Unit 3: Solid waste and its management

Solid waste is a general term used for the solid by-products produced by human activities. Managing enormous quantities of these substances has become a major challenge for today’s society. Scientific knowledge can be applied to make this task more efficient and successful. On the other hand, mismanagement or accumulation of these waste products can become a serious concern since it creates a considerable number of environmental problems as well as health hazards.

Topic & Major Objective

Subject Content

Knowledge expected

Types and sources of solid waste

Sources of waste production

a) Municipal (to include both domestic & commercial)

b) Industrial

c) Agricultural

d) Mining and construction

For each source mentioned candidates should be aware of the approximate composition of the resultant waste stream and how this impacts the final comprehensive volume of waste produced by the entire community. (E.g. In Malta the fraction of waste originating from the construction industry accounts for a very large proportion of the total volume of waste produced).

Properties of substances found in the waste stream

a) Mobility

b) Toxicity

c) Degradability

d) Hazardous nature (such as fire risk & pathogenic nature)

Candidates are expected to be able to classify waste items and to distinguish between them according to their nature. The terms toxic, hazardous, pathogenic and waste stream should be accurately defined and illustrated.

Control of solid waste

How the durability of items, the introduction of disposable products and over-packing affects waste production.

The nature and composition of the waste stream and why it is important to monitor it in order to control waste production and disposal.

The importance of reducing waste production and re-using used items as part of a comprehensive long-term waste management programme.

Methods of solid waste treatment:

a) Incineration

b) Encapsulation

c) Landfill and land raising

d) Recycling (to be treated in detail later)

Candidates are expected to:

(a) discuss the advantages and disadvantages (mainly economic and environmental) for each of the options mentioned

(b) have a wide background of the issue with knowledge from the local as well as the global situation

(c) be aware of the links between waste, wealth, standard of living and general conditions of life found in the community.

(d) be aware that there is no one option which by itself can be applied to solve the waste management problem

(e) use their scientific knowledge and their evaluation and critical skills to come up with concrete and comprehensive proposals on how to resolve the waste management problem in small island states like the Maltese Islands.

Recycling

Separation of waste at source is an indispensable measure for achieving efficient waste management.

Recycling is not always the best option. The nature of waste, recycling costs and resultant environmental impacts have to be considered before recycling waste items.

Not all waste is recyclable. A sizeable volume of solid waste still has to be disposed.

Candidates are expected to acknowledge the advantages (in terms of environmental protection, resource consumption, energy consumption, waste production and social benefits) and disadvantages of recycling.

Recycling techniques and recyclable materials:

a) Recycling of natural resources including composting and recycling of metals

b) Efficient extraction and use of resources within a manufacturing enterprise (e.g. ores & wood)

Candidates are expected to know in detail at least two recycling techniques (e.g. paper, iron, composting, aluminium).