Textile Sludge Management by Incineration Technique

Abstract

The rapid growth of textile industry in Bangladesh plays an important role in economic development. The sludge from the wastewater treatment plant in textile units is considered hazardous as it is often contaminated with heavy metals of dyestuffs and chemicals. Currently, land filling is the most common practice for textile sludge disposal. Leaching of heavy metals from textile sludge is a growing concern in Bangladesh. This study attempts to find out an environment-friendly solution for the management of the textile sludge. In this study, sludge samples were collected from treatment plants of various textile units located at Savar, Gazipur and Narsingdi. An electric incinerator was designed, fabricated and installed for the incineration of textile sludge. The sludge samples were incinerated at 5000C, 7000C and finally at 8000C for different time intervals. The volume reduction of the sludge samples was nearly 80% at 8000C. The incineration techniques were used for volume reduction and destruction of the hazardous elements. The oven dried samples were powdered and mixed at various proportions (0%, 10%, 20%, and 30%) with clay for making the ceramic products and also mixed with sand, cement and aggregates for making blocks for the stabilization of heavy metals in sludge. The properties of ceramic products such as firing shrinkage, bulk density, leaching of Heavy metals and the compressive strengths were evaluated. Incinerated ash samples were also used for ceramic tiles and block preparations. The concentrations of heavy metal in leachate from the stabilized sludge samples were very low. The compressive strength, bulk density, water absorption of the stabilized sludge and ash samples were examined and the results showed that up to 10% of the raw sludge and 10-20% ash samples could be used for stabilization and/or solidification and additionally, 80% volume reduction of the raw sludge could be obtained.