. However, S2 and S3 did not receive more than 75% of the consensus. Therefore, it is concluded that every application for the construction of a desalination plant requires the submission of an Environmental Impact Assessment (EIA) under the Schedule 1 prescribed activity, as these facilities can impact the environment during construction and operation.

Table 10 summarizes the brine management practice. According to the table, just one of the assertions in this table meets the Fuzzy Delphi Method's criteria. This result also revealed that S1 was rated the highest based on the fuzzy score. The expert consensus, however, rejected S2 and S3. The expert confirms that to construct a desalination plant, submitting an Environmental Impact Assessment (EIA) as a prescribed activity under Schedule 1 is mandatory. In Spain, the Royal Decree 1/2008 introduced aspects of public participation, modified the administrative process, and expanded the list of projects subject to EIA, as outlined in Annexes I and II. However, desalination plants in Spain with a new or additional capacity exceeding 3000m³/day of water production fall under Annex II, Group 8, Section E: Water Engineering and Management Projects [26]. It is worth noting that the proposed desalination plant in Malaysia has a production capacity of only 2500m³/day, making it fall below the specified threshold.

Table 10. Summaries of FDM for brine management strategies and technologies

The study compared Malaysia's brine waste management regulations with those of other countries, fulfilling its objectives by highlighting theoretical reasons for observed differences or similarities. Further exploration of environmental, engineering, and policy aspects is needed to achieve best practices in brine waste management.