Environmental engineering

Environmental engineering is a broad science devoted to remediation of all forms of pollution. Much of it deals with preventing pollution by application of civil engineering and chemical engineering principles to destroy or remove the pollutants before they get into the natural environment (air, water and land resources).

A formal definition of environmental engineering might be that it is a field in which one applies the basic fundamentals of mathematics, physics, chemistry and biology to the protection of human health and the natural environment.

Environmental engineering work areas

Environmental engineering involves wastewater management and treatment, air pollution control, recycling, solid waste disposal, radiation protection and public health issues. It also includes studies on the environmental impact of proposed construction projects.

Environmental engineers perform hazardous-waste management studies to evaluate the impact of such hazards, advise on their treatment and containment, and develop regulations to prevent hazardous waste problems. Environmental engineers also design municipal water supply and industrial wastewater treatment systems as well as being concerned with issues such as the effects of acid rain, ozone depletion, water pollution and air pollution from automobile exhausts and industrial sources.

At many universities, Environmental Engineering programs are offered within either the Department of Civil Engineering or the Department of Chemical Engineering. Environmental "civil" engineering programs focus on hydrology, water resources management, bioremediation, and water treatment plant design. Environmental "chemical" engineering programs, on the other hand, focus on environmental chemistry, advanced air and water treatment technologies and separation processes.

The working definition of environmental engineering has been broadened over the past few years to encompass drainage and hydrology design work and the development of drainage plans and stream flow and flood zones from developed areas. Part of this expansion also involves the restoration and remediation of various types of contaminated environments including soils and waterways.

History of environmental engineering

Many ancient civilizations constructed sewer systems in some cities. The Romans constructed aqueducts to prevent drought and to provide a clean supply of water for the city of Rome. In the 15th century, Bavaria restricted the development and degradation of the alpine countryside that was the region's source of water.

Modern environmental engineering began in London in the mid-19th century with the construction of a major sewer network for central London which was instrumental in relieving the city from cholera epidemics, while beginning the cleansing of the Thames river.

The field began to emerge as a separate engineering discipline during the middle the 20th century in response to widespread public concern about water and pollution and increasingly extensive degradation of the natural environment. The introduction of drinking water treatment and sewage treatment in industrialized countries reduced waterborne disease deaths to relative rarities.

In many cases, as societies grew, actions were undertaken to achieve certain environmental benefits which had longer-term impacts that reduced other environmental qualities. A major example was the widespread application of DDT to control agricultural pests in the years following World War II. While agricultural crop yields increased dramatically, thus reducing world hunger substantially and controlling the incidence of malaria better than it had ever been, the effect of DDT on the reproductive systems of numerous species resulted in bringing those species almost to the brink of extinction. The story of DDT as related in Rachel Carson's "Silent Spring" is considered to be the beginning of the modern environmental movement and the development of the modern field of environmental engineering.

Example applications

A good example is the control of air pollution from combustion sources such as the flue gases from the combustion of fuels in furnaces where special burner designs are used to remove nitrogen oxides and flue gas desulfurization systems are used to remove sulfur dioxide from the combustion flue gases. Currently, a great deal of research and development is being devoted to the removal, capture and disposal of carbon dioxide from flue gases.

Water pollution control relies heavily on chemistry, microbiology, biology, chemical engineering and civil engineering. In some cases, as little as 0.0001% or less of a noxious substance can contaminate a resource such as water. For example, sewage contamination of 10 parts per million (1% = 10,000 ppm) can contaminate a water resource such as a lake. The maintenance of drinking water quality is even more restrictive because the limits of many contaminants are significantly less than one part per billion (one part per billion is the equivalent of one second in 31.688 years, or 31 years, 8.5 months).