1.0 Introduction
Undeniably, many nations are facing a significant challenge of water scarcity and quality degradation. Unfortunately, the problem is expected to escalate due to increase in global population. According to Petousi et al., (2015), the world populace will increase from 6.6 billion currently to 8 billion by 20130 and 9 billion by 20150. Besides, global warming and massive changes in global weather patterns have further compounded the situation. For instance, shorter duration and more intense rainfall is witnessed in various parts of the world coupled with a higher rate of evapotranspiration, which has plummeted groundwater. However, these adverse conditions have forced nations to rethink of other alternative sources of water. According to Palese et al. (2009), the use of treated municipal water has provided a realistic way of addressing the water shortage. Most nations have embraced this aspect, which has reduced the water shortage and improved agricultural production. The study sought to determine the influence of reclaimed water in olive tree production.
2.0 Problem statement
Water shortage has been one of the most pressing environmental concerns in the Mediterranean regions. The growth of the population and agricultural production has been associated with this reduction of water. According to Palese et al. (2009), agriculture and domestic water use comprise between 50-80% of the water used. With this in mind, there is an urgent need to seek an alternative source for crop and animal production, replacing the high quality of water needed for human consumption. Treatment of municipal water provides an option, especially to nations in the Mediterranean regions. By 2040, Cyprus, Jordan, Tunisia, and Israel will use at least 70% of wastewater in agricultural production. Therefore, the use of treated water solves the challenges of water shortage and reduce environmental degradation
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The use of water in agriculture is closely linked to several health risks. Palese et al. argued that a high concentration of human pathogens such as bacteria, protozoa, and virus in wastewater pose a serious medical issue (Petousi et al., 2015). Nevertheless, most countries have adopted a legislative framework that has guided these practices. By doing so, this has ensured that the practice resolves the current environmental issue without creating another challenge. For instance, the World Health Organization (WHO) has created safety standards, which should guide such activities. Notably, the presence of heavy metal in water has been a key concern due to their adverse impact on human health. In the last decades, several studies have been conducted on the use of recycled water in different crops such as lemon trees, grapevines, cucumber, roses, carnations, mandarin trees, and nectarines. In this regard, our research sought to establish the impact of reclaimed water on olive trees, primarily by focusing on the presence of heavy metal in leaves, fruits, chemical properties of the soil, and water properties.
3.0Methodology and Material
The methodology adopted in research has a definitive impact on the outcome as it influences which variables will be evaluated. In our case, the researcher sought to determine the impact of reclaimed water on olive trees; to achieve this objective, the leaves of tree and fruit, soil and wastewater were evaluated. The presence of heavy metals, organic compounds, and other pollutants was determined from the samples collected.
3.1 Sampling of Leaves, Fruits, and Wastewater
The leaves and olive fruit samples were gathered from trees where reclaimed water was used in different periods. Besides, samples were collected from sections where reclaimed water was not used to act as a control in the experiment. After this, the specimen were dried at 70 0 c and homogenized separately using liquid nitrogen and later stored in cold conditions. Water samples were collected from the Al-Tafilah Wastewater Treatment Plant (TMWW) in pairs, and polythene sampling bottles were used. Filtration was done, and droplets of concentrated nitric acid were added and before storing them at 4 o c.
3.2 Soil Sampling
The soil samples were collected randomly using a depth of 0-10cm from sections where the leaves and fruit samples were collected. This was done to improve the reliability of outcomes and lower research errs of the data. Eight samples were collected from the soil irrigated with TMWW and tree samples from soil no irrigated with TMWW. The specimen were sieved and placed in polythene bags to maintain stability and homogeneity. The soil was analyzed to determine the presence of heavy metals such as manganese (Mn), cadmium (Cd), chromium (Cr), zinc (Zn), copper (Cu), nickel (Ni), iron (Fe), and lead (Pb). Additionally, basic cations, and the total organic content were analyzed.
3.3 Samples Analysis Procedure
The sample of fruits and leaves were crushed using pestle and mortar, and 0.5g gram samples were taken from each. The samples were mixed with 70% concentrated nitric acid and hydrogen chloride using Microwave Labstation System Model (Batarseh, Rawajfeh, Ioannis, & Prodromos, 2011). After this, the samples were digested using 1% nitric acid, and atomic graphite furnace analysis was done. Wastewater was filtered, and nitric acid was added before the analysis. The heavy metal analysis was done to samples from the fruit leaves and wastewater. Notably, heavy metal in soil was calculated by extracting them with DTPA and atomic absorption spectrophotometry. Furthermore, total organic carbon was calculated using the Walker-Black wet oxidation using potassium dichromate, while a hydrometer was used to assess the texture of the soil.
3. 4 Data Analysis
All the data collected were subjected to different analysis to ease the interpretation and more to determine the impact of each variable. Variance analysis and regression were conducted using the SPSS software, and all the parameters were compared.
4.0 Results and Discussions
4.1 Chemical properties of TMWW
The analysis of the TMWW indicated that the potential of hydrogen of the water of 7.6 which was within the limit for irrigation. The electrical conductivity high due to a high level of alkalinity, but chlorides level was slightly higher than the recommended level for irrigation of olive trees ( Bedbabis et al., 2015). The result further indicated TMWW contained a relatively high level of nitrogen, potassium and phosphorous. According to Pereira, He, Stoffella, and Melfi (2011), these are macronutrients, which are needed in various plant processes such as the manufacture of chlorophyll, seed formation, root development, the ripening of fruit among others. Moreover, the results indicated that heavy metals such as Ca, Mn, Zn, Mn, and Cd were way below the recommended levels. Evidently, the chemical properties of TMWW were within the threshold set by the irrigation board.
4.2 Heavy Metal Distribution in Soil and Olive Trees
The presence of heavy metal in the TMWW means that that they can be absorbed both in the soil and the olive trees. This distribution of heavy metals in plants and soil affects human health. The results indicated that a high level of iron and nickel in TMWW, while leaves of olive and fruits were considerably low. Comparatively, the available level of the iron and nickel were low compared to the level of accumulated in the soil. Surprisingly, the result further highlighted that the edible parts had a higher accumulation of heavy metal as compared to those found in the soil (Batarseh et al., 2011). Irrefutably, the results outline that heavy metal absorption by olive trees is a discriminative procedure, and for some metal such as lead and nickel, it largely independent on their levels in the TMWW. Conversely, this does not seem to be true for other heavy metal such as cadmium and chromium, which seem to be recommended by olive fruits and leaves. Therefore, a basic conclusion could be drawn that uptake and accumulation of toxic metals by olive trees underneath the impact of TMWW is not primarily linked to the quantity of heavy metal in TMWW.
5. 0 Proposed Solutions
Undeniably, the advancement of technologies has allowed nations to overcome environmental issues such as water shortage. According to Kamble, Singh, & Kharat (2018), innovations such as sequencing batch reactors (SBRs) has been used to treat wastewater. Ideally, the choice depends on the economic and technical factors. In our case, Al-Tafilah must adopt the SBR technologies, which will recycle more water effectively and efficiently. More so, the technology recycles more waters, despite having a high maintenance cost. Therefore, this will both the quality and volume of reclaimed water, which will be used in various agricultural practices. Notably, nations such as Israel has adopted the innovation, and the outcome has been forthcoming. The proposed engineering solution solve the shortage of water and quality.
Figure one. Design of SBR
6.0 Conclusion
Water shortage and reduction in quality are the primary challenges facing most nations. The use of reclaimed water has provided a solution to these environmental concerns. In Al-Tafilah, Jordan reclaimed water has been used in the production of olive trees. The research sought to identify the impact of TMWW on the olive trees, and results have noted heavy metal uptake is not correlated to the concentration of TMWW. Mainly, the tree has a selective mode of absorption, and also, the water has heavy metal level that falls within the threshold. Therefore, to increase the level of TMWW, SBRs must be used to increase both the volume and quality of water.
References
Batarseh, M. I., Rawajfeh, A., Ioannis, K. K., & Prodromos, K. H. (2011). Treated municipal wastewater irrigation impact on olive trees (Olea Europaea L.) at Al-Tafilah, Jordan. Water, Air, & Soil Pollution , 217 (1-4), 185-196.
Bedbabis, S., Trigui, D., Ben Ahmed, C., Clodoveo, M. L., Camposeo, S., Vivaldi, G. A., & Ben Rouina, B. (2015). Long-terms effects of irrigation with treated municipal wastewater on soil, yield and olive oil quality. Agricultural Water Management , 160 , 14-21.
Kamble, S. J., Singh, A., & Kharat, M. G. (2018). Life cycle analysis and sustainability assessment of advanced wastewater treatment technologies. World Journal of Science, Technology and Sustainable Development , 15 (2), 169-185.
Palese, A., Pasquale, V., Celano, G., Figliuolo, G., Masi, S., & Xiloyannis, C. (2009). Irrigation of olive groves in Southern Italy with treated municipal wastewater: Effects on microbiological quality of soil and fruits. Agriculture, Ecosystems & Environment , 129 (1-3), 43-51.
Pereira, B., He, Z., Stoffella, P., & Melfi, A. (2011). Reclaimed wastewater: Effects on citrus nutrition. Agricultural Water Management , 98 (12), 1828-1833.
Petousi, I., Fountoulakis, M., Saru, M., Nikolaidis, N., Fletcher, L., Stentiford, E., & Manios, T. (2015). Effects of reclaimed wastewater irrigation on olive (Olea europaea L. cv. ‘Koroneiki’) trees. Agricultural Water Management , 160 , 33-40.
