Risk Assessment of Drinking Water Using WSP for Azraq Spring-Jordan

Abstract

Water Safety Plan (WSP) is considered as a collaborative approach dedicated to the risks of water impurity in a drinking water operating system, started at the catchment and finished at the end user, to protect people’s health. The aim of this study is to accomplish a WSP for the drinking water operation system of Azraq Spring. It is located in Fuhais in the northwestern part of Balqa, about 20 km west of Amman. The catchment area is 23.71 km2 and it has a perimeter of 20.42 km. Semi-quantitative approach is used for risk assessment. Possible hazardous events and related hazards were recognized in each portion of the water operation system. WSP decreases the risk of public health, guarantees the water quality with standards requirements, increases the trust of users, and advances management of water resources due to involvement planning. New control measures are suggested by the WSP team within this study.

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Khrisat, H.T. (2022) Risk Assessment of Drinking Water Using WSP for Azraq Spring-Jordan. Open Access Library Journal, 9, 1-16. doi: 10.4236/oalib.1108899.

1. Introduction

Accomplishing good water quality requires monitoring of the environment and human health. WSP procedure is considered as a collaborative approach dedicated to exploring the risks of water impurity in a drinking water operating system, started at the catchment and finished at the end user, to protect people’s health and significantly decrease water pollution in the whole drinking water operating system (DWOS). Azraq Spring is considered the main source of drinking water for Fuhais city, but it is difficult to get all the quantity of groundwater abstraction from Azraq in past years due to the increase in E. coli and nitrate. The aim of this study is to achieve the WSP for the drinking water operation system (DWOS) of Azraq Spring, and assessment of the groundwater pollution that may result from agricultural activities and Fuhais wastewater treatment plants using WSP [1].

2. Study Area

Azraq Spring is located in Fuhais in the northwestern part of Balqa, about 20 km west of Amman at N-32˚1.232 and E-35˚45.754 as shown in Figure 1. Azraq catchment area is equal 23.71 km2 and it has perimeter equal 20.42 km. The long-term average discharge of Azraq Spring is around 1.4 MCM annually [2].

3. Methods

Figure 2 shows the flowchart of Water Safety Plan (WSP) that will be followed to achieve the objectives of the research.

3.1. Formation of a Multidisciplinary Team That Involved

This step included nomination of team member; operation manager, researchers, and environment and health protection Authority as shown in Table 1.

3.1.1. Description of Drinking Water Operation System

Azraq Spring is originated from A7/B2 aquifer which is the most exploited aquifer in Jordan. It is a highly fractured-rock aquifer, consisting of sedimentary rocks (primarily carbonates and chert) from the late Cretaceous epoch. The fractures and other discontinuities such as joints, fissures and faults that occur in the rocks are allowing it to hold huge amounts of groundwater so it can be considered as a highly productive aquifer. Average discharge of Azraq Spring is around

Figure 1. Study area.

Figure 2. WSP flowchart.

Table 1. Water safety plan team members and their roles for each one.

R: Responsible; I: Involved; A: Aware.

1.4 MCM/Annual. Azraq is used for water supply of Fuhais and Mahis. According to increasing number of microbial contaminations that associated with E. coli, the water of Azraq Spring starting treated through Shuraia treatment plant since 2007 [3]. Shuraia Treatment plant is non-conventional membrane plant that started of strainers and then three main consecutive treatment processes; Filtration by Micro-filtration, Disinfection by ultraviolet (UV), and post chlorination by residual chlorine. Each of these treatment processes provides a barrier to microbial contamination to provide greatest assurance for safe drinking water. About 90 m3 of chlorinated water returns back to Azraq tank (550 m3) which pumps water to Fuhais pumping station (PS), as shown in Figure 3. Azraq Spring was sampled regularly on a monthly basis by WAJ Lab.

3.1.2. Determination of Hazards, Hazardous Events, and Risk Assessment

What-If/Checklist analysis was applied to determine hazardous events and to assess the risk. It included brainstorming of results of the What-If/Checklist [4]. Typical hazards were analyzed, such as chemical, physical and microbial contamination, water deficiency events as shown in Table 2.

Semi-quantitative risk matrix was used as recommended by World Health Organization (WHO) guidelines as shown in Table 3, to approximating the likelihood of occurrence for each hazard and calculating the severity of consequences when hazard occurred.

Classification of likelihood and the severity of consequences are shown in Table 4, which agrees with national drinking water quality standards and health regulations. The management actions for each risk category that resulted from the risk matrix are shown in Table 5.

Figure 3. Diagram of Azraq drinking water supply system.

Table 2. Hazardous events and hazard type for each step in DWSS.

Table 3. The semi-quantitative risk matrix [5].

Table 4. Severity of consequences and likelihood classification.

Table 5. Management action for each risk category resulted from applying risk matrix.

3.1.3. Determination of Control Measures, Validation and Risk Re-Assessment

Control measures are phases in the drinking-water operation that directly effect on water quality to ensure the water regularly correspond water quality limitations as shown in Table 6. Risks were re-assessed for each hazardous event and hazard according to a new value of severity.

3.1.4. Development of an Upgrade Plan with New Control Measures to Reduce Risk Rating

Evaluating whether the control measures are effective or not, if improvement are required, establish corrective action for deviations and incidents that may occur

Table 6. Determination of control measures, validation.

and emergency responses. All control measures are important and should be afforded ongoing attention. They should be subject to operational monitoring and control, with the means of monitoring and frequency of data collection based on the nature of the control measure and the rapidity with which change may occur.

3.1.5. Development of a Monitoring Plan

This monitoring plan establishes what will be monitored, how it will be monitored, the frequency of monitoring, who will do the monitoring, and critical limits and related corrective actions. According to Jordanian Drinking Water Standards [6], drinking water must show conformity with the health standards, and carry out the necessary laboratory tests by applying the operation monitoring program of WAJ as shown in Table 7.

4. Results and Discussion

4.1. Identification of Hazardous Events, Hazards and Risk Assessment

The potential hazardous events and all related potential physical, biological, chemical or radiological hazards associated with each step in the DWOS were identified. Table 8 showed the result of risk assessment before consideration of the current control measures.

Table 7. Monitoring programs of the water authority on the quality of raw water, treatment and network.

Table 8. Risk assessment of hazards for each step in the DWSS before consideration of the current control measures.

At the catchment, Storm water event in the drinking-water catchment causing surface water runoff which leads to infiltration of polluted surface water to the shallow aquifer causing increase in turbidity and microbial contamination of the raw water at inlet of water treatment plant. This mean there is no water inlet the plant. So, the severity of consequences is 4 (considerable). Based on the information reported by the operator of the water system, the probability of occurrence more than once a year so the likelihood is considered as Frequent (5). Thus the calculated risk is very high (5 × 4 = 20). At treatment phase, inefficient filtration due to the failure of the filter membranes or before expected life time (i.e. before 18 - 24 months), microbial contamination resulted due to the presence of E. coli in the water. So the severity of consequences is major impact (4). Based on the information reported by operator of water system, the possibility of occurrence is once a year so the likelihood is most probable (4). Thus, the calculated risk is medium (4 × 4 = 16). Fifteen events of hazard were analyzed (8 at catchment, 3 at treatment and 4 in distribution phase) [7]. Risks assessing uncertainty resulted due to lack of data, poor knowledge of activities within the water operating system and their contribution of risk created. This problem was overcome by collaboration of the DWOS manager and operator through providing with information that required for WSP development, which is essential for e successful operation of WSP [8].

4.2. Identification of Control Measures and Validation, Risk Reassessment and Prioritization

Validation of control measures were by site investigation of catchment areas and validating performance monitoring procedures such as qualitative measures. If a results of control measure did not compliance with Jordanian water quality regulations the validation was considered ineffective.

As shown in Table 9, at the treatment plant there are seven MF units at full

Table 9. Identification of control measures and validation, risk reassessment and prioritization.

*E: Effective; +NE: Not Effective.

capacity 22,000 m3/h but the amount of water entering the station is about 14,000 m3/h which was 2/3 of the full capacity of the treatment plant. Currently the operator uses 5 of 7 of the MF unit and if one of the MF is damaged or need maintenance the operator used one of the MF unit that is stand by. The validation of this control measure displayed that they are effective. So that, likelihood for this hazardous event reduced from most probable to infrequent, so on the risk becomes low. But when the control measures are not effective the likelihood could not be reduced.

Assessment of likelihood must be objective. So, WSP members used historical data of monitoring programs from data bank of Laboratories and Quality Affair/Water Authority of Jordan and the facts provided by the DWOS manager and operator.

Upgrade of WSP must be done after assessment of a risk. So new control measures were identified to reduce risks for each hazard event considered that had medium to high risk rate. Stopping work of air valves lead to high pressure of the unit and which stop automatically due to the failure of the air -feeding system of the air valves in the MF filter unit and so on reducing quantities of water production of the station. So that existence of a backup air system and availability of spare parts could be considered as a new proposed effective control measures.

4.3. Upgrading Plan of a Monitoring and WSP’s Effectiveness Verification

Monitoring plan was developed after determination of new control measures, including; what should be done, how it should be done, when it should be done, where it should be done and who is responsible. Furthermore, stringent limits and related reformist actions were recognized. Stringent limit for each water quality characteristics were fixed value lower than limits of Jordanian standards [9]. An override of stringent limits needs serious reformist actions, to get safe water to users. WSP members should discussed reformist actions for each hazard event with local health authority to take a decision about application of an alternative emergency plan for water operating system.

Table 10 showed an example regards the monitoring of increase in turbidity of the water produced from the MF unit due to damage and rupture of the filter membranes. The water utility engineer and the operator should monitor the pressure differential readings of the filters (ΔP) and the measurement of the flow of the individual filters in addition to the turbidity measurement of the MF filters.

Table 10. Example of stringent limits and related reformist actions (monitoring plan of WSP).

Table 11. Example of what, where, when, how, and who will be verified in verification plan.

A verification plan was established after generating the monitoring plan. It included what will be verified, where it will be verified, when it will be verified, how it will be verified, and who will do the verification as shown in Table 11.

Table 11 showed example related with verification of biological water quality characteristics in distribution system, in order to accomplished water safety requirements for users. Biological water quality parameter (microbial pathogens, such as E. coli) must be monitored monthly. Monitoring process includes collecting water samples from drinking water treatment plant and from water distribution network randomly and analyzing it in WAJ laboratory.

5. Conclusion

WSP is an important tool for water operational and management assessment for Fuhais town. So it was discussed and shared with the water administration manager. To improve water quality, serious topics related to DWOS were determined and control measures were proposed. By implementing WSP, many advantages were realized in Azraq DWOS. It minimizes risks related to public health, confirms compliance of the water quality parameters with Jordan regulation requirements, improves the confidence of consumers about drinking water quality to use, and develops intervention planning for good resource management. Some of the new control measures proposed in WSP are already adopted by the water administration manager.

Conflicts of Interest

The author declares no conflicts of interest.

References

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