**3. Results and discussion**

### **3.1 Characterization of sludge**

**Table 1** displays the general information regarding heavy metals (HMs), parasite and solid volume contents of the sludge sample accompanied by the Egyptian Code and Environmental Protection Agency allowed standard limits. The content values of lead and cadmium are two- folds the allowed Egyptian code standard limit, in the time that nickel and zinc recorded 801.25, 8275 mg/kg respectively which are about four times more than the allowed Egyptian code standard limit. Iron and chromium are greatly pronounced with 468,750 and 1637.5 mg/kg respectively. The values of the main metal species present in the sludge under experiment are all beyond the Environmental Protection Agency limit values. Sludge volume after 30 min (SV30) recorded 650 cm3 /L an average value. The parasitic content evaluation showed a higher presence of salmonella (2.6 × 104 unit/mg). Disposal of such untreated sludge on nearby unused lands would inevitability lead to serious parasitic and heavy metal contaminations accompanied with a dangerous chain of negative effects on human and environment [52].

### **3.2 <sup>1</sup> H-NMR spectrum**


The 1 H- NMR spectrum of the ligand in deuterated DMSO showed the absence of protons of the amine and aldehyde groups belonging to the 2,3 dihydroxy

### **Table 1.**

*Physicochemical characteristics of the sewage sludge.*

succcinohydrazide and Salicylaldehyde starting material and the appearance of new peaks at 4.29 ppm corresponding to protons of the two azomethine groups (CH=N-). The chemical shift appeared in the 6.2–7.1 ppm range were assigned to the aromatic protons of the benzene moiety which appearing as multiplets, whereas the chemical shifts observed at 5.35 ppm was assigned to the protons of aromatic C-OH groups. The two protons of -NH recorded a chemical shift at 8.9 ppm, whereas the chemical shift observed at 2.8 ppm corresponded to two protons of the alcoholic OH groups (OHC-COH) [53].
