Preliminary study on novel backwash cleaning for reverse osmosis fouling control in water reuse

2010 ◽  
Vol 10 (3) ◽  
pp. 296-301
Author(s):  
Jian-Jun Qin ◽  
Maung Htun Oo ◽  
Kiran A. Kekre
Keyword(s):  
Product Quality ◽  
Reverse Osmosis ◽  
Water Reuse ◽  
High Salinity ◽  
Full Scale ◽  
Elapse Time ◽  
Secondary Effluent ◽  
Fouling Control ◽  
Membrane Flux ◽  
Preliminary Study

We have demonstrated a novel backwash cleaning technique of direct osmosis (DO)-high salinity (HS) for reverse osmosis (RO) fouling control in water reuse. An UF-RO pilot system was continuously (24-h) operated on site with the secondary effluent as the feed over 4 months. The RO plant was run at 75% recovery and at the membrane flux of 17 l m−2 h−1 (LMH) to simulate the full scale NEWater production when DO-HS treatment was conducted once per day and five times per week during the last two months. Permeability of RO membranes as a function of elapse time of the pilot operation was monitored and compared over different durations. Impact of DO-HS treatment on RO product quality in terms of TOC and conductivity was investigated. It was concluded that the DO-HS treatment preliminarily demonstrated a benefit to low RO fouling rate by 2.5–4 times in 30–60 days without interruption on RO operation and impact on RO product quality.

Assessing the potential of a UV-based AOP for treating high-salinity municipal wastewater reverse osmosis concentrate

2013 ◽  
Vol 68 (9) ◽  
pp. 1994-1999 ◽  
Author(s):  
Muhammad Umar ◽  
Felicity Roddick ◽  
Linhua Fan
Keyword(s):  
Reverse Osmosis ◽  
Municipal Wastewater ◽  
High Salinity ◽  
Oxygen Demand ◽  
Process Efficiency ◽  
Secondary Effluent ◽  
Biological Processes ◽  
Fluorescence Excitation ◽  
H2o2 Treatment ◽  
Humic Compounds

The UVC/H2O2 process was studied at laboratory scale for the treatment of one moderate (conductivity ∼8 mS/cm) and two high salinity (∼23 mS/cm) municipal wastewater reverse osmosis concentrate (ROC) samples with varying organic and inorganic characteristics. The process efficiency was characterized in terms of reduction of dissolved organic carbon (DOC), chemical oxygen demand (COD), colour and absorbance at 254 nm (A254), and the improvement of biodegradability. The reduction of colour and A254 was significantly greater than for DOC and COD for all samples due to the greater breakdown of humic compounds, as confirmed by fluorescence excitation-emission matrix spectra. Fairly small differences in the reduction of DOC (26–38%) and COD (25–37%) were observed for all samples, suggesting that the salinity of the ROC did not have a significant impact on the UVC/H2O2 treatment under the test conditions. The biodegradability of the treated ROC samples improved markedly (approximately 2-fold) after 60 min UVC/H2O2 treatment. This study indicates the potential of UVC/H2O2 treatment followed by biological processes for treating high-salinity concentrate, and the robustness of the process where the characteristics of the secondary effluent (influent to RO) and thus resultant ROC vary significantly.

Optimization of direct-osmosis–high-salinity cleaning for reverse osmosis fouling control in water reuse

2010 ◽  
Vol 10 (5) ◽  
pp. 800-805 ◽  
Author(s):  
Jian-Jun Qin ◽  
Maung Htun Oo ◽  
Kiran A. Kekre ◽  
Harry Seah
Keyword(s):  
Membrane Fouling ◽  
Driving Force ◽  
Water Reuse ◽  
Systematic Approach ◽  
High Salinity ◽  
Proof Of Concept ◽  
Salt Consumption ◽  
Fouling Control ◽  
Injection Duration ◽  
Ro Membrane

This paper focuses on the systematic approach adopted towards optimizing the salt consumption when using direct-osmosis–high-salinity (DO-HS) cleaning method for RO membranes in water reuse application. Trials were carried out on a pilot RO system with a capacity of 50 m3/day. Initially, proof of concept for the DO-HS method in water reuse application was established wherein the profile of osmotic driving force for DO backwash, DO backwash flow during HS injection, removal of foulants with DO-HS treatment and lower RO fouling rate with the DO-HS method were demonstrated. 6 months of trials further demonstrated that RO membrane fouling rate and CIP frequency could be significantly reduced with the DO-HS method and there was no impact on the performance of RO membranes. Further trials were carried out focusing of salt requirements and it was found that salt injection duration could be reduced by 68% while the 48-h interval of salt injection was not recommended. Currently, the salt consumption has been reduced from the initial at 0.5 ton to the current at 0.16 ton as per 10,000 m3/day production. The study is ongoing to achieve the target of 0.05 ton for ease of operation.

Impact of anti-scalant on fouling of reverse osmosis membranes in reclamation of secondary effluent

2009 ◽  
Vol 60 (11) ◽  
pp. 2767-2774 ◽  
Author(s):  
J. J. Qin ◽  
M. N. Wai ◽  
M. H. Oo ◽  
K. A. Kekre ◽  
H. Seah
Keyword(s):  
Calcium Phosphate ◽  
Reverse Osmosis ◽  
Membrane Fouling ◽  
Pilot Plant ◽  
Time Lag ◽  
Secondary Effluent ◽  
Conventional Activated Sludge ◽  
Membrane Flux ◽  
Pilot Trials ◽  
The Impact

The objective of the study was to evaluate the impact of anti-scalant on fouling of reverse osmosis (RO) membranes in reclamation of secondary effluent which was produced by a conventional activated sludge process at Kranji Water Reclamation Plant with the capacity of 151,000 m3/d. The study was carried out using a RO pilot plant with the capacity of 2.4 m3/h. The RO plant was in 2:1 configuration and was operated at 75% recovery and at membrane flux of 17 l m−2 h−1. Pilot trials were conducted with and without anti-scalant. Compositions of feed and concentrate streams were analyzed and the pilot data were normalized. The results of the study showed that the plant operation was stable during the first few days after stopping dosage of anti-scalant but after 3–6 days of operation the membranes were fouled. The time lag effect of anti-scalant without dosage was not reported previously and could be potentially beneficial to save chemicals. The membrane fouling was more serious at the second stage due to the formation of calcium phosphate scale when the pilot plant was operated without anti-scalant. The flux of fouled membranes could be completely recovered after clean-in-place (CIP) with citric acid, indicating that scaling dominated the fouling of the RO membranes. These findings in the study could be applied to select an appropriate anti-scalant for prevention from formation of calcium phosphate scale in the RO operation.

scholarly journals Enabling Water Reuse by Treatment of Reverse Osmosis Concentrate: The Promise of Constructed Wetlands

2021 ◽  
Author(s):  
Rachel C. Scholes ◽  
Angela N. Stiegler ◽  
Cayla M. Anderson ◽  
David L. Sedlak
Keyword(s):  
Reverse Osmosis ◽  
Constructed Wetlands ◽  
Water Reuse

scholarly journals Full-Scale Seawater Reverse Osmosis Desalination Plant Simulator

2020 ◽  
Vol 53 (2) ◽  
pp. 16561-16568
Author(s):  
Mariam Elnour ◽  
Nader Meskin ◽  
Khlaed M. Khan ◽  
Raj Jain ◽  
Syed Zaidi ◽  
...  
Keyword(s):  
Reverse Osmosis ◽  
Full Scale ◽  
Desalination Plant ◽  
Seawater Reverse Osmosis ◽  
Reverse Osmosis Desalination

Demonstrating organic contaminant removal in an ozone-based water reuse process at full scale

2016 ◽  
Vol 2 (1) ◽  
pp. 213-222 ◽  
Author(s):  
Judy Blackbeard ◽  
James Lloyd ◽  
Mirela Magyar ◽  
John Mieog ◽  
Karl G. Linden ◽  
...  
Keyword(s):  
Water Reuse ◽  
Treatment Plant ◽  
Organic Contaminant ◽  
Full Scale ◽  
Fire Fighting ◽  
Contaminant Removal ◽  
Class A ◽  
The City

The 350 ML per d Eastern Treatment Plant (ETP) tertiary facility produces “Class A” water for the city of Melbourne, Australia, which is used for irrigation, dual reticulation and fire fighting.

Treatability of organic fractions derived from secondary effluent by reverse osmosis membrane

2003 ◽  
Vol 37 (19) ◽  
pp. 4801-4809 ◽  
Author(s):  
J.Y. Hu ◽  
S.L. Ong ◽  
J.H. Shan ◽  
J.B. Kang ◽  
W.J. Ng
Keyword(s):  
Reverse Osmosis ◽  
Secondary Effluent ◽  
Reverse Osmosis Membrane ◽  
Organic Fractions

scholarly journals Application of forward osmosis in reusing the brackish concentrate produced in reverse osmosis plants with secondary treated wastewater as feed solution: a case study

2016 ◽  
Vol 6 (4) ◽  
pp. 533-543 ◽  
Author(s):  
W. D. Wang ◽  
M. Esparra ◽  
H. Liu ◽  
Y. F. Xie
Keyword(s):  
Reverse Osmosis ◽  
Membrane Fouling ◽  
Water Flux ◽  
Forward Osmosis ◽  
Pump Energy ◽  
Feed Solution ◽  
Disinfection Byproducts ◽  
Treated Wastewater ◽  
Membrane Flux ◽  
Flux Decline

This study evaluated the feasibility of forward osmosis (FO) in diluting and reusing the concentrate produced in a reverse osmosis (RO) plant in James City County, VA. Secondary treated wastewater (STW) was used as the feed solution. Findings indicated that pH had slight effects on the water flux of the FO membrane. As the concentration of total dissolved solids (TDS) in the concentrate was diluted from 12.5 to 1.0 g/L or the temperature in the STW decreased from 23 to 10 °C, the membrane flux decreased from 2.2 to 0.59 and 0.81 L/(m2 h), respectively. The FO membrane showed a good performance in the rejection of organic pollutants, with only a small part of the protein-like substances and disinfection byproducts permeating to the diluted concentrate. During an 89-hour continuous operation, water flux decline due to membrane fouling was not observed. Controlling the TDS in the second-stage FO effluent at 1.5 g/L, approximately 8.3% of the pump energy input could be saved. The consumption of groundwater was reduced from 22.7 × 103 to 10.6 × 103 m3/d. FO was proved to be an effective method in both diluting the discharged concentrate and reducing the energy consumption of RO.

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