Table 2.

Basic physicochemical properties of the tested sewage sludge

Parameter tested	Fermented sludge	Dewatered sludge
Odor	Earthy	Earthy
Form	Clammy	Lumpy
Color	Black gray	Brownish
pH	8.7 ± 0.1	9.1 ± 0.1
Total nitrogen % dm	6.6 ± 0.9	6.7 ± 0.9
Total phosphorus % dm	1.6 ± 0.2	1.8 ± 0.2
Organic substances % dm	66.6 ± 9.5	70.7 ± 10.5
Dry matter of sludge %	5.1 ± 0.7	20.4 ± 3.5
Zinc mg/kg dm	721 ± 108	865.2 ± 130
Lead mg/kg dm	13.4 ± 2.1	16.6 ± 2.5
Cadmium mg/kg dm	1.12 ± 0.2	1.35 ± 0.2
Chromium mg/kg dm	9.4 ± 1.2	11.3 ± 1.7
Copper mg/kg dm	44.8 ± 6.0	53 ± 7.4
Nickel mg/kg dm	7.3 ± 1.0	8.8 ± 1.3
Arsenic mg/kg dm	4.18 ± 0.6	5.2 ± 0.8
Mercury mg/kg dm	0.95 ± 0.1	1.14 ± 0.1