Table 1.
Input material and energy flow data for the LCA study per functional unit.a
| Process | NMT | PFT | UDDT |
|---|---|---|---|
| Raw material extraction | |||
| Faeces (kg) | 2.00E+001 | 2.00E+001 | 2.00E+001 |
| N (kg) | 1.10E-022 | 1.10E-022 | 1.10E-022 |
| P (kg) | 5.48E-032 | 5.48E-032 | 5.48E-032 |
| K (kg) | 1.10E-022 | 1.10E-022 | 1.10E-022 |
| Urine (kg) | 1.42E+013 | 1.42E+013 | 1.42E+013 |
| N (kg) | 8.22E-022 | 8.22E-022 | 8.22E-022 |
| P (kg) | 8.22E-032 | 8.22E-032 | 8.22E-032 |
| K (kg) | 3.29E-022 | 3.29E-022 | 3.29E-022 |
| Polystyrene - toilet seat (kg) | 9.39E-044 | 3.65E-044 | 3.65E-044 |
| Polystyrene - cistern (kg) | 1.64E-034 | - | - |
| Glass fibre - membrane (kg) | 1.45E-055 | - | - |
| Alloy steel - combustor (kg) | 3.32E-045 | - | - |
| Alloy steel – screw (kg) | 4.20E-045 | - | |
| Manufacture | |||
| Injection moulding (kg) | 3.33E-03 | 3.65E-04 | 3.65E-04 |
| Sanitary ceramics - toilet bowl (kg) | 8.45E-034 | 3.29E-034 | 3.29E-034 |
| Transportation (t-km) | 1.11E-02 | 3.43E-03 | 3.43E-03 |
| Operation & Maintenance | |||
| Glass fibre (kg) | 6.17E-04 | - | - |
| Water (kg) | - | 1.50E+02 | - |
| Ash (kg) | 8.00E-021 | - | - |
| P (kg) | 1.10E-026 | - | - |
| K (kg) | 1.21E-026 | - | - |
| NOx-emissions (kg) | 1.10E-021 | ||
| Waste Management | |||
| Transportation (t-km) | - | 3.82E+00 | 5.00E-02 |
| Electricity (kWh) | 6.80E-027 | 6.60E-0310 | |
| Diesel (kg) | - | - | 1.11E-0210 |
| Lime (kg) | - | 2.00E-038 | - |
| Polymer (kg) | - | 2.14E-058 | - |
| Iron chloride (FeCl3) (kg) | - | 1.42E-058 | - |
| NH3-emissions (kg) | - | - | 1.42E-0311 |
| CH4-emissions(kg) | - | - | 8.00E-0312 |
| N2O-emissions (kg) | - | 7.32E-049 | 4.80E-0413 |
| Product | |||
| Transportation | 2.72E-03 | 3.60E-0414 | 4.80E-0115 |
| N-Fertilizer (kg) | - | 1.85E-0217, 18 | 7.88E-0216, 19 |
| P-Fertilizer (kg) | 1.04E-0216 | 8.63E-0317, 18 | 1.33E-0216, 20 |
| K-Fertilizer (kg) | 1.21E-0216 | - | 4.30E-0216, 20 |
| Electricity (kWh) | 4.62E-021 | - | - |
| Treated wastewater (kg) | 9.56E+001 | 1.50E+02 | - |
(Rose et al., 2015) for a densityUrine=1.002 g/cm3.
Estimations from NMT-Project.
P and K content estimated as a percentage of 13.7% and 15.1% of total ash, respectively (Onabanjo et al., 2017).
Energy consumption of 590.69 kwh/Ml for an activated sludge treatment plant (Scheepers and van Der Merwe-Botha, 2012).
Data adopted from a WWTP with capacity of 50,000–100,000 IE treating nitrogen and/or phosphorus for a total influent volume of 1.15E-01 m3 [massfaecal sludge = 166.21 kg; densityfaecal sludge = 1443.1 kg/m3(Niwagaba et al., 2014)] (Lassaux et al., 2007).
Eq. 6.8 (Doorn et al., 2006).
Estimated as 13% of the total input N content (Hao and Benke, 2008).
Estimated based on the Eq. (4.1), for an EF = 4 g CH4/kg waste treated [composting; on wet weight basis; Mi = amount of faeces expressed in Gg and R = 0 (without gas recovery)] (Pipatti et al., 2006).
Estimated based on the eq. (4.2), for an EF = 0.24 g N2O/kg waste treated [composting on wet weight basis and Mi = amount of faeces expressed in Gg] (Pipatti et al., 2006).
Estimated for a sewage sludge of 2.76E-02 kg [sewage sludge production rate of 0.24 kg·m3 of treated wastewater](Gurjar and Tyagi, 2017).
Estimated for a compost weight of 50% of the faecal matter (Miller and Jones, 1995).
N, P and K fertilizers for ash and compost application estimated as a percentage of 45%, 95% and 100% of the applied nutrient content, respectively [average value of mid-term period values] (Lazcano et al., 2014).
N and P content in sewage sludge estimated as a percentage of 40% and 90% of the influent nutrient content (From wastewater to eco-friendly fertilizer, 2016).
N and P fertilizers estimated as a percentage of 50% and 70% of the respective applied nutrient content (Hospido et al., 2008).
N fertilizer from urine application estimated as 90% of the urine N content (Karak and Bhattacharyya, 2011).
P and K fertilizers from urine application estimated as 100% of the respective urine nutrient content (Kirchmann and Pettersson, 1995).