Abstract:
Textile dye wastewater from the dyeing process of 4 types of
dyestuffs namely, acid dyes, reactive dyes, dispersed dyes and
direct dyes as well as wastewater from the first aeration tank of
aerated lagoons system were treated by using coagulants. The
coagulants used were alum, lime and ferrous sulfate. The
experiments were carried out using the Jar Test procedure to
determine optimum pH and optimum coagulant dosage. Colour
removal was emphasized. Estimation of the cost of chemical
used was also performed. The results showed that coagulation
could only reduce colour from some types and some tones of
dyes to a certain level, while it could reduce the colour of wastewater
from the first aeration tank to a satisfactory level (less
than 300 ADM I). Chemicals cost was not high if pH adjustment
was not needed. Information from this study can be used for
design and planning of a new treatment plant or for readjustment
of an existing treatment plant