M5.7 Sewage Facilities

In all of San Diego, there is only ONE sewage facility called Point Loma Wastewater Treatment Plant. Over 175 million gallons of waste is gathered from 2.2 million residents are collected and treated daily. While it is currently meeting state and federal regulations, San Diego is reported to have multiple sewage spills over the last five years due to old sewage systems and faulty pipes. As a result, there are frequently problems caused to the nearby water sources and fish.

The wastewater is treated through five steps - preliminary, primary, advanced primary, secondary and tertiary.

• Preliminary: screening sewage to remove inorganic material (wood, plastic, cloth, sand, gravel & grit)
• Primary: process suspended organic solids to produce sludge (sedimentation basins)
• Advanced Primary: add chemicals to sedimentation basin to allow small organic particles to settle
• Secondary: add bacteria to break down organic solids ("activated sludge")
• Tertiary: remove suspended solids, filter with sand or anthracite coal