Impact assessment of treated wastewater reuse for irrigation: growth potential and development of lettuce in Al Hoceima province, Morocco

Abstract

The reuse of treated wastewater for agricultural practices is becoming increasingly important due to the growing demand for the transition to a circular economy. It has the major advantage of providing an alternative resource to the conventional water used for agricultural irrigation. The main objective of this work is to study, through tests on experimental installations, the effect of the type of irrigation water on the growth and development of lettuce. The types of irrigation water were prepared from purified wastewater, treated wastewater plus fertilizer, conventional water, and conventional water plus fertilizer. The physicochemical analyzes of wastewater from the Imzouren-Bni Bouayach WWTP resulted in different values of the parameters measured (pH, temperature, electrical conductivity, oxygen below, suspended matter, BOD5, COD, nitrate, nitrite and phosphorus) which fall within the limited range of direct discharges and comply with Moroccan standards for the quality of water intended for irrigation. The results of the characterization of the soil showed that it is a basic soil (pH= 8.5), unsalted (electrical conductivity = 2.43 ms/cm) and poor in organic and nutrient elements (Carbon 0.8%, organic matter 1.46%, nitrogen 0.06 mg/l, phosphorus 10.5 mg/l, potassium 56.4 mg/l.) The main results of the plant analysis show that the production level of this study crop irrigated with conventional water is similar to that of this study crop irrigated with treated wastewater. In other words, irrigation with treated wastewater allows lettuce to guarantee irrigated production at least at the level of conventional water. Another motivated addition of nitrogen, phosphate and potash mineral supplement in the treated wastewater improves the production potential of lettuce.