Valorizing the reuse of treated municipal wastewater for Paulownia seedlings cultivation by application of Moringa waste

A field experiment was conducted to study the effect of treated municipal wastewater and adding defatted seeds of Moringa oleifera to the soil with different levels compared to tap water on the vegetative growth and chemical composition of Paulownia hybrid seedlings as well as soil chemical properties. This experiment was carried out in the experimental area of the National Research Centre, Cairo, Egypt from March to December 2019 and 2020 for three irrigation periods (3, 6 and 9 months). The use of treated municipal wastewater individually or in combination with defatted seeds of Moringa oleifera significantly increased all the studied growth parameters comparing to tap water (the control) in all growth intervals. The treatment of treated municipal wastewater with 10 g of defatted seeds of Moringa oleifera was the best than other treatments in improving the most growth parameters. Maximal accumulation of heavy metals occurred in the roots followed by leaf and stem, respectively. A notable increase in antioxidant enzyme activity was noticed in Paulownia seedlings that were treated by treated municipal wastewater alone or with using 20 gm of defatted seeds of Moringa oleifera. The trees of Paulownia were found to be a promising species for trace metal tolerance in polluted soils and using treated municipal wastewater for irrigation. Remediation of soil with defatted seeds of Moringa oleifera had promotion effects on reducing the uptake of metal and decreasing its availability