Donald C. Tillman Reclamation Plant


            6100 Woodley Avenue, Van Nuys



PicasaWeb Slideshow

Topics Addressed

Microbiology.  Chemistry.


                6. Solutions are homogeneous mixtures of two or more substances. As a basis for    
                understanding this concept:
                    a. Students know the definitions of solute and solvent.
                    b. Students know how to describe the dissolving process at the molecular level by
                    using the concept of random molecular motion.
                    c. Students know temperature, pressure, and surface area affect the dissolving process.
                    d. Students know how to calculate the concentration of a solute in terms of grams per
                    liter, molarity, parts per million, and percent composition.
                    e.* Students know the relationship between the molality of a solute in a solution and
                    the solution’s depressed freezing point or elevated boiling point.
                    f.* Students know how molecules in a solution are separated or purified by the methods
                    of chromatography and distillation.

Description of the field trip

This fieldtrip will expose students to the process of a water reclamation plant.

Study Guide (can also be accessed at the bottom of the page)

Donald C. Tillman Water Reclamation Plant Study Guide

How many gallons of water are treated every day?
What occurs in the primary treatment?
What is RAS?
Why are bacteria added to the aeration tanks?
What is added in the tertiary treatment?
Where is some of the treated water used?
Where is the treated water sent to after it is reclaimed?
How is the water disinfected?
What are some interesting facts about the plant?
What is located next to the plant?

References and Links


The Additional Valley Outfall Relief Sewer and East Valley Interceptor Sewer carry wastewater to Tillman from about 70% of the San Fernando Valley. The plant can treat up to 80 million gallons per day. About 40% of the 80 million gallon daily flow comes from commercial uses and 60% from residences.

Grit Removal

Wastewater from the main sewer lines flow through grit channels where sand, rocks and grit are removed. These items settle to the bottom of the grit channels by gravity and centrifugal force.

Influent Pumping Facility

After grit removal, the wastewater is lifted 30-feet by eight large-diameter screw pumps to the screening facility in the Headworks building. Screw pumps are more energy efficient than centrifugal or other types of pumps. The wastewater then flows by gravity through all the remaining treatment processes at the Plant.


At the Headworks, bars and screens remove the largest solids – such as branches, plastics, and rags. Screening, along with grit removal, is called preliminary treatment.

Primary treatment – taking out the sludge

Most of the solids (sludge) are removed here after they settle to the bottom of the covered primary tanks. All of the primary sludge flows back into the main sewer system where it is sent to the Hyperion Treatment Plant for further processing. The remaining wastewater then flows by gravity to the secondary treatment system for further treatment. The primary tanks are covered to reduce odors.

Secondary Treatment – Aeration Tanks

Bacteria are added to the aeration tanks for the nitrification-denitrification process. The bacteria feed off the organic wastes in the wastewater. Oxygen is added in the nitrification process to speed up the bacteria’s rate of decomposition. The nitrification-denitrification process reduces the amount of nitrogen in the plant’s effluent. The wastewater, rich in activated sludge, then flows to the secondary clarifiers.

Secondary Treatment – Clarifiers

The second stage of secondary treatment involves the settling of activated sludge by gravity in the final settling tanks, or secondary clarifiers. A portion of this settled activated sludge is returned to the aeration tanks (returned activated sludge, or RAS) to maintain biological equilibrium in the aeration tank, while the remaining portion is discharged/ wasted (waste activated sludge, or WAS) to the sewer. All of the waste activated sludge flows to the Hyperion Treatment Plant for further processing.

Tertiary Treatment

After secondary treatment, the wastewater flows through shallow-bed sand filters to remove any remaining solids. To improve filtering, a polymer is used as a coagulant to increase the size of the remaining solids.


Disinfection is a two-step process. Liquid bleach (sodium hypochlorite) is added to the wastewater, which kills any remaining pathogens or disease-carrying organisms. The chlorine-containing water remains in the last set of holding tanks at the plant for about two hours The water is then dechlorinated (with sodium bisulfite) to protect fish and other aquatic wildlife. The treated water is then reclaimed to one of three lakes, used onsite, or discharged directly to the Los Angeles River.

Water Reclamation

Over 25 million gallons per day of reclaimed water is produced at DCT. About 2.5 million gallons per day are recycled at the plant for treatment processes, landscape irrigation, cooling of plant equipment, air conditioning, and other applications. Over 23 million gallons per day are recycled to the three nearby lakes, the Japanese Garden Lake, the Wildlife Lake and the Balboa Recreation Lake. The remainder of the Plant’s treated water is discharged directly to the Los Angeles River. The plant’s discharge, combined with the outfall from the three lakes, provides a minimum of 20 million gallons per day to the Los Angeles River for support of the river’s riparian habitat.

Donald C. Tillman
Water Reclamation Plant

About our plant

The Donald C. Tillman Water Reclamation Plant combines advanced wastewater treatment technology with the beauty and tranquility of its landscaped gardens. The Japanese gardens are irrigated with reclaimed water from the plant and are open to the public on a year round basis.

The plant provides reclaimed water to many users in the San Fernando Valley and the Department of Public Works is collaborating with other City departments to expand this program.


The Donald C. Tillman Water Reclamation Plant began continuous operation in 1985. Its facilities were designed to treat 40 million gallons of wastewater per day and serve the area between Chatsworth and Van Nuys in western portion of the San Fernando Valley. The plant was named after Mr. Tillman, who was the City Engineer from 1972 to 1980.

A major construction project that doubled the capacity of DCT was completed in 1991 – expanding the plant from 40 MGD to 80 MGD.

The Tillman Plant, together with the Los Angeles-Glendale Water Reclamation Plant are the leading producers of reclaimed water in the San Fernando Valley. The plant is able to provide critical hydraulic relief to the City’s major sewers downstream, which badly need the additional capacity to serve other portions of the city south of the Valley.

At a glance:


6100 Woodley Avenue, Van Nuys


Western San Fernando Valley

Started operating


Plant manager

Hiddo Netto

Number of employees


Annual budget

$16.0 million

Treatment processes

Tertiary Treatment

Reuse data

26 million gallons of water recycled per day

Contact us:

818-778-4138, or email JOHN.MAYS@LACITY.ORG

Report Sewer ODORS
Report Sewer SPILLS   Or CALL 311, or (213) 473-3231
More information: (213) 978-0333,
or email
City of Los AngelesDepartment of Public Works
Copyright and Disclaimer
Norman Herr,
Nov 4, 2009, 8:25 PM