Fig. 2.
Effects of mixing water hyacinth (WH) with pig manure (PM) on biogas production through fermentation: (A) 10% WH + 90% PM, (B) 15% WH + 85% PM, (C) 20% WH + 80% PM, and (D) 25% WH + 75% PM. Values in the plots were averages over a 5-day period.