Reclamation of impacted urban phreatic water through nanofiltration technology: Insight on natural organic matter removal by fluorescence spectroscopy

Nanofiltration (NF) is a promising technology called to play a relevant role in water reclamation, which lies in the core of circular economy in the water sector. The aim of this study was to assess two aromatic polyamide-based NF membranes (the looser NF270 and the tighter NF90 ones) for the treatment of urban impacted phreatic water. The focus was centred on the removal of dissolved inorganic and organic solutes and on the differences observed between solutes. Membrane ions rejection was modelled by the Solution-Electro-Diffusion Film Model (SEDFM). DOC was tracked by Fluorescence Excitation-Emission Matrices (FEEM) coupled to Parallel Factor Analysis (PARAFAC) to get insight into the character of DOC rejected by or permeated through the membranes. Results showed that the NF90 membrane systematically achieved upper values in the rejection of ions than the looser NF270 one. Variations between ions could be interpreted by the mechanisms ruling their rejection, i.e. Donnan and dielectric exclusion phenomena. Experimental rejections were also satisfactorily fit by the SEDFM, indicating that that the presence of DOC in the phreatic water did affect modelling of ions transport through the membranes. DOC was rejected at very high percentages (>90%) by both membranes, but FEEM-PARAFAC analysis revealed that humic- and tryptophan- like components were more rejected (>90% for both membranes) than tyrosine-like compounds (45% for NF270 and 57% for NF90). The finding is of relevance from a point of view of disinfection practices, as it has been observed that humic-like substances are strongly correlated with DBPs formation

Advanced hybrid system for ammonium valorization as liquid fertilizer from treated urban wastewaters: validation of natural zeolites pretreatment and liquid-liquid membrane contactors at pilot plant scale

This study evaluates a hybrid system combining zeolites as a sorption stage and a hollow fiber membrane contactor (HFMC) for ammonia (NH3) recovery from treated urban wastewater. Ion exchange with zeolites was selected as an advanced pretreatment and concentration step before the HFMC. The system was tested with wastewater treatment plant (WWTP) effluent (mainstream, 50 mg N-NH4/L) and anaerobic digestion centrates (sidestream, 600–800 mg N-NH4/L) from another WWTP. Natural zeolite, primarily clinoptilolite, demonstrated effective desorption of retained ammonium using a 2% NaOH solution in a closed-loop configuration, resulting in an ammonia-rich brine that enabled over 95% NH3 recovery using polypropylene HFMCs. A 1 m3/h demonstration plant processed both urban wastewaters, which were pretreated by ultrafiltration, removing over 90% of suspended solids and 60–65% of COD. The 2% NaOH regeneration brines (2.4–5.6 g N-NH4/L) were treated in a closed-loop HFMC pilot system, producing 10–15% N streams with potential use as liquid fertilizers. The resulting ammonium nitrate was free of heavy metals and organic micropollutants, making it suitable for use as liquid fertilizer. This comprehensive N management solution for urban wastewater applications can contribute to local economies while achieving reduced N discharge and circularity goals.LIFE ENRICH | Ref. LIFE16 ENV/ES/000375Ministerio de Ciencia e Innovación | Ref. PID2020-114401RB-C21Ministerio de Economía y Competitividad | Ref. CTM2017-85346-RGeneralitat de Cataluña | Ref. 2017-SGR-312Ministerio de Ciencia e Innovación | Ref. RYC2021-030966-

Valorisation of N and P from waste water by using natural reactive hybrid sorbents: Nutrients (N,P,K) release evaluation in amended soils by dynamic experiments

The removal of nutrients (nitrogen (N), phosphorous (P)) from waste water has become a resource recovery option in recent regulations worldwide, as observed in the European Union. Although both of these nutrients could be recovered from the sludge line, > 70-75% of the N and P is discharged into the water line. Efforts to improve the nutrient recovery ratios have focused on developing low-cost technologies that use sorption processes. In this study, a natural zeolite (clinoptilolite type) in its potassium (K) form was impregnated with hydrated metal oxides and used to prepare natural hybrid reactive sorbents (HRS) for the simultaneous recovery of ammonium (NH4+) and phosphate (PO43 −) from treated urban waste water. Three unfertile soils (e.g., one acidic and two basic) amended with N-P-K charged HRS were leached with deionized water (e.g. to simulate infiltration in the field) at two- and three-day time intervals over 15 different leaching cycles (equivalent to 15 bed volumes). The N-P-K leaching profiles for the three charged hybrid sorbents exhibited continuous nutrient release, with their values dependent on the composition of minerals in the soils. In the basic soil that is rich in illite and calcite, the release of potassium (K+) and ammonium (NH4+) is favoured by-ion exchange with calcium (Ca2 +) and accordingly diminishes the release of phosphate (PO43 −) due to its limited solubility in saturated calcite solutions (pH 8 to 9). The opposite is true for sandy soils that are rich in albite (both acidic and basic), whereas the release of NH4+ and K+ was limited and the values of both ions measured in the leaching solutions were below 1 mg/L. Their leaching solutions were poor in Ca2 +, and the release of PO43 − was higher (up to 12 mg P-PO43 −/L). The nutrient releases necessary for plant growth were provided continuously and were controlled primarily by the soil mineral dissolution rates fixing the soil aqueous solution composition (e.g. pH and ionic composition; in particular, the presence of calcite is a determinant for nutrient release, especially in alkaline soils). The N-P-K charged HRS sorbents that were used for soil amendment may be an alternative for avoiding nutrient leaching and reaching the goals of soil sustainability in agriculture and reducing the nutrient overloading of surface waters

Recovery of rare earth elements from acidic mine waters by integration of a selective chelating ion-exchanger and a solvent impregnated resin

A polymeric ion-exchange resin, incorporating methyl-amino-phosphonic (TP260) functionalities, and a solvent impregnated resin (SIR) incorporating tri-methylpentylphosphinic acid (TP272), were evaluated for the selective separation of Rare Earth Elements (REE) from Transition (TE), post -Transition (PTE), and Alkaline Earth (AE) Elements in acidic mine waters (AMW). The influence of the functional groups nature and the acidity dependence were studied and their effects on efficiencies for REE removal and separation from TE/PTE were analysed Both resins provided good separation factors of REE from TE/PTE by acidity control of the treated effluent once Fe(III), the major component in AMW, had been removed by precipitation. The TP272 resin, containing tri-methylpentylphosphinic acid (Cyanex 272) onto the polymeric network, showed higher affinity towards Heavy REE (HRRE) than for Light REE (LRRE) by acidity control (pH > 4). Higher pre-concentration factors were achieved for TP272 impregnated resin (e.g., 20–30) in comparison with the TP260 phosphonic resin (2−5), as the pH extraction window is in the moderate pH region (1−5). The integration in series of both resins could be used to separate and recover HREE and LREE from TE/PTE from AMW generated concentrates could be used to recover REE as secondary resources for the clean energy technology industry

Monitoring UF membrane performance treating surface-groundwater blends: limitations of FEEM-PARAFAC on the assessment of the organic matter role

The decrease of water quantity and quality in water scarcity areas is palliated by improving water treatments with membrane technologies. System performance and efficiency, and then cost, is mainly affected by membrane fouling, which is still not well understood and controlled appropriately. In this study, the influence of content and composition of dissolved organic matter (DOM) on a membrane ultrafiltration (UF) stage from a full-scale UF stage in a drinking water treatment plant (DWTP) fed with surface water, groundwater (or blends of them) was investigated. Excitation-emission matrix (EEM) fluorescence spectroscopy coupled with parallel factor analysis (PARAFAC) was used to characterize and assess DOM changes in water samples Water streams feeding the UF stage showed high variability in DOM content and composition. FEEM-PARAFAC analysis allowed the differentiation of seven different organic components. Additionally to the characterization and monitoring of DOM in the full-scale UF stage, a bench scale UF pilot was run to experimentally correlate the impact of water quality with membrane performance. The experiments included testing synthetic solutions of model foulants (synthetic humic acid and bovine serum albumin) and blends of complex waters. To quantify fouling, the total fouling index (TFI) and the hydraulically irreversible fouling index (HIFI) were calculated for each filtration run. According to the results obtained, the correlation plots between the PARAFAC components and the fouling indices pointed at microbial byproducts (C1) and humic-like components (C2, C4, C5) as the ones showing higher correlations

Groundwater treatment using a solid polymer electrolyte cell with mesh electrodes

This article reports the high performance of a solid polymer electrolyte cell, equipped with a Nafion® N117 membrane packed between a Nb/boron‐doped diamond (Nb/BDD) mesh anode and a Ti/RuO2 mesh cathode, to degrade the insecticide imidacloprid spiked at 1.2-59.2 mg L−1 into low conductivity groundwater by electrochemical oxidation. The natural water matrix was first softened using valorized industrial waste in the form of zeolite as reactive sorbent. Total removal of the insecticide, always obeying pseudo‐first‐order kinetics, and maximum mineralization degrees of 70 %-87 % were achieved, with energy consumption of 26.4±1.6 kWh m−3. Active chlorine in the bulk and .OH at the BDD surface were the main oxidants. Comparative studies using simulated water with analogous anions content revealed that the natural organic matter interfered in the groundwater treatment. Trials carried out in ultrapure water showed the primary conversion of the initial N and Cl atoms of imidacloprid to NO3− and Cl− ions, being the latter anion eventually transformed into ClO3− and ClO4− ions. 6‐Chloro‐nicotinonitrile, 6‐chloro‐pyridine‐3‐carbaldehyde, and tartaric acid were identified as oxidation produc

Impact of sidestream pre-treatment on ammonia recovery by membrane contactors: experimental and economic evaluation

Membrane contactor is a promising technology for ammonia recovery from the anaerobic digestion centrate. However, high suspended solids and dissolved organic matter concentrations can reduce the effectiveness of the technology. In this study, coagulation–flocculation (C/F) and aeration pre-treatments were evaluated to reduce chemical oxygen demand (COD), turbidity, suspended solids and alkalinity before the ammonia recovery stage using a membrane contactor. The mass transfer coefficient (Km) and total ammonia (TAN) recovery efficiency of the membrane contactor increased from 7.80 × 10−7 to 1.04 × 10−5 m/s and from 8 to 67%, respectively, after pre-treating the real sidestream centrate. The pre-treatment results showed that dosing aluminium sulphate (Al2(SO4)3) at 30 mg Al/L was the best strategy for the C/F process, providing COD, turbidity and TSS removal efficiencies of 50 ± 5, 95 ± 3 and 90 ± 4%, respectively. The aeration step reduced 51 ± 6% the HCO3− content and allowed reducing alkaline consumption by increasing the pH before the membrane contactor. The techno-economic evaluation showed that the combination of C/F, aeration and membrane contactor can be economically feasible for ammonia recovery. Overall, the results of this study demonstrate that C/F and aeration are simple and effective techniques to improve membrane contactor performance for nitrogen recovery from the anaerobic digestion centrate.Agencia Española de Investigación | Ref. PID2020-114401RB-C21Ministerio de Economía y Competitividad | Ref. CTM2017-85346-RAgencia Española de Investigación | Ref. PRE2018-086214Ministerio de Ciencia e Innovación | Ref. PID2019-103873RJ-I00European Commission | Ref. H2020-MSCA-RISE-2018-823971Generalitat de Catalunya | Ref. 2017-SGR-31

Fe3+/Mn2+ (Oxy)Hydroxide nanoparticles loaded onto Muscovite/Zeolite composites (powder, pellets and monoliths): phosphate carriers from urban wastewater to soil

The development of an efficient adsorbent is required in tertiary wastewater treatment stages to reduce the phosphate–phosphorous content within regulatory levels (1 mg L-1 total phosphorous). In this study, a natural muscovite was used for the preparation of muscovite/zeolite composites and the incorporation of Fe3+/Mn2+ (oxy)hydroxide nanoparticles for the recovery of phosphate from synthetic wastewater. The raw muscovite MC and the obtained muscovite/sodalite composite LMC were used in the powder form for the phosphate adsorption in batch mode. A muscovite/analcime composite was obtained in the pellets PLMCT3 and monolith SLMCT2 forms for the evaluation in fixed-bed mode for continuous operation. The effect of pH, equilibrium and kinetic parameters on phosphate adsorption and its further reuse in sorption–desorption cycles were determined. The characterization of the adsorbents determined the Fe3+ and Mn2+ incorporation into the muscovite/zeolite composite’s structure followed the occupancy of the extra-framework octahedral and in the framework tetrahedral sites, precipitation and inner sphere complexation. The adsorbents used in this study (MC, LMC, PLMCT3 and SLMCT2) were effective for the phosphate recovery without pH adjustment requirements for real treated wastewater. Physical (e.g., electrostatic attraction) and chemical (complexation reactions) adsorption occurred between the protonated Fe3+/Mn2+ (oxy)hydroxy groups and phosphate anions. Higher ratios of adsorption capacities were obtained by powder materials (MC and LMC) than the pellets and monoliths forms (PLMCT3 and SLMCT2). The equilibrium adsorption of phosphate was reached within 30 min for powder forms (MC and LMC) and 150 min for pellets and monoliths forms (PLMCT3 and SLMCT2); because the phosphate adsorption was governed by the diffusion through the internal pores. The adsorbents used in this study can be applied for phosphate recovery from wastewater treatment plants in batch or fixed-bed mode with limited reusability. However, they have the edge of environmentally friendly final disposal being promissory materials for soil amendment applications.Peer ReviewedPostprint (published version

Integration of nanofiltration and reverse osmosis technologies in polyphenols recovery schemes from winery and olive mill wastes by aqueous-based processing.

More sustainable waste management in the winery and olive oil industries has become a major challenge. Therefore, waste valorization to obtain value-added products (e.g., polyphenols) is an efficient alternative that contributes to circular approaches and sustainable environmental protection. In this work, an integration scheme was purposed based on sustainable extraction and membrane separation processes, such as nanofiltration (NF) and reverse osmosis (RO), for the recovery of polyphenols from winery and olive mill wastes. Membrane processes were evaluated in a closed-loop system and with a flat-sheet membrane configuration (NF270, NF90, and Duracid as NF membranes, and BW30LE as RO membrane). The separation and concentration efficiency were evaluated in terms of the total polyphenol content (TPC), and by polyphenol families (hydroxybenzoic acids, hydroxycinnamic acids, and flavonoids), using high-performance liquid chromatography. The water trans-membrane flux was dependent on the trans-membrane pressure for the NF and RO processes. NF90 membrane rejected around 91% of TPC for the lees filters extracts while NF270 membrane rejected about 99% of TPC for the olive pomace extracts. Otherwise, RO membranes rejected more than 99.9% of TPC for both types of agri-food wastes. Hence, NF and RO techniques could be used to obtain polyphenol-rich streams, and clean water for reuse purposes

Aproximació química al tractament de residus

En aquesta comunicació es resumeixen alguns dels treballs realitzats en la caracterització, tractament i estudi de propietats fisicoquímiques de diferent tipus de residus industrials: orgànics, metàl·lics i radioactius