Latex Paint Wastes — Municipal
Charges and Treatment
RODNEY T. WILLIAMS, Senior Sanitary Engineer
East Bay Municipal Utility District
Oakland, California 94623
INTRODUCTION
As a result of new federal regulations, municipal agencies are required to examine the
type of users contributory to the sewer system, and the quality and quantity of the
discharged wastewaters.
Firstly, the Water Pollution Control Act Amendments of 1972 (I) (PL 92-500) require
the agency to verify that all major contributing industries, as defined in the pretreatment
standards (2), meet the effluent limitations guidelines for "incompatible" pollutants. The
definition of a major contributing industry for the purpose of these regulations, has been
defined as any industry that discharges an average daily wastewater volume greater than
50,000 gallons.
Secondly, municipal treatment agencies receiving construction grants for water
pollution control facilities from the federal government will be required to recover from all
industries their portion of the grant amount. These amounts will be a charge over and above
the ongoing capital and operating expense of the municipal agency.
Thirdly, the municipal agency which receives the grant must adopt an equitable system
of cost recovery that reflects the cost of treating both the volume and quality parameters of
the wastewater. The agency must also adopt and enforce source control regulations on
industrial users (3).
In the light of these new regulations, Special District No. 1 (S.D. 1) of the East Bay
Municipal Utility District (EBMUD) in Oakland, California undertook to investigate the
industries within its jurisdiction. This paper will address primarily the latex paint
manufacturing industry and will examine the data collected on latex wash water.
INVESTIGATION
Special District No. 1 was created to intercept, treat, and dispose of waste originating
from the seven cities of Oakland, Berkeley, Albany, Piedmont, Alameda, Emeryville and El
Cerrito on the east side of San Francisco Bay. Of the 175,000 users in the District,
approximately 1,000 are classified in Division D of the Standard Industrial Classification
(SIC) Manual (4). Although the staff of the agency were aware that two or three latex paint
manufacturers discharged to the municipal system, they were not aware of the large number
of smaller industries that would be manufacturing latex paints.
The determination of the number and type of industries in all manufacturing categories
was made by the business offices of the District. This involved identifying the activities of
some 20,000 non-residential users and classifying them into categories based on the 1972
SIC Manual. The final results indicated that instead of there being 2 or 3 paint
manufacturers, there were, in fact, 16. Most of these paint manufacturers are small and
discharge volumes less than the 50,000 GPD at which volume the municipal agency is
required to enforce the pretreatment standards. However, even though the agency would
not be required to enforce any federal "pretreatment standards" on these smaller paint
industries, the District was under obligation, through the receipt of federal grants, to adopt
an equitable system of rates and charges; to enforce any source control requirements
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