- Human urine as a forward osmosis draw solution for the application of microalgae dewatering. [Journal Article]
- JHJ Hazard Mater 2019 Jun 03; 378:120724
- Human urine is a unique solution that has the right composition to constitute both a severe environmental threat and a rich source of nitrogen and phosphorous. In fact, between 4-9% of urine mass con…
Human urine is a unique solution that has the right composition to constitute both a severe environmental threat and a rich source of nitrogen and phosphorous. In fact, between 4-9% of urine mass consists of ions, such as K+, Cl-, Na+ or NH4+. Because of its high ionic strength, urine osmotic pressure can reach values of up to 2000 kPa. With this in mind, this work aimed to study the effectiveness of real urine as a novel draw solution for forward osmosis. Water flux, reverse nitrogen flux and membrane fouling were investigated using fresh or hydrolysed urine. Water flux as high as 16.7 ± 1.1 L m-2 h-1 was recorded using real hydrolysed urine. Additionally, no support layer membrane fouling was noticed in over 20 h of experimentation. Urine was also employed to dewater a Chlorella vulgaris culture. A fourfold increase in algal concentration was achieved while having an average flux of 14.1 L m-2 h-1. During the algae dewatering, a flux decrease of about 19% was noticed; this was mainly due to a thin layer of algal deposition on the active side of the membrane. Overall, human urine was found to be an effective draw solution for forward osmosis.
- Forward osmosis membrane processes for wastewater bioremediation: Research needs. [Review]
- BTBioresour Technol 2019 Jul 12; :121795
- Increasing research and development works have been made to develop forward osmosis (FO) processes as a cost-effective substitute for energy intensive water vacuum suction facility in submerged membr…
Increasing research and development works have been made to develop forward osmosis (FO) processes as a cost-effective substitute for energy intensive water vacuum suction facility in submerged membrane bioreactor (MBR) applications. Perceived to be a spontaneous water driven process without external applied pressures, the FO has been applied in lab and pilot scales for wastewater bioremediation. This paper reviewed the state-of-the-art developments on the FO unit, the process, and ways of enhancing process performance, particularly on the aspects of flux enhancement, flow resistance reduction, and draw solute with low reverse salt diffusion, which are relevant to enhanced osmotic MBR performance. The perspective to realize the use of FO processes in revision of currently existing energy intensive osmotic MBR processes is discussed with research needs being highlighted.
- Enhancing the removal efficiency of osmotic membrane bioreactors: A comprehensive review of influencing parameters and hybrid configurations. [Review]
- CChemosphere 2019 Jul 13; 236:124363
- The amount of research conducted on osmotic membrane bioreactors (OMBRs) has increased over the past decade because of the advantages of these reactors over conventional membrane bioreactors (MBRs). …
The amount of research conducted on osmotic membrane bioreactors (OMBRs) has increased over the past decade because of the advantages of these reactors over conventional membrane bioreactors (MBRs). OMBR process is a hybrid process involving a forward osmosis membrane and biologically activated sludge. It is a promising technology to reduce membrane fouling, enhance effluent water quality, and lower energy consumption compared to conventional MBR processes. Eleven years since the OMBR process was first proposed, about 60 papers regarding the OMBR process have been published. In this article, we address recent advances in OMBR technology based on a review of the literature. Typical factors that influence the performance of the OMBR process are discussed to provide a clear understanding of the current state of this technology. We also provide a critical review of OMBR applications in organic matter, nutrient, and micropollutant removal as well as direct recovery of nutrients from wastewater. We propose several hybrid configurations that can enhance the removal efficiency of OMBR systems. Finally, we present potential research directions for future OMBR research.
- Flux enhancement of thin-film composite membrane by graphene oxide incorporation. [Journal Article]
- JEJ Environ Health Sci Eng 2019; 17(1):377-382
- Reverse Osmosis (RO) is a rapid-developing desalination technology; however, it suffers from inefficient energy consumption. To reduce energy consumption, in this study, reverse osmosis thin-film com…
Reverse Osmosis (RO) is a rapid-developing desalination technology; however, it suffers from inefficient energy consumption. To reduce energy consumption, in this study, reverse osmosis thin-film composite membrane (TFC) module was prepared and composed of m-phenylenediamine (MPD), graphene oxide, and 1,3,5-benzenetricarbonyl chloride (TMC) by interfacial polymerization on the surface of a polysulfone substrate. The graphene oxide was embedded in the mentioned thin-film composite by adding it to MPD aqueous solution to enhance permeation flux and, thus, reduce energy consumption. This study assessed the performance of the membrane using a lab-scale RO setup and evaluated permeability and salt rejection. The chemical properties of TFC were also analyzed using ATR-FTIR. Incorporating various concentrations (0, 20, 40, 60, and 80 ppm) of graphene oxide into the TFC was shown to improve water flux. Flux improvement of 50% was achieved by using graphene (80 ppm), while 10% of salt rejection was lost. These flux increases resulted from the changes in surface charge, surface roughness, and hydrophilicity due to the embedment of GO nanosheets. The simplicity of the method, compatibility of GO with polyamide membrane, and quite short-time reaction are the highlights of this technique for developing novel TFC membranes for water treatment.
- Comprehensive review on wastewater discharged from the coal-related industries - characteristics and treatment strategies. [Journal Article]
- WSWater Sci Technol 2019; 79(11):2023-2035
- Wastewaters discharged from various coal-related activities deteriorate fresh water quality and inflict possibilities of groundwater contamination. Their characteristics mostly depend on the parent c…
Wastewaters discharged from various coal-related activities deteriorate fresh water quality and inflict possibilities of groundwater contamination. Their characteristics mostly depend on the parent coal properties, though some of the pollutants are cyanide, thiocyanate, ammonia, phenol, heavy metals and suspended solids. This paper has reviewed the treatment techniques along with the characteristics of all such kinds of wastewater and also identified the challenges and future perspectives. Primarily, demineralization of coal can attenuate and control release of pollutants in wastewaters if implemented successfully. Mine water from non-lignite mines can be purified using simple techniques, for its reutilization. Acidic mine water and leachates can be treated using passive bioreactors with microbial activity, different organic substrates and limestone drains. Additionally bio-electrochemical systems, membranes, macrocapsules, zeolite filters, ores, physical barriers, and aquatic plants can also be used at various stages. Coal washery wastewater can be treated using natural coagulants obtained from plant extracts along with conventional coagulants. Nitrification and denitrification bacteria fixed in reactors along with activated carbon and zero-valent iron can treat coke oven wastewater. Some other sophisticated techniques are vacuum distillation, super critical oxidation, nanofiltration and reverse osmosis. Practical use of these methods, wisely in an integrated way, can reduce freshwater consumption.
- WATER RECOVERY BY TREATMENT OF FOOD INDUSTRY WASTEWATER USING MEMBRANE PROCESSES. [Journal Article]
- ETEnviron Technol 2019 Jul 17; :1-25
- This work presents a proposal for the recovery of water through treatment of food industry wastewater using membrane processes. Three wastewater streams from the different manufacturing steps were id…
This work presents a proposal for the recovery of water through treatment of food industry wastewater using membrane processes. Three wastewater streams from the different manufacturing steps were identified as possible sources of water recovery: 1) wastewater from washing of ionic exchange resins and 2) wastewater from the concentration stage of animal proteins (type 1 and 2). The wastewater streams were treated as effluent mixtures; each one with different level of pollution. The principal characteristics of the effluent mixtures were identified as high conductivity and the presence of organic matter. Under these conditions, ultrafiltration and reverse osmosis were carried out for the treatment of wastewater. The ultrafiltration process was tested at an industrial-level plant and the reverse osmosis process was applied at a pilot-plant level. The results showed the feasibility of the proposed treatment for water recovery. The data demonstrates an efficiency greater than 95% in all the quality parameters and therefore, a high-quality in the recovered water was obtained by membrane processes. According to chemical composition of wastewater, the reversible fouling was linked to salts and protein retention, promoting the formation of a cake layer as reversible resistance; whereas, irreversible fouling was minimum during wastewater treatment.
- Application of Molasses as Draw Solution in Forward Osmosis Desalination for Fertigation Purposes. [Journal Article]
- ETEnviron Technol 2019 Jul 16; :1-22
- Certain challenges exist in forward osmosis (FO) separation technique that has to be studied yet such as selection of a proper draw solution (DS) to supply the required driving force for separation. …
Certain challenges exist in forward osmosis (FO) separation technique that has to be studied yet such as selection of a proper draw solution (DS) to supply the required driving force for separation. In this work, the performance of molasses DS in terms of water flux (Jw) was evaluated using a commercial FO membrane. Deionized water (DIW), an oilfield brackish wastewater (BWW) and seawater (SW) were used as three different feed solutions (FS). Effects of molasses concentration (CDS) and solutions cross-flow velocities on Jw were investigated. The results indicated that the relationship between Jw and CDS is non-linear that may be attributed to internal concentration polarization in the membrane support layer. Jw was improved slightly by increasing the FS velocity and enhanced moderately by increasing the DS velocity from 6 to 11.5 cm/s. Fluxes of 16.7, 13.3 and 7.5 LMH were obtained during 30 min against the feeds of DIW, BWW and SW, respectively. After 12 h, the osmotic pressure of molasses is reduced from an initial value of 79.8 bar to 54.5, 62.8 and 66.3 bar for the FSs, respectively. Reverse solute flux is increased by decreasing Jw and is more significant at values lower than 10.67 LMH for DIW feed. Based on the results, Molasses has a good performance ratio in comparison to other fertilizers and diluted molasses can potentially be used for fertigation purposes.
- Membrane-based technologies for zero liquid discharge and fluoride removal from industrial wastewater. [Journal Article]
- CChemosphere 2019 Jul 05; 236:124288
- Several defluoridation techniques for reducing high initial fluoride concentration (IFC) in wastewater have been tested, but only a few of them have achieved the permissible standards. This study exa…
Several defluoridation techniques for reducing high initial fluoride concentration (IFC) in wastewater have been tested, but only a few of them have achieved the permissible standards. This study examined the hybrid crystallization-reverse osmosis technique (HRO) in light of flux, fluoride removal efficiency, fouling tendency, mineral recovery, complying zero liquid discharge (ZLD), and effluent discharge standard (EDS). Simulated wastewater with an IFC of 6600 mg/L was utilized and the final HRO performance was compared with those of the low-pressure (30 bar) standalone reverse osmosis (SRO), nanofiltration (SNF), and membrane distillation (SMD) processes. Accordingly, the study on SRO and SNF revealed that pressure, feed pH, membrane type, and IFC were the major factors affecting performance, and SRO was unable to sufficiently defluoridate wastewater with IFC >614 mg/L, needing pretreatment. Subsequently, the HRO process was selected and it was seen that the optimum calcium dose and respective final effluent pH for attaining EDS and ZLD were 16.5 g/L & 7.1 and 19.8 g/L & 5.7 respectively. The best operating pH for all conditions in HRO was approximately 9. Additionally, HRO showed good mineral recovery tendency and less organic fouling. The overall comparisons of flux and residual fluoride for HRO, SRO, SNF, and SMD were 49.3 LMH & 1.21 mg/L; 34.9 LMH & 62 mg/L, 44.05 LMH & 301 mg/L, and 38 LMH & 0.9 mg/L respectively. Therefore, low-pressure HRO can be applied to treat wastewater with high IFC; good tendency of mineral recovery, as good as that of SMD.
- Understanding the organic micropollutants transport mechanisms in the fertilizer-drawn forward osmosis process. [Journal Article]
- JEJ Environ Manage 2019 Jul 13; 248:109240
- We systematically investigated the transport mechanisms of organic micropollutants (OMPs) in a fertilizer-drawn forward osmosis (FDFO) membrane process. Four representative OMPs, i.e., atenolol, atra…
We systematically investigated the transport mechanisms of organic micropollutants (OMPs) in a fertilizer-drawn forward osmosis (FDFO) membrane process. Four representative OMPs, i.e., atenolol, atrazine, primidone, and caffeine, were chosen for their different molecular weights and structural characteristics. All the FDFO experiments were conducted with the membrane active layer on the feed solution (FS) side using three different fertilizer draw solutions (DS): potassium chloride (KCl), monoammonium phosphate (MAP), and diammonium phosphate (DAP) due to their different properties (i.e., osmotic pressure, diffusivity, viscosity and solution pH). Using KCl as the DS resulted in both the highest water flux and the highest reverse solute flux (RSF), while MAP and DAP resulted in similar water fluxes with varying RSF. The pH of the FS increased with DAP as the DS due to the reverse diffusion of NH4+ ions from the DS toward the FS, while for MAP and DAP DS, the pH of the FS was not impacted. The OMPs transport behavior (OMPs flux) was evaluated and compared with a simulated OMPs flux obtained via the pore-hindrance transport model to identify the effects of the OMPs structural properties. When MAP was used as DS, the OMPs flux was dominantly influenced by the physicochemical properties (i.e., hydrophobicity and surface charge). Those OMPs with positive charge and more hydrophobic, exhibited higher forward OMP fluxes. With DAP as the DS, the more hydrated FO membrane (caused by increased pH) as well as the enhanced RSF hindered OMPs transport through the FO membrane. With KCl as DS, the structural properties of the OMPs were dominant factors in the OMPs flux, however the higher RSF of the KCl draw solute may likely hamper the OMPs transport through the membrane especially those with higher MW (e.g., atenolol). The pore-hindrance model can be instrumental in understanding the effects of the hydrodynamic properties and the surface properties on the OMPs transport behaviors.
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- Review article: biological mechanisms for symptom causation by individual FODMAP subgroups - the case for a more personalised approach to dietary restriction. [Review]
- APAliment Pharmacol Ther 2019 Jul 15
- CONCLUSIONS: While some clear mechanisms of action for symptom generation have been established, further research is needed to understand which patients will respond to specific FODMAP subgroup restriction. We suggest that clinicians consider in some patients a tailored, personalised "bottom-up" approach to the low-FODMAP diet, such as dietary restriction relevant to the patients' ethnicity, symptom profile and usual dietary intake.