Membrane-based pretreatment to mitigate variations in desalination plants

2018 ◽  
Vol 77 (12) ◽  
pp. 2858-2866 ◽  
Author(s):  
J. Arevalo ◽  
R. Sandin ◽  
M. D. Kennedy ◽  
S. G. Salinas Rodriguez ◽  
F. Rogalla ◽  
...  
Keyword(s):  
Pilot Plant ◽  
Colloidal Particles ◽  
High Water ◽  
Stable Operation ◽  
High Concentration ◽  
Chemical Cleaning ◽  
Membrane Performance ◽  
Water Pretreatment ◽  
Cleaning Procedures ◽  
Desalination Plants

Abstract The main source of potable water in high water-stress areas is commonly produced in brackish and seawater desalination plants. Owing to the presence of high concentration of suspended solids, organic matter and colloidal particles in raw water, pretreatment processes are needed for a stable operation of desalination plants. A submerged membrane ultrafiltration pilot plant has been operated as pretreatment of complex brackish surface water to study the filtration performance. The results show the membrane performance, chemical reagent requirements, water quality and cleaning procedures efficiency of an ultrafiltration pilot plant used as pretreatment for a reverse osmosis system. Alternative chemical cleaning procedures have been satisfactorily implemented, which maximize permeability recovery and allow a stable operation.

Feed water pretreatment for desalination plants

Desalination ◽  
2010 ◽  
Vol 264 (3) ◽  
pp. 289-296 ◽  
Author(s):  
Iris Sutzkover-Gutman ◽  
David Hasson
Keyword(s):  
Feed Water ◽  
Water Pretreatment ◽  
Desalination Plants

Automated sequencing batch bioreactor under extreme peaks of 4-chlorophenol

2003 ◽  
Vol 47 (10) ◽  
pp. 175-181 ◽  
Author(s):  
G. Buitrón ◽  
M.-E. Schoeb ◽  
J. Moreno
Keyword(s):  
Dissolved Oxygen ◽  
Metabolic Activity ◽  
Automated System ◽  
Stable Operation ◽  
High Concentration ◽  
Batch Bioreactor ◽  
On Line ◽  
The Moment ◽  
And Control ◽  
System Operating

The operation of a sequencing batch bioreactor is evaluated when high concentration peaks of a toxic compound (4-chlorophenol, 4CP) are introduced into the reactor. A control strategy based on the dissolved oxygen concentration, measured on line, is utilized. To detect the end of the reaction period, the automated system search for the moment when the dissolved oxygen has passed by a minimum, as a consequence of the metabolic activity of the microorganisms and right after to a maximum due to the saturation of the water (similar to the self-cycling fermentation, SCF, strategy). The dissolved oxygen signal was sent to a personal computer via data acquisition and control using MATLAB and the SIMULINK package. The system operating under the automated strategy presented a stable operation when the acclimated microorganisms (to an initial concentration of 350 mg 4CP/L), were exposed to a punctual concentration peaks of 600 mg 4CP/L. The 4CP concentrations peaks superior or equals to 1,050 mg/L only disturbed the system from a short to a medium term (one month). The 1,400 mg/L peak caused a shutdown in the metabolic activity of the microorganisms that led to the reactor failure. The biomass acclimated with the SCF strategy can partially support the variations of the toxic influent since, at the moment in which the influent become inhibitory, there is a failure of the system.

scholarly journals Optimization of In Situ Backwashing Frequency for Stable Operation of Anaerobic Ceramic Membrane Bioreactor

Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 545 ◽  
Author(s):  
Rathmalgodage Thejani Nilusha ◽  
Tuo Wang ◽  
Hongyan Wang ◽  
Dawei Yu ◽  
Junya Zhang ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Bioreactor ◽  
Ceramic Membrane ◽  
Pure Water ◽  
Ex Situ ◽  
Stable Operation ◽  
Chemical Cleaning ◽  
Cake Layer

The cost-effective and stable operation of an anaerobic ceramic membrane bioreactor (AnCMBR) depends on operational strategies to minimize membrane fouling. A novel strategy for backwashing, filtration and relaxation was optimized for stable operation of a side stream tubular AnCMBR treating domestic wastewater at the ambient temperature. Two in situ backwashing schemes (once a day at 60 s/day, and twice a day at 60 s × 2/day) maintaining 55 min filtration and 5 min relaxation as a constant were compared. A flux level over 70% of the initial membrane flux was stabilized by in situ permeate backwashing irrespective of its frequency. The in situ backwashing by permeate once a day was better for energy saving, stable membrane filtration and less permeate consumption. Ex situ chemical cleaning after 60 days’ operation was carried out using pure water, sodium hypochlorite (NaOCl), and citric acid as the order. The dominant cake layer was effectively reduced by in situ backwashing, and the major organic foulants were fulvic acid-like substances and humic acid-like substances. Proteobacteria, Firmucutes, Epsilonbacteria and Bacteroides were the major microbes attached to the ceramic membrane fouling layer which were effectively removed by NaOCl.

Expert control for a stable operation of a partial nitrification system to treat highly concentrated ammonium wastewater

2009 ◽  
Vol 60 (5) ◽  
pp. 1191-1199 ◽  
Author(s):  
Irene Jubany ◽  
Julián Carrera ◽  
Javier Lafuente ◽  
Juan Antonio Baeza
Keyword(s):  
Control System ◽  
Pilot Plant ◽  
Control Strategies ◽  
Biomass Concentration ◽  
High Strength ◽  
Partial Nitrification ◽  
Stable Operation ◽  
Ammonium Oxidation ◽  
Expert Control ◽  
Biomass Activity

This work presents the application of expert control strategies for a successful and stable operation of partial nitrification. A high-strength ammonium wastewater was treated in a continuous pilot plant with a configuration of three reactors in series plus a settler. The system was operated at mild temperature (around 25°C) and at high sludge retention time to obtain a significant nitrifying biomass concentration. The implemented control system with expert supervisory rules provided a stable and robust operation of the partial nitrification system even when the pilot plant was subjected to several disturbances as change in influent concentration, failure of aeration in one reactor and operation with variable biomass concentration. The control system was based on local feedback control loops for dissolved oxygen and pH with proper setpoints for nitrite oxidizing bacteria (NOB) inhibition and an inflow control loop based on Oxygen Uptake Rate (OUR) measurements, which allowed working at the current maximum ammonium oxidation capacity. Two additional expert rules were implemented for automatically determine the required OUR setpoint in accordance with the biomass activity and to produce a fast load decrease when a system overload was detected.

Stability analysis of a particle band on the fluid–fluid interface

2019 ◽  
Vol 869 ◽  
Author(s):  
Alireza Hooshanginejad ◽  
Benjamin C. Druecke ◽  
Sungyon Lee
Keyword(s):  
Stability Analysis ◽  
Colloidal Particles ◽  
Radial Flow ◽  
High Viscosity ◽  
High Concentration ◽  
Stable Suspension ◽  
Low Viscosity ◽  
Air Interface ◽  
Critical Wavelength ◽  
Hele Shaw Cell

We present experiments and theory for viscous fingering of a suspension of non-colloidal particles undergoing radial flow in a Hele-Shaw cell. As the suspension displaces air, shear-induced migration causes particles to move faster than the average suspension velocity and to accumulate on the suspension–air interface. The resultant particle accumulation generates a pattern in which low-concentration, low-viscosity suspension displaces high-concentration, high-viscosity suspension and is unstable due to the classic Saffman–Taylor instability mechanism. While the destabilising mechanism is well-understood, what remains unknown is the stabilising mechanism that suppresses fine fingers characteristic of miscible fingering. In this work, we demonstrate how the stable suspension–air interface interacts with the unstable miscible interface to set the critical wavelength. We present a linear stability analysis for the time-dependent radial flow and show that the wavenumber predicted by the analysis is in good agreement with parametric experiments investigating the effect of suspension concentration and gap thickness of the Hele-Shaw cell.

scholarly journals Formation of Water-Free Cavity in the Process of Nafion Swelling in a Cell of Limited Volume; Effect of Polymer Fibers Unwinding

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2888
Author(s):  
Barry W. Ninham ◽  
Polina N. Bolotskova ◽  
Sergey V. Gudkov ◽  
Yulchi Juraev ◽  
Mariya S. Kiryanova ◽  
...  
Keyword(s):  
Colloidal Particles ◽  
Temporal Dynamics ◽  
Polymer Surface ◽  
Volume Effect ◽  
Polymer Fibers ◽  
Exclusion Zone ◽  
Limited Volume ◽  
Water Pretreatment ◽  
A Cell ◽  
Cell Window

When Nafion swells in water, colloidal particles are repelled from the polymer surface; this effect is called the formation exclusion zone (EZ), and the EZ size amounts to several hundred microns. However, still no one has investigated the EZ formation in a cell whose dimension is close to the EZ size. It was also shown that, upon swelling in water, Nafion fibers “unwind” into the water bulk. In the case of a cell of limited volume, unwound fibers abut against the cell windows, and water is completely pushed out from the region between the polymer and the cell window, resulting in a cavity appearance. The temporal dynamics of the collapse of this cavity was studied depending on the cell size. It is shown that the cavity formation occurs due to long-range forces between polymer strands. It turned out that this scenario depends on the isotopic composition of the water, ionic additives and water pretreatment. The role of nanobubbles in the formation and collapse of the cavity were analyzed. The results obtained allowed us to conclude that the EZ formation is precisely due to the unwinding of polymer fibers into the liquid bulk.

Start-up and Steady Operation of Shortcut Nitrification System to Treat Wastewater

2012 ◽  
Vol 610-613 ◽  
pp. 1760-1763
Author(s):  
Li Xu ◽  
Xue Wu ◽  
Ming Fen Niu ◽  
Si Li ◽  
Hong Jing Jiao ◽  
...  
Keyword(s):  
Short Range ◽  
Room Temperature ◽  
Ammonia Concentration ◽  
Experimental Temperature ◽  
Nitrifying Bacteria ◽  
Stable Operation ◽  
High Concentration ◽  
Nitrogen And Phosphorus ◽  
Start Up ◽  
The Stability

The purpose of this paper is to obtain a start-up of short-cut nitrification systems to treat wastewater with high concentration of nitrogen and phosphorus under laboratory conditions. By starting the nitrification system at room temperature we can achieve the effective accumulation of nitrifying bacteria. Then by increasing experimental temperature and pH, and increasing the concentration of nitrogen and phosphorus in influent, to inhibit the growth of NOB in the systems and promote the accumulation of AOB. So we can make the effluent have a higher concentration of NO2--N. In the stable operation stage we can constantly improve ammonia concentration in the influent, to observe the stability of the each indicators of effluent. This experiment showed that the wastewater with high concentration of nitrogen and phosphorus can better promote the accumulation of AOB, to achieve the effect of short-range nitrification.

Study on Production Wastewater in Water Treatment Plants by Submerged Micro-Filtration Membrane

2011 ◽  
Vol 374-377 ◽  
pp. 982-986
Author(s):  
Jin Man Yang ◽  
Rui Bao Jia ◽  
Zhan Jin Wang ◽  
Xiao Liang Yang ◽  
Zhang Bin Pan
Keyword(s):  
Water Treatment ◽  
Membrane Filtration ◽  
High Water ◽  
Membrane Module ◽  
Stable Operation ◽  
Membrane Process ◽  
Polypropylene Membrane ◽  
Filtration Membrane ◽  
Water Treatment Plants ◽  
Operation Cycle

To verify the feasibility of micro-filtration membrane process to treat the water treatment plants production wastewater, a submerged polypropylene membrane module was applied in a test pilot plant. It was found that membrane process had remarkable characteristics of stable operation, high water quality and the membrane module were needed to chemical medicine washing as trans-membrane pressure (TMP) to 36 Kpa after running across 41day. The operation cycle was the best period for 20 minutes (filter 18 minutes, backwash 2 minutes). Membrane filtration water was showed as turbidity of 0.1-0.2NTU, CODMn generally less than 3mg / L, CODMn removal efficiency of 60% -80%.Fe2 +, Mn2 +,Al3 + and THMFP of membrane filtration water were lower than the national drinking water health standards.

Osmo-Convective Dehydration of Plum (Prunus salicina L)

2008 ◽  
Vol 4 (8) ◽  
Author(s):  
B. B Ibitwar ◽  
Bhupinder Kaur ◽  
Sadhna Arora ◽  
Pankaj B Pathare
Keyword(s):  
Osmotic Dehydration ◽  
High Water ◽  
High Water Content ◽  
Glycerol Solution ◽  
High Concentration ◽  
Solid Gain ◽  
Prunus Salicina ◽  
Constant Rate ◽  
Rate Period ◽  
Osmotic Agents

Plums, which have a high water content level, are highly perishable and it is necessary to find alternatives to minimize product deterioration. Osmotic dehydration is one of these effective alternatives. Besides water removal from the product, the process also promotes solid gain due to high concentration of solute. In this study, the effect of different osmotic agents (sugar and sugar-glycerol) was reported. The Magee model could satisfactorily describe the solid gain and water loss during osmosis. Drying was conducted at 45, 55 and 65°C. Osmotic dehydration followed by air drying reduces the drying period. Osmotic dehydration resulted in a decrease in total convective dehydration time. The osmotic dehydration in sugar and sugar-glycerol solution reduced approximately 240 and 120 minutes as compared to the osmo-convective dehydration time of lye-treated plums at 65°C. The drying rate curves contained no constant rate period and showed a linear falling rate throughout the drying process.

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