Page 100 - Materials Chemistry, Second Edition

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Solid waste Cleaner Production 79
The solid waste is mainly divided into four types according to its size:

• Wood chips: Chopped blocks of wood of different widths, thick-
nesses, and lengths.
• Wood shavings: Thin shredded wood from leveling operations.
• Sawdust: Fine wood powder or dust generated from sawing operations.
• Wood flour: Very fine wood dust generated from sanding.

The solid waste occupies a large space, exposing the workshop or factory to
fire risks if a source of ignition is present, which would result in the loss of
a valuable and expensive material. In addition, acute exposure to fine wood
dust can cause health hazards to workers such as irritation of the eyes, skin,
or respiratory tract, while chronic exposure may result in dermatitis, asthma,
or respiratory system congestion.

Polyester and polyurethane spraying emissions
The painting workshop should be equipped with spraying booths. Polyester is
always sprayed first and then sanded as discussed before. The top layer is
polyurethane. There are many health hazards associated with polyester and
polyurethane spraying. Their emissions contain acetone (from solvents),
aerosol, and other harmful chemicals. Breathing moderate to high levels of ace-
tone for short periods of time can cause nose, throat, lung, and eye irritations,
headaches, light dizziness, increased pulse rates, nausea, vomiting, uncon-
sciousness, and possibly coma. While breathing aerosol causes nearly the same
health problems in addition to coughing, wheezing, chest tightness, and asthma.

CP opportunity assessment
Solid wastes
Before going through recycling of solid waste such as small pieces of wood,
sawdust, wood shavings, etc. it is always recommended to install a dust col-
lection system such as a bag filter to protect the working environment from
any suspended solids in the air. As wood parts are machined and sanded, a
substantial amount of sawdust is generated. Dust collection systems can
provide safe, waste reduction benefits, but must be properly designed to be
effective, safe and efficient. This improves worker health and safety by keep-
ing the dust out of the breathing air and off the floor. It extends equipment
life and decreases maintenance by keeping dust away from machinery, and
collects and keeps the sawdust from becoming contaminated with dirt and
other contaminants so that it can be recycled.
Wood shavings:

• Used as animal bedding for chickens, horses, cattle, etc.
• The bedding waste could be used as a soil additive.
• Could be used as a thermal insulation.