Abstract:
Tanning efJluent from leather processing industries is very complex and leads to
environmental pollution
if discharged untreated, especially due to its high organic
loading and chromium content.
In this study five different natural clays from five
different areas were collected
for chromium adsorption process that was discharged
from Bahir Dar leather industry PLC. The leather efJluent that was taken from Bahir
Dar leather industry was checked
for its chromium value before treated by any
treatment process. After checking its chromium value the leather efJluent was treated
with different clay sample powders at different contact time
of the adsorbent and
adsorbate, different
pHvalue ofthe effluent and at different temperatures. The treated
efJluent was again checked
for its chromium value after treated by different clay
sample types and at different parameter values. Spectro Photometer model
NQ Hatch
Dr/2010 and photometer 7100 were used
for chromium determination in the waste
solution. The approximate optimum value
ofpH, temperature and contact time were
found to be 3.5, 36 0 C and 45 minutes. The effective removal efficiency ofthe clays
and the best clay in removing chromium salts were identified.
At the optimum values of
the parameters the clay with the best removal efficiency (clay collected from Debre
Markos) can remove up
to 96 % of chromium salts from the tannery liquid waste
efJluents.
All other clay. samples have the ability to adsorb chromium salts from the
waste solution samples.