**4. Conclusion**

A novel organic Schiff base chelator (HBSH) has been successfully synthesized and characterized by elemental analysis. The effect of sewage treated with varying concentration of the Schiff base chelator (0.8, 1.6 and 2.4 g/L) as well as the untreated sewage on the sludge solid reduction, removal of heavy metals and salmonella pathogens has been investigated. The settlement rate was enhanced upon addition of HBSH Schiff base, the faster settling rate as well as the highest percentage of solids settlement (58.38%) was recorded by the 2.4 g/L treated sample. The highest removal potential was recorded toward cadmium with percentage 81.25% followed by nickel (66.3%). The total counts for salmonella in the raw sludge have drastically decreased to only (25–28) MPN index/100 ml referring to successful removing of salmonella by about 99% upon treating with different concentration of Schiff base. The implementation of raw as well as treated sludge on the growth as well as the heavy metal content of radish plant have been also investigated. It was observed that, the treated sample showed a reduction in the total content of Zn, Ni, Cr and Cu and enhancements in the yield, stem length, leaves number and flourishing.
