Encyclopedia of Environmental Science and Engineering, Volume I and II

INDUSTRIAL WASTE MANAGEMENT 533

pasteurization, cleaning process, equipment, and cooling of

final product. The waste is generally characterized by high

BOD and suspended solids. The estimated total wastes from

food industry for the United States in 1968 was:

320 million cubic meters of wastewater discharged

360 million kg of BOD generated

180 million kg of suspended solids generated

8 billion kg of solids residuals

Table 4 is a brief summary of major liquid wastes, their origin,

characteristics and applicable methods of treatment for sev-

eral major industries in the food industrial category.

Paper and Allied Products Industry

Pulp is produced by mechanically or chemically processing

wood or other vegetative materials to extract usable cellu-

losic fibers as an aqueous slurry. The pulp slurry may be used

directly in paper making or it may be shipped elsewhere for

processing into paper products. The pulp and paper industry

is the ninth largest industry in the United States. The major

group of the industries in the pulp and paper industry are

pulp mills, paper mills, paperboard mills, miscellaneous

converted paper products, paperboard containers and boxes,

and building paper and board mills.

The fundamental industrial operations are divided into

two major categories: pulp mill and paper mill. The pulp mill

operation includes wood preparation, pulping, deinking, pulp

washing, screening and thickening, and bleaching. Paper mill

operations include stock preparation, paper machine opera-

tion, and finishing. Table 5 provides a summary of these

operations, origin of major wastes, major characteristics, and

treatment methods.

Chemical Industry

The chemical industry is highly diversified and supplies

products for virtually every other industry. The number of

synthetic compounds manufactured is estimated to range

between 500,000 and 600,000, and a host of new products is

introduced every year. The chemical products may be used

as primary, intermediate, or finished products.

The chemical processing industry has a variety of spe-

cial pollution problems due to the vast number of products

manufactured. The treatment processes combine process-

ing, concentration, separation, extraction, by-product recov-

ery, destruction, and reduction in concentration. The wastes

may originate from solvent extraction, acid and caustic

wastes, overflows, spills, mechanical losses, etc. Origin of

major wastes, characteristics, and treatment and disposal of

wastes in several major chemical industries are summarized

in Table 6.

Petroleum Industry

The petroleum industry is one of the most important manu-

facturing industries in the country. It is a complex industry

utilizing complex combination of interdependent operations

engaged in the storage and transportation, separation of

crude molecular constituents molecular cracking, molecu-

lar rebuilding, and solvent finishing to produce petrochemi-

cal products. Each process is responsible for production of

many waste streams containing oil, chemical oxygen demand

(COD), phenol, sulfide, chloride, and others. Treatment may

involve oil separation, precipitation, adsorption, and biologi-

cal treatment. The refining operations may be divided into

many major categories. Wastewater characteristics, origin

of major wastes, characteristics, and treatment and disposal

methods from several major processes are summarized in

Table 7.

Metals Industry

Primary metal processing and fabricated metal products man-

ufacturing comprise the metals industries. The most important

end uses of the products of the metals industries are automo-

biles, machinery, appliances, electrical equipment, structures,

THICKENING STABILIZATION CONDITIONING DEWATERING DISPOSAL

Concentrates solids Reduces pathogens, and

eliminate offensive odors

Enhances water removal Removes moisture and

produces sludge cake

Used for ultimate

disposal of residues

1. Gravity 1. Chlorine oxidation 1. Chemical 1. Vacuum filter 1. Evaporation of brine


2. Flotation 2. Line stabilization 2. Elutriation 2. Filter press 2. Incineration


3. Centrifugation 3. Heat treatment 3. Heat treatment 3. Horizontal belt filter 3. Wet Oxidation
   4. Aerobic digestion 4. Centrifugation 4. Pyrolysis
   5. Anaerobic digestion 5. Drying beds 5. Composting
   6. Land filling
   7. Deep well injection

FIGURE 1 Alternative unit operations and processes for sludge and brine processing and disposal.

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