Effect of the replacement of pig manure by water hyacinth (Eichhornia crassipes) on biogas production
One in vitro experiment was carried out to assess the effect of replacement of pig manure by water hyacinth juice on biogas production. It was a completely randomized design with six treatments and three replications by using 5 litters-flasks. The treatments were the replacement levels of the pig manure by the water hyacinth juice (WHJ) based on DM basis, which were 0, 20, 40, 60, 80 and 100% (WHJ0, WHJ20, WHJ40, WHJ60, WHJ80 and WHJ100, repectively). The pig manure and the water hyacinth juice were continuously loaded into the 5 litters-flasks during 21 days at level of 5g OM per day. The data of experiment were recorded during 42 days. The results indicated that biogas production fast increased from day 7 to day 28 and then slowly decreased in all treatments. From day 7 to day 21 the methane concentration (%) increased by incubation time and for the increasing WHJ treatments, while this was slower for the WHJ0 and WHJ20. On the 21st day, the WHJ100 treatment had the highest methane rate (60.7%) and the lowest rate for the WHJ0 treatment (58.1%). It was concluded that water hyacinth juice could be used to replace pig manure for biogas production. The replacement level of 40% pig manure with WHJ gave better in vitro biogas and methane yield.
