Encyclopedia of Environmental Science and Engineering, Volume I and II

530 INDUSTRIAL WASTE MANAGEMENT

average sample for the day. Individual hourly samples are the

grab samples representing the condition at that instant.

Frequency and Duration of Sampling

The frequency of sampling depends on the flow rate, waste-

water characteristics, and variability in quality and volume.

The expected range in flow rate and waste concentration

should be determined by a preliminary survey. Although

most of the time the frequency is one sample per hour, the

frequency for highly variable waste streams could be as high

as one sample every three minutes.

An intensive plant survey will generally last between

five to ten days of normal plant operation. Since the treat-

ment facilities must be designed to treat the highest pollution

load expected, it is important to consider seasonal variations

(if applicable).

Sample Handling

In order to obtain a representative sample it is necessary for

the sampling point to have sufficient hydraulic turbulence.

Sufficient volume of the sample must be obtained to perform

all analyses planned. The minimum volume of grab sample

should be between one to two liters. Sample containers and

sampling device should be clean and uncontaminated. Before

the sample is taken, the container should be rinsed several

times with the wastewater. Each sample should be labeled

with an identification card containing the following infor-

mation: date and time, sample location, method of sampling

(grab or composite), and notation of information obtained

from field analyses of parameters that may change before

laboratory analyses are made (temperature, pH, appearance).

The sample should be analyzed as quickly as possible.

Storage should be in a manner that insures that the charac-

teristics to be analyzed are not altered. Refrigeration in most

instances is necessary. In some cases a special chemical may

have to be added to prevent changes in chemical or biological

characteristics.

Parameters Measured

A major item in any industrial monitoring program is the cost

of analytical measurement. It is important that the parameters

be properly selected to represent inplant waste streams; and

waste characterization, treatment and reuse requirements. In

some cases the necessary analyses will be time-consuming

and relatively expensive. In many cases, an alternative ana-

lytical technique may be used that are less expensive. Major

constituents of interest in industrial pollution monitoring are

listed in Table 1.

Analytical Considerations

Good analytical procedures are of the utmost importance in

a monitoring program. The basic references for wastewater

analytical procedures and techniques are EPA publications,

Standard Methods for Examination of Water and Wastewater,

and ASTM Standards. 17 – 20 The analysis may fall into several

major categories including routine wet chemistry, selective

ion electrodes, automated wet chemistry, and bioassary tests.

Data Analysis

Data obtained through a well-planned and executed moni-

toring program will provide valuable information for waste

process selection, plant design and operation, and assist the

industry in evaluating the manufacturing process. The mon-

itoring program may result from changes in chemical use

and/or industrial process, inplant spills or dumping of baths.

Variability of the parameters may be random or cyclic. The

data should be analyzed to establish the fluctuations with

time, location, work shifts, and type of operation.

Statistical techniques should be used to develop rela-

tionships such as average or mean, standard deviation and

extreme conditions, and regression coefficients. With a

knowledge of basic probability theory and the use of statis-

tical techniques, such as least squares, curve fitting, analysis

of variance, regression and correlation analysis, chi-squared

goodness of fit, and others, it is possible to construct math-

ematical models and curves for almost any level of preci-

sion desired. Such techniques help to evaluate information

having wide variations, so that an estimate of the best value

of the parameter being measured can be developed. For

more information the reader should consult several excellent

references on statistical methods. 21 – 24

TREATMENT PROCESSES

Industrial wastewater treatment utilizes a number of unit

operations and processes to achieve the desired degree of

treatment. The collective treatment schematic is called a flow

scheme, flow diagram, flow sheet, process train, or flow sche-

matic. Basic considerations for developing a flow scheme

include: (1) the manufacturing process and its flow scheme;

(2) characteristics of wastewater streams and degree of treat-

ment; (3) requirements of the regulatory agency; (4) construc-

tion cost; (5) level of expertise of treatment plant operation

personnel; and (6) operation and maintenance costs.^2

The wastewater treatment facilities are designed to process

liquids and solids or sludges. It is essential that in-plant waste

management and control techniques be utilized if cost-effec-

tive methods of liquid and solids treatment are to be attained.

Some application of in-plant controls include waste reduc-

tion, waste segregation, water conservation and recycle, and

process modifications. Generally, controlling wastes within

the plant is much more cost-effective than implementation

of treatment. Certain innovative processes that reduce waste

production have resulted in improved process yield or by-

product recovery and utilization.

Waste Reduction

A basic materials balance procedure should be developed that

accounts for all materials that enter and leave an individual

department or processing area. Some specific waste reduction

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