Page 22 - Materials Chemistry, Second Edition

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Current Practice and Future Sustainability
Recycling: What cannot be reduced at the source is pumped in the waste
stream. The above discussion shows that reuse has much to do with cultural
habits and this is also the case with recycling but recycling involves additional
technical know-how and could involve some capital investment. Recycling
is the process of converting these wastes to raw material that can be reused
to manufacture new products.
Through regulations governments have a great role to play in promoting
recycling. Such regulations are even emerging in developing countries. For
example, the Republic of Korea explicitly prescribes the Extended Producer
Recycling system under the Resources Conservation and Recycling Promotion
Law, amended in 2003 (IGES, 2005). In India and the Philippines, laws on the
management of MSW have been enacted recently and the importance of
material cycles is clearly mentioned in the laws (IGES, 2005).
Recovery: Recovery of materials or energy can take numerous forms. It is
clear that material recovery is a limited activity worldwide and is mainly
concerned with the recovery of energy from burning wastes. For example,
the Oregon Department of Environmental Quality in the USA states that
“construction and demolition wastes makes up the majority of the wastes
being processed at MSW Recovery Facilities, followed by ‘dry’ commercial
and industrial loads; virtually no recovery from residential garbage route
trucks occurs” (ODEQ, 1997).
Recovery differs from recycling in that waste is collected as mixed
refuse, and then various processing steps remove the materials. Separating
oil from waste water effluent by a gravity oil separator (GOS) in the oil and
soap industry is material recovery from waste. This material is then sold to
another type of soap industry or returned to the industrial process within
the same factory. The difference between recycling and recovery, the two
primary methods of returning waste materials to industry for manufactur-
ing and subsequent use, is that the latter requires a process to remove the
material from the waste while the former does not require any processes for
separation, sorting can be done manually.

1.3 Treatment
Treatment or end-of-pipe treatment or pollution control is one of the very
important technologies for the traditional waste management hierarchy and
environmental compliance for any industry. There is a variety of traditional
treatment technologies for wastes to choose from depending on several factors
such as physical form of the waste (solid, liquid, or gaseous), quantity of
waste, characteristics, combined or segregated wastes, degree of treatment
required, etc. The treatment technologies can be categorized into physical,
chemical, thermal, or biological treatment. Combinations of treatment
technologies are often used to develop the most cost-effective, environmen-
tally acceptable solutions for waste management.