Evaluation of chemically-enhanced seeded precipitation of RO concentrate for high recovery desalting of high salinity brackish water

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• 作者：Brian C. McCool^a ; Anditya Rahardianto^a ; Jose I. Faria^b ; Yoram Cohen^a ; ^{yoram@ucla.edu}
• 关键词：Field demonstration ; Brackish water desalination ; Seeded gypsum precipitation ; Antiscalant removal ; RO concentrate treatment
• 刊名：Desalination
• 出版年：2013
• 出版时间：15 May, 2013
• 年：2013
• 卷：317
• 期：Complete
• 页码：116-126
• 全文大小：1786 K

文摘

The feasibility of utilizing chemically-enhanced seeded precipitation (CESP) for primary reverse osmosis (PRO) concentrate demineralization was evaluated, via both experimental field tests and process analysis, to assess its potential use in enabling recovery enhancement via secondary RO (SRO) desalting. Field evaluations of batch CESP along with process simulations for desalting of agricultural drainage (AD) water (6700-14,400 mg/L TDS, SIg = ~ 0.9) have suggested that a PRO-CESP-SRO desalting approach is both technically and economically feasible to enable overall desalting recovery of about 83 % and, with partial concentrate recycling, of up to 93 % . In the CESP process, initial partial lime treatment provides adsorptive removal of residual antiscalant from the PRO concentrate. This enables subsequent concentrate desupersaturation (with respect to the major scaling salt calcium sulfate) to occur via seeded gypsum precipitation, unimpeded by residual antiscalant. The desupersaturated PRO concentrate (~ 34 % reduction in SIg from ~ 1.7 to ~ 1.1) can then be further desalted in an SRO step up to the limit that is feasible with antiscalant dosing for scale control. When considering the cost of residual brine disposal, the cost of AD water desalination by PRO-CESP-SRO on the basis of desalted water volume is lower than RO by up to 39 % .