A study by the CSIR-National Institute for Interdisciplinary Science and Technology (NIIST), Thiruvananthapuram, has found indiscriminate levels of odour and volatile organic compounds emanating from six industrial units in the Edayar industrial area.
An interim report submitted by the agency before the State Pollution Control Board (PCB) revealed that the odour threshold level was beyond the limit at all the sampling points in the units. The board had entrusted NIIST with the task of investigating the operational efficiency of industrial gas biofilters installed in 20 industrial units in Edayar after unchecked emissions caused health problems among local residents. The study by NIIST was led by Partha Kundu, senior scientist. The erring units were mostly involved in rubber, meat and waste processing activities.
The report said the odour threshold had gone up to 2,50,00,000 OU (odour units) per cubic metre, while the permissible limit for odour in air around an industrial area is 7 OU and 2 OU in residential areas. The average concentration of total volatile organic compounds was beyond the limit in a majority of the sampling points. The highest level of total volatile organic compound recorded was 271 ppm (parts per million), while the permissible limit for volatile organic compound in the air remained in the range between 0.001 and 0.1 ppm, according to the guidelines on odour pollution and its control issued by the Central Pollution Control Board.
The study found that biofilters, used to remove pollutants and odour from air impacted by industrial and manufacturing processes, were not functioning properly in the units. The investigating team reported that fumes were emanating from the top of biofilters. There was a pungent smell too not to mention the strong smell on plant premises. The water sprinkling system and suction hoods were found damaged in a few units. There was no leachate collection system for biofilter in one unit, according to the report.
