Characterisation of Organomineral Fertilisers Derived from Nutrient-Enriched Biosolids Granules

Table 2

Physical properties determined on OMF₁₅, OMF₁₀, biosolids granules, and urea.

Fertiliser material	𝑛	OMF15	OMF10	Biosolids granules	𝑛	Urea
Physical property		Mean ± SD				Mean (or value) ± SD
𝑑16 (mm)	4	2.52±1.0	2.40±0.6	2.74±3.1	1	2.52
𝑑50 (mm)	4	4.60±2.8	4.45±2.8	4.87±5.6	1	3.03
𝑑84 (mm)	4	7.24±4.4	6.91±5.2	7.08±7.5	1	3.73
𝑑 (mm)	∞	5.42±2.6	5.28±2.9	4.97±5.5	∞	3.10±0.35
GSI (%)	4	49.3±14.3	43.6±16.1	48.9±7.7	1	20.0
A (m^2 kg)	4	20.9±32.2	13.6±21.2	7.0±5.1	1	1.61
𝑈𝑖 (%)	4	15.7±9.6	22.7±16.2	24.7±4.8	1	57.3
𝜌𝑏 (kg m^−3)	4	603±73.1	623±85.5	578±87.2	3	748±5.7
𝜌𝑝 (kg m^−3)	100	1357±178	1297±263	1333±315	100	1432±255
𝜂 (m^3 m^−3)	4	0.56±0.05	0.52±0.07	0.57±0.07	3	0.48±0.01
^a𝜏 (N mm^−2)	2	4.10±0.11	4.33±0.08	5.85±0.26	2	4.25±0.06
^b𝜏 (N mm^−2)	2	2.85±0.09	2.78±0.11	1.64±0.04	2	3.11±0.05
^c𝜏 (N mm^−2)	2	2.14±0.23	2.12±0.14	2.24±0.34	2	1.38±0.02
^d𝜏 (N mm^−2)	2	1.25±0.04	1.18±0.06	1.23±0.02	—	—

(For 𝜏, particle size ranges were: ^a2.00–3.35 mm; ^b3.35–4.00 mm; ^c4.00–5.50 mm; ^d5.50–7.10 mm. For urea, particles in the sample were smaller than 5.50 mm in diameter; therefore, 𝜏 is not shown for the range of 5.50 to 7.10 mm. The standard deviation (SD) is shown as ± the mean value, except for 𝑛=1).