CLEANING METHOD FOR RO MEMBRANES
| The temperatures and pH listed in table 3 are applicable for BW30, BW30LE, LE, XLE, TW30, TW30HP, SW30HR, SW30HR LE, SW30XLE, |
| SW30 and NF90 membrane elements. For more information regarding the allowed temperatures and pH for cleaning, please refer to table 1. |
| Notes: | 1. (W) denotes weight percent of active ingredient. |
| 2. Foulant chemical symbols in order used: CaCO3 is calcium carbonate; CaSO4 is calcium sulfate; BaSO4 is barium sulfate. | |
| 3. Cleaning chemical symbols in order used: NaOH is sodium hydroxide; Na4EDTA is the tetra-sodium salt of ethylene diamine tetraacetic acid and is available from the Dow Chemical Company under the trademark VERSENE* 100 and VERSENE 220 crystals; Na-DSS is sodium salt of dodecylsulfate; Sodium Laurel Sulfate; HCI is hydrochloric acid (Muratic Acid); H3PO4 is phosphoric acid; NH2SO3H is sulfamic acid; Na2S2O4 is sodium hydrosulfite. |
|
| 4. For effective sulfate scale cleaning, the condition must be caught and treated early. Adding NaCl to the cleaning solution of NaOH and Na4EDTA may help as sulfate solubility increases with increasing salinity. Successful cleaning of sulfate scales older than 1 week is doubtful. | |
| 5. Citric Acid is another cleaning alternative for metal oxides and calcium carbonate scale. It is less effective. It may contribute to biofouling especially when it is not properly rinsed out. |