**3.7 Raw and treated Schiff base-sludge as fertilizers for radish plant**

Organic fertilizers are used to encounter the requirements of vegetable and plant production. Sewage sludge is an important factor that can be utilized for vegetable and plant production in view of its high organic matter content and rich macro and micro nutrients. However extreme care is to be taken to avoid the entry of the heavy metals and other organic compounds in the food chain. In our study, we investigated

**Figure 10.**

*Effect of (a) raw and (b) treated sludge with 2.4 g/L Schiff base on the growth and flourishing of radish plant.*

**Figure 11.**

*Variation in heavy metals concentrations in radish plant fertilized by raw and treated sewage at 2.4 gL−1 of the Schiff base.*

the implementation of raw as well as treated sludge with Schiff base at 2.4 g/L on the growth as well as the heavy metal content of radish plant. It was observed that the application of sewage sludge enhanced soil fertility and that crop yield in the treated sludge was higher than in the raw one. The treated sample showed enhancement in the radish yield, stem length, leaves number and flourishing (**Figure 10**). The total heavy metal content in radish have been also estimated in the radish treated with the raw and Schiff base- sludge. The results showed the application of 2.4 g/L of Schiff base showed a reduction in the total content of zinc (Zn), nickel (Ni), chromium (Cr) and cobber (Cu) in the plant. Concentrations of nickel and chromium ions showed a significantly reduction upon treating the plant with the Schiff base rather than that treated with the raw sludge with 82.75 and 70.96% respectively (**Figure 11**). Schiff base treating sludge showed also promising results regarding copper and zinc ions [58, 59].
