Technologies for the treatment of molasses based distillery effluents

Article Index

 

1. Objectives

The primary objective of this report is to present the following aspects of the “Technologies for the Treatment of Molasses based Distillery Effluents”:

a. The relationship and the importance of the selected subset of technology to the broad one to which is belongs;
b. The current status of the technology in the World and our Country;
c. Assessment of the technology and options available to India;
d. The economic aspect of technologies along with their feasibilities which lead to the preferred options(s);
e. Impact of the preferred option by itself, its linkages to the broad area of technology and spin offs. And
f. Identification of agencies/group/individuals and suggested action plan.

2. Methodology

The report is based on the findings of mail survey and field visits and the information collected through desk research.

3. The Need for Treating Distillery Effluent

The Indian distillery industry produces alcohol from molasses, a by-product of sugar manufacture. During 1990-91, India produced about 1,025 million liters of alcohol, India produced about 15 liters of effluent is produced per liter of alcohol, India produced about 15,375 million liters of distillery effluent during 1990-91. The effluent is foul smelling, dark brown coloured and has a very high BOD (Biochemical Oxygen Demand – a measure of pollution).

The most damaging effect of distillery effluent on a water stream is caused by high concentration of readily decomposable organic matters present in the effluent which case rapid depletion of the oxygen content of water and render it totally unit for propagating aquatic life and for drinking and other purposes. The receiving stream assumes an unsightly appearance. The colour persists over a long stretch in the stream and gives an impression that the stream is highly polluted.

As on 8/7/91, India had 212 distilleries (about 10% of the distilleries are considered to be non-functional/bottling units). Of the above, 44 distilleries had completed and 49 distilleries had started the construction of Effluent Treatment Plants (ETPs). It is reported that several units are doing spade work prior to commencement of construction of ETPs.

4. The Importance of the Alcohol Industry

In 1931, India had 29 sugar factories which produced about 1.2 lakh tonnes of sugar and about 50,000 tonnes of molasses. The number of sugar factories increased dramatically to 135 by 1935-36 taking sugar production to 9.34 lakh tonnes and molasses production to 3.36 lakh tonnes. The country was not prepared for such a sudden increase in the production of molasses. This was one of the factors which induced the Government to encourage alcohol production using molasses. Thus, molasses which was considered a waste during the early years of the Indian sugar industry became a valuable by-product used in the manufacture of alcohol. In the absence of distillery industry, it is difficult to comprehend the extent of environmental damage that would have been caused by molasses. Without the distillery industry the Indian sugar industry could not have grown to its present size.

The distillery industry plays an important role in the Indian economy by providing alcohol. As on 31/3/91, India had 212 distilleries with an installed capacity of 1933 million liters of alcohol per annum. The production of alcohol has been showing a steady increase over the years. During 1990-91, India produced 1,025 million liters of alcohol. India’s sugar production is expected to increase to 17 million tonnes by the end of the current decade (13.3 million tonnes during 1991-92). The expected corresponding rise in molasses output will help to improve alcohol availability considerably.

Of the total alcohol output, about 50 to 52 percent is utilized for industrial purposes and the balance is utilized for potable purposes.

The importance of alcohol as a feedstock for the manufacture of organic chemicals has been steadily improving. The current foreign exchange scarcity together with the mounting crude oil import bill is likely to further increase the reliance on alcohol for the manufacture of organic chemicals.

The estimated demand for some of the important organic chemicals (alcohol route) by the turn of the century and the resultant overall demand for alcohol are follows:

2-thyl Hexanol 52,500 tonnes
N-butanol 46,700 tonnes
Vinyl Acetate 44,000 tonnes
Styrene 120,000 tonnes
Acetone 64,700 tonnes
Alcohol

 

2,000 million liters


 

For the State Governments, alcohol is an important source of revenue. Between 12 to 14 percent of the States own revenues come from the State excise duties levied on potable alcohol. In addition, on inter-state sales, Central sales tax and various kinds of fees are also levied                                                                                                                                                                          Back