Mineralization and Crop Uptake of Nitrogen from Textile Manufacturing Wastewater Sludge Cake

Table 1

Comparison of determinations for the textile wastewater sludge (𝑛=4) to wastewater sludge materials (𝑛=17) reported [24] for analyses on a dry-mass basis for total C and N, C/N ratio, ammonium-N, and nitrate-N; s.d. = standard deviation; n.d. = not determined.

Property	Units	Sludge in present study		Published data
		Mean	s.d.	Minimum	Maximum	Median
Total N	g kg^−1	40.0	5.0	12	100	36
C	g kg^−1	261	19	175	531	290
C/N ratio	none	6.6	1.2	5.3	18.8	8.3
NH4–N	g kg^−1	1.49^a	0.04	0	20.1	1.7^b
NO3–N	g kg^−1	0.020^a	0.003	n.d.	n.d.	n.d.

^a2.0 M KCl with 5 : 1 extract-to-sludge ratio.
^b1.0 M KCl with 100 : 1 extract-to-sludge ratio.