Dewatering and Drying Characteristics of Water Hyacinth (Eichhornia crassipes) Petiole. Part I. Dewatering Characteristics

I. C. O. Akendo, L. O. Gumbe, A. N. Gitau

Abstract


The broad objective of the study was to identify and relate the parameters that are important
in dewatering of water hyacinth petiole. This involved identification of the pertinent
properties that influence dewatering of water hyacinth petiole and then developing predictive
empirical equations for the identified factors. Field work involved collection of samples from
Nairobi dam. Experiments were carried out using a triaxial system to obtain dewatering data
and behaviour of stress versus strain rate curves. Mean volume of expelled fluid during
dewatering was 20.66 ml (SD = 3.5, n = 16) as at point of sample failure. Highest strain rate,
at which deviatoric stress begun to be realised in the samples, was around 1.5 h-1. This value
was observed to decrease to strain rate below 0.75 h-1, but not passing 0.5 h-1 mark, where
strain rate remained constant as deviatoric stress increased. Mean deviatoric stresses required
for expelled fluid to be realised were 20.85, 34.90, 29.75 and 28.19 kPa at confining stresses
of 300, 400, 500 and 600 kPa. The developed predictive equations described dewatering
characteristics of the water hyacinth petiole accurately. The significance of this study is seen
in the role the results obtained will have in influencing the design of suitable dewatering
equipment.

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