| dc.description.abstract | Four tanneries, two in Nairobi and one each in
Thika and Athi River township were identified for
this study. Water samples from all the four tanneries
were collected, at two different times, from the raw
effluent, the treated effluent and either the receiving
streams or the oxidation ponds depending on the mode
of discharge of each of the tannery. The following
quality parameters were determined for each sample
collected:
(a) Temperature
(b) Hydrogen ion concentration
(c) Total sulphide
(d) Biochemical oxygen demand
(e ) Chemical oxygen demand
(f) Total non-filtrable residue (suspended
solids)
(g) Total filtrable residue (dissolved
solids)
(h) Profile of the elements present with
special attention to chromium using
X-ray fluorescence spectrometry.
The quality parameters analysed indicated that
treatment of raw tannery effluents in the selected
tanneries was generally inadequate. Where the
effluents are discharged into waterways, self
purification of the waste waters was found to occur
downstream probably through aerial oxidation and
sedimentation processes. Holding the effluents in
oxidation ponds without aeration was found to result | en |
