Ultimate Disposal of
Concentrated Wastes by Incineration
A. R. BALDEN, Staff Engineer
Product Planning and Development
Chrysler Corporation
Detroit, Michigan
INTRODUCTION
Until quite recently, it had been assumed that if pollutants were removed
from the wastewater stream, the nation's waterways and aquifers would be protected. It is now recognized that unless definite steps are taken to prevent these
wastes, concentrated from plant effluents, from finding their way to the water table or its tributaries, the efforts exerted to remove these contaminants will be
fruitless. My discussion today will describe briefly the procedures by which the
pollutants are removed from the liquid plant wastes. We will also discuss in some
detail a few of the experiments that have been conducted to achieve ultimate disposal of these concentrated waste materials. An installation by which disposal of
an oily waste is currently being achieved will be described.
Those waste materials requiring ultimate disposal of most general concern to
Chrysler Corporation are 1) oily scum resulting from the treatment of wastewater
from machining plants, and 2) water base paints and acrylic enamel waste solids
from assembly plants.
TREATMENT OF METHODS
Oily Scum
Oily scums typically result from the treating of wastewater from a machining
plant. The equipment normally used by Chrysler Corporation plants to
treat this water consists of (1) primary clarifiers to remove most of the oil; (2) an
afr flotation unit to further clean the effluent;and, (3) if necessary, a final lagoon
or other settling device to remove the final trace of particulates with occluded oil.
In the primary clarifier, the blended waste is acidified with sulfuric acid to a pH
of 3.5 to 4.0 to neutralize the emulsion and allow the liberated oil to separate
from the water by gravity. The oil is skimmed and stored for use later as auxiliary
fuel. After removal of the oil, the effluent is treated with aluminum sulfate, the
pH adjusted to 4.5 to 5.0 with caustic soda, and then further cleaned of its waste
load by afr flotation (Figure 1). The scum which floats to the surface is then removed by flight sweeps. This scum consists of 1) the tiny afr bubbles released
when the pressurized effluent is returned to atmospheric pressure; 2) the aluminum
hydroxide "floe" caught by the afr bubbles; and 3) the oils, free, emulsified, and
invert, occluded thereto. This scum usually amounts to one to five per cent of the
total flow of water through the treatment unit. Treatment with sufficient sulfuric
acid to reduce the pH to 1.0 or less and the providing of vigorous agitation will
reduce this sludge to ten per cent of its original volume or 0.1 to 0.5 per cent of
the wastewater flow.    This sludge must be treated further to render it innocuous.
Paint Solids
The water base paint solids originate in the underbody paint dip procedure
specified to protect these areas from corrosion. The paint wasted from this process
is washed from the floor with a flow of water. The water is treated with a mixture
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