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Table 2

Energy and ash characterization of dried feces and fecal sludge

OriginBoulder
Kampala
Fecal sludgeSewage sludgee
Sample IDFeces12123
Energy content (MJ/kg) 
 HHV 20 10.4 14.6 14.7 15.5 12.8 10.9–19.1a,b,c,d 13.5 ± 1.5 
Ash content (%ds) 
 Ash 13.5* 51.2* 36.8* 37.9 36.6 27.4 47.0–58.7a 41.3 ± 8.9 
Ash elemental analysis (% ash) 
 P2O5 41.0* 27.0* 30.6* 17.2 17.2 16.9  13.8 ± 7.2 
 MnO 2.0* 1.1* 1.0* 0.1 0.1 0.2   
 Fe2O3 0.5* 1.2* 0.7* 2.1 1.9 2.7  14.0 ± 8.2 
 MgO 8.9“ 6.6* 5.6* 6.8 6.7 12.1  2.2 ± 0.8 
 SiO2 3.6* 10.8* 4.3* 15.8 13.2 18.9  32.5 ± 7.7 
 Al2O3 0.3* 3.3* 1.2* 5.2 4.9 6.1  11.9 ± 3.8 
 CaO 20.5* 18.0* 22.4* 9.1 8.7 12  12.8 ± 6.1 
 TiO2 0.0* 0.3* 0.3* 0.3 0.3 0.4  0.9 ± 0.4 
 Na22* 9.9* 9.9* 10.2 12 6.6  1.5 ± 1.6 
 K218.3* 14.2* 11.6* 16.9 18.7 8.2  1.5 ± 0.8 
Alkali index (kg alkali/GJ) 
 Alkali index 1.4 11.9 5.4 7.2 3.2  0.9 
Chlorine content (%ds) 
 Chlorine 0.1 8.8 0.04–0.14a 0.2 ± 0.8 
OriginBoulder
Kampala
Fecal sludgeSewage sludgee
Sample IDFeces12123
Energy content (MJ/kg) 
 HHV 20 10.4 14.6 14.7 15.5 12.8 10.9–19.1a,b,c,d 13.5 ± 1.5 
Ash content (%ds) 
 Ash 13.5* 51.2* 36.8* 37.9 36.6 27.4 47.0–58.7a 41.3 ± 8.9 
Ash elemental analysis (% ash) 
 P2O5 41.0* 27.0* 30.6* 17.2 17.2 16.9  13.8 ± 7.2 
 MnO 2.0* 1.1* 1.0* 0.1 0.1 0.2   
 Fe2O3 0.5* 1.2* 0.7* 2.1 1.9 2.7  14.0 ± 8.2 
 MgO 8.9“ 6.6* 5.6* 6.8 6.7 12.1  2.2 ± 0.8 
 SiO2 3.6* 10.8* 4.3* 15.8 13.2 18.9  32.5 ± 7.7 
 Al2O3 0.3* 3.3* 1.2* 5.2 4.9 6.1  11.9 ± 3.8 
 CaO 20.5* 18.0* 22.4* 9.1 8.7 12  12.8 ± 6.1 
 TiO2 0.0* 0.3* 0.3* 0.3 0.3 0.4  0.9 ± 0.4 
 Na22* 9.9* 9.9* 10.2 12 6.6  1.5 ± 1.6 
 K218.3* 14.2* 11.6* 16.9 18.7 8.2  1.5 ± 0.8 
Alkali index (kg alkali/GJ) 
 Alkali index 1.4 11.9 5.4 7.2 3.2  0.9 
Chlorine content (%ds) 
 Chlorine 0.1 8.8 0.04–0.14a 0.2 ± 0.8 

*Mean values, n = 3; otherwise n = 1 for data in this study. Sewage sludge n = 7–44. Undetermined values indicated by ‘-’. Ash and chlorine are reported as mass percent of dry solids (%ds); ash speciation is reported as mass percent of the ash.

Literature data from aGold et al. (2017), bMuspratt et al. (2014), cByrne et al. (2015), dSeck et al. (2015), ePhyllis2.

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