AGRO - BASED INDUSTRIES :

Among the large and medium scale industries In India, more than 45% are depending on the agricultural sector as a source of their raw materials, i.e. almost one-half of our industries are agro-based. The major segments of the agro-based industries comprise of :

  1. Coir Retting Units
  2. Dairies;
  3. Edible Oils & Vanaspati Industries
  4. Fermentation Industries. (Distilleries, Maltries & Breweries)
  5. Flour Mills
  6. Food and Fruit Processing Industries
  7. Jute Rettlng Units;
  8. Pulp & Paper Mill
  9. Starch (Maize Products)lndustrie
  10. Sugar Mills
Most of the major agro-based ind- are located in the States of Andhra Pradesh, Gujarat, Karnataka, ) Madhya Pradesh, Maharashtra, Tamil Chairman Nadu and Uttar Pradesh ( See Table 1).

Table 1 : Number and Locations of Agro-based industries
S. No.
Industry Segment
Total No. of Units
Annual Processing/ Production Capacity
Locations
1.
Dairy
96
5.5 x 10.66 KilolitreUttar Pradesh, Maharashtra, Gujarat, Tamil Nadu, Rajasthan
2.
Edible Oils & Vanaspati
725
4.5 x 106 tonneMaharashtra, Andhra Pradesdh, Gujarat, Madhya Pradesh, Uttar Pradesh
3.
Fermentation
225
2 X 106 KilolitreUttar Pradesh, Maharashtra, Andhra Pradesdh, Madhya Pradesh, Karnataka, Tamil Nadu
4.
Food & Fruit Processing
204
-
Maharashtra, Tamil Nadu, Andhra Pradesdh, Karnataka, West Bengal
5.
Pulp & Paper
89
1 x 106 tonneUttar Pradesh, Maharashtra, Andhra Pradesdh,
6.
Starch (Maize Products)
11
0.2 X 106 tonneGujarat, Andhra Pradesdh, Uttar Pradesh, Haryana
7.
Sugar
400
10 x 106 tonneMaharashtra, Uttar Pradesh, Andhra Pradesdh,Gujarat, Karnataka, Tamil Nadu
Water Consumption
The agro-based industry is characterised by its water intensive nature. The industry consumes considerable quantities of water for their processes. Apart from process water requirements, large volumes of water are use for cleaning and washing purposes. Volumes of water consumed vary widely from plant to. plant within the segments of the agro-based industry. There are significant variations between these segments (Table 2) also.

Table 2: Water Consumption, Wastewater.Generation and Organic Pollution Load in Agro-based Industrie
S. No.
Industry
Specific Water Consumption (Cubic meters)
Waste Water generation, Cubic Metre
Pollution load
(in terms of Kg of BOD)
1.
Dairy (Integrated)
(per kilo litre of milk)
8.7
6.0
11.0
2.
Edible Oils & Vanaspati
(per tonne oil)
3.0
2.0
7.5
3.

Fermentation
(i) Brewery
(per Kilo litre of beer)
(ii) Distillery
(per kilo litre of alcohal)
(iii) Maltry
(per tonne of grain)
11.5


130.0

8.5
9.5


90.0

3.5
24.0


600.0

2.0
4.
Pulp & Paper
(per tonne of Paper)
300.0
250.0
375.0
5.
Stratch (Maize Products)
(per tonne of maize)
8.0
5.5
44.0
6.
Sugar
(Per tonne of cane crushed)
2.0
0.4
0.5
* Figrue are per unit of processing/production

Pollution Problems
Pollution Problems in agro- based industry are caused mainly due to the wastewater and solid wastes generated during their manufacturing processes (refer Table 2). Air pollution problems are caused by such industriesduring the material handling and combustion processes.

Water Pollution
Concomitant with water consumption, agro- based industry generates large volumes of effluents. The agro-based industry, is the second largest generators of pollution due to organic matters in the cQuntry, standing next only to the domestic sewage. However, the effluents are bio-degradable because they contain mainly organic pollutants and are devoid of any toxic material, thereby making them amenable to biological treatment.

Solid Wastes
Sizeable quantities of hulls, shells, stalks, steeps etc. are produced during the processing of raw materials and refining the products, Frequently, these materials can be utilised as animal feed or manure or further refined to based produce useful and marketable products.

 Air Pollution
Steam and heat are used in large quantities in agro-based industry , and burning fuels results in particulate emissions. Particulate emissions also occur during handling of raw materials before processing and in the handling and use of wastes after processing.

Apart from particulate emissions, odour is one of the major problems In agro-based Industry. In most of the cases, the, mal-odorous conditions are due to poor handling and the management of wastes generated

Management of Wastes
The wastes of agro-based Industry are relatively easy to manage because of the following factors:

  1. In most of the cases, the discarded materials from one segment may be a by-product and can be used as raw material for other segments, For example, the molasses and the bagasse are discards from a sugar mill; but, they are the raw materials in distilleries and pulp & paper mills respectively
  2. ) By building auxilliary units to process all the byproducts, like the one explained above, the agro-based industry could be made Materials "environmentally compatible", as the environmental impact of excess materials in the form of discards, will be reduced. This will also help better utilisation of all materials resulting in greater benefit to the economy by elimination of the import of raw materials and transport of materials from one place to another
  3. When coupled with good by-product recovery process, a considerable proportion of the cost of waste treatment can be offset.
  4. A large segment of the agro- industry is in rural/agricultural setting, where the availability of land for treatment as well as Air Pollution disposal is not a limiting criterion;
Waste Minimisation
Environmental management in industries has so far been focused mainly on pollution control through 'end-of-pipe' treatment technologies, which is a curative approach for pollution problems. By adopting appropriate preventive measures, generation of wastes can be minimised, This will help in two ways; firstly, it will reduce the cost of treatment, and secondar, it will conserve a raw materials by way of reducing their wasteful usages.

The three golden principles of , waste minimisation are :
  1. What can be measured, can be managed
  2. Nothing comes from nowhere {Cor.: Everything comes from somewhere)
  3. Nothing goes away nowhere {Cor.: Everything goes somewhere)

In case of agro-based industry the following "waste-minimisation" practices may be adopted.

  1. Accounting and Balancing of Raw and Other Resources:
    By proper record keeping of quantities of raw materials and other resources used for various unit operations and analysing the fate of all the throughputs, a check on the excess use of these resources can be made, This will also help in identifying the gaps in the stoichiometric and the actual requirements of the required inputs and hence the (in) efficiency of a particular unit operation/process.
  2. Characterlsatlon of process water and wastewater:
    A careful survey of water usage and waste generation points in various processes and measurement of their quantities and characteristics will help identifying any possibility for the recycle of discarded waters, such as cooling water, condensate water etc. An excellent example for this case is the sugar industry. A lot of hot condensate water is generated in a sugar mill during the manufacturing processes which can be recycled as boiler feed and imbibitions water for the better extraction of juice from sugarcane.
  3. Segregation of Waste Streams :
    It is better to segregate less or mildly polluted streams from highly polluted ones. For example, black liquor from the pulping process In a paper mill should be segregated for recovory of lignin, and then It could be mixed wIth other streams to make the combined waste easily amenable for further biological treatment.
  4. Combining the Compatible Waste Streams:
    Characterlsation of various waste streams will help in identifying compatible streams. By combining such streams, cost of their . treatment can be minimised. For example, acidic stream from the juicing section in a fruit processing industry can be combined with the alkaline streams from the other sections to neutralise both the streams and save cost on chemicals.
    With the waste minimisation practices, generation of wastewaters from almost all the agro- based industries can be reduced to a large extent. There are some examples already existing in cases of sugar mills, where the II} wastewater generation has been reduced b more than 50% and the pollution load by over 70%.
Effiuent Treatment Technologies
Biodegradability of the effluents from agro-based industry makes it relatively easier to treat the wastewater. Almost all the conventional biological treatment systems employed in sewage treatment, such as anaerobic/aerobic lagoons, activated sludge processes, trickling filter, septic tanks, land treatment systems etc., are applicable to agro-based industrial effluents as well.

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