Table 4.
Water quality of the groundwater samples in the Esilalei area (samples 1–4 were analyzed at Engler-Bunte Institute (EBI-KIT), and sample 5 was analyzed at the Beijing University of Chemical Technology (BUCT). Sample 5 was used as the feed solution in this study. Water quality variation occurs with location, season (in particular, rainfall) and probably extraction method/volume.
|
Unit | Sample 1 | Sample 2 | Sample 3 | Sample 4 | Sample 5 | WHO Guideline [11] |
|---|---|---|---|---|---|---|---|
| Electrical conductivity | μS/cm | 16,150 | 27,100 | 27,600 | 28,500 | 14,340 | 400 |
| pH | - | 8.99 | 8.08 | 8.49 | 8.18 | 8.98 | 6.5–8.5 |
| Turbidity | NTU | 38.96 | 14.55 | 1.14 | 15.79 | 11.36 | 5 |
| Sodium | mg/L | 4730.9 | 8472.5 | 9012.5 | 7256.7 | 4240.5 | 200 |
| Potassium | mg/L | 91.9 | 272.0 | 288.5 | 271.0 | 123.4 | 20 |
| Calcium | mg/L | 10.1 | 10.1 | 128.3 | 122.8 | 210.5 | 100 |
| Magnesium | mg/L | 8.0 | 605.4 | 638.9 | 505.2 | 327.2 | 50 |
| Strontium | mg/L | 1.2 | 8.2 | 8.0 | 10.4 | 10.3 | - |
| Chloride | mg/L | 486.1 | 569.0 | 554.0 | 593.1 | 587.2 | 250 |
| Fluoride | mg/L | 56.6 | 9.2 | 8.9 | 4.6 | 6.2 | 1.5 |
| Sulfur | mg/L | 1974.3 | 5860.0 | 6204.4 | 6391.5 | 2473.4 | - |
| Inorganic carbon | mg/L | 908.0 | 420.2 | 580.8 | 960.0 | 454.0 | - |
| TOC | mg/L | 58.2 | 57.2 | 46.6 | 107.0 | 70.9 | - |