Wastewater Treatment Facility Switches to LEDs, Cuts Energy Use 50%


The city of Santa Cruz, Calif,. wastewater treatment facility, which processes an average daily flow of 10 million gallons, has reduced its lighting energy use and cost by more than 50 percent.

The facility recently upgraded its exterior and site lighting from high-pressure sodium (HPS) and mercury vapor (MV) fixtures to LED fixtures in an effort to reduce energy use and improve visibility. The HPS and MV fixtures required constant maintenance, generated poor light quality and were more expensive to operate.

The lighting upgrade project, which took five days to complete the installation, is expected to pay for itself in a little more than three years through efficiency improvements, reduced maintenance costs and a local incentive that provided a $5,000 rebate based on energy savings.

The LED lights are expected to last more than 10 years. LED fixtures draw, on average, less than half the wattage of high pressure sodium and mercury vapor.

The lighting upgrade is part of a citywide Climate Action Program to reduce energy use. The wastewater treatment facility replaced 82 fixtures in its solids dewatering building, pre-aeration and tricking filters with LED fixtures.

8 LED Factoids You May Not Know


1. In 2012, about 49 million LEDs were installed in the U.S. — saving about $675 million in annual energy costs. Switching entirely to LED lights over the next two decades could save the U.S. $250 billion in energy costs, reduce electricity consumption for lighting by nearly 50 percent and avoid 1,800 million metric tons of carbon emissions.

2. The first visible-spectrum LED was invented by Nick Holonyak, Jr., while working for GE in 1962. Since then, the technology has rapidly advanced and costs have dropped tremendously, making LEDs a viable lighting solution. Between 2011 and 2012, global sales of LED replacement bulbs increased by 22 percent while the cost of a 60-watt equivalent LED bulb fell by nearly 40 percent. By 2030, it’s estimated that LEDs will account for 75 percent of all lighting sales.

3. Since the Energy Department started funding solid-state lighting R&D in 2000, these projects have received 58 patents. Some of the most successful projects include developing new ways to use materials, extract more light, and solve the underlying technical challenges. Most recently, the Energy Department announced five new projects that will focus on cutting costs by improving manufacturing equipment and processes.

4. LEDs contain no mercury, and a recent Energy Department study determined that LEDs have a much smaller environmental impact than incandescent bulbs. They also have an edge over compact fluorescent lights (CFLs) that’s expected to grow over the next few years as LED technology continues its steady improvement.

5. From traffic lights and vehicle brake lights to TVs and display cases, LEDs are used in a wide range of applications because of their unique characteristics, which include compact size, ease of maintenance, resistance to breakage, and the ability to focus the light in a single direction instead of having it go every which way.

6. Unlike incandescent bulbs — which release 90 percent of their energy as heat — LEDs use energy far more efficiently with little wasted heat.

7. Good-quality LED bulbs can have a useful life of 25,000 hours or more — meaning they can last more than 25 times longer than traditional light bulbs. That is a life of more than three years if run 24 hours a day, seven days a week.

8. A light-emitting diode, or LED, is a type of solid-state lighting that uses a semiconductor to convert electricity into light. Today’s LED bulbs can be six-seven times more energy efficient than conventional incandescent lights and cut energy use by more than 80 percent.