Abstract:
Textile industries are doing on to minimize their production costs by using
sustainable technologies and by inventing new methods. Pretreatment is the
heart of textile production. Bahir Dar Textile Share Company is using combined
pretreatment process with exhaust and semi-continuous method. After the
treatment is over, the residual chemicals are drained out into effluent treatment
plant. The purpose of this project is to reuse the residual chemicals by
replenishing the measured amounts of chemicals again for combined
pretreatment process. The concentration of main chemicals, after pretreatment,
before draining was analyzed. In case of jigger pretreatment process, the liquor
is drain out after six ends with chemicals, then the main chemical concentrations
(H2O2 and NaOH) was checked at this stage. In case of pad roll bleaching, the
fabric rotates in the steaming chamber six up to twelve hours and washed with
counter current washing machine. The chemicals are analyzed after washing is
over. Based on the chemical analysis results, by replenishing with measured
amounts of chemicals, pretreatment is done in both laboratory scales up to four
times without changing water and on the bulk production; it has been done by
mixing used water and fresh water. The effectiveness of pretreatment was
evaluated in terms of absorbency; whiteness and the effect in subsequent dyeing
parameters are checked. The dyeing and printing performance is also evaluated
by doing dyeing and printing after each pretreatment is over. Acceptable results
are found which can fulfill the products of the factory. Finally the amount of cost
saved by fabric pretreatment, raw water and waste water treatment chemicals is
calculated and also the amount of water which can be saved is shown.