As shown in Table 1, FS from vacuum trucks in Kampala and Dakar contained over 95% water. FS contained 0.8–3.4% DM in Kampala and 1.2% DM in Dakar. These results are similar to those previously reported, 0.5–0.9% DM for FS in Dakar, and 2.2–4% DM for septic tank FS and lined pit latrine FS in Kampala (Fichtner Water & Transportation 2008; Niwagaba et al. 2014; Sonko et al. 2014; Seck et al. 2015; Gold et al. 2016). Industries commonly require fuels with less than 10% water, therefore, effective dewatering and drying technologies are key for the production of dried fuels from FS (Diaw, personal communication; Holcim (Schweiz) AG 2013; Seck et al. 2015).

Table 1

Physical-chemical characteristics of FS loaded onto drying beds

ParameterDry massCODBOD5
Unit%
g O2/L
g O2/L
MeanSDMeanSDMeanSD
FS Kampala
Septic tank FS 0.8 – 8.9 – 8.4 –
Lined pit latrine FS 2.3 – 11.5 – 6.6 –
Mixed FS 1 2.3 – 8.1 – 5.5 –
Mixed FS 2 3.4 – 21.0 – 12.0 –
FS Dakar
Un-thickened FS 1.2 0.6 12.4 7.6 3.3 1.8
Thickened FS 4.9 3.1 36.0 28.0 9.5 9.7
ParameterDry massCODBOD5
Unit%
g O2/L
g O2/L
MeanSDMeanSDMeanSD
FS Kampala
Septic tank FS 0.8 – 8.9 – 8.4 –
Lined pit latrine FS 2.3 – 11.5 – 6.6 –
Mixed FS 1 2.3 – 8.1 – 5.5 –
Mixed FS 2 3.4 – 21.0 – 12.0 –
FS Dakar
Un-thickened FS 1.2 0.6 12.4 7.6 3.3 1.8
Thickened FS 4.9 3.1 36.0 28.0 9.5 9.7

SD: standard deviation.

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