Accelerated desupersaturation of reverse osmosis concentrate by chemically-enhanced seeded precipitation

A perspective on reverse osmosis water desalination: Quest for sustainability

“…These feed pretreatment processes, while effective for minimizing membrane fouling due to particulate deposition, organic adsorption, and biological growth, do not remove mineral scale precursors. Mineral scaling is typically mitigated via: (a) the addition of polymeric antiscalants additives to the feed to suppress the nucleation and/or growth of mineral crystals and promote dispersion of crystals, (b) feed pH adjustment if calcium carbonate is an issue of concern, (c) regulation of water recovery to keep the level of retentate concentration within acceptable limits (as governed by mineral scaling kinetics), (d) periodic membrane cleaning (e.g., via fresh water flush, osmotic backwash, feed flow reversal, or chemical cleaning), and (e) removal of scale precursors via crystallization, nanofiltration, or ion exchange . In certain cases where boron and carbon dioxide removal are necessary and where silica scaling is to be avoided (at high recovery), RO operation at high pH may be necessary .…”

Uses of the reject brine from inland desalination for fish farming, Spirulina cultivation, and irrigation of forage shrub and crops

“…One approach of the management of brine involves the treatment of the reject brine to minimize the resulting flow and its salinity: two-step reverse osmosis with chemical precipitation between the stages (intermediate chemical demineralization) [23,24], two-step reverse osmosis with biological treatment between the stages [25,26], reverse osmosis with softening pre-treatment and high pH [27], two-step nanofiltration [28], and SPARRO process (Seeded Slurry Precipitation and Recycle Reverse Osmosis) [29][30][31]. Emerging technologies that are growing in importance are membrane distillation or pervaporation (aka pervaporative separation) [32], capacitive deionization [33], and FO (forward osmosis) [34][35][36].…”

Nanofiltration and Reverse Osmosis Applied to Gold Mining Effluent Treatment and Reuse

“…Mineral scale precursors are subsequently removed from the concentrate via precipitation and solid-liquid separation techniques. That lowers the concentrate mineral scaling propensity and thereby enables additional water recovery in a secondary NF/RO step (Gabelich et al, 2011;Rahardianto et al, 2007;Rahardianto et al, 2010) To verify the permeate applicability for industrial reuse, the physical-chemical properties of the treated effluent obtained with the optimal operational conditions (NF90 membrane, at feed pH 5.0 and RR of 40%) were compared with process water quality used in the gold mining company (Table 10). With the exception of arsenic, all parameters showed high retention efficiencies and proved the effectiveness of the proposed treatment.…”