Environmental Engineering Reference
In-Depth Information
1.13.13 Machine guarding (29 Cfr 1910.212)
The wastewater treatment process would quickly come to a halt
if it were not for the machines that provide the motive force to move
the wastestream through the process. From sewage lines to intercep-
tor lines through pumping stations and the pressurizing process, the
influent is literally forced into the treatment plant by machines (grav-
ity flow systems excepted). Additionally, the work of machines is not
finished yet. Upon entering the plant, a variety of other machines and
machine-operated devices screen the flow, remove grit from the flow,
and then provide the force necessary to push the flow into primary and
then secondary treatment. The need for additional machines continues
as the wastestream enters and leaves the various treatment processes;
for example, during the treatment process huge motor-driven blowers
are used to aerate the flow. Later, when liquids and solids are separated,
both wastestreams continue to move along, powered by machines.
It should be evident from the preceding discussion that the waste-
water treatment process uses several different machines. When properly
maintained and operated these machines make the operator's job easier,
his or her performance more efficient, and his or her workplace safer.
As stated, worker safety is enhanced by machines, but only if the
machine itself is safe. The basic purpose of machine guarding is to
prevent contact of the human body with dangerous parts of machines.
When body parts such as arms, fingers, or hair make contact with mov-
ing machinery, the result can be disastrous and sometimes fatal. Some
of the most gruesome accident investigations involve body-part amputa-
tions caused by contact with unguarded moving machinery.
The plant safety person must quickly become familiar with the
plant's moving machinery. Moreover, the plant safety person must be
familiar with the methods of machine guarding. OSHA has published an
excellent machine guarding reference source, Concepts and Techniques
of machine Safeguarding (Publ. No. 3067), that is highly recommended. It
can be obtained from the Superintendent of Documents, U.S. Government
Printing Office, Washington, D.C. 20402.
1.13.14 Chains, slings, and ropes
This section describes the various types of hoisting apparatus
used in wastewater treatment. Specifically, the hoisting apparatus in
the form of chains, slings, and ropes is addressed. Moreover, safety con-
siderations and inspection of these devices are also discussed. OSHA
has published two excellent references, Sling Safety (Publ. No. 3072)
and materials handling and Storage (Publ. No. 2236), both of which can
be obtained from the Superintendent of Documents, U.S. Government
Printing Office, Washington, D.C. 20402.
During safety audits particular attention must be paid to hoisting
apparatus. Considering the large number of different types of hoisting
apparatus used in the wastewater industry, it is not surprising that these
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