Organic Waste Recycling

Biofuels production 167

Figure 4.7 Low-cost biogas digester (note a unique mixing device)

Table 4.6 Characteristics of raw materials used to prepare influent mixing

Material Total
organic
carbon
(%)

Total

Kjeldahl

nitrogen

(%)

Total

phos-

phorus

(%)

Total

volatile

solids

(%)

Carbon/

nitrogen

ratio

Moisture

content

(%)

Nightsoil 47.6 4.5 0.7 85.6 10.7 82.3
Rice straw 42.7 0.9 0.1 77.3 50.3 14.1
Water hyacinth 37.8 1.4 0.4 68.0 27.0 43.7

Inlet Outlet

Outlet pipe

Mixing device

Water

pressure

tank

Gas

vent

Fermentation tank

Gas storage tank