Before adopting any measure to control pollution, both the capital and energy expenditure involved should be studied at, the quality of the commodity obtained or service provided, examined and an assessment made to see whether it is indeed “a good measure” or not. For this, the concept of resource should be clarified, the rate of its depletion determined, the life style, as reflected in the waste, we produce, and its composition, should be analyzed to assess what can be reclaimed/recovered from it.
A detailed examination of the refuse will, then, enable assessment to be made of the recovery or conversion potential. One of the most economical methods of controlling pollution seems to be the recycling arrangement, i.e.
, one in which the pollutants are, by and large, processed at the place of their generation itself, and converted into products which could be used there or as raw material for more useful products. Recycling is a much abused term, generally taken to mean getting something back from waste, e.g., newspaper recovery by de-inking, followed by repulsing, to make more newsprint.
In fact, recycling falls into three main categories: 1. Re-use 2. Direct recycle 3. Indirect Re-use is typified by the returnable bottle or tin; it means several steps from the bottler to the consumer and back again, where it is cleaned and refilled. Once it is unfit for re-use, it may be cleaned and broken down for cullet, i.e.
, glass which is remolded at the glass works and used to make new bottles. The latter process comes under the heading of direct recycling, which is dependent on the quality of recycled material and on its cost, which should not exceed that of the fresh raw material. It is quite probable that the bottle may eventually end up in domestic refuse, where it can be extracted by screening and separation in conjunction with other bottles. These bottles will probably be of different colors, and at varying degrees of cleanliness, which might render them unsuitable for cullet, unless optical sorting is opted which would, however, raise costs.
The bottles may, however, be ground and used for a highly skid-resistant and durable road surfacing material. This is an example of indirect recycling. Other examples are: (a) the conversion of refuse to combustible gases by parolee- sis (b) direct heating by means of incineration with heat recovery.