TM 5-814-3/AFM 88-11, Volume III
e. Monitoring of other operations. For other treatment prcesses (advanced treatment), measurement
of the appropriate performance parameters is required.
f.
Instruments involved. The various instruments and meters used for monitoring are discussed in
WPCF Manual of Practice No.8 under "Instrumentation and Control" and EPA handbook Monitoring
Industrial Wastewater Table 18-1 describes the types of flow measuring devices applicable to wastewater
treatment.
18-4. Sampling.
Wastewater sampling at various points in the sewage treatment process is useful in evaluating operation
efficiency. This can be used internally to optimize the process and is also used by regulatory agencies to judge
whether treatment plant regulations are satisfied. Sampling is also used to establish changes when treating
industrial wastes. Provisions for sampling sites must be made in the plant design. The type of sampling
provisions (flow proportional, composite, or grab-sample collection) will be dictated by the type of sampling
required in the NPDES discharge permit. Forward flow, recycled flow, sludge flow, chlorine residual, pH
and dissolved oxygen are some of the process control parameters that can be monitored on a continuous
basis.
18-5. Odor control.
Odor arising from biological decomposition can be prevented by disinfecting the waste stream at appropriate
points in the sewer system or treatment system. Chlorination is commonly used in this application, although
supernatant return streams can upset odor control effectiveness. Other biological odors can be reduced by
improved in-plant housekeeping practices. Ventilation and air washing can also reduce in-plant odors. Air
washing is usually done with air scrubbers using hypochlorite or chlorine dioxide solution sprays. Oxidation
by chlorine, hydrogen peroxide, potassium permanganate or ozone is effective in destroying certain odors
such as hydrogen sulfide. Ozone also acts as an odor-masking agent, with ozone commonly being produced
on-site. Dispersion can also reduce odors significantly but it is usually not good practice in urban areas. Plant
design will provide for the retention, collection and disposal of any odorous gases produced in treatment
processes when practical.
18-8
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