Environmental engineering encompasses a wide range of disciplines, including pollution control, sustainable technology development, and environmental impact assessment, with the ultimate goal of protecting and preserving the environment.

Oxygen is not an air pollutant, as it is a vital component of the Earth's atmosphere and is necessary for life.

Water treatment is the process of removing contaminants and impurities from wastewater to make it safe for discharge or reuse.

Hydropower is a renewable energy source that generates electricity from the energy of flowing water.

Recycling is the process of converting waste materials into new materials and objects, reducing the amount of waste sent to landfills.

Carbon dioxide is a greenhouse gas that traps heat in the Earth's atmosphere, contributing to global warming.

Maximum contaminant level (MCL) is the maximum allowable concentration of a pollutant in drinking water set by regulatory agencies to protect public health.

Electrostatic precipitators, catalytic converters, and scrubbers are all common methods used to control air pollution from industrial sources.

Nitrification, denitrification, and phosphate removal are all processes used to remove excess nutrients from wastewater.

Green building, passive house, and net-zero energy building are all types of sustainable building design that aim to minimize environmental impact.

Environmental impact assessment is the process of assessing the environmental impact of a proposed project or activity.

Drip irrigation is a water-efficient irrigation method that delivers water directly to the roots of plants, reducing water loss through evaporation and runoff.

Anaerobic digestion is the process of converting organic waste into biogas, a mixture of methane and carbon dioxide, in the absence of oxygen.

Contour plowing, terracing, and reforestation are all common methods used to control soil erosion.

Water resources management is the process of managing and protecting water resources to ensure their sustainable use.