Environmental technology (envirotech), green technology (greentech) or clean technology (cleantech) is the application of one or more of environmental science, green chemistry, environmental monitoring and electronic devices to monitor, model and conserve the natural environment and resources, and to curb the negative impacts of human involvement. The term is also used to describe sustainable energy generation technologies such as photovoltaics, wind turbines, etc. Sustainable development is the core of environmental technologies. The term environmental technologies is also used to describe a class of electronic devices that can promote sustainable management of resources.
Main article: Recycling
Water purification: The whole idea/concept of having dirt/germ/pollution free water flowing throughout the environment. Many other phenomena lead from this concept of purification of water. Water pollution is the main enemy of this concept, and various campaigns and activists have been organized around the world to help purify water.
Air purification: Basic and common green plants can be grown indoors to keep the air fresh because all plants remove CO2 and convert it into oxygen. The best examples are: Dypsis lutescens, Sansevieria trifasciata, and Epipremnum aureum. Besides using the plants themselves, some species of bacteria can also be added to the leaves of these plants to help remove toxic gases, such as toluene.
Sewage treatment is conceptually similar to water purification. Sewage treatments are very important as they purify water per levels of pollution. The most polluted water is not used for anything, and the least polluted water is supplied to places where water is used affluently. It may lead to various other concepts of environmental protection, sustainability, etc.
Environmental remediation is the removal of pollutants or contaminants for the general protection of the environment. This is accomplished by various chemical, biological, and bulk methods.
Solid waste management is the purification, consumption, reuse, disposal and treatment of solid waste that is undertaken by the government or the ruling bodies of a city/town.
Main article: Sustainable energy
Concerns over pollution and greenhouse gases have spurred the search for sustainable alternatives to our current fuel use. The global reduction of greenhouse gases requires the adoption of energy conservation as well as sustainable generation. That environmental harm reduction involves global changes such as:
Since fuel used by industry and transportation account for the majority of world demand, by investing in conservation and efficiency (using less fuel), pollution and greenhouse gases from these two sectors can be reduced around the globe. Advanced energy efficient electric motor (and electric generator) technology that are cost effective to encourage their application, such as variable speed generators and efficient energy use, can reduce the amount of carbon dioxide (CO2) and sulfur dioxide (SO2) that would otherwise be introduced to the atmosphere, if electricity were generated using fossil fuels. Greasestock is an event held yearly in Yorktown Heights, New York which is one of the largest showcases of environmental technology in the United States. Some scholars have expressed concern that the implementation of new environmental technologies in highly-developed national economies may cause economic and social disruption in less-developed economies.
Main article: Renewable energy
Renewable energy is the energy that can be replenished easily. For years we have been using sources such as wood, sun, water, etc. for means for producing energy. Energy that can be produced by natural objects like the sun, wind, etc. is considered to be renewable. Technologies that have been in usage include wind power, hydropower, solar energy, geothermal energy, and biomass/bioenergy.
Energy conservation is the utilization of devices that require smaller amounts of energy in order to reduce the consumption of electricity. Reducing the use of electricity causes less fossil fuels to be burned to provide that electricity.
Egain forecasting is a method using forecasting technology to predict the future weather's impact on a building. By adjusting the heat based on the weather forecast, the system eliminates redundant use of heat, thus reducing the energy consumption and the emission of greenhouse gases.
Courses aimed at developing graduates with some specific skills in environmental systems or environmental technology are becoming more common and fall into three broads classes:
((cite web)): CS1 maint: archived copy as title (link) “What is Water Purification”. Retrieved June 16th, 2009,  “Sewage Treatment”. Retrieved June 17th, 2009 "Archived copy". Archived from the original on 2009-03-26. Retrieved 2009-06-24.
((cite web)): CS1 maint: archived copy as title (link) “Environmental Remedies and water Resource