In this division, engineers and scientists assess the impacts of a proposed project on environmental conditions. They apply scientific and engineering principles to evaluate if there are likely to be any adverse impacts on water quality, air quality, habitat quality, flora and fauna, and agricultural capacity and to study traffic impacts, social impacts, ecological impacts, noise impacts, visual impacts, etc. If impacts are expected, then they develop mitigation measures to limit or prevent such impacts. An example of a mitigation measure is the creation of wetlands in a nearby location to mitigate the filling in of wetlands necessary for road development if it is not possible to reroute the road.
Water supply and treatment
Engineers and scientists work to secure water supplies for potable and agricultural use. They evaluate the water balance within a watershed and determine the available water supply, the water needed for various needs in that watershed and the seasonal cycles of water movement through the watershed, and develop systems to store, treat and convey water for various uses. Water is treated to achieve water quality objectives for the end uses. In the case of potable water supply, water is treated to minimize the risk of infectious disease transmittal and the risk of non-infectious illness, and to create a palatable water flavour. Water distribution systems are designed and built to provide adequate water pressure and flow rates to meet various end-user needs such as domestic use, fire suppression and irrigation.
Wastewater conveyance and treatment
Most urban and many rural areas no longer discharge human waste directly to the land through outhouses, septic systems and honey bucket systems, but rather deposit such waste into water and convey it from households via sewer systems. Engineers and scientists develop collection and treatment systems to carry this waste material away from where people live and produce the waste and discharge it into the environment. In developed countries, substantial resources are applied to the treatment and detoxification of this waste before it is discharged into a river, lake or ocean system. Developing nations are striving to obtain the resources to develop such systems so that they can improve the water quality of their surface waters and reduce the risk of water-borne infectious diseases.
There are numerous wastewater treatment technologies. A wastewater treatment train can consist of a primary clarifier system to remove solid and floating materials, a secondary treatment system consisting of an aeration basin followed by flocculation and sedimentation basins or an activated sludge system and a secondary clarifier, and a tertiary biological nitrogen removal system for a final disinfection process. The aeration basin/activated sludge system removes organic material by growing bacteria. The secondary clarifier removes the activated sludge from the water. The tertiary system, although not always included due to costs, is becoming more prevalent to remove nitrogen and phosphorus and to disinfect the water before discharge to a surface water stream or ocean outfall.
Air quality management
Engineers apply scientific and engineering principles to the design of manufacturing and combustion processes to reduce air pollutant emissions to acceptable levels. Scrubbers, electrostatic precipitators, catalytic converters and various other processes are utilized to remove particulate matter, nitrogen oxides, sulphur oxides, volatile organic compounds (VOC), reactive organic gases (ROG) and other air pollutants from flue gases and other sources prior to allowing their emission into the atmosphere. Scientists have developed air pollution dispersion models to evaluate the concentration of a pollutant at a receptor or the impact on overall air quality from vehicle exhausts and industrial flue gas stack emissions. To some extent, this field overlaps the desire to decrease carbon dioxide and other greenhouse gas emissions from combustion processes.
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