1987 SEWAGE SPILLS AND DIVERSIONS

The city of Los Angeles disposes of about 400 million gallons a days of sewage by releasing it from the Hyperion Sewage Treatment plant into Santa Monica Bay. Most is in the form of treated wastewater piped five miles off Playa Del Rey and released in a deep, submarine canyon. Sludge, the solid material gleaned from the wastewater, is deposited on the ocean floor by a pipeline seven miles offshore.

But in 1987, recurring troubles have caused about 38.6 million gallons of wastewater and raw sewage to be released closer to shore, causing alarm about public health. Beaches along the Los Angeles County coastline have been closed the last two weekends because of sewage contamination.

KINDS OF INCIDENTS

Diversions: A release of fully or partly treated sewage, usually deliberate, through a pipe that empties one mile off Playa del Rey. Diversions occur most often after power failures at the Hyperion plant.

Spills: Unplanned dumping of sewage, often untreated, into creeks and drains that empty onto beaches or into Santa Monica Bay.

Overflows: Occur when rain water floods sewer mains, washing effluent into Ballona Creek and out to the bay. The state permits this until sewer system repairs are completed in 1994.

SEWAGE TREATMENT

Raw Sewage: Untreated waste that spilled before reaching any treatment plant.

Primary Sewage: Effluent with most solids removed by screens and settling, but still tainted by high levels of bacteria. Must be released five miles from shore.

Secondary Sewage: Effluent that received extra treatment to remove nearly all organic material that bacteria feed on. Safest when released five miles offshore.

Chlorination: Treatment sometimes used to kill bacteria when sewage spills or is diverted close to shore.

Volume in Date mil. gal. Discharge Location Cause May 3 9.4000 Chl sec Hyperion plant Power Failure May 25 2.7000 Chl Hyperion plant Power Failure June 5 1.5000 Chl sec Hyperion plant Power Failure June 6 0.0300 Chl Hyperion plant Power Failure 2.4000 Raw & Chl Venice canals Power Failure June 18 0.0200 Chl sec Hyperion plant Power Failure July 16 3.1200 Chl sec Hyperion plant Power Failure 2.6500 Chl pri Hyperion plant Power Failure July 17 .6250 Chl sec Hyperion plant Valve Malfunction July 23 .0100 Overchl sec. Hyperion plant Operator Error Aug. 5 3.700 Chl sec Hyperion plant Power Failure Aug. 18 4.900 Chl sec Hyperion plant Power Failure Sept. 6 .0015 Chl sec Hyperion plant Irrigation break Sept. 26 3.050 Chl sec Hyperion plant Power Dip .0350 chl Pacific Palisades Power Failure Oct. 17 .0300 Raw & Chl Chatsworth Vandalism Oct. 22 .0300 Chl Pacific Palisades Power Failure Oct. 23 2.700 Raw & Chl Jackson Avenue** Storm Water Oct. 25 .0025 Chl South-Central L.A. Blockage Oct. 30 .0250 Raw & Chl Pacific Palisades power outage Oct. 31 4.100 Raw & Chl Jackson Avenue** storm water

Legal Type Date Status* Type May 3 Permitted Div May 25 Violation Div June 5 Permitted Div June 6 Violation Div Violation Spill June 18 Permitted Div July 16 Permitted Div Violation Div July 17 Permitted Div July 23 Violation Div Aug. 5 Permitted Div Aug. 18 Permitted Div Sept. 6 Permitted Spill Sept. 26 Permitted Div Under Invest. Spill Oct. 17 Under Invest. Spill Oct. 22 Under Invest. Spill Oct. 23 Permitted Over Oct. 25 Under Invest. Spill Oct. 30 Under Invest. Spill Oct. 31 Permitted Over

** Jackson Avenue Overflow Structure in Culver City

* Determined by California Regional Water Quality Control

Source: California Regional Water Quality Control Board