Experimental materials and methods are described hereunder for understanding the textile sludge disposal using
incineration techniques. Textile wastewater sludge samples were collected from greater Dhaka district. Normally
each sample weighing 20 kg was collected at a time. The Grab sampling methods were used for the sampling
purpose. Sampling was carried out at location where sludge was routinely removed from the wastewater treatment
for subsequent disposal and some cases the sludge samples were not routinely removed, occasionally this was used
by the ETP.
All the collected samples were bone dried and kept in air tight plastic container for further analysis. The sludge
samples were digested (EPA3050B method) and the digested samples were preserved in disposable small plastic
bottles and kept in a cool dry place before analysis. The leachate samples were also preserved in plastic bottles and
the analysis was done within a short time after collection of sample for good results. The performance of the
incinerator was investigated and the temperature was increased slowly with time. Initially the temperature was set at
2000C for 20 minutes, and in the next 20 minutes the temperature reached 5000C and within 1 hour it was 8000C.
The maximum reachable temperature of the electric incinerator was 10000C. The incineration process was continued
up to 8000C and 4 hours. During the incineration process the sludge sample reduces their volume as well as mass.
Incinerated ash samples contain heavy metal and the heavy metal analysis was performed by the AAS. The waste
water treatment sludge was added in proportion of 5wt%, 10wt%, 20wt%, 30wt% to clay. One batch of 100% clay
was prepared for reference purpose. Therefore, a small amount of water was sprayed to add to the moisture of the
powder. The moisture content of the mixture must be above 2% so that the samples are not brittle when formed and
samples were produced by using manual press operated at 90psi. The samples were dried in an oven at 80˚C for 18
hours. Drying is necessary to avoid warp and cracks in the samples due to the variations in the moisture during high
temperature firing stage. Then, the samples were fired at 1200˚C by natural gas. This is the process where the
sample gains strength, hardness and reduced porosity. The fired samples were tested for strength, water absorption,