Potential applications of quarry dolomite for post treatment of desalinated water

TY - JOUR

T1 - Potential applications of quarry dolomite for post treatment of desalinated water

AU - Birnhack, Liat

AU - Fridman, Noga

AU - Lahav, Ori

PY - 2009/1

Y1 - 2009/1

N2 - Recent WHO publications recommend a minimum concentration of 10 mg Mg/L in desalinated water. Dolomite dissolution was investigated as means of adding magnesium ions to desalinated water at the post treatment stage, in addition to Ca2+ ions and carbonate alkalinity. The results show that dolomite dissolution per se is not feasible for post treatment purposes, because dolomite stops dissolving at a relatively low pH, rendering the alkalinity and Calcium Carbonate Precipitation Potential values very low and negative, respectively. To overcome this problem three combined dolomite-calcite dissolution alternatives were investigated. The results show that the most promising method is to dissolve dolomite and then use the CO2(aq)-rich effluent to further dissolve calcite. Applying such in-series dissolution, it is possible to produce water with the following quality criteria: alkalinity = 75 mg/L as CaCO3, [Mg2+] = 12.4 mg/L, [Ca2+] = 120 mg/L as CaCO3, pH 8.17. However, the resultant total hardness value is high (170 mg/L as CaCO3). The operational costs of this alternative were approximated at 0.042 $ m!3 product water.

AB - Recent WHO publications recommend a minimum concentration of 10 mg Mg/L in desalinated water. Dolomite dissolution was investigated as means of adding magnesium ions to desalinated water at the post treatment stage, in addition to Ca2+ ions and carbonate alkalinity. The results show that dolomite dissolution per se is not feasible for post treatment purposes, because dolomite stops dissolving at a relatively low pH, rendering the alkalinity and Calcium Carbonate Precipitation Potential values very low and negative, respectively. To overcome this problem three combined dolomite-calcite dissolution alternatives were investigated. The results show that the most promising method is to dissolve dolomite and then use the CO2(aq)-rich effluent to further dissolve calcite. Applying such in-series dissolution, it is possible to produce water with the following quality criteria: alkalinity = 75 mg/L as CaCO3, [Mg2+] = 12.4 mg/L, [Ca2+] = 120 mg/L as CaCO3, pH 8.17. However, the resultant total hardness value is high (170 mg/L as CaCO3). The operational costs of this alternative were approximated at 0.042 $ m!3 product water.

KW - Calcite dissolution

KW - Desalination

KW - Dolomite dissolution

KW - Magnesium

KW - Post treatment

UR - http://www.scopus.com/inward/record.url?scp=74949093948&partnerID=8YFLogxK

U2 - 10.5004/dwt.2009.132

DO - 10.5004/dwt.2009.132

M3 - 文章

AN - SCOPUS:74949093948

VL - 1

SP - 58

EP - 67

JO - Desalination and Water Treatment

JF - Desalination and Water Treatment

SN - 1944-3994

IS - 1-3

ER -