scholarly journals Self-adaptive cycle-to-cycle control of in-line coagulant dosing in ultrafiltration for pre-treatment of reverse osmosis feed water

Desalination ◽  
2017 ◽  
Vol 401 ◽  
pp. 22-31 ◽  
Author(s):  
Larry X. Gao ◽  
Han Gu ◽  
Anditya Rahardianto ◽  
Panagiotis D. Christofides ◽  
Yoram Cohen
Keyword(s):  
Reverse Osmosis ◽  
Feed Water ◽  
Adaptive Cycle ◽  
Pre Treatment ◽  
Self Adaptive

Study of fouling in two-stage reverse osmosis desalination unit operating without an inlet pH adjustment: diagnosis and implications

2017 ◽  
Vol 17 (6) ◽  
pp. 1682-1693 ◽  
Author(s):  
Khaled Touati ◽  
Mehdi Hila ◽  
Kalthoum Makhlouf ◽  
Hamza Elfil
Keyword(s):  
Reverse Osmosis ◽  
Treatment Process ◽  
Membrane Surface ◽  
Periodic Acid ◽  
Feed Water ◽  
Kaolinite Clay ◽  
Ph Adjustment ◽  
Second Stage ◽  
Pre Treatment ◽  
Reverse Osmosis Desalination

Abstract In the current work, the diagnosis of a reverse osmosis desalination unit is reported. Over the two last decades, the studied desalination unit was supplying a 1,200 bed hotel. The feed water was driven from a well near the sea. The desalination unit has two stages giving an average recovery equal to 81%. The behaviour of all water streams with respect to aggressiveness and scaling tendency was assessed. The second stage reject water was shown to exhibit a very high scaling behaviour with an instantaneous precipitation in the absence of feed water pH adjustment. The analyses have shown that the produced water was very aggressive. The second stage module autopsy has revealed a sharp decrease in the membrane performances because of mineral as well as organic fouling. The inorganic scale was essentially made of coesite, calcite and kaolinite clay. The presence of silica and clay was attributed to an inadequate pre-treatment process, whereas the presence of calcite crystals at the membrane surface reveals that the chemical inhibition performed at the pre-treatment process without adjusting the pH was not able to prevent calcium carbonate precipitation. A periodic acid wash of the second stage membranes is then necessary to guarantee the desired objectives of this stage.

scholarly journals Managing the reverse osmosis concentrate from the Western Corridor Recycled Water Scheme

2010 ◽  
Vol 5 (1) ◽  
Author(s):  
David Solley ◽  
Claire Gronow ◽  
Stephan Tait ◽  
Jon Bates ◽  
Alison Buchanan
Keyword(s):  
Reverse Osmosis ◽  
Environmental Risks ◽  
Feed Water ◽  
Nutrient Reduction ◽  
Recycled Water ◽  
Reduction Strategies ◽  
Feasible Option ◽  
Full Capacity ◽  
Pre Treatment ◽  
Nitrogen Phosphorus

The Western Corridor Recycled Water Scheme consists of three advanced water treatment plants (AWTPs), with the combined capacity to recycle 232 ML/d. Each AWTP process consists of pre-treatment, microfiltration (MF), reverse osmosis (RO), UV/peroxide advanced oxidation and chlorination. A key objective of the project is to improve the environmental health of regional waterways, particularly in relation to nutrient discharges. Reverse osmosis processes produce a concentrate stream (ROC), which is the main reject stream of the AWTPs. Options for management of ROC were assessed, and ultimate disposal to nearby waterways was the only feasible option identified. ROC flows for the scheme total 41 ML/d at full capacity, divided between the three AWTPs. The contaminants in this stream are generally 6 to 7 times more concentrated than in the feed water. Environmental risks were identified due to potential increased toxicity associated with these higher concentrations, which were exacerbated due to chlorine and ammonia dosed in the AWTP process. Target ROC contaminants have been identified as nitrogen, phosphorus, ammonia, metals and chlorine. The paper presents the selected toxicity management and nutrient reduction strategies for each AWTP, and the results of full-scale operation to date are also summarised.

scholarly journals Applying the coagulation and reverse osmosis for water recovery from evaporative water

2014 ◽  
Vol 46 (4) ◽  
pp. 291-300
Author(s):  
Magdalena M. Michel ◽  
Lidia Reczek ◽  
Tadeusz Siwiec ◽  
Piotr Rudnicki
Keyword(s):  
Reverse Osmosis ◽  
Organic Compounds ◽  
Membrane Filtration ◽  
Raw Material ◽  
Feed Water ◽  
Water Recovery ◽  
Evaporative Water ◽  
Water Turbidity ◽  
A Value ◽  
Pre Treatment

Abstract Applying the coagulation and reverse osmosis for water recovery from evaporative water. Evaporative water from the concentration of yeast slurry is a potential raw material for water recovery. It is characterized by low pH (4.6-6.3), increased turbidity (3.65-13.7 NTU), and high content of total organic carbon (356-754 mg/L). Its treatment in the volume coagulation process using NaOH and coagulant PIX 111, was studied. Water turbidity was lowered to a value below 1 NTU, but coagulation did not allow for the removal of organic compounds. Coagulation was effective at temperatures of 20 and 40°C. Pretreatment of the feed water for RO included alkalization, coagulation, sedimentation, and 5 μm fine filtration (variant I), as well as single 5 μm fine filtration (variant II as a blank). In variant I the feed with improved properties was achieved. Membrane filtration allowed for effective desalination of evaporative water, 98 and 73% conductivity retention was obtained, depending on the method of the feed pre-treatment. The organic compounds were removed less efficiently, at 94 and 84%, respectively.

scholarly journals Novel pre-treatment method for seawater reverse osmosis: Fibre media filtration

Desalination ◽  
2010 ◽  
Vol 250 (2) ◽  
pp. 557-561 ◽  
Author(s):  
J.J. Lee ◽  
M.A.H. Johir ◽  
K.H. Chinu ◽  
H.K. Shon ◽  
S. Vigneswaran ◽  
...  
Keyword(s):  
Reverse Osmosis ◽  
Treatment Method ◽  
Seawater Reverse Osmosis ◽  
Pre Treatment

scholarly journals Measuring Biofouling Potential in SWRO Plants with a Flow-Cytometry-Based Bacterial Growth Potential Method

Membranes ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 76
Author(s):  
Nirajan Dhakal ◽  
Sergio G. Salinas-Rodriguez ◽  
Joshua Ampah ◽  
Jan C. Schippers ◽  
Maria D. Kennedy
Keyword(s):  
Flow Cytometry ◽  
Bacterial Growth ◽  
Potential Method ◽  
Absolute Number ◽  
Growth Potential ◽  
Added Value ◽  
Feed Water ◽  
Dissolved Air Flotation ◽  
Ultra Filtration ◽  
Pre Treatment

Measuring the bacterial growth potential of seawater reverse osmosis (SWRO) feed water is an issue that is receiving growing attention. This study developed and demonstrated the applicability of the flow-cytometry (FCM)-based bacterial growth potential (BGP) method to assess the biofouling potential in SWRO systems using natural microbial consortium. This method is relatively fast (2–3 days) compared to conventional bioassays. The effect of the potential introduction of nutrients during measurement has been studied thoroughly to achieve the lowest measure value of about 45,000 cells/mL, which is equivalent to about (10 µg-C glucose/L). The BGP method was applied in two full-scale SWRO plants that included (i) dissolved air flotation (DAF) and ultra-filtration (UF); (ii) dual-media filtration (DMF) and cartridge filter (CF), which were compared with the cleaning frequency of the plants. A significant reduction (54%) in BGP was observed through DAF–UF as pre-treatment (with 0.5 mg Fe3+/L), while there was a 40% reduction by DMF–CF (with 0.8 mg Fe3+/L). In terms of the absolute number, the SWRO feed water after DAF–UF supports 1.5 × 106 cells/mL, which is 1.25 times higher than after DMF–CF. This corresponds to the higher cleaning-in-place (CIP) frequency of SWRO with DAF–UF compared to DMF–CF as pre-treatment, indicating that the BGP method has an added value in monitoring the biofouling potential in SWRO systems.

scholarly journals Multiobjective optimization design of the solar field and reverse osmosis system with preheating feed water using Genetic algorithm

2018 ◽  
Vol 6 (6) ◽  
pp. 624-642 ◽  
Author(s):  
Iman Ebrahimi Ghoujdi ◽  
Hasti Hadiannasab ◽  
Mokhtar Bidi ◽  
Abbas Naeimi ◽  
Mohammad Hossein Ahmadi ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Multiobjective Optimization ◽  
Reverse Osmosis ◽  
Optimization Design ◽  
Feed Water ◽  
Solar Field

scholarly journals A feasibility study on UV pretreatment for microfiltration and reverse osmosis membrane processes in wastewater reclamation

2013 ◽  
Vol 3 (3) ◽  
pp. 260-267
Author(s):  
Ho-Young Jeong ◽  
Yoon-Jin Kim ◽  
Ji-Hee Han ◽  
Dong-Ha Kim ◽  
Jinsik Sohn ◽  
...  
Keyword(s):  
Reverse Osmosis ◽  
Membrane Fouling ◽  
Treatment Options ◽  
Human Consumption ◽  
Feed Water ◽  
Reverse Osmosis Membrane ◽  
Wastewater Reclamation ◽  
Important Place ◽  
Quality Water ◽  
Small Footprint

Wastewater reclamation is where wastewater from various sources is purified so the water can be used by human consumption. Among many treatment options, membranes have gained an important place in wastewater reclamation. It allows the production of high quality water from wastewater, with a small footprint and affordable energy consumption. Nevertheless, membrane fouling is regarded as a serious problem due to the high fouling potential of wastewater. In this study, we applied ultraviolet (UV) processes as a pretreatment for membrane systems that are used for wastewater reclamation. Low pressure UV (LUV) and pulsed UV (PUV) were used to decompose or alter the organics in the feed water of the membranes. Effluent organic matter was characterized by total organic carbon (TOC) and UV absorbance (UVA). Also the effect of UV pretreatment on membrane fouling was investigated for microfiltration (MF) and reverse osmosis (RO) processes. The pretreatment of membranes using LUV or PUV was effective to control fouling of hollow fiber MF membranes. This is probably because of the reduction and modification of organics after UV treatments. However, the effect of UV pretreatment on RO flux was less significant, which is attributed to low fouling prophecy after MF treatment.

scholarly journals Vapor Trapping Membrane for Reverse Osmosis

2010 ◽  
Author(s):  
Jongho Lee ◽  
Sean O’Hern ◽  
Rohit Karnik ◽  
Tahar Laoui
Keyword(s):  
Water Vapor ◽  
Reverse Osmosis ◽  
Calcium Ion ◽  
Size Range ◽  
Salt Water ◽  
Applied Pressure ◽  
Flux Measurement ◽  
Feed Water ◽  
Self Assembled Monolayer ◽  
Microfluidic Flow

This paper presents a concept for desalination by reverse osmosis (RO) using a vapor-trapping membrane. The membrane is composed of hydrophobic nanopores and separates the feed salt water and the fresh water (permeate) side. The feed water is vaporized by applied pressure and the water vapor condenses on the permeate side accompanied by recovery of latent heat. A probabilistic model was developed for transport of water vapor inside the nanopores, which predicted 3–5 times larger mass flux than conventional RO membranes at temperatures in the range of 30–50°C. An experimental method to realize short and hydrophobic nanopores is presented. Gold was deposited at the entrance of alumina pores followed by modification using an alkanethiol self-assembled monolayer. The membranes were tested for defective or leaking pores using a calcium ion indicator (Fluo-4). This method revealed the existence of defect-free areas in the 100–200 μm size range that are sufficient for flux measurement. Finally, a microfluidic flow cell was created for characterizing the transport properties of the fabricated membranes.

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