Antiscalant removal in accelerated desupersaturation of RO concentrate via chemically-enhanced seeded precipitation (CESP)

Abstract The purpose of the current study is to experimentally investigate the reduction of sodium adsorption ratio (SAR) from a concentrated stream of reversed osmosis (RO) using natural zeolites. In order to reduce the salinity of solution, experiments were carried out using zeolites of varying concentration, pretreatment of adsorbents, and the addition of Ethylenediaminetetraacetic acid (EDTA). The results show that both zeolites can be used in an RO brine treatment; however, Rhyolitic tuff is more effective than clinoptilolite for the reduction of water salinity. The experiments show that Rhyolitic tuff decreases salinity of RO concentrate to nearly one – third of the initial value. Statistical analyses show that the effect of zeolite concentration is negligible. Furthermore, the addition of EDTA and pretreatment of zeolite increase the SAR values.

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Development of an integrated membrane process for water reclamation

Water Science & Technology ◽

10.2166/wst.2005.0668 ◽

2005 ◽

Vol 51 (6-7) ◽

pp. 455-463 ◽

Cited By ~ 14

Author(s):

C.H. Lew ◽

J.Y. Hu ◽

L.F. Song ◽

L.Y. Lee ◽

S.L. Ong ◽

...

Keyword(s):

Retention Time ◽

Unique Feature ◽

Inhibitory Effect ◽

Water Reclamation ◽

The Novel ◽

Membrane Process ◽

Treatment Efficiency ◽

Effluent Quality ◽

Toc Removal ◽

Ro Concentrate

An integrated membrane process (IMP) comprising a membrane bioreactor (MBR) and a reverse osmosis (RO) process was developed for water reclamation. Wastewater was treated by an MBR operated at a sludge retention time (SRT) of 20 days and a hydraulic retention time (HRT) of 5.5 h. The IMP had an overall recovery efficiency of 80%. A unique feature of the IMP was the recycling of a fraction of RO concentrate back to the MBR. Experimental results revealed that a portion of the slow- and hard-to-degrade organic constituents in the recycle stream could be degraded by an acclimated biomass leading to an improved MBR treatment efficiency. Although recycling concentrated constituents could impose an inhibitory effect on the biomass and suppress their respiratory activities, results obtained suggested that operating MBR (in the novel IMP) at an F/M ratio below 0.03 g TOC/g VSS.day could yield an effluent quality comparable to that achievable without concentrate recycling. It is noted in this study that the novel IMP could achieve an average overall TOC removal efficiency of 88.94% and it consistently produced product water usable for high value reuse applications.

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Treatment of RO concentrate by means of a combination of a willow field and electrodialysis

Resources Conservation and Recycling ◽

10.1016/j.resconrec.2012.06.003 ◽

2012 ◽

Vol 65 ◽

pp. 116-123 ◽

Cited By ~ 25

Author(s):

Karel Ghyselbrecht ◽

Emmanuel Van Houtte ◽

Luc Pinoy ◽

Johan Verbauwhede ◽

Bart Van der Bruggen ◽

...

Keyword(s):

Ro Concentrate

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Recycling of Reverse Osmosis Concentrates to the Membrane Bioreactor in the MBR-RO Process for Water Reuse: effect on mbr performances

Revue des sciences de l eau ◽

10.7202/1040057ar ◽

2017 ◽

Vol 30 (1) ◽

pp. 1-10 ◽

Cited By ~ 1

Author(s):

Thi Thu Nga Vu ◽

Manon Montaner ◽

Christelle Guigui

Keyword(s):

Organic Matter ◽

Reverse Osmosis ◽

Membrane Fouling ◽

Water Reuse ◽

High Performance ◽

Membrane Bioreactor ◽

Membrane System ◽

Size Exclusion ◽

Ro Concentrate ◽

The Impact

Wastewater effluents can be treated by an integrated membrane system combining membrane bioreactor (MBR) and reverse osmosis (RO) for effective removal of micropollutants in the field of high-quality water reuse. However, discharging the RO concentrate waste stream directly into the natural environment could lead to serious problems due to the toxic components contained in the concentrates (micropollutants, salts, organic matter). A possible solution could be the recirculation of RO concentrate waste to the MBR. However, such an operation should be studied in detail since the recirculation of non-biodegradable organic matter or high concentrations of salts and micropollutants could directly or indirectly contribute to MBR membrane fouling and modification of the biodegradation activity. In this context, the work reported here focused on the recirculation of such concentrates in an MBR, paying specific attention to MBR membrane fouling. Lab-scale experiments were performed on a continuous MBR-RO treatment line with RO concentrate recirculation. The main goal was to determine the recovery of the RO unit and of the global process that maintained good process performance in terms of biodegradation and MBR fouling. The results demonstrate that the impact of the toxic flow on activated sludge depends on the recovery of the RO step but the same trends were observed regardless of the organic matter and salt contents of the concentrates: the concentration of proteins increased slightly. Size-exclusion high performance liquid chromatography (HPLC-SEC) was employed to study the effects of RO concentrate on the production of protein-like soluble microbial products (SMPs) and demonstrated a significant peak of protein-like substances corresponding to 10-100 kDa and 100-1 000 kDa molecules in the supernatant. Thus a significant increase in the propensity for sludge fouling was observed, which could be attributed to the increased quantity of protein-like substances. Finally, the effect of the concentrate on sludge activity was studied and no significant effect was observed on biodegradation, indicating that the return of the concentrate to the MBR could be a good alternative.

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