Section One
PRETREATMENT PROGRAMS
1    SEATTLE METRO'S INDUSTRIAL PRETREATMENT
PROGRAM: A CASE STUDY FOR REGULATION OF
THE BOEING COMMERCIAL AIRPLANE COMPANY
Vallana M. Ciccolo, Industrial Waste Investigator
Municipality of Metropolitan Seattle
Metro Environmental Laboratory
Seattle, Washington 98119
WHAT IS METRO?
The Municipality of Metropolitan Seattle is a regional public agency which provides public mass
transit and water pollution control services to the people of King and South Snohomish Counties in
the State of Washington. The Public Transit Department of Metro serves 1.3 million people in a
service area of 2128 square miles. Metro Transit employs 3076 employees to operate 1100 diesel,
trolley, and articulated buses over 7000 miles of routes at an annual operating cost of $117 million.
Metro's Water Pollution Control Department provides sewage collection and treatment services for
1 million people in the Puget Sound region. Metro maintains 5 wastewater treatment plants ranging in
size from 5 to 150 million gallons per day (MGD) which provide primary and secondary treatment for
effluent discharges to Puget Sound. The two largest plants are West Point (150 MGD) and Renton (42
MGD) which handle most of the industrial wastewaters from Metro's service area. The collection
system includes 184 miles of trunk sewers ranging in size from 10 inches to 12 feet in diameter and 54
pumping and regulator stations. Metro treats an average of 186 MGD of wastewater, but during
winter wet weather as much as 500 MGD peak flows pass through Metro's plants.
Metro's wastewater treatment plants generate 200 tons per day of sludge which is recycled by forest
silviculture and land reclamation. In addition to being actively involved in silviculture/land application research, Metro monitors water quality for the region's 50 lakes and streams, as well as Puget
Sound and its beaches. Monitoring and analyses are performed out of Metro's new $6 million
environmental laboratory.
Metro's total capital investment in the treatment and collection system is $750 million. Currently,
Metro is building new major capital improvement projects to expand and upgrade treatment plants to
secondary treatment and divert treated effluent from the Green River to Puget Sound under orders
from the EPA and State Department of Ecology.
INDUSTRIAL PRETREATMENT PROGRAM
What Does Metro Regulate?
U.S. EPA Region 10 delegated the authority to administer the industrial waste control program to
the State of Washington which then delegated it to Metro in 1976. The objective of the program is to
regulate industrial dischargers to the public sewer system. Metro regulates the discharge of toxic
metals, solvents, explosives, cyanides, pH, corrosives, oil and grease, toxic organics, high flow, high
strength wastes (BOD, SS), and any material which may cause physical obstruction.
Why Does Metro Regulate?
There are several important reasons for controlling industrial discharges to the public sewer works.
The federal Clean Water Act of 1972 and subsequent Categorical Pretreatment Standards, Washington Administrative Code 173, and Metro Resolution No. 3374 provide the legal requirements for
environmental and treatment works protection from harmful industrial discharges.