Do you have data on the aquifer mineralogy or no elemental composition? no from nearby MAR no yes no monitoring indicate operations Fe>0.1 mg/L in No Fe(III) ambient >0.3 mg/L? Has Fe been clogging groundwater? no confirmed in the storage zone? yes yes yes No Fe release recovered expected water data or baseline oxidised or contain aerobic Is Fe present with (oxidised) or aerobic expected oxidised anaerobic (reduced) yes (ie oxides) or reduced minerals? (ie sulfide) minerals? Does Fe(III) the clogging reduced or anaerobic expected the storage zone)? expected Will source water lower the pH of the no No storage zone? contain O2, NO3 Fe Does source water contain OC (ie will lower the Eh of yes yes and no yes no Fe release may be slow Dissolution of Fe(III) oxide and Fe(II) release expected yes expected oxidation, No reductive Fe(III) oxy/ dissolution of hydroxide Fe(III) oxide precipitate P expected Increased Fe in recovered water Fe(III) No Fe release clogging expected expected Eh = a measure of redox potential the propensity for oxidation and reduction reactions; MAR = managed — aquifer recharge; OC = organic carbon. Figure A7.2 Decision tree for identifying potential for iron mobilisation or iron
Do you have data on the aquifer mineralogy or no elemental composition? yes Has Fe been confirmed in the storage zone? yes data or baseline no monitoring indicate Fe>0.1 mg/L in ambient groundwater? yes recovered water no from nearby MAR no operations >0.3 mg/L? yes No Fe release expected no No Fe(III) clogging Is Fe present with oxidised (ie oxides) or reduced (ie sulfide) minerals? oxidised or aerobic Does the contain aerobic (oxidised) or anaerobic (reduced) minerals? reduced or anaerobic yes Fe(III) clogging expected expected Will source water lower the pH of the no storage zone? Does source water contain OC (ie will lower the Eh of the storage zone)? contain O2, NO3 No Fe expected yes yes no yes Dissolution of Fe(III) oxide and Fe(II) release expected and no Fe release may be slow yes No reductive dissolution of Fe(III) oxide expected Increased Fe in recovered water expected oxidation, Fe(III) oxy/ hydroxide precipitate No Fe release expected Fe(III) clogging expected Eh = a measure of redox potential — the propensity for oxidation and reduction reactions; MAR = managed aquifer recharge; OC = organic carbon. Figure A7.2 Decision tree for identifying potential for iron mobilisation or iron P
water-recycling-guidelines-mar-24.docx