Textile industry is one of the oldest and largest sectors in India. The exports for the year 2007-08 stood up to $20.5 billion. Even it is a value adding industry, it has several environmental impacts causing land and water pollution with toxicity. Effluent sludge waste management becomes a big problem nowadays. Except engineered landfills, rest of the methods for dumping, leads ground water contamination and there by other socio-economic impacts. Many studies have been conducted in this area and reported that the pollution level is high in ground water and nuisance due to dumping in the treatment plant area premises. There is a growing need to find alternative solutions for the sludge management. In the present study, an attempt has been made to utilize the textile ETP sludge (dry) in making of construction materials. Even to analyze the sludge, process variables for particular sludge generation can be studied. For inducing strength materials like fly ash, silica fume can be used. Textile sludge was incorporated in fly ash brick manufacturing and it was observed that with increase in sludge content, there is a decrease in compressive strength of bricks. Pulverized and sieved bricks show better compressive strength when compared with pulverized form and grinded form. There is increase in compressive strength with increase in sand, fly ash, cement and quarry dust proportion.
Keywords: Sludge, sand, Fly ash, quarry dust, cement, compressive strength
The textile units are scattered all over India; out of 21,076 units, Tamilnadu alone has 5285 units (Bal et al, 1999). Textile industry involves processing or converting raw material/fabric into finished cloth materials employing various processes, operations and consumes large quantities of water and produces extremely polluting waste effluents. Textile industry is one of the water intensive industries, which consumes large quantities of water for various processes and discharge equally large volumes of waste water containing a variety of pollutants. In textile industries, all the three types of wastes i.e. liquid, solids and gaseous are generated and the liquid effluent is essentially a mixture of dissolved, colloidal and suspended materials. The solid waste usually comprises of fibre/ yarn/ scared from spinning unit, waste fabric, packaging materials and sludge from effluent treatment plants. The gaseous waste is generally produced by volatile reactants/by products and the gases from boilers.
There is more number of textile industries in Erode and Tiruppur District of Tamilnadu. According to records of the Tamilnadu state pollution control board (TNPCB), there are 830 units engaged in textile industry processes in Tiruppur. These industries have established eight common effluent treatment plants (CETPs). About 200 tons/day of textile sludge are generated in Tiruppur. Although some of the sludge is disposed in an engineered landfill, much of the sludge is openly dumped, which leads to soil, surface water and groundwater contamination. The inorganic salts and toxic metals in the sludge pose a threat to residents (Thomson et al, 1999; Palanivelu and Rajakumar, 2001). There is a growing need to find alternative solutions for textile sludge management. As per TNPCB records, there are about large number of units engaged in textile industry processes in India. These industries have established several common effluent treatment plants and several individual effluent treatment plants. It is estimated that when these units function to full capacity 400 million tons of sludge is generated during the treatment process consisting of coagulation (by addition of aluminium/iron salts), flocculation and liquid/solid separation. The sludge produced is classified as hazardous, as per category No.12 of earlier hazardous waste, 1989 rules of our country. The recent amended rules of January 2000 also classify the sludge as hazardous. This sludge creates more negative impacts in many ways as far as the correct disposal techniques are not adopted.
The authors are associated with Department of Textile Technology, A. C. College of Technology, Anna University, Chennai, India