Using Wastewater in Irrigation: The Effects on Infiltration Process in a Clayey Soil

Ammar A Albalasmeh,Mamoun A Gharaibeh,Alessia Flammini,Renato Morbidelli,Carla Saltalippi,Ma’In Z Alghzawi,Teamrat A Ghezzehei

doi:10.3390/w12040968

Ammar A Albalasmeh, Mamoun A Gharaibeh + Show 5 more

Open Access

https://doi.org/10.3390/w12040968

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Abstract

Soil water infiltration is a critical process in the soil water cycle and agricultural practices, especially when wastewater is used for irrigation. Although research has been conducted to evaluate the changes in the physical and chemical characteristics of soils irrigated by treated wastewater, a quantitative analysis of the effects produced on the infiltration process is still lacking. The objective of this study is to address this issue. Field experiments previously conducted on three adjacent field plots characterized by the same clayey soil but subjected to three different irrigation treatments have been used. The three irrigation conditions were: non-irrigated (natural conditions) plot, irrigated plot with treated wastewater for two years, and irrigated plot with treated wastewater for five years. Infiltration measurements performed by the Hood infiltrometer have been used to estimate soil hydraulic properties useful to calibrate a simplified infiltration model widely used under ponding conditions, that were existing during the irrigation stage. Our simulations highlight the relevant effect of wastewater usage as an irrigation source in reducing cumulative infiltration and increasing overland flow as a result of modified hydraulic properties of soils characterized by a lower capacity of water drainage. These outcomes can provide important insights for the optimization of irrigation techniques in arid areas where the use of wastewater is often required due to the chronic shortage of freshwater.

Highlights

A quantitative study of water movement in the vadose zone allows us to identify strategies for water conservation, flood/runoff and erosion control, and the assessment of aquifer potential contamination due to migration of water-soluble chemicals [1]
Based on the Philip model parameters estimated for the three experimental plots/treatments and shown in Table 3, it can be deduced that the sorptivity markedly decreases with increasing the period of irrigation using treated wastewater (TWW)
The A parameter is rather similar for all treatments. These results suggest that A, which is related to the saturated hydraulic conductivity and connectivity of the largest pores, is not affected by the TWW movement

Summary

Introduction

A quantitative study of water movement in the vadose zone allows us to identify strategies for water conservation, flood/runoff and erosion control, and the assessment of aquifer potential contamination due to migration of water-soluble chemicals [1]. It is a key dynamic process to be considered for the design of irrigation systems and optimization, irrigation scheduling, and irrigation management [3]. This process assumes much more importance in arid and semi-arid regions where, because of short periods and low amounts of rainfall, water is a scarce resource considered as a limiting factor for agricultural production. In these areas, the chronic water shortage has compelled the decision-makers to look for non-conventional water sources for irrigation. One of these is the treated wastewater (TWW) [4], which gives the advantage of low cost if compared with other solutions

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