Michał Bodzek

Application of membrane techniques to water purification. Removal of phthalates

Abstract Driving force membrane processes seem to be most useful for water treatment. Reverse osmosis, nanofiltration and ultrafiltration have been applied to phthalate removal from water. In the experiment three membranes RO-DS3SE were tested for reverse osmosis, membrane NF-DS5DK for nanofiltration and UF-DSGM for ultrafiltration, all of them from Osmonics, Inc. (USA). All membranes were tested under specified conditions (for RO, NF −2.0 MPa, UF −0.3 MPa) and they showed a high degree of phthalate removal from water — from 97.6% to almost 99.9%. Microextraction (solid phase extraction, SPME with CV/DVB-carbowax/divinylobenzene phase) was used for phthalate extraction from the aquatic matrix, while gas chromatography (GC) with FID detector was used for their quantitative-qualitative monitoring.

Application of membrane techniques in a water softening process

Abstract The paper presents the results of tests carried out on selected membranes, SEPA (Osmonics Inc., USA). The efficiency of membrane water softening was evaluated on the basis of permeate flux and the physicochemical analysis of raw water and permeate. The transport-separation properties of the membranes were determined using (a) the model solutions of NaCl and MgSO4 and (b) the natural waters of high degree of hardness. The performed tests indicate that the DS-5-DK and DS-3-SE membranes may be applied to the softening of water for drinking and household purposes. The model based on the extended Nernst—Planck and the Donnan equations has been quantitatively fitted to the experimental data. The obtained values of model parameters indicate that in the case of RO membranes a mechanism other than the Donnan exclusion is responsible for the high retention of ions. The membrane filtration modelling will be performed in the next stage of project.

Modelling of nanofiltration in softening water

In this work, the results of membrane filtration of natural water together with theoretical description (modelling) are presented. The obtained results were described in terms of the semi-empirical mass transport models and the extended Nernst-Planck equation. The model of NF based on that equation, taking into account membrane structural parameters and ionic composition of waters, effective for ternary systems, in the case of real multi-ionic solutions (no. of ions 8) needs further improvement.

APPLICATION OF A HYBRID UF-RO PROCESS TO GEOTHERMAL WATER DESALINATION. CONCENTRATE DISPOSAL AND COST ANALYSIS

Abstract M embrane-based water desalination processes and hybrid technologies are often considered as a technologically and economically viable alternative for desalination of geothermal waters. This has been confirmed by the results of pilot studies concerning the UF-RO desalination of geothermal waters extracted from various geological structures in Poland. The assessment of the feasibility of implementing the water desalination process analysed on an industrial scale is largely dependent on the method and possibility of disposing or utilising the concentrate. The analyses conducted in this respect have demonstrated that it is possible to use the solution obtained as a balneological product owing to its elevated metasilicic acid, fluorides and iodides ions content. Due to environmental considerations, injecting the concentrate back into the formation is the preferable solution. The energy efficiency and economic analysis conducted demonstrated that the cost effectiveness of implementing the UF-RO process in a geothermal system on an industrial scale largely depends on the factors related to its operation, including without limitation the amount of geothermal water extracted, water salinity, the absorption parameters of the wells used to inject water back into the formation, the scale of problems related to the disposal of cooled water, local demand for drinking and household water, etc. The decrease in the pressure required to inject water into the formation as well as the reduction in the stream of the water injected are among the key cost-effectiveness factors. Ensuring favourable desalinated water sale terms (price/quantity) is also a very important consideration owing to the electrical power required to conduct the UF-RO process.

A study of selected phytoestrogens retention by reverse osmosis and nanofiltration membranes - the role of fouling and scaling

Fouling and scaling are common phenomena that accompany membrane filtration and are caused by the presence of organic and inorganic matter in water, which may affect the removal of low-molecular mass organic micropollutants. Comparative filtration of deionized water containing selected phytoestrogens (biochanin A, daidzein, genistein, and coumestrol) was carried out using one new membrane and one contaminated with organic or inorganic matter. Two commercial Osmonics DS membranes were selected for the research, reverse osmosis DS3SE and nanofiltration DS5DK. Filtration was carried out in the dead-end mode. Higher removal of phytoestrogens was caused by reverse osmosis and retention depended on the molar mass of the compound. The decrease in membrane efficiency associated with fouling or scaling brings about an increase in the retention coefficient of phytoestrogens during both reverse osmosis and nanofiltration. The highest increase in phytoestrogen retention was found for the nanofiltraton membrane which was more susceptible to fouling than the osmotic one. This confirms the effect of membrane porosity on the phenomenon studied. The increase in micropollutants removal observed after fouling or scaling was caused by the modification of the membrane surface, hindered diffusion of the compound, and intensified or limited adsorption of micropollutants on the membrane surface.

Pressure driven membrane techniques in the treatment of water containing THMs

The paper presents the investigations concerning membrane treatment of water containing chloroform. Reverse osmosis (RO), nanofiltration (NF) and ultrafiltration (UF) techniques were applied. Removal degrees of chloroform and flux drop during membrane filtration were determined. Basing on the results of flux-time relationship, two models for flux drop have been adapted: resistance model and Hermii model. It was stated that RO, NF and UF could be used for THMs removal from water and the proposed models are suitable to describe the change of permeate flux during membrane filtration.

Application of hybrid biological techniques to the treatment of municipal wastewater containing oils and fats

Abstract The research into the treatment of wastewater containing oils and fats (O&F) was carried out with a biological technique under aerobic conditions. Four laboratory installations were used: (1) activated sludge tank equipped with a secondary settling tank (AS-ST), (2) AS-ST and an ultrafiltration (UF) membrane module (AS-ST-UF), (3) membrane bioreactor (MBR) and (4) MBR with a nanofiltration (NF) membrane module (MBR-NF). AS-ST produced different wastewater treatment results from 46.1 to 91.5% (COD), 79.3% on average and from 85 to 92.5% (BOD5), 91.2% on average. The application of additional treatment of wastewater with membrane techniques (AS-ST-UF) enables an increase in the effectiveness of the entire process up to 86% (COD). However, the formation of concentrates is its disadvantage. MBR yielded high and stable effectiveness of wastewater treatment containing O&F from 91.5 to 92.8% (COD), 92.2% on average and from 89.1 to 92.4% (BOD5), 91.1% on average. In order to produce a very high effectiv...

Pervaporative desulfurization of gasoline – separation of thiophene/n-heptane mixture / Perwaporacyjne odsiarczanie benzyny – separacja mieszanin tiofen/n-heptan

Abstract This paper presents the recent advances in pervaporative reduction of sulfur content in gasoline. Methods of preliminary selection of membrane active layer material are presented. Interactions between gasoline components (typical hydrocarbon and sulfur species) and membranes are showed. Influence of pervaporation process parameters i.e. feed temperature, downstream pressure and feed flow rate on the separation efficiency is discussed. Investigations of the influence of sulfur concentration in fluid catalytic cracking (FCC) gasoline on membrane performance have been conducted. A series of PV tests was carried out to investigate the separation properties of the commercial composite membrane with an active layer made of poly(dimethylsiloxane) and to determine the efficiency of organic sulphur compound (thiophene) removal from model thiophene/n-heptane mixture depending on its concentration. W pracy zaprezentowano dotychczasowe osiągnięcia w perwaporacyjnym odsiarczaniu benzyny krakingowej. Przedstawiono kryteria wstępnego doboru materiału warstwy aktywnej membran. Omówiono ponadto wpływ typowych węglowodorów oraz związków siarkoorganicznych obecnych w benzynie krakingowej na selektywność i właściwości transportowe membran jak również wpływ parametrów procesowych (temperatury nadawy, ciśnienia po stronie permeatu oraz szybkości przepływu nadawy) na efektywność procesu perwaporacyjnego odsiarczania. W pracy przedstawiono możliwość zastosowania komercyjnych membran kompozytowych z warstwą aktywną wykonaną z poli(dimetylosiloksanu) (PDMS) w procesie perwaporacyjnego odsiarczania benzyny pochodzącej z fluidalnego krakingu katalitycznego (FCC). Określono wpływ stężenia organicznych związków siarki na efektywność ich usuwania z organicznych mieszanin tiofen/n-heptan metodą perwaporacji próżniowej.

Application of membrane techniques for the removal of micropollutants from water and wastewater

A number of inorganic anions and heavy metals, microorganisms, natural organic matter, and organic micro-pollutants, among them disinfection by-products, pharmaceutical active compounds and endocrine disrupting compounds, have been found in potentially harmful concentrations in numerous water sources. The maximum permissible levels of these compounds, in drinking water and wastewaters discharged to environment, set by the WHO and a number of countries are very low (from µg/L to a few mg/L). Several common treatment technologies, which are nowadays used for removal of inorganic and organic contaminants from natural water supplies, represent serious exploitation problems. Membrane processes such as RO and NF, UF and MF in integrated systems, Donnan dialysis and electrodialysis as well as MBR and liquid membranes, if properly selected, offer the advantage of producing high quality drinking water as well as purified wastewater which can be drained off to natural water sources. High-pressure membrane techniques, i.e. RO and NF can be used for direct removal of inorganic and organic micropollutants, while low-pressure (MF and UF) in integrated systems, first of all with coagulation and adsorption and in MBR as well as after complexion with polymers or surfactants. Processes with ion-exchange membranes are suitable for micropollutants having electrical charge. Because of that property they are used in many large scale applications including the separation of ions, desalination, removal of ionic species etc.

INORGANIC MICROPOLLUTANTS REMOVAL BY MEANS OF MEMBRANE PROCESSES - STATE OF THE ART

Abstract A number of inorganic anions and metals, especially heavy metals, at certain conditions, have been found in potentially harmful concentrations in numerous water sources. The maximum permissible levels of these compounds, in drinking water and wastewaters discharged to environment, set by the WHO and a number of countries are very low (from μg/dm3 to a few mg/dm3). Several common treatment technologies, which are nowadays used for removal of inorganic contaminants from natural water supplies, represent serious exploitation problems. Membrane processes such as reverse osmosis and nanofiltration, ultrafiltration and microfiltration in integrated systems, Donnan dialysis and electrodialysis as well as membrane bioreactors, if properly selected, offer the advantage of producing high quality drinking water without inorganic substances as well as purified wastewater which can be drained off to natural water sources Abstrakt Szereg anionów nieorganicznych i metali, w tym metale ciężkie, występuje w potencjalnie szkodliwych stężeniach w licznych źródłach wody do picia. Maksymalne dopuszczalne wartości ich stężeń w wodzie do picia, ustalone przez WHO i szereg krajów, są bardzo niskie (w zakresie od μg/dm3 do kilku mg/dm3). Kilka tradycyjnych technologii, które stosuje się obecnie do usuwania zanieczyszczeń nieorganicznych ze źródeł wody naturalnej, stwarza poważne problemy eksploatacyjne. Procesy membranowe, odwrócona osmoza (RO), nanofiltracja (NF), ultrafiltracja (UF) i mikrofiltracja (MF) w systemach zintegrowanych, dializa Donnana (DD) i elektrodializa (ED) oraz bioreaktory membranowe (MBR), właściwie dobrane, umożliwiają produkcję wody do picia o wysokiej jakości i pozbawioną mikrozanieczyszczeń nieorganicznych, jak również oczyszczone ścieki, które mogą być odprowadzone do źródeł wód naturalnych