Environmental engineering is a type of engineering that works with environmental science. It uses knowledge from many areas, such as chemistry, biology, ecology, geology, hydraulics, hydrology, microbiology, and mathematics, to create solutions that help protect and improve the health of living things and the environment. Environmental engineering is a part of both civil engineering and chemical engineering. In civil engineering, environmental engineering focuses mainly on sanitation, which involves managing waste and ensuring clean water.

Environmental engineering uses science and engineering to improve and keep the environment healthy. This helps protect human health, preserve natural ecosystems, and improve the quality of life for people. Environmental engineers create solutions for managing wastewater, controlling water and air pollution, recycling materials, and safely disposing of waste. They design systems for clean water supply and industrial wastewater treatment. They also plan ways to prevent diseases spread by water and improve sanitation in cities, rural areas, and recreational spaces. These engineers study how to handle dangerous waste, assess the risks it poses, suggest ways to treat or contain it, and help create rules to prevent accidents. They also apply environmental laws, such as checking how new construction projects might affect the environment.

Environmental engineers study how technology affects the environment. They work on problems like acid rain, global warming, thinning of the ozone layer, water pollution, and air pollution from cars and factories.

Most places require environmental engineers to be licensed or registered to work professionally.

Etymology

The word environmental comes from the French word environ, which means to surround or include. In 1827, the writer Thomas Carlyle used the word environment to describe all the conditions in which a person or thing lives. Later, in 1956, the word environment was used in a new way, related to ecology, the scientific study of how living things interact with their surroundings.

The word engineer has roots in Latin and was used in 14th-century French as engignour, meaning someone who builds military machines like trebuchets, harquebuses, longbows, cannons, catapults, ballistas, stirrups, armor, and other weapons. The word engineer began to mean someone who designs public works, such as roads or bridges, in the 16th century. This meaning became widely known during the time of John Smeaton.

History

Environmental engineering has been practiced since early civilizations when people learned to change the environment to meet their needs. As people realized that their health depended on the quality of their surroundings, they created systems to improve their environment. The ancient Indus Valley Civilization (3300 B.C.E. to 1300 B.C.E.) had advanced water management systems. Public structures at their sites included wells, public baths, water storage tanks, a drinking water system, and a city-wide sewage collection system. They also built an early canal irrigation system to support large-scale farming.

Between 4000 and 2000 B.C.E., many civilizations developed drainage systems and some had sanitation facilities, including the Mesopotamian Empire, Mohenjo-Daro, Egypt, Crete, and the Orkney Islands in Scotland. The Greeks also built aqueducts and sewer systems that used rainwater and wastewater to irrigate and fertilize fields.

The first aqueduct in Rome was built in 312 B.C.E., and the Romans continued constructing aqueducts for irrigation and safe water supply during droughts. They also created an underground sewer system as early as the 7th century B.C.E., which drained into the Tiber River, turning marshes into farmland and removing sewage from the city.

Little progress occurred until the 19th century, when efforts to improve public health in crowded cities increased. Modern environmental engineering began in London in the mid-19th century when Joseph Bazalgette designed the first major sewer system after the Great Stink. At the time, the River Thames provided most of the city’s drinking water, but it also carried raw sewage, leading to cholera outbreaks. Treating drinking water and sewage in industrialized countries later reduced waterborne diseases to rare events.

Environmental engineering became a separate academic field in the mid-20th century due to public concern about pollution and environmental damage. As society and technology grew more complex, they caused unintended harm to the environment. For example, the widespread use of the pesticide DDT after World War II led to environmental issues. Rachel Carson’s book Silent Spring (1962) highlighted these problems and is seen as the start of the modern environmental movement, which led to the development of environmental engineering as a discipline.

As human populations grew and impacted the environment more, environmental engineering focused on solving major global challenges. Five key areas where environmental engineers can make a positive impact include:

• Providing food, water, and energy in a sustainable way
• Reducing climate change and adapting to its effects
• Creating a future with no pollution or waste
• Designing cities that are efficient, healthy, and resilient
• Helping people make informed decisions about the environment

A sixth challenge, educating future workers, was also identified.

Building on these ideas, Daniel B. Oerther and others defined Environmental Engineering 3.0 as addressing "the health, safety, and welfare of the public, as well as the health of the planet." Modern environmental engineering combines engineering fields to solve problems related to the planet’s health.

Education

Many universities provide environmental engineering programs through civil engineering or chemical engineering departments. These programs may include electronic projects to help manage and improve environmental conditions. Environmental engineers in civil engineering programs often study hydrology, managing water resources, cleaning polluted areas (bioremediation), and designing systems for treating water and wastewater. Engineers in chemical engineering programs usually focus on environmental chemistry, advanced methods for cleaning air and water, and processes that separate substances. Some areas within environmental engineering include managing natural resources and engineering related to agriculture.

Students take courses in several main areas:

• Mechanical engineering classes that teach how to build machines used in environmental projects like water treatment plants, pumping stations, garbage sorting facilities, and other mechanical systems.
• Environmental engineering or environmental systems classes that focus on creating structures and landscapes that work with or protect the environment.
• Environmental chemistry, sustainable chemistry, or environmental chemical engineering classes that teach about how chemicals affect the environment, including processes in mining, pollution, and chemical reactions in nature.
• Environmental technology classes that train students to create electronic or electrical tools that monitor, measure, and control environmental effects, such as managing energy from renewable sources like wind or solar power.

A typical environmental engineering curriculum includes the following topics:

• How substances and energy move in the environment.
• Environmental chemistry, including inorganic, organic, and nuclear chemistry.
• Models for population growth, resource use, and economic development.
• Evaluating risks, identifying dangers, and assessing how people are exposed to harmful substances.
• Water pollution, sources of water pollution, how pollutants move, and methods for treating water and wastewater.
• Air pollution, including emissions from industries, transportation, and homes; types of harmful air pollutants; modeling pollution spread; and controlling air pollution.
• Changes in the global environment, such as the greenhouse effect, changes in Earth's temperature, and how carbon, nitrogen, and oxygen cycles work. This also includes effects of climate change on oceans and the atmosphere.
• Managing solid waste and recovering resources, including evaluating the environmental impact of products, reducing waste, collecting and transporting waste, recycling, converting waste to energy, and managing landfills.

Applications

Environmental engineers study the water balance in a watershed to understand how much water is available, how much is needed for different uses, and how water moves through the area during different seasons. They also create systems to store, clean, and transport water for uses like drinking, farming, and firefighting.

Water is cleaned to meet quality standards for its intended use. For drinking water, cleaning helps reduce the risk of illness and ensures the water tastes good. Water distribution systems are built to provide enough water pressure and flow for homes, fire hydrants, and crops.

Wastewater treatment involves several steps. A primary clarifier removes solid and floating materials. A secondary treatment uses an aeration tank and activated sludge to break down organic waste, followed by a secondary clarifier to separate the sludge from water. A tertiary system may be added to remove nitrogen and phosphorus and disinfect water before it is released into rivers or oceans.

Scientists use models to predict how air pollution spreads from sources like car exhaust or factory smokestacks. These models help assess how pollution affects air quality and relate to efforts to reduce greenhouse gases from burning fuels.

Environmental engineers use science and engineering to check if projects might harm water quality, air quality, wildlife, plants, farmland, traffic, ecosystems, or noise levels. If harm is expected, they create plans to reduce or prevent it. For example, building wetlands nearby might help balance the loss of wetlands needed for a road project.

In the United States, the National Environmental Policy Act (NEPA) was officially used starting January 1, 1970. This law requires federal agencies to consider environmental impacts of their actions. Since then, over 100 countries have created similar laws or adopted practices from other nations.

Regulatory agencies

The U.S. Environmental Protection Agency (EPA) works with environmental engineers to solve important problems. A key part of the EPA's job is to protect and improve air, water, and the environment's quality to stop or reduce the harmful effects that could cause damage.