Studies on the decontamination of industrially polluted Orathupalayam dam sediments using bioremediation techniques

Abstract

The Orathupalayam dam is constructed across Noyyal river in Erode District, Tamil Nadu, India, in 1992 to store flood water for irrigating about 10000 acres. The capacity of the dam is 17.44 mm3. As part of the research activity, the author studied the quality of effluent discharge by the textile bleaching and dyeing units in Tiruppur. Monthly composite samples were collected at the out let the seven functional CETPs for one year and got analyzed in the laboratory. The quality of surface water of Noyyal River and Orathupalayam dam was also monitored for one year. Ground water quality was also studied in the Tiruppur and Orathupalayam dam area. Two types of approaches were carried out on the sediment sample collected from the Orathupalayam dam. (i). bioremediation by icrocosm (biopile), (ii) bioremediation by composting. Accordingly experiments were conducted under three conditions: a). natural attenuation with simple aeration without addition of any nutrient or culture supplementation, b). biostimulation with aeration and nutrient addition, c). bioaugmentation with aeration and addition of nutrient and inoculum of the microbial consortium enriched from the contaminated soil. The composting period was 23 weeks. The final compost obtained was found to be alkaline, pleasantly earthy in smell and dark brown in colour. C/N ratio was within the recommended value of 10-15. From this study it is inferred that composting can be addressed as a bioremediation methodology for decontamination of the Orathupalayam dam sediments. It is also suggested that in order to protect the dam from further contamination, the industrial discharge into the Noyyal River should be completely stopped. The solid waste arising from wastewater treatment should go for secured land fill facility or coprocessing in cement factories. The Tiruppur domestic sewage shall be completely collected, treated and used for framing activity. Periodical desilting of the dam is also very essential. newline