Innovative constructed wetlands
Indice degli argomenti
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The implementation and O&M of CWs is subject to several challenges, among which stand out a higher implementation surface, compared to gray or intensive technologies, greater control of operating parameters and the increase of the effective surface of the wetland and performances.
In the living lab of AMAYA (Agencia de Medio Ambiente y Agua), located in Carrion de los Céspedes Experimental Plant, in Seville, in the framework of the MENAWARA project, innovative Constructed Wetlands (CW) have been included in the treatment train to improve the wastewater treatment processes according to the "fit for purpose" principle including technical solutions allowing reconciling the requirements of low cost and simplicity in the O&M, while guaranteeing safe water quality for public health and the environment and giving priority to aspects related to sustainable development and the circular economy.
The innovative wetlands have been realized to:- Increase outlet performances: by designing hybrid configurations (subsurface vertical with horizontal and vertical with free water surface);
- Ensure effective areas of the sub-surface vertical CW: by laying the feed pipes above the substrate to avoid burying them.
Innovations are explained in more detailed as follows:
👉 Hybridation processes in CWs, through the combination of different types of CWs.
1. Combination of vertical and horizontal subsurface CWS, (VSSF-1 and HSSF, respectively) to improve the performance of nitrification-denitrification processes.
The most important characteristics of the wetlands are as follows:
Vertical subsurface flow wetland (VSSF1)
(a) Area: 317 m²
(b) Filling material: i. Bottom: Gravel 25-40 mm, 15 cm; ii. Top: Gravel 4-12 mm,60 cm
(c) Vegetation: Phragmites australis
Horizontal subsurface flow wetland (HSSF)
(a) Area: 120 m²
(b) Filling material: Gravel 4-12 mm, 60 cm
(c) Vegetation: Phragmites australis
2. Combination of vertical subsurface and free water surface CWs, (VSSF-3 and FWS, respectively). The free water surface CW is working as tertiary treatment, improving the final performance.
The most important characteristics of the wetlands are:
Vertical subsurface flow wetland (VSSF-3)
(a) Area: 317 m2
(b) Filling (from bottom to top): i. Gravel 25-40 mm, 15 cm; ii. Gravel 4-12 mm, 10 cm; iii. Gravel 3-8 mm, 30 cm; iv. Gravel 4-12 mm, 30 cm
(c) Vegetation: Papyrus, Iris
Free water surface wetland (FWS)
(a) Area: 237 m2
(b) Water sheet: 20 – 50 cm
(c) Bottom gravel layer, 30 cm
(d) Vegetation: Iris, Thypa, Scirpus, Cladium
One of the problems detected during several years of operation with vertical subsurface flow CWs is the burial of feeding pipes by the filling material of the wetland. In this sense, with the aim of avoiding it, the design has been innovated, incorporating feeding pipes of larger diameters and elevated above the surface of the filling material. In this way, the water is distributed throughout the entire effective surface of the bed and achive an increase on performance.
The working configurations of (5) above mentioned CWs is as follows:
👉 Intensification of the extensive process in CWs.
In synergie with the European project (LIFE INTEXT, https://life-intext.eu/ ), in the living lab of Carrion de los Céspedes Experimental Center the following innovative wetlands have been realized to increase outlet performances, also reducing the implementation surface and increasing the operation control:
- Intermittent and aerated vertical-horizontal CW. The CW is innovative not only for its configuration and intensification of the process, but also because it works as a primary treatment, receiving pre-treated water;
- Floating macrophytes, with the possibility of operating with aeration and recirculation, with several aerated and non-aerated zones.
Treated wastewater through the aforementioned CWs is diverted to a storage lagoon, where an ultrasound treatment has been installed for microalgae and E.coli removal, followed by a filtration system consisting of a pressure sand filter. followed by manual cleaning mesh filter. Finally, reclaimed water by this post-treatment is conveyed by means of a pressure group to the olive grove plot, where irrigation is carried out by surface dripping. The complete flowchart is shown below:
Fields of applications
They are technologies that have great potential for the efficient treatment and management of wastewater in rural, decentralized and economically deficient areas.
Beneficiaries
- Local communities
- Farmers
- Depuration and Irrigation water managers
- Privator sector( depuration and irrigation water companies)
- Water user associations
- Irrigation communities
- Extension agents and decision makers
- Environment
Water quality and quantity
Contrary to what is commonly thought, given that CWs are low-cost technologies and simple in O&M; They must be designed, operated and maintained correctly, for which adequate technical knowledge is needed.
References/online resources
C. Alcaide; I. García; I. Martín; E. Camacho and J.A. Rodríguez. (2021). Spatio-temporal analysis of nitrogen variations in an irrigation distribution network using reclaimed water for irrigating olive trees. Agricultural water management. Volume 262, 31 March 2022. https://doi.org/10.1016/j.agwat.2021.107353 ;
C. Alcaide; R. González; J.A. Rodríguez; I. Fernández; E. Camacho; I. Martín and K. Fahd. (2020). Manual for programming precision fertigation of the olive grove with reclaimed water. ISBN 978-84-09-22063-2
Y Zhao, B Ji, R Liu, B Ren, T Wei (2020). Constructed treatment wetland: Glance of development and future perspectives. Water Cycle, Volume 1, 2020, Pages 104-112 . Elsevier
Virtudes Martínez-Hernández; Maria Leal; Raffaella Meffe; Ángel de Miguel; Covadonga Alonso-Alonso; Irene de Bustamante; Javier Lillo; Isabel Martín; Juan José Salas. (2018). Removal of emerging organic contaminants in a poplar vegetation filter. Journal of Hazardous Materials 342 (2018) 482-491
Avila. C., Bayona, J.M., Martín, I., Salas, J,J. and García, J. (2014). Emerging organic contaminant removal in a full-scale hybrid construscted wetland system for wastewater treatment and reuse. ECOLENG-D-14-00144R1
García, J., Salas, J.J., Martín, I., and Vymazal, J. (2013). Editorial and Guest Editors. Special Issue: Research and innovation on ecotechnologies applied to improve wastewater treatment efficiency. Ecological Engineering. ISS 0925-8574. Volume 50, issue (January, 2013), p. 44- 51. ISSN: 0925-8574 DOI: 10.1016/j.ecoleng.2012.08.009
Avila, C.; Salas, J.J.; Martin, I.; Aragon, C.; Garcia, J. (2013). Integrated treatment of combined sewer wastewater and stormwater in a hybrid constructed wetland system in southern Spain and its further reuse. Ecological Engineering, Volume 50, issue (January, 2013), p. 13-20. ISSN: 0925-8574 DOI: 10.1016/j.ecoleng.2012.08.009
Kadlec, R.H., Wallace, S.D. (2008). Treatment Wetlands. Second Edition. ISBN 978-1-56670-526-4.
Vymazal, J., Kröpfelová, L. (2008). Wastewater treatment in Constructed Wetlands with Horizontal Sub-Surface Flow. ISBN 978-1-4020-8579-6
Contacts
Isabel Martin
📧isabel.martin.garcia@juntadeandalucia.es
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