6. Conclusion
This study has shown that water lettuce-based waste stabilization
ponds can be used for effective and economical treatment of
wastewater from rubber processing industries. The maximum BOD,
COD and total coliform removal efficiencies of 90.6%, 85.5% and
97.9% respectively were obtained in the 12th week of treatment.
The treated effluent obtained in this study was found to have plant
nutritive values and can be used as biofertilizer in the production
of maize and other annual crops. Though the use of treated effluent
as biofertilizer could reduce the farmers’ cost of production since
effluent is normally discharged freely as waste, end users must be
careful and should adhere to international and national safety rules
in order to protect public health. The treated effluent liquid was
found to greatly increase the growth and yield of the maize plant.
The chemical composition of the resulting water lettuce biomass
makes it suitable as forage for animal feeding. Biological treatment
using water lettuce based ponds is therefore recommended for the
treatment of industrial wastewater in developing nations following
its low investment cost and the purification efficiency. Biofertilizers
are eco-friendly, relatively cheap and could contribute to solving
food insecurity problem