Wastewater treatment by adsorption and/or ion-exchange processes for resource recovery

Nowadays, resource recovery is a trending topic following the circular economy schemes proposed by the European UnionPostprint (published version

Ionic behavior assessment of surface-active compounds from corn steep liquor by exchange resins

Depending on their ionic nature, biosurfactants can be classified as nonionic, anionic, cationic, or amphoteric. The ionic behavior of biosurfactants is an important characteristic that dictates their use in industrial applications. In this work, a biosurfactant extract obtained from corn steep liquor was subjected to anionic or cationic resins, in order to study the ionic behavior under different operational conditions using response surface methodology. The independent variables included in the study are the dilution of biosurfactant solution, the amount of cationic or anionic resin, and the extraction time, whereas the dependent variables studied consisted of the surface tension of biosurfactant aqueous solution, after contacting with anionic or cationic resin. The results showed that biosurfactant extracted from corn steep liquor is amphoteric, since both resins were able to entrap this biosurfactant, making it particularly suited for use in personal care preparations for sensitive skin.Peer ReviewedPostprint (author's final draft

Coagulation and flocculation optimization process applied to the sidestream of an urban wastewater treatment plant

Ammonium (NH4+) recirculation from the streams generated in the dehydration stage of the sludge generated in the anaerobic digestion of urban wastewater treatment plants (WWTPs), known as centrate or sidestream, produces a reduction in the efficiency of WWTPs. Given this scenario and the formulation that a WWTP should be considered a by-product generating facility (biofactory), solutions for ammonia/ammonium recovery are being promoted. These include a nitrogen source that reduces the need for ammonia production through the Haber–Bosch process. Therefore, the recovery of nutrients from urban cycles is a potential and promising line of research. In the case of nitrogen, this has been aimed at recovering NH4+ to produce high-quality fertilizers through membrane or ion exchange processes. However, these techniques usually require a pretreatment, which could include an ultrafiltration stage, to eliminate suspended solids and organic matter. In this case, the coagulation/flocculation (C/F) process is an economical alternative for this purpose. In this work, the sidestream from Vilanova i la Geltrú WWTP (Barcelona, Spain) was characterized to optimize a C/F process before being treated by other processes for ammonium recovery. The optimization was performed considering a bibliographic and experimental analysis of several operating parameters: coagulant and flocculant agents, mixing velocity, and operation time, among others. Then, the removal efficiency of control parameters such as turbidity, chemical oxygen demand (COD), and total suspended solids (TSS) was calculated. This optimization resulted in the use of 25 mg/L of ferric chloride (FeCl3) combined with 25 mg/L of a flocculant composed of silicon (SiO2 3%), aluminum (Al2SO4 64.5%), and iron salts (Fe2O3 32.5%), into a 1 min rapid mixing process at 200 rpm and a slow mixing for 30 min at 30 rpm, followed by a final 30 min settling process. The numerical and statistical results of the process optimization reached 91.5%, 59.1%, and 95.2% removal efficiency for turbidity, COD, and TSS, respectively. These efficiencies theoretically support the enhanced coagulation/flocculation process as a pretreatment for a higher NH4+ recovery rate, achieving 570.6 mgNH4+/L, and a reduction in the dimensioning or substitution of other membrane processes process due to its high TSS removal value.Peer ReviewedPostprint (published version

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-

Essential oil-water emulsions containing a biosurfactant from Lactobacillus paracasei

[Excerpt] Surfactants play important roles in cosmetic products due to diverse properties including as emulsifier, foaming, wetting, detergency and solubilizer agents, among others. However, the market for beauty and personal care products based on natural ingredients has shown a relevant growth. In this sense, biosurfactants being non-toxic, biodegradable and ecofriendly natural compounds are suitable replacers of the chemical-based surfactants showing equal or better performances [1]. In addition, essential oils are natural ingredients extracted from plants that also are interesting ingredients for novel cosmetic formulations.The aim of this study was to formulate oil-water emulsions using a biosurfactant from Lactobacil/us paracasei in combination with several essential oils (wheat germ, almond, rosemary and jojoba oil). [...]Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BI0/04469/2013 unit, COMPETE 2020 (POCl-01-0145-FEDER-006684) and the project RECl/BBB-EBl/0179/2012 (FCOMP-01-0124-FEDER-027462

Characterization of ionic nature of biosurfactant extracted from corn steep liquor using ionic exchange resins

[Excerpt] Resins have been used for years for the purification and characterization of ionic substances. The use of these resins allows not only remove impurities or increase the concentration of metabolites from industrial streams, but also allows define their ionic structure. In general, surfactants can be classified as non-ionic, anionic, cationic or amphoteric, what is going to define their future application at industrial scale. For example, anionic surfactants present the greatest wetting and emulsifying properties, while cationic ones have excellent antibacterial properties as well as good emulsifier capacities. Otherwise, amphoteric surfactants, which may have anionic or cationic properties depending on pH, are widely used in personal care products because of their less irritability to skin and eyes in comparison with other types of surfactants. [...]Spanish Ministry of Economy and Competitiveness (FEDER funds under the project CTM2015-68904)University of Vigo (Spain

Adsorption capacity evaluation of a lipopeptide biosurfactant on human hair

[Excerpt] Nowadays, surfactants are used in a wide variety of applications in several fields, such as cosmetic and health care, environmental issues and, generally, as detergents. They present valuable characteristics since they can decrease water surface tension and solubilize molecules that cannot be eliminated in an aqueous media in normal conditions. Due to their surface active nature, synthetic surfactants can result toxic in the media in which they are applied. These drawbacks can be overcome by using biosurfactants, since they result environmentally friendly because of their biodegradability and low toxicity. Therefore, it would be interesting to replace synthetic detergents by biosurfactants in cosmetic and personal care formulations. From this point of view, Vecino et al., [1] have extracted biosurfactants from an industrial stream of corn wet milling industry, consisting of a lipopeptide that could have important applications in the formulation of natural shampoos. This biosurfactant is able to reduce the surface tension of water in more than 30 units. Thus, the aim of this work was to study the adsorption of this biosurfactant in human hair. [...]Spanish Ministry of Economy and Competitiveness (FEDER funds under the project CTM2015-68904University of Vigo (Spain

The influence of the medium composition on the biosurfactants produced by Lactobacillus paracasei

[Excerpt] Lactic acid bacteria is an interesting group of microorganisms for the production of biosurfactants. In addition, these bacteria are generally recognized as safe by the American Food and Drug Administration. An example is the Lactobacil/us paracasei that was isolated from a Portuguese dairy industry and has been previously reported by Gudina and collaborators [1] forthe production of biosurfactants.The biosurfactants produced by LAB are cell-bound biosurfactants contrarily to the most well-known extracellular biosurfactants produced by Pseudomonas or Bacillus species. The main bottleneck of their industrial production and application is related with the production and recovery costs. Therefore, many studies are focusing on the use of renewable agroindustrial wastes as carbon sources in the fermentative processes [2]. The aim of this work was the production and characterization of biosurfactants by L. paracasei using a lignocellulosic residue (vineyard pruning waste) as carbon source. The vineyard pruning waste was subjected to a fractionation process to obtain cellulose, which was next submitted to a saccharification step with enzymes in order to convert cellulose in a glucose-based fermentation media. Once this glucose solution was obtained, it was further supplemented with 1 O g/L of yeast extract and 1 O g/L of corn steep liquor. [...]Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BI0/04469/2013 unit, COMPETE 2020 (POCl-01-0145-FEDER-006684) and the project RECl/BBB-EBl/0179/2012 (FCOMP-01-0124-FEDER-02746

Antimicrobial study of biosurfactants from Lactobacillus strains against skin pathogens

[Excerpt] Human skin microflora is composed by resident1 temporarily resident and transient microbial species. Therefore, gram-positive bacteria from the genera Propionibacterium, Staphylococcus, Micrococcus, Corynebaderium and Acinetobacter are the majority microorganisms present in the resident microflora [1 ]. For instance, Staphylococcus epidermidis is the main constituent of skin microflora, which protects the human skin from infections; whereas Staphylococcus aureus is a common transient species, which causes skin infections [2]. Anti-bacterial preservatives such as triclosan, methylparaben or bronopol, among others, are currently used as ingredients in the skin and oral care cosmetic products. However, there is a growing demand for cosmetics free of synthetic preservatives [3]. In this sense, biosurfactants from lactic acid bacteria, which are generally recognized as safe by the American Food and Drug Administration, are natural compounds that exhibit antimicrobial activity and therefore, could be used as an alternative to the chemically synthetized preservatives. The aim of this study was to evaluate the antimicrobial activity of biosurfactants obtained from two different Lactobacillus strains (L. pentosus and L. paracasef) against skin pathogenic microorganisms. [...]Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BI0/04469/2013 unit, COMPETE 2020 (POCl-01-0145-FEDER-006684) and the project RECl/BBB-EBl/0179/2012 (FCOMP-01-0124-FEDER-027462

Potential applications of multifunctional extract obtained from corn industry in food packaging

[Excerpt] Nowadays, in the food industry exists an increased demand, by the consumers, of natural additives that can replace those chemical additives obtained from non renewable resources. In this work extracts with surfactant and antioxidant properties were obtained from corn steep liquor (CSl) with potential applications in food packaging. the extraction process was carried out using ethyl acetate and the operational conditions consisted of: CSl/ethyl acetate 1:3 (v/v), at 25°C during 45 min with agitation system at 150 rpm. the antioxidant activity of the extract was determined by the dPPh (2,2-diphenyl-1-picrylhydrazyl) radical scavenging method; whereas the surface active properties was evaluated by the wilhelmy plate method in a force tensiometer with a platinum plate (easy dyne k20, kruSS gmbh), at room temperature. Fatty acid composition of extract was analyzed by gas chromatography coupled to a mass spectrometer (Bruker Scion 451-gC). [...