Table 4.
Assessment of hazardous events at brackish desalination plants by seven raters.
| Hazard | Hazardous event | Likelihood avg (SD) | Severity avg (SD) | Risk level avg (SD) |
|---|---|---|---|---|
| Microbial | Low level of disinfection below the recommended limit | 3.27 (1.00) | 3.60 (1.05) | 12.71 (6.55) (high risk) |
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| Chemical and microbial | The power outages affect the efficiency of the desalination process | 3.25 (3.23) | 2.24 (2.23) | 10.04 (9.99) (high risk) |
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| Chemical and microbial | Desalinated water is mixed with nondesalinated water | 2.49 (1.34) | 2.49 (1.38) | 7.95 (7.32) (medium risk) |
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| Physical, chemical, and microbial | The cap of the desalinated water tank is absent or partially opened | 1.97 (1.07) | 2.27 (1.28) | 5.76 (5.79) (low risk) |
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| Microbial | Water discontinuity or stored for an extended period inside the tank | 2.04 (0.94) | 2.25 (1.11) | 5.57 (4.87) (low risk) |
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| Physical, chemical, and microbial | Presence of foreign objects inside of desalinated water storage tank | 1.88 (0.89) | 2.23 (1.25) | 5.23 (4.79) (low risk) |
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| Microbial | The discharge pipes and hoses touch the ground | 1.95 (1.07) | 2.05 (1.19) | 5.22 (5.71) (low risk) |
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| Physical and microbial | Air vents unscreened allowing ingress of insects | 2.49 (1.07) | 1.83 (0.75) | 5.21 (3.90) (low risk) |
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| Chemical, physical, and microbial | The desalination plant is unlicensed and nonmonitored by the Ministry of Health | 2.01 (1.60) | 1.60 (0.87) | 4.54 (5.64) (low risk) |
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| Chemical and microbial | Excessive algal formations in filters due to irregular backwashing of filters | 1.71 (1.21) | 1.76 (1.25) | 4.47 (6.46) (low risk) |
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| Microbial | Desalination plant's fence or roof cover inadequate, which are allowing animals or birds entry | 1.72 (0.82) | 1.91 (1.07) | 4.11 (4.26) (low risk) |
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| Chemical | The desalinated water storage tank made of corrosive metal | 1.69 (1.50) | 1.40 (0.90) | 3.68 (5.90) (low risk) |
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| Chemical and microbial | Human excreta, sewage collection within 50 m of the desalinated water storage tanks | 1.44 (1.14) | 1.50 (1.27) | 3.60 (6.76) (low risk) |
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| Chemical, physical, and microbial | The drainage hole at the bottom of the tank is not available | 1.83 (1.23) | 1.48 (0.75) | 3.53 (4.30) (low risk) |
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| Microbial | There is leakage between desalination points and desalinated water storage tank | 1.71 (0.81) | 1.68 (0.78) | 3.42 (3.01) (low risk) |
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| Microbial | Spilled water forms stagnant ponding within 10 m of the desalinated water storage tanks | 1.71 (0.81) | 1.63 (0.71) | 3.32 (2.90) (low risk) |
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| Microbial | The desalinated water storage tank made of opaque plastic | 1.42 (1.13) | 1.41 (1.09) | 3.23 (6.10) (low risk) |
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| Chemical and microbial | The water storage tank used to store other liquids other than desalinated water | 1.44 (0.93) | 1.43 (0.92) | 2.78 (4.09) (low risk) |
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| Chemical | Accidental spillage of diesel within 100 m of the desalinated water storage tanks | 1.38 (1.07) | 1.26 (0.73) | 2.51 (4.53) (low risk) |
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| Chemical | Overdosing of treatment chemicals (such as chlorine) | 1.06 (0.31) | 1.06 (0.31) | 1.23 (1.17) (low risk) |
Risk level = likelihood ∗ Severity.