Where the Water Goes : Purifying the Valley’s Waste Water

What goes around comes around, in the realm of San Fernando Valley waste water. A flush of the toilet in Tarzana or the water from a shower in Sylmar may end up floating dinghies in Lake Balboa or nourishing the exotic plants in the Japanese Gardens, both of which are part of the Sepulveda Basin. After leaving homes and businesses, most Valley waste water travels along some of the system’s 6,400 miles of sewers on its way to the Donald C. Tillman Water Reclamation Plant. There, after approximately 11 hours of treatment, it is ready to be reused. Before Lake Balboa opened last year, most of the treated waste water ended up flowing down the Los Angeles River to the harbor. Now the water refills the lake. Other uses under consideration include irrigating nearby golf courses and making the water clean enough to drink by pumping it into the Valley’s underground aquifer for natural filtration.

Tillman is one of four waste-water treatment plants operated by the Los Angeles Bureau of Sanitation. Together they treat waste produced by 4 million people in a 600-square-mile area. The p1818324596544175208 - House: A family of four produces an average of 281 gallons of waste water daily.

- Street sewer lines lead to main lines in the west and northeast areas of the Valley that feed into Tillman.

- About half of the treated water is pumped to Lake Balboa, Japanese Garden and a wildlife lake; the rest flows to the L.A. River.

- Solid waste piped to Hyperion Treatment Plant in El Segundo; after more processing it is used as fertilizer in Arizona and the Antelope Valley or burned as fuel to run the treatment plant772407297

Reclamation Process

Typically, 0.05 to 0.1% of waste water is organic and inorganic materials. The Tillman plant removes more than 65 tons of such debris daily.

1. Grit, or inorganic material, settles and is removed.

2. Water is pumped up 30 feet to a comb-like screen; anything larger than 3/4 inch is caught. 3. It takees two hours for screened waste water to flow through tanks; sludge settles and scu1830839916 4. Sludge to Hyperion.

5. Effluent to aeration basin, where living microorganisms feed on organic pollutants. Air bubbling up from below mixes the pollutants and microorganisms and supplies oxygen.

6. Fattened microorganisms settle and are returned to the aeration basin to start the process again. Excess organisms are pumped to Hyperion.

7. Chemicals added to aid in the formation of particles large enough to be washed through sand filters.

8. Remaining solids removed.

9. Chlorine disinfectant added.

10. Chlorine removed by sulfur dioxide solution.

*

Sources: Los Angeles Dept. of Public Works, Donald C. Tillman Water Reclamation Plant