Ammonium recovery from municipal wastewater by ion exchange: Development and application of a procedure for sorbent selection

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

Geopolymers adsorbents: Production and use

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Batch and Continuous Flow Adsorption of Phenolic Compounds from Olive Mill Wastewater: A Comparison between Nonionic and Ion Exchange Resins

The goals of this work were (i) to compare two anion ion exchange resins (IRA958 Cl and IRA67) and a non-ionic 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 proved less performant than non-ionic 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 non-competitive 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 g sorbed phenolics/kg resin) and phenolics/COD enrichment factor (from 1.2 to 2.5). An axial dispersion model with non-equilibrium adsorption accurately interpreted the phenolic compounds and COD experimental curves

Innovative Research Approaches to Cope with Water Security in Africa

To achieve a water\u2010secure world, water management should be approached from a multidimensional and integrative perspective, addressing the water\u2010related issues of health, household supply, economics, the environment, and resilience to water\u2010related 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\u2010related 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\u20105b\u20102015 \u201cA coordination platform\u201d and Water\u20105c\u20102015 \u201cDevelopment of water supply and sanitation technology, systems and tools, and/or methodologies.\u201d The innovations presented in this special series include both technological advancements and w'ater management approaches, given that the development of water\u2010related 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