Pollution Prevention and Control Technologies for Plating
Section 1 - Overview of Project Results
1.2 Overview of Users Survey Results
1.2.3 Wastewater and Discharge Characterization
Exhibit 1-8 provides an overview of the
wastewater data contained in the Users Survey database. Column
1 shows the shop code. Column 2 indicates the type of wastewater
discharge (direct-to a stream or river, indirect-to
a publicly owned treatment works or POTW, or zero discharge-no
wastewater discharge). Column 3 indicates the average discharge
rate from the plating operations. The database also contains data
for the maximum plating discharge and the average and maximum
total industrial discharge. Column 4 indicates the amount of flow
reduction that has been achieved through the implementation of
pollution prevention techniques and methods. The next two columns
indicate the type of effluent regulations that apply to each shop.
These are shown as either standard or non-standard (i.e., CFR
413 or CFR 433) and aquatic-toxicity-based.
The majority of the respondents to the Users Survey are indirect
dischargers. The percentage of shops that are either indirect,
direct, both indirect and direct, and zero discharge are shown
in Exhibit 1-9. These data indicate that captive shops are more
likely to be direct dischargers than are job shops. EPA estimates
in 1984 indicated a similar trend (ref. 517).
The electroplating discharge rates (average daily flows) of the
survey respondents vary from 0 gpd to 420,000 gpd (some higher
discharge rates were reported for combined plating and non-plating
industrial discharges). The average and median plating discharge
rates for respondents were 34,600 gpd and 14,000 gpd, respectively
(see Exhibit 1-10 for a graphical summary
of discharge data). Many shops indicated that they have made drastic
progress in reducing wastewater flow rates, the most significant
of which are listed in Section 2.
The respondents to the Users Survey are required to meet either
CFR 413 (Electroplating Categorical Standards), CFR 433 (Metal
Finishing Categorical Standards), or non-standard effluent limitations.
Non-standard limitations are more stringent than the categorical
standards for one or more pollutant parameters. Some of the non-standard
limitations are written in terms of pollutant mass and flow rates
(e.g., 0.37 lbs/day of chromium with a maximum flow of 40,000
gpd) rather than concentration limitations. The percentage of
respondents that are required to meet each type of effluent limitation
are as follows:
40 CFR 413: 28%
40 CFR 433: 8%
In addition to concentration or pollutant mass discharge standards,
16% of the respondents indicated that they are also subject to
aquatic-toxicity-based effluent standards. These limits require
that an industrial wastewater be sufficiently treated such that
certain percentages of organisms (typically fish and water fleas)
are able to survive in the effluent for a given time period.
More detailed data on regulations and the compliance experience
for each shop are contained in the database. For example, the
Users Survey asked platers to list the pollutant parameters for
which they have compliance difficulty. A summary of their responses
is shown in Exhibit 1-11.
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