Civil Engineering Reference
In-Depth Information
Industrial solid waste is commonly broken down into four categories:
• Inert waste from extractive, brick and similar industries, to which can
also be assimilated debris from building demolition. This can easily be
reused for road construction and public works.
• Urban waste: This includes plastics, paper, rubber, and, in limited
quantities, glass. These can be treated as urban waste.
• Industrial waste includes all industrial waste with the exceptions of the
abovementioned categories (inert and urban waste) and hazardous
waste. It involves some risks for the environment, but it can be made
less harmful by appropriate treatment or reused in processes. It
includes organic and inorganic materials, liquids, sludges, and solids
with limited concentrations of pollutant.
• Hazardous and infectious waste, which is industrial waste with high
concentrations of toxics or pollutants.
Urban waste is commonly landfilled, but this is no longer an acceptable disposal
method because of environmental problems and the scarcity of space. Utilities are
very interested in burning waste to produce electricity and steam, but air pollution
must be avoided. Urban waste treatment is not discussed here in detail, our main
concern being industrial waste and its on-site utilization.
Non-hazardous industrial waste can be treated as urban waste, but the quantity
produced by a single medium-sized factory is generally too small for on-site reuse
in heat-recovery plants. As a general rule, on-site treatment is economically viable
if the quantity of waste is not less than hundreds of t/year (500-1,000). This
depends on the type of waste and particular situations, but it can be assumed as a
general indication.
16.2 Waste Management
Waste-management strategies comprise a few main sections, some of which are the
and accounting, analysis of local environmental regulations, engineering analyses,
and investment proposals based on feasibility studies, personnel training, and
information.
Several factors must be considered:
• Incidence of waste costs on turnover and added value
• Waste as a percentage of production
• Identification and quantification of waste following the flow of raw materials and
energy inside the factory
• Selection of significant indexes valid for the whole factory and for single-
production lines
• Possibility of recycling inside the factory or outside
• Level of pollution and compatibility with local regulations
