Citation: Oueslati, A.; Dabbou, S.; Methneni, N.; Montevecchi, G.; Nava, V.; Rando, R.; Bartolomeo, G.; Antonelli, A.; Di Bella, G.; Ben Mansour, H. Pomological and Olive Oil Quality Characteristics Evaluation under Short Time Irrigation of Olive Trees cv. Chemlali with Untreated Industrial Poultry Wastewater. Sustainability 2023, 15, 4198. https://doi.org/10.3390/ su15054198 Academic Editors: Amélia Martins Delgado and Pasqualina Laganà Received: 15 January 2023 Revised: 18 February 2023 Accepted: 19 February 2023 Published: 25 February 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). sustainability Article Pomological and Olive Oil Quality Characteristics Evaluation under Short Time Irrigation of Olive Trees cv. Chemlali with Untreated Industrial Poultry Wastewater Amira Oueslati 1 , Samia Dabbou 2 , Nosra Methneni 1 , Giuseppe Montevecchi 3 , Vincenzo Nava 4 , Rossana Rando 4 , Giovanni Bartolomeo 4 , Andrea Antonelli 3 , Giuseppa Di Bella 4 and Hedi Ben Mansour 1, * 1 Research Unit of Analysis and Process Applied on the Environment—APAE UR17ES32—Higher Institute of Applied Sciences and Technology of Mahdia, University of Monastir, Mahdia 5100, Tunisia 2 Unit of Bioactive and Natural Substances and Biotechnology UR17ES49, Dentistry Faculty, University of Monastir, AvicenneStreet, Monastir 5019, Tunisia 3 Department of Life Sciences (Agro-Food Science Area), BIOGEST-SITEIA Interdepartmental Centre, University of Modena and Reggio Emilia, Piazzale Europa 1, 42124 Reggio Emilia, Italy 4 BioMorf Department, University of Messina, Viale Annunziata, Polo Universitario, 98168 Messina, Italy * Correspondence: hdbenmansour@gmail.com Abstract: The aim of this work was the investigation of the effect of wastewater generated from the poultry meat industry on the irrigation of olive trees, during a short time period, in order to evaluate its impact on pomological criteria and olive oil quality. Olive trees were subjected to irrigation with different water qualities: (i) poultry wastewater (PWW), (ii) poultry wastewater diluted with tap water 50:50 (v/v) (PWTWW), (iii) rain-fed cultivation system (control). The results showed that PWTWW contains the optimal mineral proportions, leading to improved pomological criteria. However, the highest significant pulp oil content was obtained using poultry wastewater irrigation (69.51%), while this was 66.71% using diluted poultry wastewater, and 58.03 % for the control. Poultry wastewater irrigation yielded the best results in oil standard quality indices. In addition, an enrichment in oil total polyphenols content was achieved. The oil fatty acid profile was not affected following irrigation with poultry wastewater. Nevertheless, there was a significant increase in the contents of oleic acid and alcohols, accompanied by a decrease in total sterols. However, heavy metals accumulation was observed in both fruits and olive oil. In conclusion, our results suggest that among the three water qualities, poultry wastewater is the best alternative to improve olive oil quality. Keywords: Olea europaea; fruits; agro-industrial wastewater reuse; water shortage 1. Introduction Statistical estimations suggest that, given the current demographic trends, about 60% of the worldwide population may suffer water scarcity by the year 2025 [1]. This dramatic situation is due to climate change as a result of greenhouse gas emissions from industrial activities [2]. It has been predicted that increasing temperatures will contribute to about 20% of the global expansion in water scarcity [3], which would affect the development and functioning of social and economic communities. In arid and semi-arid countries such as Tunisia, this problem is accentuated, since they have limited freshwater resources [4]. Agriculture is by far the largest consumer sector of freshwater, accounting for 69% of annual global water withdrawals, followed by industry (19%) and households (12%) [5]. In order to manage water demand well, current governmental strategies are geared towards the reuse of wastewater in crop irrigation. In fact, wastewater has been considered as a source of nutrients for crops, leading to a reduction in chemical fertilizer use [6,7]. Furthermore, it has been mentioned that the cost of agricultural production could be reduced by 10–20% [8]. Sustainability 2023, 15, 4198. https://doi.org/10.3390/su15054198 https://www.mdpi.com/journal/sustainability