Water treatment

[CEST2019_00952] “LafargeHolcim's Greece (Heracles Group) journey to a Water Secure Future
by Rosario-Chan M., Koumenides C.

Water is considered a precious resource globally. It is not only a source of life, but is also essential in most manufacturing processes. The demand for water is growing and the competition for its use is intensifying. Water will require more management attention in the future as it is already considered a sustainability challenge. Although the construction material industry is not a large consumer of water compared to other industries, water is an essential resource in cement operations. Managing water resources as efficiently as possible is not only a corporate social responsibility, but also is a good industry practice in today’s world.
Over the last four years, LafargeHolcim has reduced its freshwater withdrawal in its cement plants by around 19 percent (73 liters) per tonne of cementitious material. With this initiative it has created water awareness in its plants and implemented improved measurement methodologies. It has reduced its freshwater withdrawal and consumption by optimizing site-level water efficiency through water recycling, rainwater harvesting and storm water management. In some communities, LafargeHolcim has achieved already a net positive water impact through greater access to water, recharging the groundwater table, protecting and promoting biodiversity, and improving agricultural practices by reducing water use.

Session: 43, Room: A, at Sat, 09/07/2019 - 11:45 to 12:00
Oral presentation in Water treatment

Pollution by heavy metals is a serious global problem, both for the environment and for any form of life. There is a growing interest to find low cost agricultural by-products with high adsorption capacity for the removal of heavy metals. In the present study the adsorptive capacity of chemically modified rice husk was evaluated for the removal of copper ions from aqueous solutions. Equilibrium isothermal experiments were conducted and five mathematical models were used to investigate the adsorption isotherm. The three parameters models Sips and Redlich-Peterson fitted better the experimental data. The maximum adsorption capacity of modified rice husk for copper ions was 34.38 mg/g and the maximum adsorption removal was 92.76%. Modified rice husk could be one of the low costs and effective adsorbent for copper removal from aqueous solutions.

Session: 43, Room: A, at Sat, 09/07/2019 - 12:00 to 12:15
Oral presentation in Water treatment
[CEST2019_00936] Application of dissolved air flotation (DAF) and liquid ferrate on mitigation of algal organic matter (AOM) during algal blooms
by Abdullah H., Alshahri A., Fortunato L., Leiknes T.

In the Middle East, Harmful algal blooms (HABs) are considered a major contributor to membrane biofouling in Seawater Reverse Osmosis desalination plants. The presence of HABs in the raw feed water leads to the increase of membrane fouling rate, the increase of chemical consumption, leading to a temporary plant shutdown. Effective pretreatment can reduce the amount of organic foulants reaching the RO membrane and alleviate the problem of flux decline during RO operation and increasing the membrane lifetime. This research compared the effect of Liquid Ferrate and Ferric Chloride in combination with dissolved air flotation (DAF) for the treatment of the algal cells and algal organic matter (AOM) during algal blooms events. The experiments were performed using a bench-scale DAF unit; HABs conditions were simulated by harvesting AOM from cultivating Chaetoceros Affinis (CA) in raw seawater to a concentration of around 10 mg C/L of total organic carbon (TOC). The liquid ferrate was generated in-situ by wet oxidation of ferric chloride in an alkaline media. The best performances were registered with the combined use of liquid ferrate and DAF with removal of algal cells up to 100%, with ATP removal up to 99.99%, and AOM removal up to 70%.

Session: 31, Room: A, at Fri, 09/06/2019 - 16:30 to 16:45
Oral presentation in Water treatment
[CEST2019_00897] Application of TPMS architectures in water technology: Amazing potential for cost and energy savings and reduced environmental impacts
by Arafat H.

Additive manufacturing, also known as three-dimensional (3D) printing, is a state of the art technology that has been gaining momentum in several applications including aerospace, automotive industry and the medical field. Recently, 3D printing has also gained attention as a promising fabrication pathway for key components of membrane-based systems for desalination and water treatment as well. The unique benefit of 3D printing over conventional manufacturing processes lies in its ability to fabricate structures with complex morphologies that can be optimized for fluid flow, heat transfer, etc., based on the targeted application. One such class of complex geometries are triply periodic minimal surfaces (TPMS), which can be described mathematically such that they have no self-intersecting or enfolded surfaces. “Triply periodic” means that the structure can be patterned in the 3D space and “minimal surface” means that it locally minimizes surface area for a given boundary such that the mean curvature at each point on the surface is zero. These shapes have been shown to have been investigated for applications ranging from aerospace to biomedical tissue engineering. They have various properties with regards to enhanced, smooth fluid flow that make them ideal candidates for a number of applications in water research. Primary among these applications is the design of feed spacers, which was investigated by our research group over the last 3 years.

Session: 31, Room: A, at Fri, 09/06/2019 - 15:00 to 15:30
Oral presentation in Water treatment

Preparation of an efficient activated carbon for the removal of metal pollutants is a challenging research today. The characteristic features of an efficient phosphate functionalized activated carbon, synthesized by following chemical activation process followed by subsequent functionalization from Indian gooseberry seed shells for the copper (II) adsorption are reported. Indian gooseberry seed shells based activated carbon showed the BET surface area of 1359 m2/g, the adsorption capacity of 44.84 mg/g at 30 °C and at a pH value of 9.52. The adsorption process was satisfied by the pseudo-second-order kinetic model along with the Langmuir adsorption isotherm. This AC could be used as a favorable and cost-effective copper (II) adsorbent in wastewater treatment to remove the metal contaminants.

Session: 43, Room: A, at Sat, 09/07/2019 - 12:51 to 12:54
Flash presentation in Water treatment

Ensuring the world's population access to drinking water is one of the millennium's challenges, for although our planet is made up of 70% of water, poor distribution and water quality are problems that concern world leaders, being among the objectives of development 2030 agenda set by the ONU. The proposed work aimed at the microbiological treatment of water through cold plasma technology at atmospheric pressure, the control to confirm the efficiency of the treatment was through the analysis of thermotolerant coliforms. The reduction was 93.33% for thermotolerant coliforms and cold plasma technology reduces the time of microbiological treatment of water by 90% over traditional methods due to high energy density, ozone generation and ultraviolet radiation, thus reducing costs because the energy expenditure was low and there is no need to add chemicals.

Session: 43, Room: A, at Sat, 09/07/2019 - 12:48 to 12:51
Flash presentation in Water treatment

Catalysts on the basis of copper (Cu) and the reducing agent borohydride (BH4-) have been successfully used for reduction of chlorinated aliphatics with low substitution degree which are usually resistant to zero-valent iron (ZVI) and hydrodehalogenation catalysts, such as Pd. Reactivity screening towards a broad spectrum of halogenated organic compounds (HOCs) helped to reveal the possible application areas of the Cu/BH4- system in water treatment compared to Pd and ZVI. The HOC reactivity was found to depend on: i) the nature of the C‑X bond to be cleaved, ii) the functional groups adjacent to the C-X bond and linked to it, iii) the bond dissociation energy (BDE). The use of the deactivation-stable Cu/BH4- can be recommended as alternative reduction method to ZVI and Pd catalysts for on-site treatment of aliphatic HOCs.

Session: 43, Room: A, at Sat, 09/07/2019 - 11:30 to 11:45
Oral presentation in Water treatment

Different nanomaterials graphene, zinc nanorode and zinc nanosephere were used in membrane preparation. Polyethersulphone as a main polymer was blended with nano-soultions of these nanomaterials. This Support layer was coated by a composite coating layer formed of polyvinylacohol and titanium dioxide nanotubes to provide strength and enhance hydrophilicity of such membranes. M2 (using graphene) provides highest permeate flux 30.6 L/m2.h due to its highest hydrophilicity, but it was lowest salt rejection 48.9% at feed concentration of 5000 ppm. M3 and M4 provide high salt rejection 99% for M4 and 89% for M3. The highest mechanical strength was found clear with M3 formulation, which gives about 8.8 N/cm2 tensile strength and elongation of 20 mm.

Session: 43, Room: A, at Sat, 09/07/2019 - 12:30 to 12:45
Oral presentation in Water treatment

Untreated pharmaceutical pollution and their possibly more toxic metabolites, resulting from outdated traditional wastewater treatment processes, end up in aquatic environments and are hazards to the ecosystem homeostasis. Biological wastewater remediation could supplement traditional methods and overcome the dumping of these biologically active compounds in the environment. Mycoremediation is especially promising due to the unspecific nature of fungi to decompose compounds through exoenzymes and the uptake of compounds as nutrients. In the present study, we improved on the previous advances made using the fungus Mucor hiemalis to remediate one of the most commonly occurring pharmaceuticals, acetaminophen (APAP), at higher concentration. The adjustment of pH, nitrogen limitation, and comparison with, as well as co-cultivation with the white-rot fungus Phanerochaete chrysosporium were tested. Nitrogen limitation did not significantly improve the APAP remediation efficiency of M. hiemalis. Maintaining the pH of the media improved the remediation restraint of 24 h previously seen. The APAP remediation efficiency of P. chrysosporium was far superior to that of M. hiemalis and co-cultivation of the two resulted in a decreased remediation efficiency compared to P. chrysosporium in single.

Session: 43, Room: A, at Sat, 09/07/2019 - 11:15 to 11:30
Oral presentation in Water treatment

As an obstacle against the widespread application of membranes in larger scales, fouling via different materials could cause a severe decline in water permeation. Herein, we fabricated a novel mechanically-stable electro-conductive membrane by simple pressure-assisted laminating of reduced Graphene Oxide-Polyaniline (rGO-PANI) suspension on the commercial polyethersulfone (PES) support layers. Field emission scanning electron microscopy (FESEM) and water contact angle measurements were used to characterize rGO-PANI membranes. Using PANI improved the mechanical stability of laminated film and reduced the water contact angle, making a more hydrophilic surface. Organic fouling behaviors of newly fabricated membranes were also investigated by applying a DC voltage to membranes. The experimental results showed a significant improvement in water flux recovery when 2 V DC potential is applied on the surface of the rGO-PANI membrane.

Session: 43, Room: A, at Sat, 09/07/2019 - 11:00 to 11:15
Oral presentation in Water treatment

We propose a novel desalination scheme which employs the hydrogels as a tool to draw salt ions from a brine with low salinity to a brine with high salinity. As a driving force we use the fact that the volume of polyelectrolyte gel does depend on the surrounding salinity. While the salinity defines the gel volume in open system, i.e. in equilibrium with big aqueous solution bath, in closed system (in equilibrium with small bath) salinity is defined by the gel volume. The compression and swelling in open and closed system processes are combined into four stages thermodynamic cycle working between two bathes of different salinities. The cycle implies reversibility at any stage, so, in principle, the method can achieve the maximum thermodynamic efficiency. We have shown that for weak polyelectrolyte gels the dependence between the salinity and gel volume appears to be non-monotonic. Depending on the model parameters the surrounding salinity may increase or decrease during compression. In both cases we consider the possible use of this relation in desalination cycle.

Session: 43, Room: A, at Sat, 09/07/2019 - 12:15 to 12:30
Oral presentation in Water treatment

Gamma radiolysis can serve as an effective method for the degradation of organic water pollutants, due to the production of reactive species, oxidative (OH•, OOH•, O2•-) or reductive (eaq-, H•). The application of scavengers enables the selective production of these species. Our aim was to explore the effects of the radiolytically produced reactive species, on commonly occuring water taste and odour compounds (T&O), 2-methyl isoborneol (MIB) and geosmin (GSM). Transformation products (TPs) were identified using liquid extraction followed by GC-MS/MS and confirmed with Linear Retention Indexes (LRI). The diversity and proposed structure of the TPs depend on the reactive species present in the solution. Structure elucidation of TPs revealed that reaction pathways are strongly dependent on the presence of individual reactive species. The oxidative degradation of MIB via OH• proceeds with the production of carbonyl- (camphor) and hydroxyl-containing TPs, a subsequent ring opening, arriving to linear structured products. Fewer TPs are produced upon the effect of OOH•, starting with a ring opening and addition of one hydroxyl group. The oxidative pathway of GSM via OH• occurs with an initial ring opening, formation of carboxyl-group and subsequent second ring opening. The reductive pathway is currently under study.

Session: 43, Room: A, at Sat, 09/07/2019 - 12:45 to 12:48
Flash presentation in Water treatment

TiO2 photocatalysis offers an attractive alternative to conventional water treatment technologies leading directly to the degradation of organic pollutants, compared to transferring them from one phase to another as in the case of membranes or activated carbon. There is an increasing interest on using photocatalysis for water treatment, rendering reliable evaluation of performance of the catalytic materials necessary. Methods for testing photocatalysts used in water treatment are generally not harmonized. Two ISO standards are available for assessing the photocatalytic activity of surfaces with regards to water purification, which are based on the photo-bleaching of methylene blue and the oxidation of DMSO, respectively. A new European standard for assessing the photocatalytic activity of materials has been developed and is under publication by the European Committee for Standardization, CEN TC386/WG3. Evaluation of the performance of photocatalytic materials in water purification is based on measurement of phenol degradation with UV irradiation under controlled conditions. The proposed standard method is applicable to materials in the form of powders (suspensions in water, slurries). İn this study, the new CEN standard test will be presented, while its differentiation from the existing ones, its applicability and the process followed for its validation, will be discussed.

Session: 37, Room: A, at Sat, 09/07/2019 - 10:00 to 10:15
Oral presentation in Water treatment

Homogeneous photocatalytic processes are receiving increased interest with regards to drinking water treatment for emerging pollutants. Especially the UV/Cl2 technique has a potential for real large-scale applications as it can combine disinfection with chemical oxidation using processes that are more familiar and widely applied by water supplies. However, more research is needed to understand the complex mechanisms involved, including formation of hydroxyl and chlorine radicals among others, as well as overall performance against various groups of emerging pollutants, such as the less-studied water taste and odor compounds (T&O). We present results on the UV/Cl2 degradation of β-cyclocitral as a model of common cyanobacterial nor-carotenoid T&O in water. The study was conducted using a novel photoreactor set-up with custom-made UV-LED arrays, precise control of irradiance, continuous spectrophotometric – GC/MS monitoring and sensory evaluation of the process. Effects of key process parameters i.e. irradiance, concentration of Cl2 and β-cyclocitral, water matrix (ultrapure and typical drinking water) on the kinetics as well as key degradation products and proposed pathways are presented. Effectiveness, efficiency and prospects of real applications of UV/Cl2 for removal of hazardous T&O from drinking water are discussed.

Session: 37, Room: A, at Sat, 09/07/2019 - 10:15 to 10:30
Oral presentation in Water treatment

Membrane technology is an energy-efficient separation process that is expected to dominate the water treatment industry. However, the high vulnerability of membranes to fouling has limited the expansion of sustainable and energy-efficient membrane processes. Surface patterning has been proven to be an effective method to improve the performance of membranes by increasing the permeate flux and lowering the attachment of fouling materials on membrane surfaces. In this study, a new generation of patterned membranes was prepared using a novel hydrogel facilitated phase separation (HFPS) method. Hydrogel contains a high water content which initiates phase separation as a nonsolvent upon contact with the polymer solution. Structuring a hydrogel mold provides the ability to control the location of the skin layer on the patterned side of the membrane. The performance of the patterned and the unpatterned membranes made with HFPS was examined in a cross-flow filtration system; a significant increase in the pure water flux (~100%) was observed for the patterned membrane. Moreover, a fouling experiment with bovine serum albumin (BSA) solution showed that the patterned membranes maintained 76% higher flux after 90 minutes of operation.

Session: 31, Room: A, at Fri, 09/06/2019 - 16:15 to 16:30
Oral presentation in Water treatment

We describe the deployment of a novel water purification technology, which was initially conceptualized in the context of a readily successful FP7 project (CLEAN WATER, Grant Agreement no 227017, 2009-2012) and is now in the progress of been upgraded and upscaled thanks to the grants awarded by a LIFE Environment and Resource Efficiency project (LIFE PureAgroH2O, LIFE17 ENV/GR/000387, 2018-2021). The technology is currently recognizable with the term “Photocatalytic Nanofiltration Reactor” (PNFR) and combines in a synergetic way the processes of nanofiltration (NF) and photocatalysis in a single-stage, targeting to the complete elimination of pesticides and other organic and inorganic (heavy metals) pollutants from the wastewater of the Fruits & Vegetables Industry (F&VI) and to the reuse of 15 m3 of treated water on a daily basis.

Session: 37, Room: A, at Sat, 09/07/2019 - 09:30 to 09:45
Oral presentation in Water treatment

Novel ternary catalysts TiO2/CoFe2O4/Ag with variable ferrite content were synthesized, characterized and used for the photocatalytic reduction of Cr+6 pollutant, under UV and visible light illumination. Both TiO2 and CoFe2O4 were synthesized using the sol-gel method followed by hydrothermal treatment to prepare TiO2/CoFe2O4 (TCF) composite. Silver nanoparticles were successfully loaded on the surface of TCF to get three different composites, named as Ag/TCF. The crystal structure of the composites was analyzed by application of physicochemical characterization techniques. The presence of pure anatase phase TiO2, cubic CoFe2O4, and silver nanoparticles was indicated in both XRD patterns and Raman spectra. It was found that the addition of silver nanoparticles has a great contribution to the photocatalytic reduction of Cr+6 species. The photocatalytic reaction mechanism was studied by applying scavenging reaction process, revealing that electrons were strongly supported for the photocatalytic reduction of Cr+6. After the photocatalytic experiments, the composite catalyst can be easily separated from the reaction solution by external magnetic bar and re-used.

Session: 37, Room: A, at Sat, 09/07/2019 - 09:45 to 10:00
Oral presentation in Water treatment
[CEST2019_00437] Susceptibility of Algal Toxins to Advanced Oxidation Processes
by Dionysiou D., Duan X., Kong M.

Harmful algal blooms (HABs) occur more frequently and severely in recent years due to the climate change and increasing nutrient inputs, causing higher potential for the algal toxins to enter drinking water supplies. When HABs formation is intensive, conventional water treatment is insufficient to remove those toxins, so that further advanced technologies are necessary to be added. In this presentation, Professor Dionysiou will give an overview of recent progress in the destruction of several algal toxins, such as microcystin variants (MCs) and cylindrospermopsin, using light-based advanced oxidation processes (AOPs). The discussion will focus on the kinetics and transformation pathways of the destruction by hydroxyl radical, sulfate radical, chlorine related radicals, and other reactive species generated in various AOPs. The role of the specific amino acids in the reactivity of the MCs will be emphasized. The effect of solution co-contaminants in field water samples will be presented with the focus on identifying parameters that play important roles in process performance and oxidation pathways. Finally, coupling of AOPs with conventional technologies for the removal of algal toxins will be showcased, considering also potential application of some of these technologies in a treatment plan.

Session: 37, Room: A, at Sat, 09/07/2019 - 09:00 to 09:30
Oral presentation in Water treatment

The aim of this study is to check the vertical water quality profile of Aposelemis Reservoir. The water quality was studied in nine (9) different water reservoir depth points: S9: 0 m, S8: 02 m, S7: 03 m, S6: 05 m, S5: 07 m, S4: 09 m, S3: 10 m, S2: 13 m and S1: 15 m. A sudden change in the temperature of the water was observed at the water depth of 7 m (thermocline phenomenon) and a change in pH (from pH> 8 to pH <7.5) at the depth of 3 m. A sharp increase in metal concentration was identified in greater water depth, as well as prevalent the soluble form of them (Mn, Fe, etc.). Relating to microbial load, it was much lower in water depth > 2m, compared to 0-2 m. As the water sampling depth was increasing, the Total Organic Carbon (TOC) was decreasing, in contrary with the nutrient concentration (N, P) which was increasing. Color and odor values appear elevated in water depth greater than 5 m.

Session: 31, Room: A, at Fri, 09/06/2019 - 15:30 to 15:45
Oral presentation in Water treatment

The purpose of this study is to present the annual monitoring data of the main water quality operational parameters of Aposelemis Water Treatment Plant (WTP). The main quality parameters studied are: turbidity, pH, suspended solids, conductivity, manganese (Mn), coliform bacteria, Escherichia Coli and Clostridium Perfringens of the untreated and treated surface water of the Aposelemis reservoir. There is a seasonal variation in the turbidity and in the microbiological parameters of WTP incoming water. The Suspended Solids fluctuation follows the entry water turbidity fluctuation. There is no significant difference between the water entry and exit conductivity. The produced water by Aposelemis WTP is of high quality and fulfills all the legislation requirements for water intended for human consumption.

Session: 31, Room: A, at Fri, 09/06/2019 - 16:45 to 17:00
Oral presentation in Water treatment

Nanofiltration membranes (NF) are considered and used extensively in seawater softening, food, textile, and mining industries for the removal of di-and multi-valents to increase RO lifetime by decreasing fouling rates, and chemical cleaning intervals. In this work, blend membranes of polyethersulfone and polyamide11 were prepared by phase inversion process. The membranes were characterized by scanning electron microscopy (SEM),pore size distribution, mechanical properties and membranes performance. The results indicated that, the membrane (N2), which was prepared using PA11 (1 wt%) with a solution of sodium dodecyl sulphate (0.5wt%) and TiO2 (1 wt%) provides the best performance according to rejection percentage. Where, the rejection percentage of magnesium sulfate reached 99 %, 97% and 91% as a function of feed synthetic salt solution of concentration 1g/l, 2 g/l, and 5 g/l respectively. Permeate flux of (N2) was the lowest one due to having a dense top layer of this membrane and low mean pore size (7.7 nm) which was 66.7 L/m2.h, 64.2 L/m2.h and 53.5 L/m2.h as a function of feed synthetic salt solution of concentration 1g/l, 2 g/l and 5 g/l respectively. The fouling test was carried out using methylene blue dye, where the membrane (N2) exhibits good antifouling properties.

Session: 31, Room: A, at Fri, 09/06/2019 - 16:00 to 16:15
Oral presentation in Water treatment

From the process control point of view, any reliable and online Oil-in-Water (OiW) measurement could provoke a brand new control paradigm for produced water treatment. However, the real-time OiW monitoring is still an open and ad-hoc situation in recent decades. The fundamental issue, i.e., the OiW measurement is methodology dependent, leads to numerous challenges, such as (i) how to verify the reliability and accuracy of a specific methodology/instrument; (ii) how to handle and interpret the measured data in a most objective manner; and (iii) how to keep a cost-effective on-site calibration and maintenance under the harsh offshore conditions etc. The paper reports our latest achievements and observations in usage of fluorescence- and microscopy-based OiW monitoring technologies for advanced Produced Water Treatment (PWT) control and evaluation, particularly by focusing on the de-oiling hydrocyclone installations.

Session: 31, Room: A, at Fri, 09/06/2019 - 15:45 to 16:00
Oral presentation in Water treatment