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Ion exchange represents one of the most promising processes for ammonium recovery from municipal wastewater (MWW). However, most previous studies on ammonium ion exchange did not optimize the process or evaluate its robustness under real operational conditions. This experimental study aimed at (i) developing a procedure for the selection of a sorbent for selective ammonium removal/recovery from MWW, (ii) validating the procedure by applying it to several sorbents, (iii) performing a preliminary optimization and robustness assessment of ammonium removal/recovery with the selected sorbent. The application of the procedure to natural and synthetic zeolites and a cation exchange resin confirmed that batch isotherm tests need to be integrated by continuous-flow tests. The selected sorbent, a natural mixture of Chabazite and Phillipsite, resulted in high performances in terms of cation exchange capacity (33 mgN gdry resin-1), ammonium operating capacity (5.2 mgN gdry resin-1), ammonium recovery yield (78-91%) and selectivity towards ammonium. The process performances resulted stable during 7 adsorption/desorption cycles conducted with MWW treatment plant effluents in a 60-cm column. The switch to a highly saline effluent produced in a hotspot of seawater intrusion did not determine significant changes in performances. Contact time was reduced to 6 min without any decrease in performances. Potassium – well tolerated by crops – was selected as the regenerating agent, in the perspective to produce a desorbed product to be re-used as fertilizer. The study shows that Chabazite/Phillipsite has a high capacity to recover ammonium from MWW in a circular economy approach.

Chlorinated solvents are toxic and poorly biodegradable pollutants frequently found in contaminated aquifers. Experimental data of chloroform (CF) aerobic cometabolic biodegradation in a sand column with butane as growth substrate were simulated with a system of non‐stationary second‐order partial differential equations with non‐linear kinetic terms. A MATLAB optimization code based on the Gauss‐Newton method and coupled with the Comsol Multiphysics finite elements solver was developed to calibrate the model. For each experimental phase, the best‐fit quality was evaluated by an innovative multi‐variable model adequacy test. The proposed code solved systems of up to 5 partial differential equations and optimized up to 6 unknown parameters, leading to statistically acceptable best‐fits. The optimization of the butane/oxygen pulsed feed led to an 82 % CF biodegradation and to a 0.27 gCF/gbutane transformation yield. When the substrate/pollutant ratio was minimized, the standard model of aerobic cometabolism initially tested required additional terms aimed at taking into account the depletion of reducing energy, in order to attain a statistically acceptable best‐fit. This is the first work in which a model of aerobic cometabolism taking into account reducing energy availability was applied to a continuous‐flow process. The proposed optimization code can be used for model calibration in a wide range of physical problems described by non‐stationary, non‐linear partial differential equations, a task that no commercial software can perform. The developed code is made available in the Supplementary Material.

In Agadir, a water-scarce Moroccan region, municipal and industrial wastewater is tertiary-treated to be reused in golf courses. Wastewater reuse has been constrained by severe clogging of emitters, which caused technical and financial problems. This study aimed to perform an in-depth characterization of the treated wastewater (TWW) in relation to its susceptibility to cause clogging, and to assess the capacity of an aeration post-treatment to reduce the clogging potential. The post-treatment consisted of injecting different airflows (0–33 L/(h Lreactor) into the TWW. The structural, morphological and elemental composition of the clogging matter collected in the irrigation pipeline was characterized using scanning electron microscopy, scanning transmission electron microscopy, X-ray diffraction and X-ray energy dispersive spectroscopy. The 15-day aeration post-treatment at 16.5 L/(h Lreactor) presented the best cost–benefit ratio. Organic matter was totally degraded. Calcium was reduced by 9%, bicarbonates by 54%. The analysis of the deposits induced by the aeration post-treatment revealed a relevant decrease of the major constituents of the clogging deposits found in the irrigation pipeline. The results show the effectiveness of post-aeration in biodegrading residual organic matter and precipitating several salts, thus reducing the clogging potential.

To achieve a water‐secure world, water management should be approached from a multidimensional and integrative perspective, addressing the water‐related issues of health, household supply, economics, the environment, and resilience to water‐related and climate change hazards. Although water security has significantly improved since 2000 in Africa, there are still vast inequalities in access to water suitable in terms of quantity and quality, especially in rural areas. To achieve water‐related sustainable development of African economies, a broad scope of innovative technological and management solutions is required, involving governments, research institutions, private sector parties, and civil society. This special series, composed of 8 papers, illustrates a selection of the most relevant results achieved by the 7 research projects selected and financed by the European Union under 2 dedicated Horizon 2020 calls in 2015: Water‐5b‐2015 “A coordination platform” and Water‐5c‐2015 “Development of water supply and sanitation technology, systems and tools, and/or methodologies.” The innovations presented in this special series include both technological advancements and w'ater management approaches, given that the development of water‐related technologies in developing countries needs to be integrated into water management strategies and economic instruments. This special series aims to help policy makers take informed decisions on how to implement innovative approaches to increase water security in African countries. Integr Environ Assess Manag 2020;16:853–855. © 2020 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC), KEY POINTS To achieve a more water secure world, water management should be approached from a multidimensional and integrative perspective.This special series aims to help policy makers take informed decisions on how to implement innovative approaches to increase water security in African countries.

Microbial degradation of 1,1,2,2-tetrachloroethane has been rarely analysed under aerobic conditions. In this work, the catabolic potential of a TeCA-degrading aerobic propanotroph consortium (C2) and the optimal bioreactor configuration for an on-site TeCA-bioremediation strategy with C2 were defined. More specifically, the diversity of alkane-oxidizing bacteria in C2 was assessed by means of clone libraries of genes coding for alkane monooxygenases (MOs) of different families (AlkB-like alkane hydroxylase, soluble di-iron MO and cytochromes P450). A large number of alkane MO sequences retrieved in this study showed the highest similarity with reference sequences belonging to Rhodococcus genus, suggesting a key role of this genus in TeCA/propane co-metabolism, while the remaining alkane MO sequences were mainly attributed to other Actinobacteria, to Bradhyrizobiaceae, and Cupriavidus genus. Further, the feasibility of an on-site TeCA bioremediation strategy with C2 was evaluated by simulating a continuous-flow aerobic co-metabolic process with different bioreactor configurations. Our results show that the configuration with a suspended-cell continuous stirred-tank reactor (CSTR) followed by a suspended-cell plug-flow reactor (PFR) was the one giving the best performance with consortium C2.

While the specific recovery of valuable chemicals from waste streams represents an environmentally-friendly and potentially economically-relevant alternative to synthetic chemical productions, it remains a largely unmet challenge. This is partially explained by the complexity of designing sorption materials able to target one specific compound and able to function in complex matrices. In this work, a series of cyclodextrin-based polymers (CDPs) were designed to selectively extract phenolic compounds from a complex organic matrix that is olive oil mill wastewater (OMW). In order to endow these polymers with selective adsorption properties, several monomers and cross-linkers were screened and selected. The adsorption properties of the CDPs produced were first tested with selected phenolic compounds commonly found in OMW, namely syringic acid, p-coumaric acid, tyrosol and caffeic acid. The selected CDPs were subsequently tested for their ability to adsorb phenolic compounds directly from OMW, which is known to possess a high and complex organic content. It was demonstrated through high-performance liquid chromatography-mass spectroscopy analyses that efficient removal of phenolic compounds from OMW could be achieved but also that two compounds, namely tyrosol and hydroxytyrosol, could be selectively extracted from OMW.

A procedure for the selection of the optimal adsorbent for phenolic compounds (PC) recovery from PC-rich wastes and wastewaters was innovatively proposed and applied to compare 4 neutral resins (Amberlite XAD16N, Optipore SD-2, Amberlite FPX66, Amberlite XAD761) and 1 ion-exchange resin (Amberlite IRA958 Cl) for PC recovery from a Tunisian olive mill wastewater (OMW). In the initial batch isotherm tests a neutral resin (XAD16N) performed best thanks to its high PC sorption capacity (81 mgPC/gdry resin) and PC content in the sorbed product (0.19 gPC/gvolatile solids). Also ion-exchange resin IRA958, used in OH form in this work, resulted interesting thanks to its satisfactory performances and very low cost (8 €/L). These two pre-selected resins were further compared by means of continuous-flow adsorption/desorption tests conducted in a 1-m packed column. The results indicate that if a low (20%) breakpoint is selected, XAD16N leads to a PC-richer sorbed product (0.14 gPC/gvolatile solids) and a higher operating capacity (0.30) than IRA958. Conversely, if a very high (90%) breakpoint is selected, the two resins produce similar desorbed products in terms of both PC content (0.19–0.21 gPC/gvolatile solids) and antioxidant capacity (4.6–4.9 gascorbic acid equivalent/gPC). Resin-specific dynamic desorption procedures led to very high PC desorption yields (87–95%). The identification of the actual PCs present in the final desorbed product indicated for XAD16N a higher capacity to preserve the integrity of the PC mixture of the studied OMW. OMW microfiltration (0.2 μm pore-size) led to a 99.8% suspended solid removal – thus protecting the packed column from potential clogging – with a very low PC loss.

A continuous-flow adsorption/desorption process for the recovery of phenolic compounds (PCs) from olive mill wastewaters (OMWs) was developed in a 0.53 m packed column, using a previously selected resin (Amberlite XAD16) and an actual OMW. The main goals of the study were (i) to evaluate the PC adsorption/desorption performances of XAD16 by means of adsorption isotherms and adsorption/desorption breakthrough tests, and (ii) to develop a reliable model of the process. A combination of centrifugation and microfiltration resulted necessary to attain a high suspended solid removal (98.5%) and thus avoid clogging of the packed bed. The quality of two packing procedures was evaluated by means of frontal analysis tests. XAD16 performed well in terms of both adsorption yield at 20% breakthrough (87–88%) and PC/COD selectivity (PC/COD adsorption constant = 7–9). The desorption solvent (acidified ethanol) was effectively regenerated by vacuum distillation. The adsorption breakthrough curves were successfully simulated with a 1-D convection/dispersion model with mass-transfer (R2 = 0.95–0.99; kLa = 0.8–2.5 · 10−3 1/s), whereas an equilibrium adsorption model with dispersion failed to predict the experimental data. In the perspective of a process scale-up, the simulation of the best-performing operational condition was used to evaluate the process performances for different column lengths (0.5–10 m). A precise and automated HPLC method for total PC measurement was developed and compared to the traditional Folin–Ciocalteu methodology. Further research is needed to optimize the desorption step, to scale up the process and to evaluate the long-term resin performances.

2,3-Butanediol (BD) is a largely used fossil-based platform chemical. The yield and productivity of bio-based BD fermentative production must be increased and cheaper substrates need to be identified, to make bio-based BD production more competitive. As BD bioproduction occurs under microaerobic conditions, a fine tuning and control of the oxygen transfer rate (OTR) is crucial to maximize BD yield and productivity. Very few studies on BD bioproduction focused on the use of non-pathogenic microorganisms and of byproducts as substrate. The goal of this work was to optimize BD bioproduction by the non-pathogenic strain Bacillus licheniformis ATCC9789 by (i) identifying the ranges of volumetric and biomass-specific OTR that maximize BD yield and productivity using standard sugar and protein sources, and (ii) performing a preliminary evaluation of the variation in process performances and cost resulting from the replacement of glucose with molasses, and beef extract/peptone with chicken meat and bone meal, a byproduct of the meat production industry. OTR optimization with an expensive, standard medium containing glucose, beef extract and peptone revealed that OTRs in the 7–15 mmol/L/h range lead to an optimal BD yield (0.43 ± 0.03 g/g) and productivity (0.91 ± 0.05 g/L/h). The corresponding optimal range of biomass-specific OTR was equal to 1.4–7.9 $${\text{mmol}}_{{{\text{O}}_{2} }} /{\text{g}}_{\text{CDW}} /{\text{h}}$$ , whereas the respiratory quotient ranged from 1.8 to 2.5. The switch to an agro-industrial byproduct-based medium containing chicken meat and bone meal and molasses led to a 50% decrease in both BD yield and productivity. A preliminary economic analysis indicated that the use of the byproduct-based medium can reduce by about 45% the BD production cost. A procedure for OTR optimization was developed and implemented, leading to the identification of a range of biomass-specific OTR and respiratory quotient to be used for the scale-up and control of BD bioproduction by Bacillus licheniformis. The switch to a byproduct-based medium led to a relevant decrease in BD production cost. Further research is needed to optimize the process of BD bioproduction from the tested byproduct-based medium.

Summarization: Mediterranean-African countries (MACs) face a major water crisis. The annual renewable water resources are close to the 500 m3/capita threshold of absolute water scarcity, and water withdrawals exceed total renewable water resources by 30%. Such a low water availability curbs economic development in agriculture, which accounts for 86% of freshwater consumption. The analysis of the current situation of wastewater treatment, irrigation, and water management in MACs and of the research projects targeted to these countries indicates the need for 1) an enhanced capacity to analyze water stress, 2) the development of water management strategies capable of including wastewater reuse, and 3) development of locally adapted water treatment and irrigation technologies. This analysis shaped the MADFORWATER project (www.madforwater.eu), whose goal is to develop a set of integrated technological and management solutions to enhance wastewater treatment, wastewater reuse for irrigation, and water efficiency in agriculture in Egypt, Morocco, and Tunisia. MADFORWATER develops and adapts technologies for the production of irrigation-quality water from drainage canals and municipal, agro-industrial, and industrial wastewaters and technologies for water efficiency and reuse in agriculture, initially validated at laboratory scale, to 3 hydrological basins in the selected MACs. Selected technologies will be further adapted and validated in 4 demonstration plants of integrated wastewater treatment and reuse. Integrated strategies for wastewater treatment and reuse targeted to the selected basins are developed, and guidelines for the development of integrated water management strategies in other basins of the 3 target MACs will be produced. The social and technical suitability of the developed technologies and nontechnological tools in relation to the local context is evaluated with the participation of MAC stakeholders and partners. Guidelines on economic instruments and policies for the effective implementation of the proposed water management solutions in the target MACs will be developed. Integr Environ Assess Manag 2018;14:447–462. © 2018 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC). Presented on

The aim of this work is to test the Levemberg Marquardt and BFGS (Broyden Fletcher Goldfarb Shanno) algorithms, implemented by the matlab functions lsqnonlin and fminunc of the Optimization Toolbox, for modeling the kinetic terms occurring in chemical processes of adsorption. We are interested in tests with noisy data that are obtained by adding Gaussian random noise to the solution of a model with known parameters. While both methods are very precise with noiseless data, by adding noise the quality of the results is greatly worsened. The semi-convergent behaviour of the relative error curves is observed for both methods. Therefore a stopping criterion, based on the Discrepancy Principle is proposed and tested. Great improvement is obtained for both methods, making it possible to compute stable solutions also for noisy data.

The purpose of this work was to perform the preliminary development and optimization of a volatile fatty acid (VFA) separation process from an actual effluent of grape pomace acidogenic anaerobic digestion by ion exchange (IE) resins. Batch IE and desorption tests were performed with acetic acid, VFA synthetic mixtures and an actual digestate. The comparison of four amino IE resins led to the selection of Amberlyst A21, a tertiary amino resin characterized by a relatively low price and high IE performances. The latter increased by increasing VFA chain length, this suggesting a relevant contribution of physical adsorption for high molecular weight VFAs. The best IE performances were obtained at pH 3–4.5 in the presence of acetic acid alone, and at pH 6.5 with the actual digestate. Basified ethanol allowed a complete desorption of all the adsorbed VFAs. Solvent recovery by evaporation, obtained with negligible losses of the desorbed VFAs, allowed the production of a highly concentrated water solution of the recovered VFAs. This result represents a crucial feature for the development of innovative VFA-fed biotechnological processes such as polyhydroxyalkanoate production ones. A model taking into account VFA IE, the competitive effect exerted by other anions and the HCO3−/CO32− buffering effect that characterizes actual digestates led to a satisfactory prediction of the experimental data, and represents an effective tool to identify the optimal operational conditions. Overall, Amberlyst A21 represents an effective candidate for the development of an adsorption/desorption process for VFA recovery from the effluents of acidogenic fermentations.

This review analyses kinetic studies of aerobic cometabolism (AC) of halogenated aliphatic hydrocarbons (HAHs) from 2001-2015 in order to (i) compare the different kinetic models proposed, (ii) analyse the estimated model parameters with a focus on novel HAHs and the identification of general trends, and (iii) identify further research needs. The results of this analysis show that aerobic cometabolism can degrade a wide range of HAHs, including HAHs that were not previously tested such as chlorinated propanes, highly chlorinated ethanes and brominated methanes and ethanes. The degree of chlorine mineralization was very high for the chlorinated HAHs. Bromine mineralization was not determined for studies with brominated aliphatics. The examined research period led to the identification of novel growth substrates of potentially high interest. Decreasing performance of aerobic cometabolism were found with increasing chlorination, indicating the high potential of aerobic cometabolism in the presence of medium- and low-halogenated HAHs. Further research is needed for the AC of brominated aliphatic hydrocarbons, the potential for biofilm aerobic cometabolism processes, HAH-HAH mutual inhibition and the identification of the enzymes responsible for each aerobic cometabolism process. Lastly, some indications for a possible standardization of future kinetic studies of HAH aerobic cometabolism are provided.

The goals of this work were (i) to compare two anion ion exchange resins (IRA958 Cl and IRA67) and a nonionic resin (XAD16) in terms of phenolic compounds adsorption capacity from olive mill wastewater and (ii) to compare the adsorption capacity of the best resin on columns of different length. The ion exchange resins performed worse than nonionic XAD16 in terms of resin utilization efficiency (20% versus 43%) and phenolic compounds/COD enrichment factor (1.0 versus 2.5). The addition of volatile fatty acids did not hinder phenolic compounds adsorption on either resin, suggesting a noncompetitive adsorption mechanism. A pH increase from 4.9 to 7.2 did not affect the result of this comparison. For the best performing resin (XAD16), an increase in column length from 0.5 to 1.8 m determined an increase in resin utilization efficiency (from 12% to 43%), resin productivity (from 3.4 to 7.6 gsorbed phenolics/kgresin), and phenolics/COD enrichment factor (from 1.2 to 2.5). An axial dispersion model with nonequilibrium adsorption accurately interpreted the phenolic compounds and COD experimental curves.

Adsorption, chromatography-based techniques, nanofiltration (NF), and electrodialysis (ED) are con- solidated operations that could be applied in the fourth stage of the Universal Recovery Process (Chap- ter 3). Since engineering aspects of such conventional techniques are well known, they could be applied with a large range of raw materials, depending on the chemical/physical compositions of such matri- ces. Recovery yields generally depend on the concentration of target molecules and on their relative amounts with respect to those compounds having similar features (size, charge, chemical structure, etc.). The latter compounds compete with the former ones within the recovery processes. This chapter is dedicated to briefly describing the main features of the above-mentioned technologies and proposes practical suggestions for the development of processes aimed at the selective recovery of chemicals from wastes. Furthermore, a number of case studies and recent works are presented.