Session 43 - 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

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

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

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

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