Reuse of Sewage Sludge as Organic Agricultural Products: An Efficient Technology-Based Initiative

Table 3

Concentration of metals in the sludge.

Metal contaminants	Concentration of metals (mg/kg)
	Maximum permissible limit	In in-house compost	In STP sludge compost
Arsenic	10	3.77 ± 0.72	3.00 ± 0.05
Cadmium	5	0.65 ± 0.09	0.84 ± 0.07
Mercury	0.15	0.67 ± 0.02	1.39 ± 0.04
Lead	100	13.18 ± 0.12	18.01 ± 0.17
Chromium	50	10.61 ± 0.26	14.15 ± 0.97

Source of specification: fertiliser control order (FCO), 1985 [29].