Waste Treatments - doe-std-1128-98

DOE-STD-1128-98

Whatever the system, it is important that each employee be trained to effectively

use the system and that well-intentioned housekeeping efforts do not result in

excessive waste volumes.

8.4.3

Waste Treatments

The primary treatments for aqueous waste are

pH adjustment

liquid-solid separation such as flocculation and filtration

ion exchange

distillation

purification by reverse osmosis

solidification.

The primary treatments for organic solvents are:

-- Solvent extraction

-- filtration

-- incineration.

Virtually all of these processes (except pH adjustment) are likely to result in

secondary waste that requires treatment and/or disposal. In all cases, recycling of

the primary solution is desirable because it reduces monitoring cost and waste-

disposal liability and cost. A brief description of the use of each of these treatment

methods is given below. Extensive design and engineering should be done before

any method is selected in order to ensure meeting design objectives.

8.4.3.1 pH Adjustment

This treatment is used on aqueous systems to meet discharge limitations or

to make the solution amenable to other treatment. A mineral acid, such as

sulfuric, hydrochloric, or nitric, is normally used to lower the pH. A base,

such as sodium, potassium hydroxide, or occasionally ammonia, is used to

raise the pH. The solubility of some contaminants will be affected by the

pH of the solution. For example, an acidic solution containing iron may

show a copious precipitate of ferric hydroxide upon the addition of a base.

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