Speaker
Description
Constructed wetland systems (CWs) have been recognized as one of the most acceptable technologies for sustainable agricultural wastewater management. They represent green infrastructures and provide solutions to treatment of wastewaters that agricultural activities produce in different ways depending on the type of agro-industrial production [1]. Particularly, CWs offer the advantages of treated wastewater (TWW) reuse for irrigation purpose and allow to save freshwater (FW) and nutrients with respect to conventional fertilization and irrigation [2]. In those areas subject to prolonged period of water shortage, these systems have the potential to provide various benefits in agronomic and environmental terms [3].
The aim of this paper was to highlight the potential functionality of CWs in agricultural areas by a critical assessment of a set of experiments carried out on two pilot-scale systems and literature. In particular, the experimental studies were carried out in Sicily (Italy) in order to assess: i) the pollutant removal efficiency of the CW plants; ii) the reuse of TWW for irrigation of some open field crops. The two pilot-scale CWs were planted with different macrophytes and had different size. They were fed with pre-treated wastewater and showed different values in hydraulic parameters. Experimental fields of turfgrasses and tomato were set up close to the two systems and irrigated with both FW and TWW. The results showed excellent organic pollutant removal (BOD5 65–75%, COD 70–75%), whilst macronutrient removal was found to be lower (Total Nitrogen 45–55%, Total Phosphorus 40–45%). Pathogens load removal was found to be approximately 90%. In the short-term period, irrigation with TWW resulted in a significant variation in plant biomass rate in accordance with literature. Savings in FW and mineral fertilizers were deemed significant. These results highlight that CWs are efficient in the treatment and reuse of wastewater for irrigation purposes, especially in arid and semi-arid areas. Furthermore, they greatly contribute to sustainability of agricultural systems.
References
[1] Wang M., Zhang D., Dong J., Tan S.K., “Application of constructed wetlands for treating agricultural runoff and agro-industrial wastewater: a review”, Hydrobiologia, 805, 1–31, (2018).
[2] Avellán T., Gremillion P., “Constructed wetlands for resource recovery in developing countries”, Renewable and Sustainable Energy Reviews, 99, 42–57, (2019).
[3] Wu H., Wu, H., Wang R., Yan P., Wu S., et al., “Constructed wetlands for pollution control”, Nature Reviews Earth & Environment, 4, 218–234 (2023).
