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Table 1 The resource usage, waste generation, GHG emission, and land use of the Thai CSPP (per 1000 kg of starch). Three scenarios of starch production are (1) a factory without integrated biogas system, (2) a factory with integrated biogas installation using wastewater as a raw material, and (3) a factory with biogas system using both wastewater and cassava pulp as raw materials

From: Implementing circular economy concept by converting cassava pulp and wastewater to biogas for sustainable production in starch industry

  Scenario 1 Scenario 2 Scenario 3
Resource usage
 Cassava root (kg dry basis) 1.56 × 103 1.56 × 103 1.56 × 103
 Fresh water (m3) 16.7 15.1 15.1
 Chemical (kg) 0.26 0.26 0.66
 Recycled water (m3) 0 1.57 4.45
 Biogas production (m3) 0 59.3 357.7
 Electricity from grid (kWh) 197.8 176.6 0
 Electricity from biogas (kWh) 0 21.2 197.8
 Fuel oil consumption (m3) 4.52 × 10−2 1.57 × 10−2 0
 Biogas for drying (m3) 0.0 64.5 98.8
Waste generation
 Wastewater to final open lagoons (m3) 19.2 14.7 17.6
 COD of wastewater to final open lagoons (g m−3) 12,200 715 715
 Cassava pulp (kg dry basis) 1.55 × 103 1.55 × 103 1.01 × 103
 Peel (kg dry basis) 50 50 50
 Rhizome (kg dry basis) 530 530 530
 Sand/soil (kg dry basis) 400 400 400
GHG emission
 Wastewater (kg CO2eq) 398.7 15.7 15.7
 Cassava pulp fermentation (kg CO2eq) 0.71 0.71 0.47
 Electricity consumption in biogas system (kg CO2eq) 0 0.15 19.93
 Electricity consumption in cassava starch production (kg CO2eq) 115.2 106.4 33.3
 Thermal consumption in biogas system (kg CO2eq) 0 0 3.00 × 10−3
 Thermal consumption in cassava starch production (kg CO2eq) 121.4 89.6 74.9
 Total (kg CO2eq) 636.0 212.6 144.3
 Land use (m2) 5.92 × 105 4.72 × 105 1.89 × 105