Search results for "Reverse Osmosi"
showing 10 items of 29 documents
Energy saving in two-stage reverse osmosis systems coupled with ultrafiltration processes
2005
In this paper the optimization of the main design parameters is performed for a double-stage seawater reverse osmosis (SWRO) system coupled with an ultrafiltration process; the minimal energy consumption is the goal of the optimization process. The energetic benefits for the membrane process are calculated, deriving from the use of a hybrid two-stage/two-pass lay-out with ultrafiltration pre-treatment, which is a typically a low energy consumption process. Also the benefits on membranes’ efficiency and duration are assessed by examining the very low Silt Density Index (SDI) of the water exiting the ultrafiltration section. The analysed system includes a SWRO membrane in the high pressure st…
A Review of the Water Desalination Technologies
2021
Desalination is commonly adopted nowadays to overcome the freshwater scarcity in some areas of the world if brackish water or salt water is available. Different kinds of technologies have been proposed in the last century. In this paper, the state of the mainstream solutions is reported, showing the current commercial technologies like reverse osmosis (RO), Multi-Stages Flash desalination (MSF) and Multi-Effect Distillation (MED), and the new frontiers of the research with the aim of exploiting renewable sources such as wind, solar and biomass energy. In these cases, seawater treatment plants are the same as traditional ones, with the only difference being that they use a renewable energy s…
Nanofiltration of secondary effluent for wastewater reuse in the textile industry
2008
Abstract Textile industries represent an important environmental problem due to their high water consumption. In many Spanish regions with water scarcity, this fact can be an argument to make wastewater reuse necessary. In this work, a biologically treated wastewater from a cotton thread factory was subjected to nanofiltration (NF) in two ways, direct NF treatment and NF after a pre-treatment stage by ultrafiltration (UF). Nowadays, the factory effluent is treated by an activated sludge process. This effluent has high values of COD (200mgO 2 L −1 ) and TDS (5000mg L −1 ) which makes its use in the textile processes impossible. In such situations, reverse osmosis (RO) has been typically used…
A sustainable phenolic compound extraction system from olive oil mill wastewater
2017
Abstract The reduction of environmental impact and the achievement of economic advantages based on by-product recovery is the aim of applying methodologies for phenolic compounds extraction from Olive Oil Mill Wastewater. Volume reduction of Olive Oil Mill Wastewater could generate important advantages in terms of waste disposal cost abatement and, in addition, reuse in the production of foods with health properties could lead to economic benefits. Despite the fact that literature shows that several techniques have been developed, few economic approaches have been presented. This paper assesses the economic feasibility of a system based on membrane filtration and reverse osmosis processes f…
Material transport and organizing phenomena of Langmuir—Blodgett membranes from polymerizable built up diacetylene amphiphiles on hydrophobic supports
1986
Abstract Langmuir—Blodgett multilayers of polymerized diin amphiphiles on different porous, hydrophobic ultrafilters have been studied as composite membranes under the conditions of reverse osmosis. Influences of differently structured surfaces of the supports on structure and phase change occurring during polymerization have been investigated by scanning electron microscopy and X-ray diffraction and are discussed with reverse osmosis data. When conditioned, fine porous hydrophobic supports become permeable to aqueous solutions at low pressures. Under these conditions permeate flux and retention were found to depend on the number of layers deposited.
Prediction models to analyse the performance of a commercial-scale membrane distillation unit for desalting brines from RO plants
2018
Abstract Desalting brines from Reverse Osmosis (RO) plants is one of the most promising applications of Membrane Distillation (MD) systems. The development of accurate models to predict MD system performances plays a significant role in the design of this kind of industrial applications. In this paper, a commercial-scale Permeate-Gap Membrane Distillation (PGMD) module was modelled by means of two different approaches: Response Surface Methodology (RSM) and Artificial Neural Networks (ANN). Condenser inlet temperature, evaporator inlet temperature, feed flow rate and feed water salt concentration were selected as inputs of the model, while permeate flux and Specific Thermal Energy Consumpti…
Phenolic profiles of olive mill wastewaters treated by membrane filtration systems
2014
BACKGROUND Olive mill wastewater is an important by-product obtained after olive oil extraction. In this investigation, the phenolic composition of olive mill wastewater treated with a semi-industrial membrane filtration system, including ultrafiltration and reverse osmosis modules, was studied. In particular, untreated olive mill wastewater was compared with the permeate and the concentrate fractions of each filtration step. RESULTS 3,4-(dihydroxyphenyl) ethanol and p-(hydroxyphenyl) ethanol were the main compounds of all olive mill wastewater analyzed. A total of 32 compounds, detected at 240 or 280 nm by HPLC-DAD, were considered for phenol quantification. Ultrafiltration reduced phenol …
Optimal design of cogeneration plants for seawater desalination
2004
Multi-stage flash (MSF) and reverse osmosis (RO) are the most common techniques for seawater desalination. A significant difference between these methodologies consists of their different energy requirements, i.e., thermal energy for MSF and mechanical energy for RO plants. The presence of both desalination systems (MSF and RO) appears to be suitable for cogeneration plants. The reject heat from the power cycle can feed an MSF section, while some power feeds the RO section and the MSF auxiliary equipment; the rest is sold to the grid. A criterion for the optimal design of such tri-functional cogeneration plants is proposed, based on exergo-economics and on profit maximization. In particular…
Some Features of Polymeric Membranes for Water Purification via Membrane Distillation
2011
Polymeric membranes are currently adopted in water purification processes, such as reverse osmosis (RO) and membrane distillation (MD). This latter technique is very promising for separation effectiveness and energy savings. A valuable and effective MD unit must be equipped with polymeric membranes that exhibit specific properties, for example, hydrophobicity, a narrow pore size range, a high water penetration pressure, and a large vapor permeability. In this work, we present and examine the main features of membranes for MD processes, with the aim of experimentally evaluating the related performances. Scanning electron microscopy analysis was carried out for a first estimate of the pore si…
Coupling electrodialysis desalination with photovoltaic and wind energy systems for energy storage: Dynamic simulations and control strategy
2020
Abstract The presence of desalination systems in polygeneration facilities is usually limited by important difficulties in operating under non-stationary regimes typical of renewable energy sources. Reverse osmosis, namely the most common desalination technology, is characterised by slow dynamics that rarely adapts to the power fluctuations of renewables. Therefore, the possibility of using electrodialysis coupled with a hybrid photovoltaic/wind energy source was investigated in this work. In particular, the combination of photovoltaic and wind energy is very attractive in order to achieve a more stable energy production, while electrodialysis is claimed to be a more flexible process compar…