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It is well known that industry is an important contributor to the development process of any country. Much of the developments are based on the use of increasing amount of raw materials, energy, chemicals and synthetics. The scale and complexity of requirements for these resources have increased greatly with the rising levels of population and production.

Following India's entry into the global market and the ever-increasing competition in the market, it has become necessary that apart from reduced manufacturing cost, industry must improve its profitability to survive and remain competitive in the international market. To a large extent the product cost in an industry is dependent on its diverted resources towards "End-of-Pipe" pollution control, where pollution created by the industry is treated after the waste has been generated. This approach first allows wasteful use of resources in manufacturing and then consumes further resources to resolve the environmental problems.

The experience over the last two decades has indicated that this approach is only a short term remedy and cannot lead to sustainable industrial developmental, particularly in developing countries. The additional financial burden brought about by the cost of pollution control and end-of-pipe treatment has dissuaded the industry from voluntary adopting pollution control approach. It is now being realised that it is better to adopt the preventive approach i.e. reduce the generation of pollution itself as against the curative approach of taking care after it has been created. It is therefore, important to adopt a strategy of pollution prevention based on technologies that conserve resources, minimise pollution and reuse wastes as secondary resources to the extent possible.

Cleaner Technologies (CT) are the practical application of knowledge, methods and means within the need of man, to provide the most rational use of natural resource and energy and in turn to protect the environment. Such technologies are based on improved manufacturing methods that require less raw materials and energy to obtain equitable levels of output of identical or better quality. Cleaner technologies also make greater, if not full, use of wastes and recyclable materials and are dependent upon innovation and high level of cooperation between different industries, particularly when exchanges of certain wastes are involved.

For this approach, different agencies prefer to use different terms. For example, UNEP uses the term "Cleaner Production", USEPA uses "Pollution Prevention" and UNIDO prefers to use "Waste Minimization". Some other names under which the concept is being advocated are "Low and non-waste Technologies", "Environmentally Sound Technologies", "Waste Recycling", "Residue Utilization" and "Resource Recovery Technologies".

There are three broad approaches in cleaner technologies of industrial production. (a) Waste minimization technologies involving raw material substitution, process changes, improved housekeeping, equipment redesign and product reformulation. (b) End-of-pipe treatment technologies involving recovery of raw materials, water, energy and useful byproducts. (c) Waste utilization technologies involving reclamation and utilization of wastes as secondary raw materials in other industrial units.

One good example that provides a cleaner technology scenario can be found in the agro-based sugar industry. The waste by products, such as sugarcane bagasse and molasses, form the key raw material for the pulp and paper and distillery industry, respectively. The press mud generated during the purification of juice which was a waste few years ago is now viewed as a rich source of clean energy. Not only this, press mud has proved to be a good organic manure for sugarcane crop. The reuse of hot condensate in juice extraction in the crusher units and as a boiler feed water, not only conserves the fresh water resources but also minimize the quantum of effluent discharge by the industry.

The use of surplus bagasse in the boiler house helps in conserving the energy resources and at the same time potash rich boiler ash is produced which is a good fertilizer for the sugarcane crop. According to an estimate by the Central Pollution Control Board (CPCB) approximately $15,000$ to $2,000$ litres of water is used per tonne of cane crushed. The recycling and reuse of hot condensate water can reduce this water consumption to as low as $100$ to $200$ litres. Proper house keeping, periodic checking and maintenance of pipe joints, valves and glands can further reduce this water consumption. Ideally, the industry can be brought down to zero effluent discharging unit.

Bio-methanation of spentwash in distillery industry, chrome recovery in tanneries, caustic recovery in large pulp and paper mills and fibre recovery in small pulp and paper industry are the few other options provided by cleaner technologies. Adoption of such technologies in these sectors would certainly reduce the burden on environment.

The major constraint to promotion of cleaner technologies is lack of information regarding needs of the industry, local conditions, raw materials, and technologies available in developed countries. There is certain perceived risk that discourages entrepreneurs from adopting the relatively new concept of cleaner technologies. A combination of informational, financial, economic and legal measures, therefore, needs to be devised to promote waste minimization through cleaner technologies. There is also lack of coordination and direction in $R$ & $D$ efforts and inadequate thrust for technology transfer from laboratories to commercial scale. These problems arise mainly due to insufficient mission oriented approach of laboratories; inadequacy of design, pilot-scale demonstration of laboratory results; and low value placed on technology transfer by scientific and technological personnel engaged in $R$ & $D$ work.

To overcome these constraints, CPCB sponsored a project at NEERI, Nagpur to develop a database on cleaner technologies through analysis of information available nationally and internationally. This involved studying published literature, accessing established databases and interaction with the $R$ & $D$ centres within industries associations and eminent experts in the field and also technical wings of financial institutions. Information on $509$ case studies have been collected for $14$ industrial sectors. Regarding any information on cleaner technologies CPCB and NEERI can be approached by industries, consultants and other related organisations.

In order to disseminate information on cleaner technologies among the variety of industries, CPCB has planned industry wise seminars and workshops. The experiences from demonstration plants and feedback from the industries would be discussed in such seminars.

Investment in environmental technology gives ample opportunities to promote cleaner alternatives. With the appropriate measures adopted, one can not only increase profitability, but also minimize pollution generation. It is therefore, the need of the hour, to look into the positive aspects that cleaner technology, has provided to the industry and environment. This will certainly result into a healthy economy and cleaner environment.

For pollution prevention we must adopt a method based on technologies that:

1. Conserves resources
2. Minimises pollution
3. Reuses wastes as secondary resources to the extent possible
4. All of these