Plant Facts and Figures

The San Jose/Santa Clara Water Pollution Contol Plant (Plant) protects public health and the South San Francisco Bay environment, and is co-owned by the cities of San José and Santa Clara. Upon inception in 1956, the Plant served residents and businesses, mostly canneries at that time. Today, the Plant serves 1.4 million residents and businesses in the cities of San José, Santa Clara, Milpitas, Monte Sereno, Los Gatos, Cupertino, Campbell, and Saratoga. Each day, the Plant discharges 110 million gallons of treated fresh water into the South San Francisco Bay. The water flows from sinks, toilets, showers, dishwashers, washing machines and commercial and industrial processes in regional homes and businesses.

• The Plant averages 120 million gallons of wastewater per day from November through March.
• The Plant discharges 100 to 110 million gallons of treated wastewater per day from April through October.
• The Plant has the capacity to treat 167 million gallons of wastewater per day; the 2007 Wet Weather Reliability Projects accommodates a peak of 400 million gallons of wastewater per day during wet weather periods.
• 10 million gallons of wastewater per day are recycled through South Bay Water Recycling.
• The Plant was named EPA's National Plant of the Year in 2000 based on its operations and maintenance excellence.
• The Plant meets 100 percent of its state and federal water quality and discharge requirements.

Use the links below to view more Plant facts and figures:

Costs
Plant Lands
Sanitary System
Digesters
Drying Beds
State-of-the-Art Laboratory
Engines
Energy
Processing and Infrastructure
Primary Treatment (physical process)
Secondary Treatment (biological process)
Filtration
Water Quality
South Bay Water Recycling

Costs

• Each gallon of water costs two cents to treat.
• The Plant has an estimated $2 billion replacement value.
• Over the next 5 years, about $260 million will be spent to keep the Plant in operating condition.
• Repair and rehabilitation costs over the next 15 to 20 years are estimated at $1 billion.

Plant Lands - Acreage

The Plant property consists of:

• about 2,600 acres.
• about 180 acres is for the treatment plant.
• several hundred acres for current and past biosolids drying beds and lagoons
• about 400 acres of bufferlands.
• about 856-acre Pond A18.

Sanitary System

• There are about 2,200 miles of sanitary sewer pipelines.
• The sewer system has 16 pumping stations and about 35,000 manholes.
• It takes up to 10 hours for wastewater to travel from homes and businesses to the Plant.
• It takes about 18 hours for the Plant to treat wastewater to near drinking water standards.

Digesters

• Digesters were constructed in the original 1956 Plant design.
• The Plant uses an anaerobic digestion process, incorporating oxygen-free bacteria to treat the wastewater.
• Bacteria digest solids from the primary and secondary processes and produce methane gas.
• Digesters are about 98 degrees inside.
• Digesters have floating roofs that move up and down inside the tank.
• The Plant has 16 digesters that each hold about 2 million gallons of wastewater.

Drying Beds

• The drying beds, called lagoons, were constructed in 1956.
• Microorganisms living at a constant temperature in an oxygen-free environment aid solids decomposition. The solids are "stabilized" within about three years.
• The "stabilized" solids are used as daily cover at the nearby Newby Island Landfill. The solids layer prevents wind damage and discourages scavengers.

State-of-the-Art Laboratory

• The 30,000 square-foot laboratory houses state-of-the-art analytical equipment.
• The laboratory monitors the Plant's treatment process around-the-clock.
• 30 professionals, including chemists, biologists, toxicologists, and microbiologists, manage the laboratory. 
• The laboratory researches water quality and watershed issues, and has been a national leader in mercury and nickel research.
• 50,000 analyses are conducted each month. 

Engines

• Three 4,000-horsepower electric motors power blowers that pump air (about 80 thousand cubic feet per minute each) to the aeration basins.
• 15 large engines power generators that produce between seven and eight megawatts of energy each month.
• Two Turbo-Diesel powered generators (16-cylinder and 12-cylinder) are each able to generate 2.8 megawatts of power - enough for about 1,400 homes.

Energy
The treatment process requires energy to move water and sludge, and to aerate the bacteria that treat the water. About two-thirds of the Plant's energy use is supplied by methane gas from the Plant's own digesters, and from the nearby Newby Island Landfill.

• About 35 percent of the Plant's energy needs are met by methane gas produced by the bacteria in the Plant's anaerobic digesters.
• About 25 percent of the Plant's energy needs are met by methane gas produced by the bacteria in the nearby Newby Island Landfill.
• About 40 percent of the Plant's energy needs are met by purchasing natural gas, which is blended with the methane gas.

Processing and Infrastructure

• Water flows from our homes and businesses to the Plant service area by a separate stormwater and sewage system.
• Stormwater is untreated and flows directly to rivers.
• Before being discharged, the Plant treats wastewater for about 18 hours - essentially, an acceleration of the natural process.
• The computer-controlled Plant is operated and maintained around-the-clock by 200 operators, mechanics, electricians, engineers, chemists, biologists, technicians, and support staff.
• Two-thirds of the Plant is underground - there are 4 miles of tunnels.

Primary Treatment (physical process)

• The Plant has 24 primary treatment basins.
• Wastewater spends about 1.5 hours in primary treatment.
• The process removes debris that settle easily, including fats, oils, grease, and lightweight floating material.
• 50 percent of wastewater contaminants are removed in this first step.

Secondary Treatment (biological process)

• The secondary treatment process was constructed in 1964.
• 95 percent of pollutants are removed in this second step.
• The Plant has a total of 40 secondary basins that are each 12 feet deep.
• Secondary treatment is an aerobic, or oxygen-rich, process.
• The aeration process consumes most of the Plant's energy.
• Each one of the 42 clarifiers holds from 1 to 1.5 million gallons of water.
• Water stays in clarifiers for one to three hours.

Filtration

• The Plant's filtration facility was constructed in 1979.
• 99 percent of contaminants are removed in this third step.
• Filtration addresses the need to remove specific "heavy metals," including mercury, nickel, and silver.
• Wastewater is filtered through graded beds of sand and anthracite charcoal.
• Wastewater is disinfected with gaseous chlorine to kill any remaining bacteria.
• Chlorine is neutralized using sulfur dioxide before reaching the outfall channel so it won't harm the Bay's environment and aquatic life.
• Water samples are taken to insure compliance with regulations and permit conditions.

Water Quality

• Biological Oxygen Demand (BOD) assesses how fast biological organisms use up oxygen in a body of water.
• Suspended Solids refers to small particles of solid pollutants that resist separation by conventional methods.
• At the Plant, the BOD is 10 parts per million (ppm) and Suspended Solids are 10 ppm. Plant performance is 2 ppm for both BOD and Suspended Solids.

South Bay Water Recycling

• The $250 million South Bay Water Recycling facility and pipeline was constructed in 1998.
• About 10 million gallons of recycled water per day is sent through more than 100 miles of pipelines to portions of San José, Santa Clara, and Milpitas.
• Recycled water is used by schools, parks, golf courses, and other commercial customers to irrigate landscaping and for other industrial purposes.
• The Metcalf Energy center is the largest recycled water consumer, using the water to cool the power generation facility.