UW Electrical & Computer Engineering


New Haven, IA, June 24, 2008 -- Dozens of home appliances were brought to a lot on Broadway Street when the water began receding from the June 9 flooding of Beaver Creek. Refrigerators, freezers, stoves, water heaters, and other household items sit awaiting the junk man. Photo by Greg Henshall / FEMA

Appliances in WEEE (e-waste)

Appliances are pieces of equipment we use in our day-to-day to life, typically to serve a specific purpose in the home. Items such as washers, dryers, toasters, and vacuum cleaners are all appliances. These items are NOT electronic devices, which are also known as consumer electronics, but instead tend to be larger and perform a specific domestic function such as washing, drying, cooking, etc.  Select one of the appliances below to learn more about what makes up a particular appliance and how the appliance impacts the environment once it reaches the end of its useful life.

Clothes Dryers    |    Microwave Ovens   |    Refrigerators   |    Washing Machines

Clothes Dryers

What’s in a Clothes Dryer?

In general, a clothes dryer contains seven main components, although newer models tend to contain more components that improve overall efficiency.  These six components are the drum, filter, water drain, motor, heating element, electronic controls, and housing. captureThe drum is the main area of the dryer where clothes are processed or dried and most commonly is made from stainless steel.  The filter is typically located near the door of the clothes dryer and captures fibers or lint shed from clothes in order to quicken the drying process.  Filters contain mesh screens which are usually made of polyester or in other cases, stainless steel. Typically found near the bottom of the dryer, the water drain removes excess water from clothes and is often made of metal, usually copper.   The motor is used to rotate the drum in order to dry clothes and is typically made from copper and iron while the heating element, located in the back of the dryer, warms incoming air and is manufactured of metal, typically nichrome (a combination of nickel and chromium).   Finally, electronic controls consist of both sensors and timers that monitor and control the dryer cycle.   Their functions include timing the dry cycle or monitoring the moisture content within the dryer.  As with all electronics, theses controls consist primarily of printed circuit boards, electronic components, connectors (containing copper, gold, and other conductive elements), other plastics, and silicon (in integrated circuits).   Holding all these components together, the dryer housing is often made of stainless steel.


How do Clothes Dryers impact the E-Waste Stream?

Due to their importance within our day-to-day household activities, clothes dryer sales are increasing steadily each year. Close to 5.62 million dryers were shipped in 2015 and this number is expected to increase by 4% or more each year.  A typical clothes dryer lasts anywhere between 10 to 13 years and many are reused, but due to their size, they have a major impact on the volume of the e-waste stream.

How do Clothes Dryers impact the environment?

One of the most immediate environmental impacts of a clothes dryer is in electricity usage in a typical home. The average clothes dryer uses just over 75 kWh of energy per month. Depending on the source of electricity (or gas) used to power a clothes dryer, significant carbon dioxide (CO2) emissions can result. If consumers in the US were to use other methods of drying clothes (such as line drying) as opposed to using a clothes dryer, residential emissions of CO2 could decrease up to 3.3%.


Lint filters in clothes dryers pose a hidden danger to public health.  These filters often containing large amounts of lint, which is flammable, and have the potential to spark a fire. Lint fires can occur in filters left unrecovered in landfills and they can also begin in the home if lint builds up in a clothes dryer whose filter is not cleaned often enough. In the United States, over 15,500 fires and 10 deaths per year are attributed to lint filters in clothes dryers.


The significant volume of metal found in clothes dryers also represents a wasted resource. When disposed of in landfills, much of this metal takes up valuable space but more importantly, if not recycled and reused, leads to more metals than necessary being extracted from mines across the world, diminishing reserves every year.   Recycling clothes dryers to recover scrap metal not only reduces metal volume in landfills but also eases the burden on natural resources.


Lastly, electronic components in a clothes dryer pose the same risk as any other electronic product upon disposal and recycling.  The impacts of e-waste on air, water, and soil as it relates to both ecosystem and human health are discussed in detail here. 

Microwave Ovens

What’s in a Microwave Oven?

Despite the availability of many models, sizes, and prices among microwave ovens, all microwaves consist of the same basic components:  a high voltage transformer, magnetron tube, wave guide, stirrer fan, electronic controls, and the outer frame of the oven.  The high voltage transformer is typically made of insulated copper (or aluminum wire) coils and a core made from steel. It uses multiple capacitors to transform voltage from the power supply (A/C residential outlet power) to the higher voltages necessary for proper microwave operation.  Once the voltage is high enough, it supplies current to the magnetron tube, which consists of a short copper cylinder (containing a metal cathode) and is located to the right within the microwave. The magnetron tube produces microwave energy to heat food.  The energy from the magnetron tube is funneled into the waveguide which directs the energy to the food. The stirrer fan then distributes the resulting energy uniformly within the contents of the microwave.  Both waveguide and stirrer fan are made of metals, typically brass, copper, silver or aluminum.   A variety of electronic controls, including control switches, timers, and relays, allow the user to control the functionality of the microwave oven. Some controls signal the oven to provide power to the transformer while other controls regulate food heating and power level. As with all electronics, theses controls consist primarily of printed circuit boards, electronic components, connectors (containing copper, gold, and other conductive elements), other plastics, and silicon (in integrated circuits).   Keeping all these components together, the microwave oven housing is often made of stainless steel and is designed to ensure that no microwave energy escapes the oven while it is in use. The inside panels and doors are usually made of stainless steel whereas the cooking surface is composed of ceramic or glass.

How do Microwave Ovens impact the E-Waste Stream?

Unlike the other appliances discussed, microwave sales have surprisingly tapered off in the last decade. Sales reached a peak in 2005, with over 15 million units being sold and shipped. Since 2005, the number has now fallen to between 8 and 9 million units every year.  Despite slowing sales, microwaves still make up a large portion of electronic appliance waste. Research from United Nations University found that microwave ovens along with dishwashers and other kitchen/laundry appliances made up over 60% of the 41.8 million tons of electronic waste thrown away globally in 2014. A study conducted by the University of Manchester found that of over 2.5 million microwaves thrown away yearly in the United Kingdom, a vast majority of these appliances just needed simple repairs.

How do Microwave Ovens impact the environment?

Like most other electronic appliances, microwave ovens often end up in landfills at the end of their useful life. Though not as large as other appliances, microwave ovens still present some threats to our environment.


The significant amounts of metal found in microwave ovens represent a wasted resource. When disposed of in landfills, much of this metal takes up valuable space and remains in landfills indefinitely. In order to replace this wasted resource, more metals are extracted from mines across the world, leaving less and less every year.   Thus, proper recycling of microwave ovens is essential to recover scrap metal and reduce metal volume in landfills.


Lastly, electronic components in a microwave oven pose the same risk as any other electronic product upon disposal and recycling.  The impacts of e-waste on air, water, and soil as it relates to both ecosystem and human health are discussed in detail here. 


What’s in a Refrigerator?

In the modern world, refrigerators tend to consist of some basic components: electronic controls, an exterior cabinet including the door, an interior cabinet, insulation between the interior and exterior cabinets, the cooling system, the refrigerant, and the fixtures. The electronic controls contain one or more printed circuit boards (PCBs) that electronically control the refrigerator and are made primarily of fiberglass, copper, and silicon and to a lesser extend gold, tin, and aluminum.  The inner and outer cabinets as well as the door tend to be made of sheet metals consisting of aluminum or steel. The insulation consists of fiberglass or polyfoam, made primarily from a type of plastic called polystyrene.  The fixtures in refrigerators consist mostly of thermoset plastic, which cannot be recycled.


The components in the cooling system consist of the compressor, condenser, evaporator and refrigerant (vapor or fluid).  Liquid refrigerant under high pressure enters into the evaporator (made of aluminum tubes) where it absorbs heat from the inside of the refrigerator (and cools it down in the process).  In the process of absorbing heat, the liquid refrigerant evaporates into a gas and then flows into the compressor (made of steel) where it is compressed into a high pressure gas.   The high pressure refrigerant gas then passes to the condenser (the copper coils outside the refrigerator) and cools back to liquid form.  From the condenser, the liquid refrigerant enters the evaporator and the cooling system cycle starts all over again. Older refrigerators use Freon as the refrigerant, but due to the damage Freon does to the ozone layer, newer refrigerators now use HFC-134a (also known as 1,1,1 2-Tetrafluoroethane) which while not damaging the ozone layer, nevertheless is a potent greenhouse gas.

How do Refrigerators impact the E-Waste Stream?

Since they are so instrumental in keeping food fresh and edible, refrigerators are a standard appliance in almost every American home.  In the U.S. alone, over 8 million refrigerators are purchased each year, with the average lifespan of a typical refrigerator of around 14 years. A typical refrigerator will cost between $400 and $1500. On the other end of the refrigerator’s life cycle, about 2.5 million refrigerators are disposed of every year in the U.S.

How do Refrigerators impact the environment?

Refrigerators can have a tremendous impact on the environment if not disposed of properly. Refrigerant fluid is a significant and unique hazard of improper disposal of refrigerators.   The older refrigerant Freon has a major destructive effect on the ozone layer, and has been banned.  However, it’s replacement HFC -134a is known as a “super” greenhouse gas that has over a thousand times the global warming effect of carbon dioxide.


Refrigerator components can also be damaging to both human health and environment.  For example, many refrigerators use ABS (acrylonitrile butadiene styrene) as the plastic of choice. Like all plastics, these are not biodegradable and like a subset of plastics called thermosets, if burned at low temperatures (which is often done during informal or improper disposal), can release dioxins, furans, and polycyclic aromatic hydrocarbons (PAHs). These toxins have a wide range of negative impacts on both wildlife and human health.  For example, PAHs, cause skin, liver, bladder, and stomach cancers as well as cardiovascular disease and problems in fetal development. Polystyrene, used for foam insulation in some refrigerators, is another plastic that can be hazardous. It is composed of benzene and styrene, both of which are human carcinogens and can cause multiple neurological problems. If improperly disposed, these and other plastics can also end up in the world’s oceans where various forms of marine life can ingest or become entangled in these plastics. Burning polystyrene can also release potentially fatal gases like carbon monoxide and styrene vapors which can damage the central nervous system.


The metals found in refrigerators also represent a wasted resource. With human need for such appliances growing day by day, the natural resources needed to make them are shrinking. Proper recycling of refrigerators can allow for the scrap metal to be reused which will help preserve a limited supply of many metals as well as to help reduce the enormous amount of metal volume that enters into landfills every year.  Like many other appliances, refrigerators also contain electronics which pose the same risk as any other electronic product upon disposal and recycling.  The impacts of e-waste on air, water, and soil as it relates to both ecosystem and human health are discussed in detail here. 


In addition to their resource demands and direct environmental hazards, refrigerators also tend to use a lot of energy. In most homes across the US, refrigerators tend to use the second largest amount of electricity (almost 13.7%) in a typical home, second only to the air conditioner. Older models (those made before 2001) tend to be even more inefficient.  Thus, properly replacing a refrigerator with a more modern refrigerator not only reduces environmental hazards directly but reduces electricity usage and the consequences of producing this energy.


Washing Machines

What’s in a Washing Machine?

A washing machine is comprised of many different parts. Some of the main components are the water pump, the tub, agitator, the motor, housing, and the electronic controls. The water pump is usually made with an aluminum housing and is composed of parts made from steel and iron. It helps to circulate water during the wash cycle and then drains water during the spin cycle. The tub actually refers to two types of tubs; the inner and outer, both of which are made of stainless steel. The inner tub is what we see when we open a washer. It contains many small holes to let water come through during the wash cycle. The outer tub, on the other hand, is what holds the water for the inner tub and is completely water tight. The agitator is responsible for the cleaning operations and is composed of hardened plastic and metals such as copper or steel. It rotates in order to produce a strong rotating current of water which helps clothes to shed dirt and become clean (some washing machines may use discs in place of the agitator). The motor is usually joined with the agitator (or disc), and is what produces rotation needed to wash the clothes. The raw materials used in motors usually consist of copper or iron. The electronic controls include the timers, relays and water temperature controllers.  As with all electronics, theses controls consist primarily of printed circuit boards, electronic components, connectors (containing copper, gold, and other conductive elements), other plastics, and silicon (in integrated circuits).  The other parts in a washing machine include the hoses and water leakage insulators, which are composed of rubber and plastic. All of these components are in enclosed and kept together in a stainless steel housing.

How do Washing Machines impact the E-Waste Stream?

Close to 9 million washers are sold each year in the United States alone, with the average washing machine lasting 11 years. Machines made post-2005 use a lot less water (around 27 gallons per load) than older machines (around 40 gallons per load) and also consume less electricity. With the average household in the US doing 300 loads a year, the difference in water consumption between old and new technologies is tremendous.


How do Washing Machines impact the environment?

The multiple metals used in washing machines, including copper and aluminum, are all mined on a large scale and like other large appliances, represent a significant volume when disposed of in a landfill and an unnecessary waste of resources.  If metal recycling does not increasingly replace disposal of these metals, the earth will face a dwindling of these natural resources which in turn will stimulate political/social tension down the road. Proper recycling of appliances such as washing machines can help preserve these important resources as well as reduce the amount of metal volume in landfills.

While metals have a negative impact on land usage, the plastics used in washing machines and other appliances can have a more profound impact on ecosystem and human health if improperly handled outside of a regulated landfill environment.  While incineration at regulated landfills is at high enough temperatures to avoid the emission of toxic fumes, burning of plastics outside of the landfill in the backyard or in informal e-waste recycling facilities has serious consequences to air quality and health.   Low temperature burning of hard plastics that don’t melt releases a range of toxic fumes including but not limited to dioxins and furans which are the most toxic substances in the world.


The electronics in washing machines, while a small percentage of the overall appliance volume nevertheless have similar impacts to many other electronic devices when e-waste is improperly or illegally dumped or recycled informally without properly regulated handling facilities.  The impacts of e-waste on air, water, and soil as it relates to both ecosystem and human health are discussed in detail here. 

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© 2016 Denise Wilson