Water Reclamation Research Articles

Wastewater reuse and recycling of the steel industry in China: history, current situation, and future perspectives

Abstract China is the largest steel producer in the world. Effective methods to alleviate the contradiction between water supply and water demand of the iron and steel industry in China are to implement the recycling of wastewater from the iron and steel industry and develop unconventional water resources. This paper reviews the development of wastewater recycling in the iron and steel industry in China in the past 40 years (1980–2020). During this period, steel output has increased from 36 to 1,053 million tons, freshwater consumption per ton of steel has decreased from 35.9 to 2.45 tons, and water resources reuse has soared from 61.2 to 98.02%. Four typical cases, including the Anyang Steel Group, the Tangshan Steel Group, the Tianjin Steel Group, and the Taihang Steel Group, were analyzed. In addition, a water efficiency research project of iron and steel enterprises in China was carried out in 2019. Statistical analyses on wastewater recycling rate, reuse rate, direct cooling water circulation rate, and other indicators were performed. The recycling of wastewater in the iron and steel industry would be continuously improved by policy drivers, economic drivers, and technical drivers.

Parametric modelling and analysis to optimize adsorption of Atrazine by MgO/Fe3O4-synthesized porous carbons in water environment

BackgroundPesticide contamination to water, continues to raise ecotoxicological and human concerns. Studying the application of green adsorbents for removing pesticides from water can significantly reduce ecotoxicological impacts and sustain reclamation of water bodies.ResultsThe current study investigated the adsorption capacity of MgO/Fe3O4 modified coconut shell biochar (MCSB) towards Atrazine removal in water. The prepared adsorbents were structurally constricted and obtained relative amount of mesopore spaces filled by nanoparticles which equally provided active occupancy/binding sites for Atrazine molecule deposition. Equilibrium isotherm studies under temperature regimes of 300 K, 318 K and 328 K were best described by the Freundlich isotherm (R2 = 0.95–0.97) with highest adsorption capacity corresponding to the highest temperature range (328 K) at (KF = 9.60 L mg−1). The kinetics modelling was best fitted to the pseudo second-order kinetic (R2 = 0.90–0.98) reaction pathways revealing that Atrazine uptake and removal occurred majorly over non-homogenous surfaces and high influence of surface functional groups in the process. Atrazine uptake by the adsorbent were mostly efficient within pH ranges of 2–6. Thermodynamics values of free energy ΔG° were negative ranging (ΔG° = − 27.50 to − 29.77 kJ mol−1) across the varying reaction temperature indicating an exothermic reaction, while enthalpy (ΔH°) (34.59 kJ mol) and entropy (ΔS°) (90.88 JK−1/mol) values were positive revealing a degree of spontaneity which facilitated Atrazine uptake. The adsorbents regeneration capacities over five cycles were observed to decrease proportionally with maximum yields up to 50–60%. Optimization of the adsorption condition by response surface modelling (RSM) and Central Composite Design (CCD) could reveal optimum conditions for Atrazine removal through interaction of different variables at pH = 12, adsorbate initial concentration at 12 mg L−1, adsorbate dosage at 0.5 g and reaction temperature at 54 °C. The overall mechanisms of the adsorption could be contributed by availability of surface functional groups on the MCSB surface through increase in hydrophilicity facilitating easy Atrazine molecule attachment via hydrogen bonding and improved surface complexation.ConclusionsThe as-synthesized MCSB adsorbent could uptake and remove Atrazine in water. A high pH, low concentration, low adsorbent dosage and high reaction temperature could be optimized conditions to attain highest Atrazine removal by the synthesized adsorbent.Graphical

Assessment of natural tannin-based coagulant for effective ultrafiltration (UF) of UASB effluent: Fouling mechanisms, pollutant removal and water reclamation feasibility

In this work, tannin coagulant (TANm) was applied at different dosages and compared with a PACl for UASB effluent filterability enhancement during membrane ultrafiltration. The results showed that TANm exhibited the greatest potential to improve UASB effluent filterability. Flux decay, total fouling resistance, and specific cake layer resistance were all reduced by both coagulants. However, the highest flux (55%) and fouling resistance reduction (70%) were obtained with 40 mg.L−1 of TANm, which was caused by an increase in particles larger than 200 μm, facilitating its removal by cross-flow filtration. Protein and carbohydrate reduction in the membrane was only observed at 25 mg.L−1 for both coagulants, with a higher influence of proteins in strongly/very strongly bound for all samples. In addition, fouling irreversibility increases, with a strong correlation between TANm dosage and Rirr and complete and intermediate pore blocking pointed as the main mechanisms responsible for irreversibility for both coagulants. Based on these and other findings, the mechanisms of the fouling layer adhered to the membrane with coagulants included the formation of complexes with proteins that were more strongly adhered (related to UASB effluent zeta potential increase), the density of the cake layer due to the presence of compact aggregates, and action of the coagulants themselves as foulants. Lastly, the economic evaluation revealed that the system without coagulant would have a lower total cost, but payback showed that the application of TANm has a lower investment time of return due to a lesser CAPEX.

Hierarchical 3D Flower-like Metal Oxides Micro/Nanostructures: Fabrication, Surface Modification, Their Crucial Role in Environmental Decontamination, Mechanistic Insights, and Future Perspectives.

Hierarchical micro/nanostructures are constructed by micro-scaled objects with nanoarchitectures belonging to an interesting class of crystalline materials that has significant applications in diverse fields. Featured with a large surface-to-volume ratio, facile mass transportation, high stability against aggregation, structurally enhanced adsorption, and catalytical performances, three dimenisional (3D) hierarchical metal oxides have been considered as versatile functional materials for waste-water treatment. Due to the ineffectiveness of traditional water purification protocols for reclamation of water, lately, the use of hierarchical metal oxides has emerged as an appealing platform for the remediation of water pollution owing to their fascinating and tailorable physiochemical properties. The present review highlights various approaches to the tunable synthesis of hierarchical structures along with their surface modification strategies to enhance their efficiencies for the removal of different noxious substances. Besides, their applications for the eradication of organic and inorganic contaminants have been discussed comprehensively with their plausible mechanistic pathways. Finally, overlooked aspects in this field as well as the major roadblocks to the implementation of these metal oxide architectures for large-scale treatment of wastewater are provided here. Moreover, the potential ways to tackle these issues are also presented which may be useful for the transformation of current water treatment technologies.

Simultaneous ammonia recovery and water reclamation from brackish aquaculture effluent via reactive vacuum membrane distillation

Due to the high volatility of ammonia and contemporaneous condensation of water and ammonia on permeate side, it remains a challenge to obtain a high concentration of ammonia or high-quality water using conventional vacuum membrane distillation (VMD). In this study, a reactive VMD (RVMD) with a two-stage downstream system was developed for simultaneous recovery of ammonia and water from brackish aquaculture effluent with dilute ammonia content. Notably, the RVMD system allowed for complete recovery of dilute ammonia in acid solution. Compared to a conventional VMD system, both the separation factor (SF) and concentration factor (CF) were intensified by 16 times within 2 h using the RVMD system. In the RVMD system, ammonia was first dissolved in acid solution without chilling using immersed trap tube; followed by water vapor condensation under chilling to obtain clean water. It was found that more diluted acid (0.0025 M of sulphuric acid or 0.005 M of phosphoric acid) could be applied to absorb the same amount of ammonia by using this system. Through this system, the recovered ammonia from brackish aquaculture effluent could be concentrated by 23 times (from 19.83 to 465 mg/L) with an SF of 148, while very low ammonia content (0.04 mg/L) was detected in the recovered water. These findings demonstrate that RVMD with a two-stage downstream system outperforms conventional VMD in concentrating ammonia and purifying water.

Water treatment and reclamation by implementing electrochemical systems with constructed wetlands

Seasonal or permanent water scarcity in off-grid communities can be alleviated by recycling water in decentralized wastewater treatment systems. Nature-based solutions, such as constructed wetlands (CWs), have become popular solutions for sanitation in remote locations. Although typical CWs can efficiently remove solids and organics to meet water reuse standards, polishing remains necessary for other parameters, such as pathogens, nutrients, and recalcitrant pollutants. Different CW designs and CWs coupled with electrochemical technologies have been proposed to improve treatment efficiency. Electrochemical systems (ECs) have been either implemented within the CW bed (ECin-CW) or as a stage in a sequential treatment (CW + EC). A large body of literature has focused on ECin-CW, and multiple scaled-up systems have recently been successfully implemented, primarily to remove recalcitrant organics. Conversely, only a few reports have explored the opportunity to polish CW effluents in a downstream electrochemical module for the electro-oxidation of micropollutants or electro-disinfection of pathogens to meet more stringent water reuse standards. This paper aims to critically review the opportunities, challenges, and future research directions of the different couplings of CW with EC as a decentralized technology for water treatment and recovery.

WNK1, a molecular crowding sensor, links phase separation to cellular physiological stress.

WNK1, a molecular crowding sensor, links phase separation to cellular physiological stress.

Treated municipal wastewater as option to the use of fresh water for the cultivation of valuable pastoral species Buffel grass (Cenchrus ciliaris L.)

AbstractThe increasing aridity exacerbated by climatic changes is leading to loss of perennial herbaceous plants Cenchrus ciliaris, an apomictic, polyploid grass used as forage in hot and dry areas, and is currently under threat for the increased scarcity of water. In this study, treated municipal wastewater (TWW) was used to irrigate two ploidy levels of C. ciliaris for two consecutive years. The objectives were (1) to assess the possibility of using unconventional water for watering C. ciliaris and (2) to identify at what extent TWW irrigation affected growth and nutritive properties of C. ciliaris that differed for polyploidy level. TWW irrigation positively affected growth and physiological plant parameters. In leaves of TWW watered C. ciliaris, the concentration of Nt, P and K significantly increased. The tetraploid C. ciliaris showed a better growth and quality than the hexaploid ones, appearing the most suitable cultivar to be irrigated with TWW for feed uses. In short, TWW can be strategically used for irrigating forage species with the double output of ameliorating soil properties, recovering degraded area and improving the nutritive values of fodder species contributing to the promotion of a green and sustainable circular economy, more in climatically under pressure developing countries.

Sensitivity Analysis for Multi-Criteria Decision Analysis Framework for Site Selection of Aquifer Recharge with Reclaimed Water

The pressure on Egypt’s limited water resources has increased as a result of the country’s growing industrial and agricultural sectors, coupled with climate change impacts and population growth. To overcome the current water stress situation, the utilization of new technologies such as managed aquifer recharge (MAR) is thought to be key for expanding the use of non-conventional water resources and providing necessary water supplies. Managed aquifer recharge can boost groundwater recharge and promote greater water accessibility. Suitability maps for MAR are widely offered as a tool to aid in decision-making in the context of balancing water demand and supply. Conducting a sensitivity analysis to validate suitability mapping can enhance the understanding of the results and pinpoint the influencing factors. The West Delta region was chosen as a case study given the existence of two MAR sites to examine the suitability of implementing MAR projects with reclaimed water. In this work, a spatially explicit sensitivity analysis is performed on a newly developed framework for MAR suitability maps that use multi-criteria decision analysis (MCDA) to determine suitable locations for MAR implementation, using spreading methods techniques. The performed sensitivity analysis uses spatial visualization to examine the effect of various weighted criteria on the final outputs and identifies criteria that are especially sensitive to weight changes. The results of the sensitivity analysis indicate that the applied MCDA framework for the suitability mapping in West Delta produced robust results in terms of the most suitable sites for MAR. The obtained results also indicate the possibility of the use of the suggested framework for arid environments with comparable data availability. Moreover, the results emphasize the possible use of suitability maps in sustainable groundwater management plans to support the actual implementation of MAR projects in the West Delta.

Quantifying the Benefits of Membranes with Ultrahigh Vapor Permeability for Membrane Distillation

Water reclamation from unconventional resources has attracted heightened interest worldwide. Membrane distillation (MD) is a promising technology for hypersaline wastewaters/brines reclamation. Since the key component in MD is the membrane, a myriad of research effort on MD has been devoted to developing MD membranes with ultrahigh vapor permeabilities. In this study, we perform a comprehensive analysis of the performance of practical MD operations to evaluate the benefits of developing MD membranes with ultrahigh vapor permeabilities. For coupon-scale MD operations (i.e., bench-scale systems), regardless of the membrane vapor permeability, the membrane vapor flux is limited by temperature polarization, and with the feed/distillate temperature of 60/20 °C under practical operating conditions, the membrane vapor flux can barely exceed 200 kg m–2 hr–1. For module-scale MD operations (i.e., large-scale systems), increasing the membrane vapor permeability by 15 folds only reduces the energy consumption by ∼26%, and despite the substantial saving of membrane area, the membrane cost needs to be considered. The results from our analysis demonstrate questionable benefits of membranes with ultrahigh vapor permeabilities in practical MD operations, casting doubt on the necessity of developing such membranes for MD applications. Last, we highlight the critical needs for robust MD membranes that can overcome challenges of membrane fouling, wetting, and scaling, shedding light on future MD membrane development.

Pilot-scale demonstration of dissolved organic nitrogen removal from an advanced water reclamation facility using enhanced coagulation

Most wastewater treatment facilities that satisfy stricter discharge restrictions for nutrients, remove dissolved inorganic nitrogen (DIN) species efficiently, leaving dissolved organic nitrogen (DON) to be present at a higher proportion (up to 85 %) of total nitrogen (TN) in the effluent. Discharged DON promotes algae growth in receiving water bodies and is a growing concern in effluent potable reuse applications considering its potential to form hazardous nitrogenous disinfection byproducts (N-DBPs). Enhanced coagulation is an established process in the advanced water treatment train for most potable reuse applications. However, so far, no information has been collected at the pilot scale to address DON removal efficiency and process implications by enhanced coagulation under real conditions. This study performed a comprehensive evaluation of DON removal from the effluent of the Truckee Meadows Water Reclamation Facility (TMWRF) by enhanced coagulation over the course of 11 months at the pilot scale. Three different coagulants (aluminum sulfate (alum), poly‑aluminum chloride (PACl), ferric chloride (FC)) and a cationic polymer coagulant aid (Clarifloc) were used. Optimum doses for each coagulant and polymer and ideal pH were determined by jar tests and applied at the pilot. Alum (24 mg/L) resulted in highly variable DON removal (6 % – 40 %, 21 % on average), which was enhanced by the addition of polymer, leading to 32 % DON removal on average. PACl (40 mg/L) and FC (100 mg/L) resulted in more consistent DON removal (on average 45 % and 57 %, respectively); however, polymer addition exerted minimal enhancement for these coagulants. Overall, enhanced coagulation effectively reduced DON in the tertiary effluent at the pilot scale. The treatment showed auxiliary benefits, including dissolved organic carbon (DOC) and orthophosphate removal.

Application of nonwoven microfiltration membrane on activated sludge final effluent: improving wastewater quality for reuse

The application of membrane technology in wastewater treatment for reuse is one of the alternatives to reduce the demand of water in domestic, agricultural and industrial sectors. This study attempts to improve wastewater quality effluent, prior to disinfection, for re-use. Clarifier effluent from a biological nutrient removal (BNR) treatment plant was diverted to a nonwoven membrane pilot filtration unit. It was thus positioned to further enhance the clarifier effluent as a polishing arrangement. Water Quality Index (WQI), Single Factor Pollution Index (Pi), Water Use License (WUL) and removal efficiency methods were used to interpret the water quality data for BNR clarifier effluent and nonwoven membrane permeate. The results showed that this nonwoven microfilter membrane is able to improve wastewater quality from BNR clarifier effluent. Escherichia coli (E. coli) reduction was the highest with a removal efficiency of 90%, followed by chemical oxygen demand 25%, NH4+ 22%, NO3− 12.6%, PO4 7.8%, suspended solids 6.3%. The lowest reduction was electrical conductivity of 5.2%. Permeate results indicated that physiochemical and microbial parameters were complying with the limits of WUL. Pi has revealed that BNR clarifier effluent water quality is medium polluted versus slightly polluted permeate. WQI results for BNR clarifier effluent showed good water quality and the water can be reused for domestic, irrigation and industrial purposes, while permeate WQI results indicated excellent water quality and the water can be reused for drinking, domestic, irrigation and industrial purposes. Outstanding permeate water quality improvement was observed on E.coli counts improving from 4974.48 to 294.33 counts/L. The standard of E.coli according to the WUL at this wastewater care works is 500 counts/L. Results indicate that nonwoven membrane filtration can improve microbial contamination and decrease the demand of chlorine for disinfection of wastewater final effluent. The nonwoven membrane filtration can decrease the water scarcity gap in South Africa for direct water reclamation by improving effluent wastewater.

Modified Electrospun Membranes Using Different Nanomaterials for Membrane Distillation.

Obtaining fresh drinking water is a challenge directly related to the change in agricultural, industrial, and societal demands and pressure. Therefore, the sustainable treatment of saline water to get clean water is a major requirement for human survival. In this review, we have detailed the use of electrospun nanofiber-based membranes (ENMs) for water reclamation improvements with respect to physical and chemical modifications. Although membrane distillation (MD) has been considered a low-cost water reclamation process, especially with the availability of low-grade waste heat sources, significant improvements are still required in terms of preparing efficient membranes with enhanced water flux, anti-fouling, and anti-scaling characteristics. In particular, different types of nanomaterials have been explored as guest molecules for electrospinning with different polymers. Nanomaterials such as metallic organic frameworks (MOFs), zeolites, dioxides, carbon nanotubes (CNTs), etc., have opened unprecedented perspectives for the implementation of the MD process. The integration of nanofillers gives appropriate characteristics to the MD membranes by changing their chemical and physical properties, which significantly enhances energy efficiency without impacting the economic costs. Here, we provide a comprehensive overview of the state-of-the-art status, the opportunities, open challenges, and pitfalls of the emerging field of modified ENMs using different nanomaterials for desalination applications.

Simulation and Regulation of Sustainable Utilization of Water Resources in China Based on Improved Water Resources Ecological Footprint Model

The original ecological footprint model of water resources was improved here to explore the rational policy of water resources development and utilization. Aiming to address the problems of high complexity, weak applicability, and insufficient systematicness and dynamics of the existing water resources ecological footprint model, the grey water footprint was introduced into the model to quantify the water for decontamination. In the calculation of the water resources ecological footprint index, the rainwater collection project, seawater desalination, and water resources regeneration, unconventional water sources were considered, and when combined with the system dynamics simulation technology, the SD model of water resources sustainable utilization in China was established. We carried out research on the regulation and control of sustainable utilization of water resources in China. The results showed that the development and utilization of water resources in China remained within the ecological carrying capacity as a whole from 2000 to 2017, and the development of water resources still had potential, but the supply and demand of water resources were unbalanced. Given this, from the perspective of throttling, open-source, and pollution control, six control schemes for sustainable utilization of water resources in China were set up, including the continuation of the current situation, green throttling, pollution control, strict planning for water source development, and comprehensive treatment. Among them, the comprehensive coordination plan for 2018-2050 could properly solve the problem of water resources supply and demand under the conditions of meeting the ecological sustainability of water resources and reasonable water resources load and was the best regulation plan to realize the sustainable utilization of water resources in China. At present, the development of water resources in China lags, which does not match the growth rate of social and economic development on water resources consumption. It is necessary to further strengthen the efforts of open-source, water-saving, and pollution control based on the original policies, so as to alleviate the ecological stress of water resources.

Detection of Carbamazepine, Diclofenac, and Ketoprofen via a SPE-HPLC-PDA Method in a Municipal Wastewater Treatment Plant in East Texas, USA

Increased demand for water reuse, recycling and reclamation heightens the need for improvements in the design of wastewater treatment plants that minimize or remove toxic pollutants or their metabolites. In this study, solid-phase extraction (SPE) technique utilizing C-18 cartridge was used for separation of three commonly used pharmaceuticals, namely, carbamazepine (CBZ), diclofenac (DF), and ketoprofen (KT) in wastewater samples. High performance liquid chromatography-photodiode array detector (HPLC-PDA) method was used for detection of CBZ, DF, and KT along the treatment stages (aeration, clarifier, raw activated sludge (RAS), chlorine contact chamber (CCC), and sulfur dioxide chamber) from Nacogdoches wastewater treatment plant (NWWTP), in East Texas, USA. Highest concentrations were found in the RAS followed by influent aeration stage. Pharmaceutical concentrations detected from the influent or RAS samples were 2.115 × 10−3 mg/L, 8.95 × 10−4 mg/L and 8.55 × 10−4 mg/L for CBZ, KT and DF, respectively. Highest detected total concentrations of pharmaceuticals were: carbamazepine (1.285 – 2.117 μg/L), diclofenac (0.600 – 0.865 μg/L), and ketoprofen (0.815 – 0.885 μg/L). The calculated % removal efficiencies along the treatment stages follow the order; CBZ: RAS > SO2 > clarifier ≈ aeration > CCC; KT: RAS > SO2 > aeration > CCC > clarifier; DF: RAS ≈ aeration ≈ CCC > clarifier > SO2. Determined removal efficiencies follow the order carbamazepine (∼ 39.2%) > diclofenac (∼ 30.6%) > ketoprofen (∼8.8%). Removal efficiencies of pharmaceuticals in the NWWTP may be affected by the human body, transition through activated wastewater treatment processes, and their metabolism and/or usage by humans.

Mesocosm Evaluation of the Safety of the Use of Reclaimed Water Regarding Emerging Pollutants in Murcia, Spain

The increasing shortage of conventional water for crop irrigation in arid and semiarid regions is encouraging the use of nonconventional water resources. Nevertheless, concern about the presence and possible negative effects of emerging contaminants in reclaimed water can cause individuals to avoid using these water sources. To clarify the guarantees that reclaimed water offers, a mesocosm study was carried out. Lettuce plants were cultivated in pots watered with three different types of water (distilled, reclaimed, and spiked with contaminants of emerging concern). The results showed low concentrations of contaminants in the leachates and plant tissues when the reclaimed water was used. However, their concentrations were high when the pots were watered with the spiked water; this was mainly true for carbamazepine, which reached a maximum of 2982 ng L−1 in the leachates and 45.2 ng g−1 in the plant roots. In the lettuce watered with the spiked water, carbamazepine was found in the edible part at very low concentrations that did not imply any human risk. Finally, an acute toxicity test was performed on the leachates, which were found to be only slightly toxic in the spiked water. This work indicates that with the current technical improvements in active sludge water treatment, reclaimed water can be used for irrigation without the risk of contamination by contaminants of emerging concern.

Designing for Sustainability: A Web-based Tool for Water Reclamation

Technological innovation has increasingly become important in addressing the most pressing problems in society. To create better and sustainable solutions, project teams often strive to bring the people they are designed for to the innovation process. While the human-centered design approach has become popular in guiding design in the private sector, its place in addressing larger challenges beyond human needs is still not well defined. Using our experiences in designing the WasteWATER app, an open-source decision making tool intended to help design sustainable water reclamation systems, we illustrate the synergy between analytical research and human-centered design, through the convergence of design and anthropology in creating applied outcomes in universities. Analytical research can help understand complex problems such as the sustainability of water reclamation. At the same time, embedding design thinking in applied research projects can help researchers in academic institutions refine their solutions through collaborative and iterative design with stakeholders.

TINGKAT KEBERHASILAN KEGIATAN REHABILITAS DAERAH ALIRAN SUNGAI (DAS) DI PT BORNEO INDOBARA LOKASI DESA ARTAINKECAMATAN ARANIO KABUPATEN BANJAR PROVINSI KALIMANTAN SELATAN

PT Borneo Indobara as the holder of a Borrow-to-Use Forest Area Permit and has obligations as the executor of rehabilitation activities. Forest development activities through rehabilitation, especially on critical land in watershed areas (DAS) are one of the efforts that can be made to reduce the adverse effects of forest degradation. Watershed management is a series of efforts made by humans to rationally utilize watershed natural resources in order to fulfill their daily needs and improve their standard of living. Analyzing the success of the activity by looking at the percentage of growth of watershed rehabilitation plants at PT. Borneo Indobara, Artain Village, Evaluate the implementation of activities in the field with the Technical Design on plant growth factors, Analyze the types of plants with the requirements for plant growth, Make recommendations in the Technical Design activities on plant growth factors. The average yield of growth (height and diameter) of plants in 45 land units was 0.67 in height and 0.625 in diameter, 33 in 0.53 in height and 0.475 in land units, 0.57 in 52 in height and 0.505 in diameter. The percentage of survival on land unit 45 was 65.56%, land unit 33 was 64.17%, land unit 52 was 66.36%. Based on the analysis of plant survival percentage, it shows that the average survival percentage of plants is still below 65%, this means that the selected watershed rehabilitation plants need to be evaluated. sea sengon, mahogany, johar, pioneer species of trembesi which are relatively adapted to thin solums. Plant recommendation models are proposed for reclamation plant improvement starting from technical design, to field application so that reclamation plants can show high plant success.

Impact of Nanoclays on Polyvinylidene Fluoride Mixed Matrix Membranes for the Efficient Treatment of Oily Wastewater

Background: Membrane technology demonstrated a sustainable methodology for water reclamation from oily-wastewater, but it is prone to fouling during longer filtration runs. In this study, fouling resistant polyvinylidene fluoride (PVDF) mixed matrix membranes (MMMs) containing nanoclays such as halloysite (HT) and montmorillonite (MMT) were fabricated for the effective treatment of oily wastewater. Methods: Phase inversion technique was followed for the fabrication of HT-PVDF and MMT-PVDF MMMs. Physiochemical characterization and filtration experiments were studied to evaluate the influence of nanoclays on PVDF membrane performance. Results: Fourier transform infrared spectroscopy (FTIR) and morphology analyses indicated that both nanoclays are layered structured with abundant hydrophilic functional groups. The dispersions of HT and MMT were confirmed by surface morphology and topography analysis of PVDF MMMs. The hydrophilicity property was improved in HT-PVDF and MMT-PVDF MMMs, which was evident in the contact angle analysis. Among the membranes, MMT-PVDF MMMs held the higher water permeability of 2.59 x10-8 m/s.kPa. For oil-water filtration, HT-PVDF and MMT-PVDF MMMs displayed higher normalized flux with maximum rejection of more than 95%. Conclusion: Overall, MMT would be cost-effective nanofiller for the development of antifouling PVDF MMMs against oil-water filtration.

Costs-benefit Analysis for the use of Shallow Groundwater as non-conventional Water Resource

Encouraging the implementation of non-conventional water resources (NCWR) is a fundamental strategy to face the future challenges due to urban population growth and resource scarcity. The implementation of a systematic process of Cost Benefit Analysis (CBA) offers reliable economic indicators to support decision makers in taking actions shifting towards NCWR. While infrastructure costs are directly estimated, while the benefits depend upon the considered stakeholders and require a tough estimation of the achieved ecosystem services. This research provides a framework for CBA analysis adopting NCWR at municipal level. The framework has been then applied to two case studies in Milan focused on the exploitation of shallow groundwater, where the obtained economic indicators has stressed out the importance of considering a complete benefits analysis that could support incentive policies on shifting part of the financial benefits to direct users leading to benefits for the whole community.