In India bioethanol is mainly produced by the fermentation of diluted sugar cane molasses solution. After fermentation, alcohol is separated by distillation and the residual liquid is discharged as Distillery Spent Wash or effluent. This effluent is dark brown in colour, of low pH and contains all the ingredients found in molasses except fermentable sugar. For every litre of alcohol produced, about 12-15 litres of effluent is generated. This effluent contains a large amount of oxidisable (biodegradable) organic matter and the residual yeast cells. Until recently laws relating to pollution control were not stringent. Yet, distilleries used whatever technology was available, to reduce the degradable organic matter to a respectable limit before discharging the effluent into the streams or on land. Today, the Pollution Control Boards have laid down rather rigid standards for the treatment and disposal of distillery wastes, which de difficult to achieve in Indian conditions. However, the Government of India has recently modified the environment protection rules and allowed utilisation of pretreated effluent for the ferti-irrigation of land. Distilleries represent a large fermentation industry which produce the largest amount of effluent. At present, for the installed capacity of 2.40 billion litres of alcohol per annum, the amount of effluent produced in a year would be of the order of about 28 similar to 36 billion litres (28 similar to 36 million cubic meters). However, at the capacity utilisation level of about 50 %, this would be about 14-18 billion litres per annum. The large volume, and poor composition makes this a problematic effluent and its treatment beyond a certain limit is extremely difficult. The available technologies of treatment are capital intensive and are effective only up to a certain limit beyond which they become unviable in achieving the standards. In recognition ofenvironmental problems, distilleries have initiated action to eliminate pollution by adopting economically viable technologies and 150 distilleries out of 250 have already completed primary treatment systems. The present case study furnishes a brief account of the current status of the problem and its remediation as per standards required.
|Title of host publication||Unknown Host Publication|
|Number of pages||16|
|Publication status||Published (in print/issue) - 1996|
|Event||ENVIRONMENTAL BIOTECHNOLOGY - PRINCIPLES AND APPLICATIONS - |
Duration: 1 Jan 1996 → …
|Conference||ENVIRONMENTAL BIOTECHNOLOGY - PRINCIPLES AND APPLICATIONS|
|Period||1/01/96 → …|