ELECTRODIALYTIC PROCESS OF NANOFILTRATION CONCENTRATES – PHOSPHORUS RECOVERY AND MICROCYSTINS REMOVAL

doi:10.1016/j.electacta.2015.04.081

Electrochimica Acta

Volume 181, 1 November 2015, Pages 200-207

https://doi.org/10.1016/j.electacta.2015.04.081 Get rights and content

Abstract

Toxic cyanobacteria blooms are associated with nutrient enrichment of surface waters. Nanofiltration (NF) is a pressure-driven process that can be used in water treatment plants, to effectively remove particulate matter and organic contaminants, including cyanobacteria toxins, and nutrients. NF produces a nutrient and toxin-enriched stream, e.g. with microcystin-LR (MC-LR), that has to be safely disposed of.

The suitability of the electrodialytic (ED) process for phosphorus recovery and decrease of MC-LR concentrations from NF waste stream was assessed. In ED experiments running between 5 and 12 h, phosphorus electromigrated towards the anode compartment promoting an isolated clean phosphorus product. The maximum obtained phosphorus recovery was 84%, varying with the NF waste stream (membrane concentrate) characteristics, cell design and treatment time. After the application of the ED process the concentration of MC-LR was also reduced. These results encourage further tests, aiming the inclusion of this hybrid technology (NF followed by ED) in water treatment plants, contributing not only for the phosphorus recovery, but also for the decrease in the toxicity of the NF concentrate, lowering the costs and promoting safe disposal.

Graphical abstract

Section snippets

INTRODUCTION

The increase fluxes of nutrients arriving to water bodies, namely phosphorus and nitrogen, due to agricultural runoff/sewage treatment plants/other anthropogenic sources is one of the main factors to promote the existence of cyanobacterial blooms [1].

Microcystins are hepatotoxic cyclic peptide toxins (Fig. 1) released by freshwater cyanobacteria. Microcystin-LR (MC-LR) is the most common and toxic variant [2]. The contamination in freshwater sources may have severe health effects, leading the

Production of membrane concentrates

The production of membrane concentrate was carried out using a plate-and-frame unit (Lab-unit M20) described in detail elsewhere [10]. A thin film composite NF membrane with an hydraulic permeability of 82.2 kg/(h.m².bar) at 21 °C and a membrane molecular weight cut-off of ca. 114 Da, NF90 (DowFilmtec), was used. The experiments consisted of concentration runs, mimetizing industrial NF operation at different water recovery rates (defined between permeate and initial feed volumes).

The concentrate

Phosphorus separation from membrane concentrates

Experiments A and B were carried out with the same membrane concentrate (#4; 1476 μS/cm) but different applied currents which led to different durations (7 and 5 h, respectively). Experiment C (10 mA; #5; 1276 μS/cm) had a similar duration as experiment A due to similar characteristics between the membrane concentrates used. Experiments A to C were considered finished when voltage started to be more constant, whereas Experiment D continued for 2 more hours to search for additional phosphorus

CONCLUSIONS

The suitability of the ED process to recover phosphorus and decrease of MC-LR concentrations from NF concentrate was assessed.

The electromigration of phosphorus towards the anode compartment resulted in recoveries between 32% and 84%, which were mainly dependent on membrane concentrate characteristics, cell design and time of the ED process. The behaviour of phosphorus migration may help a cost-benefit analysis of the best time needed to perform the nutrient recovery.

In the tested conditions,

ACKNOWLEDGEMENTS

Financial support for the work was provided by projects FP7-PEOPLE-2010-IRSES-269289-ELECTROACROSS - Electrokinetics across disciplines and continents: an integrated approach to finding new strategies for sustainable development and PTDC/ECM/111860/2009 - Electrokinetic treatment of sewage sludge and membrane concentrate: Phosphorus recovery and dewatering. Authors also thank RIARTAS-Red Iberoamericana de Aprovechamiento de Residuos Industriales para el Tratamiento de Suelos y Aguas

References (24)

S. Corbel et al.
Cyanobacterial toxins: Modes of actions, fate in aquatic and soil ecosystems, phytotoxicity and bioaccumulation in agricultural crops
Chemosphere
(2014)
V.K. Sharma et al.
Destruction of microcystins by conventional and advanced oxidation processes: A review
Separation and Purification Technology
(2012)
J. Meriluoto
Chromatography of microcystins
Anal. Chim. Acta
(1997)
J. Chang et al.
Ozonation degradation of microcystin-LR in aqueous solution: Intermediates, byproducts and pathways
Water Research
(2014)
T. Fotiou et al.
Evaluation of the photocatalytic activity of TiO2 based catalysts for the degradation and mineralization of cyanobacterial toxins and water off-odor compounds under UV-A, solar and visible light
Chemical Engineering Journal
(2015)
L.C.V. Jacobs et al.
Photocatalytic degradation of microcystin-LR in aqueous solutions
Chemosphere
(2013)
A.J. Gijsbertsen-Abrahamse et al.
Removal of cyanotoxins by ultrafiltration and nanofiltration
Journal of Membrane Science
(2006)
M. Ribau Teixeira et al.
Neurotoxic and hepatotoxic cyanotoxins removal by nanofiltration
Water Research
(2006)
P. Guedes et al.
2015. Potential of the electrodialytic process for emerging organic contaminants remediation and phosphorus separation from sewage sludge
Electrochimica Acta
(2015)
P. Guedes et al.
Phosphorus recovery from sewage sludge ash through an electrodialytic process
Waste Management
(2014)

R. Simons

The origin and elimination of water splitting in ion exchangemembranes during water demineralisation by electrodialysis

Desalination

(1979)

R. Simons

Electric field effects on proton transfer between ionizable groupsand water in ion exchange membranes

Electrochimica Acta

(1984)

Cited by (15)

Recent advances in nanofiltration-based hybrid processes
2023, Desalination
As a kind of pressure-driven membranes, the nanofiltration (NF) membrane and process can separate molecules and ions with different molecular weights and valences, which are well applicable in purification, concentration, recovery of resources across various industries. However, in some complex applications, an individual NF membrane often faces the problems of deficient separation efficiency and membrane instability. Researchers have developed NF based hybrid processes, which not only solve the above problems faced by single NF, but also enhance the overall efficiency of hybrid systems involving other separation processes. Currently, there is a notable surge in publications regarding the NF-based hybrid processes, but a systematic review is still lacking. The objective of this review is to provide a comprehensive analysis of the key integration approaches and application areas in which NF-based hybrid process have been utilized in recent years. The challenges awaiting the researcher in the field of NF-based hybrid process are also provided.
Insight into technologies for phosphorus recovery from municipal wastewater treatment plants
2023, Resource Recovery in Municipal Waste Waters
This study examines the various technologies developed for the recovery of phosphorus (P) from municipal wastewater. Depending upon the source of waste, the P recovery technologies have been divided into three categories: liquid phase recovery technologies, sewage waste recovery technologies, and sewage ash recovery technologies. This chapter provides information about the principle techniques, efficiency of P recovery, process parameters (pH, temperature, chemicals, algae, and bacteria culture), and the final P products formed in the process. Technologies based on the use of algae and bacterial consortium, adsorption, and biological reactors enhance P recovery without the addition of chemicals. New technologies explore the use of anaerobic processes in the treatment for the recovery of energy. The end products also formed have greater bioavailability when used as a component of fertilizer. Sewage ash has shown the highest potential for P recovery and should be further explored. Technologies like Ostara Pearl, alkaline fermentation, MNRC, forward osmosis, and Airprex have shown a P removal range of 25%–92% from the liquid phase, NuReSys, Gifhorn, MEC, and EF have shown a P removal range of 34%–97% from sewage sludge, EcoPhos, Ashdec have shown P recovery >95% from sewage sludge ash of municipal wastewater. Further, research should focus on bridging the gap between theory and practice for the sustainable and socioeconomic implementation of the technologies. A legal framework for P recovery from municipal wastewater needs to be developed to encourage P recycling.
Application of membrane separation processes in phosphorus recovery: A review
2021, Science of the Total Environment
Citation Excerpt :
It is worth noting that although the solid phase of Pb is very stable during ED, a small amount of it associated with lead phosphate was synchronously released with the release of phosphate and then migrate to the cathode. While research on emerging organic pollutants (EOCs) (Pronk et al., 2006a; Guedes et al., 2015; Shi et al., 2020) and the microcystin-LR (Couto et al., 2015) have shown that these pollutants degrade better during ED, the remaining toxins still have the opportunity to bind to the recovered phosphorus. Research by Ferreira et al. (2018) suggests that removals were higher when using an AEM (60–72%) instead of a CEM (8–63%) for all EOCs, with the exception of caffeine when the effluent was placed in the cathode compartment, where there was no removal in any of the experiments.
The depletion of phosphorus resources and the excess discharge of phosphorus into waste streams are contrasting problems. The key to solving both problems is to recover phosphorus from the waste streams. Current phosphorus recovery technologies require high phosphorus concentrations and lack the ability to separate toxic substances from recovered phosphorus products. Membrane separation processes such as nanofiltration, forward osmosis, and electrodialysis are examples of effective methods for solving some of these issues. In this paper, the mechanisms, performance, and influential factors affect phosphorus recovery from membrane separation are reviewed. Membrane fouling, energy consumption, and the selectivity of toxic substances in membrane separation processes were evaluated. This work will serve as a basis for future research and development of phosphorus recovery by membrane separation processes and as a response to the increasingly pressing issues of eutrophication and the growing depletion of phosphorus resources.
New frontiers from removal to recycling of nitrogen and phosphorus from wastewater in the Circular Economy
2020, Bioresource Technology
Nutrient recovery technologies are rapidly expanding due to the need for the appropriate recycling of key elements from waste resources in order to move towards a truly sustainable modern society based on the Circular Economy. Nutrient recycling is a promising strategy for reducing the depletion of non-renewable resources and the environmental impact linked to their extraction and manufacture. However, nutrient recovery technologies are not yet fully mature, as further research is needed to optimize process efficiency and enhance their commercial applicability. This paper reviews state-of-the-art of nutrient recovery, focusing on frontier technological advances and economic and environmental innovation perspectives. The potentials and limitations of different technologies are discussed, covering systems based on membranes, photosynthesis, crystallization and other physical and biological nutrient recovery systems (e.g. incineration, composting, stripping and absorption and enhanced biological phosphorus recovery).
Opportunities and challenges in sustainable treatment and resource reuse of sewage sludge: A review
2018, Chemical Engineering Journal
Citation Excerpt :
Similarly, other investigations have also reported a remarkable P content of >95% and ammonia >50% solubilization via various combined thermochemical treatments [182–184]. Guedes al. [181] and Couto et al. [185] presented a viable method for P-recovery by an electro dialysis approach from WAS. The process gave a total yield of 30–85% including some amounts of gypsum, thus necessitating further research to evaluate the opportunity of utilizing residues as dopants for construction materials.
Sludge or waste activated sludge (WAS) generated from wastewater treatment plants may be considered a nuisance. It is a key source for secondary environmental contamination on account of the presence of diverse pollutants (polycyclic aromatic hydrocarbons, dioxins, furans, heavy metals, etc.). Innovative and cost-effective sludge treatment pathways are a prerequisite for the safe and environment-friendly disposal of WAS. This article delivers an assessment of the leading disposal (volume reduction) and energy recovery routes such as anaerobic digestion, incineration, pyrolysis, gasification and enhanced digestion using microbial fuel cell along with their comparative evaluation, to measure their suitability for different sludge compositions and resources availability. Furthermore, the authors shed light on the bio-refinery and resource recovery approaches to extract value added products and nutrients from WAS, and control options for metal elements and micro-pollutants in sewage sludge. Recovery of enzymes, bio-plastics, bio-pesticides, proteins and phosphorus are discussed as a means to visualize sludge as a potential opportunity instead of a nuisance.
A review of phosphorus recovery methods at various steps of wastewater treatment and sewage sludge management. The concept of “no solid waste generation” and analytical methods
2017, Journal of Cleaner Production
Citation Excerpt :
Also, many countries that do not have large natural deposits of phosphorus could become, in this matter, independent from the previously mentioned leaders in that field, such as the US, China and Morocco. It is likely that a broad implementation of such a technology could prevent some economic conflicts in the future (Couto et al., 2015; Guedes et al., 2014). One must not forget about the widespread problem of world hunger.
Phosphorus deposits around the world are rapidly depleting, therefore phosphorus recovery methods are gaining more and more interest both in science and industry. This article presents the main methods of phosphorus recovery from sewage sludge. The described approaches are divided in two groups: phosphorus recovery from sewage sludge and leachate, and recovery of phosphorus from sewage sludge ashes. The latter seems to have more advantages connected with both ecological and economical aspects. The need for development of “no solid waste generation” strategy is becoming more and more urgent. The concept of comprehensive management of all solid residues after what is currently considered the most ecological process of sewage sludge incineration connected with phosphorus recovery based on acidic extraction, is described in the article. Solid residues after phosphorus recovery from sewage sludge ashes by means of acidic extraction can be stabilized with solid residues after sewage sludge incineration exhaust gas treatment. Such an approach may enable production of phosphoric raw material together with stabilized construction material. Advantages and disadvantages of the discussed approaches are given. An analysis of the composition of ashes produced in different sewage sludge treatment plants indicates that the proposed technology could be successfully applied in most of such units, especially because the concentrations of elements such as K, Mg, Na, P are sufficiently high, respectively 1.5–12.1 g/kg; 9.9–14.9 g/kg; 3.6–13,3 g/kg and 27,4–99,0 g/kg. However, a phosphorus recovery method should be developed separately for each treatment plant. Only then all comprehensive management methods will be ecologically and economically justified. Analytical methods which could be of use at every step of designing a proper phosphorus recovery process are described.

View all citing articles on Scopus

View full text

ELECTRODIALYTIC PROCESS OF NANOFILTRATION CONCENTRATES – PHOSPHORUS RECOVERY AND MICROCYSTINS REMOVAL

Abstract

Graphical abstract

Section snippets

INTRODUCTION

Production of membrane concentrates

Phosphorus separation from membrane concentrates

CONCLUSIONS

ACKNOWLEDGEMENTS

Chemosphere

Separation and Purification Technology

Anal. Chim. Acta

Water Research

Chemical Engineering Journal

Chemosphere

Journal of Membrane Science

Water Research

Electrochimica Acta

Waste Management

Desalination

Electrochimica Acta