1.2 Types of liquid and solid waste
The aim of this section is to introduce the different types of solid and liquid wastes and to clarify what we mean by the term ‘waste’. The Basel Convention (an international agreement on the exporting of hazardous waste) states that (UNEP, 2011):
‘wastes’ are substances or objects which are disposed of or are intended to be disposed of or are required to be disposed of by the provisions of national law.
You should note that this definition includes both solids and liquids. Solid and liquid wastes are usually transported and treated in different ways, so in this Module we will consider the two wastes separately. Note that all human excreta (urine and faeces) are considered to be liquid wastes.