2018年9月26日星期三

Environmental engineering

Environmental engineering system is the branch of engineering concerned with the application of scientific and engineering principles for protection of human populations from the effects of adverse environmental factors; protection of environments, both local and global, from potentially deleterious effects of natural and human activities; and improvement of environmental quality.

Environmental engineering system can also be described as a branch of applied science and technology that addresses the issues of energy preservation, protection of assets and control of waste from human and animal activities. Furthermore, it is concerned with finding plausible solutions in the field of public health, such as waterborne diseases, implementing laws which promote adequate sanitation in urban, rural and recreational areas. It involves waste water management, air pollution control, recycling, waste disposal, radiation protection, industrial hygiene, animal agriculture, environmental sustainability, public health and environmental engineering law. It also includes studies on the environmental impact of proposed construction projects.

Environmental engineers system study the effect of technological advances on the environment. To do so, they conduct studies on hazardous-waste management to evaluate the significance of such hazards, advise on treatment and containment, and develop regulations to prevent mishaps. Environmental engineers design municipal water supply and industrial wastewater treatment systems. They address local and worldwide environmental issues such as the effects of acid rain, global warming, ozone depletion, water pollution and air pollution from automobile exhausts and industrial sources.

Many universities offer environmental engineering programs at either the department of civil engineering or the department of chemical engineering at engineering faculties. Environmental "civil" engineers focus on hydrology, water resources management, bioremediation, and water treatment plant design. Environmental "chemical" engineers, on the other hand, focus on environmental chemistry, advanced air and water treatment technologies and separation processes. Some subdivision of environmental engineering include natural resources engineering and agricultural engineering.

More engineers are obtaining specialized training in law (J.D.) and are utilizing their technical expertise in the practices of environmental engineering law.

Most jurisdictions also impose licensing and registration requirements.

Development
Ever since people first recognized that their health is related to the quality of their environment, they have applied principles to attempt to improve the quality of their environment. The ancient Indian Harappan civilization utilized early sewers in some cities more than 5000 years ago. More specifically, the Indus Valley Civilization (also called the Harappan civilization) had advanced control over the water in their society. The public work structures found at various sites in the area include wells, public baths, storage tanks, a drinking water system, and a city-wide sewage collection system. They also had an early version of a canal irrigation system that was needed for their large scale agriculture. The Romans constructed aqueducts to prevent drought and to create a clean, healthful water supply for the metropolis of Rome. In the 15th century, Bavaria created laws restricting the development and degradation of alpine country that constituted the region's water supply.

The field emerged as a separate environmental discipline during the middle third of the 20th century in response to widespread public concern about water and pollution and increasingly extensive environmental quality degradation. However, its roots extend back to early efforts in public health engineering. Modern environmental engineering began in London in the mid-19th century when Joseph Bazalgette designed the first major sewerage system that reduced the incidence of waterborne diseases such as cholera. The introduction of drinking water treatment and sewage treatment in industrialized countries reduced waterborne diseases from leading causes of death to rarities.

In many cases, as societies grew, actions that were intended to achieve benefits for those societies had longer-term impacts which reduced other environmental qualities. One example is the widespread application of the pesticide DDT to control agricultural pests in the years following World War II. While the agricultural benefits were outstanding and crop yields increased dramatically thus reducing world hunger substantially, and malaria was controlled better than it ever had been, numerous species were brought to the verge of extinction due to the impact of the DDT on their reproductive cycles. The story of DDT as vividly told in Rachel Carson's Silent Spring (1962) is considered to be the birth of the modern environmental movement and of the modern field of "environmental engineering."

Conservation movements and laws restricting public actions that would harm the environment have been developed by various societies for millennia. Notable examples are the laws decreeing the construction of sewers in London and Paris in the 19th century and the creation of the U.S. national park system in the early 20th century.

Scope
The following topics typically make up a curriculum in environmental engineering:

1.Mass and Energy transfer

2.Environmental chemistry
Inorganic chemistry
Organic Chemistry
Nuclear Chemistry

3.Growth models
Resource consumption
Population growth
Economic growth

4.Risk assessment
Hazard identification
Dose-response Assessment
Exposure assessment
Risk characterization
Comparative risk analysis

5.Water pollution
Water resources and pollutants
Oxygen demand
Pollutant transport
Water and waste water treatment

6.Air pollution
industry, transportation, commercial and residential emissions
Criteria and toxic air pollutants
Pollution modelling (e.g. Atmospheric dispersion modeling)
Pollution control
Air pollution and meteorology

7.Global change
Greenhouse effect and global temperature
Carbon, nitrogen, and oxygen cycle
IPCC emissions scenarios
Oceanic changes (ocean acidification, other effects of global warming on oceans) and changes in the stratosphere (see Physical_impacts_of_climate_change)

8.Solid waste management and resource recovery
Life cycle assessment
Source reduction
Collection and transfer operations
Recycling
Waste-to-energy conversion
Landfill

Environmental impact assessment and mitigation
Scientists have 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. They apply scientific and engineering principles to evaluate if there are likely to be any adverse impacts to water quality, air quality, habitat quality, flora and fauna, agricultural capacity, traffic impacts, social impacts, ecological impacts, noise impacts, visual (landscape) impacts, etc. If impacts are expected, they then develop mitigation measures to limit or prevent such impacts. An example of a mitigation measure would be the creation of wetlands in a nearby location to mitigate the filling in of wetlands necessary for a road development if it is not possible to reroute the road.

In the United States, the practice of environmental assessment was formally initiated on January 1, 1970, the effective date of the National Environmental Policy Act (NEPA). Since that time, more than 100 developing and developed nations either have planned specific analogous laws or have adopted procedure used elsewhere. NEPA is applicable to all federal agencies in the United States.

Water supply and treatment
Engineers evaluate the water balance within a watershed and determine the available water supply, the water needed for various needs in that watershed, the seasonal cycles of water movement through the watershed and they 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 a potable water supply, water is treated to minimize the risk of infectious disease transmission, the risk of non-infectious illness, and to create a palatable water flavor. 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 treatment
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 or an activated sludge system and a secondary clarifier, a tertiary biological nitrogen removal system, and a final disinfection process. The aeration basin/activated sludge system removes organic material by growing bacteria (activated sludge). 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 pollution management
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.

Environmental Protection Agency
The U.S. Environmental Protection Agency (EPA) is one of the many agencies that work with environmental engineers to solve key issues. An important component of EPA's mission is to protect and improve air, water, and overall environmental quality in order to avoid or mitigate the consequences of harmful effects.

Ecological engineering for sustainable agriculture in arid and semiarid West African regions
Ecological engineering offers new alternatives for the management of agricultural systems that are more tailored to the ever-changing social and environmental necessities in these regions. This requires managing the complexity of agrosystems, while striving to mimic the functioning of natural ecosystems of West African drylands and taking advantage of traditional practices and local know-how resulting from a long process of adaptation to environmental constraints.

Acting on biodiversity. Biodiversity is essential to the productivity of ecosystems and their temporal stability under the impact of external disturbances. Several ecological processes related to biodiversity may be intensified for the benefit of agrosilvopastoral systems: promoting diversity and soil microorganism activity to benefit plants, associating and utilizing the mutual benefits of plants
Utilizing organic matter and nutrient cycles. The productivity of agrosystems with low chemical input use in dryland regions is primarily based on efficient organic resource management, and in turn on the nutrient and energy flows they induce. It is thus possible to intervene at several levels: enhancing crop-livestock farming integration to preserve natural resources, restoring the biological activity of soils via specific organic inputs, supplying nutrients to plants locally.
Enhancing available water use. Water supplies are limited and irregular in dryland areas. Current management of these supplies—which involves capturing rainwater and surface runoff—could be improved in several ways: adapting to erratic rainfall or drought risks by focusing on: (i) the organization of the farm and community (farm plot patterns in association with the random rainfall distribution, etc.), and on (ii) cropping techniques to reduce crop water needs (plant choices, weeding, etc.), preserving water in crop fields by hampering runoff, accounting for the essential role of trees regarding soil and water in drylands.
Managing landscapes and associated ecological processes. Ecological crop pest regulation by their natural enemies is one ecosystem service provided by biodiversity. Better pest management could be considered in association with promoting biodiversity at different scales, e.g. from the plant to the landscape.

Education
Courses aimed at developing graduates with specific skills in environmental systems or environmental technology are becoming more common and fall into broad classes:

Mechanical engineering courses oriented towards designing machines and mechanical systems for environmental use such as water treatment facilities, pumping stations, garbage segregation plants and other mechanical facilities;
Environmental engineering or environmental systems courses oriented towards a civil engineering approach in which structures and the landscape are constructed to blend with or protect the environment;
Environmental chemistry, sustainable chemistry or environmental chemical engineering courses oriented towards understanding the effects (good and bad) of chemicals in the environment. Focus on mining processes, pollutants and commonly also cover biochemical processes;
Environmental technology courses oriented towards producing electronic or electrical graduates capable of developing devices and artifacts able to monitor, measure, model and control environmental impact, including monitoring and managing energy generation from renewable sources.

Career objectives
Contribute to the control and prevention of the deterioration of natural resources generated by industrial, economic or social projects.

Profile of the Professional
Professional with a solid knowledge in Basic Sciences oriented to the environment and its relation with the productive processes.
It carries out the study of the environmental impact of the industrial and technological developments, identifying its vulnerable points and supporting in a practical way its processes so that they comply with current regulations.
It includes the balance between the environmental impact generated by the project and the country's requirements for its development.
Tasks or specific activities that are carried out in the profession.

In the company performs
Environmental impact studies of production processes to visualize their effects on the environment.
It formulates environmental projects from its base study.
It is in charge of the management systems of environmental quality, health and occupational safety of the personnel of the company.
It establishes pollution control and monitoring methods as monitoring systems, in order to minimize emissions and waste.
It develops, calculates and puts into practice the different technical solutions that minimize the negative effects of the industrial process on the environment.
Determines the migration measures that must be carried out to counteract the emissions issued.
It carries out evaluation of projects and legal advice to companies.
Take care of the environment
Search for sustainable alternatives

In the public sector
Collaborates with compliance with current legislation to protect the environment in accordance with economic, social and political possibilities.
Carry out the integral management of waste.
It carries out citizen environmental awareness campaigns.
Management of protected wild areas as well as protection of urban ecosystems.
Conducts control of water, soil, air and waste pollution in the city
It manages the optimal use of natural resources for obtaining eco-efficient products and processes.
Performs environmental audits in various sectors.
Interpret and perform calculations for the evaluation and quantification of air pollutants, as well as the design of equipment and processes used in their control.
Choose the most viable option for the management of waste and contaminated soil.
Conducts groups of interdisciplinary work in territorial planning and planning, analyzing the complex systems of interrelation between natural, economic and social factors.

As an independent professional
It carries out studies, evaluations, audits, opinions and environmental certifications for all those economic and social sectors that require it.
Teaching and research.

Performance of the environmental engineer
Like any engineer, the environmental engineer has the function of solving specific problems using technology. For this reason, its labor market is quite heterogeneous and is distributed among the central administration, its decentralized services at the regional level, the local administration, industrial companies, consulting firms, service companies, non-governmental organizations, research and teaching institutions higher.

One of the activities that the environmental engineer must develop is the evaluation of the duration, magnitude and reversibility of the alterations caused by human activity in the environment, regardless of their adverse or beneficial nature.

The environmental engineer must be empowered to:

Plan the sustainable use of the environment.
Propose environmental policies.
Prepare environmental impact studies.
Environmental management.
Mitigation measures and control of polluting processes.
Diagnose and evaluate environmental aspects.
Develop environmental solutions.
Monitor environmental processes.
Monitor natural resources.
Propose solutions or manage environmental facilities, such as final disposal plants for hazardous waste, final disposal plants for common waste, transfer stations, etc.

Occupational field
Public bodies at central, regional and municipal government level.
In companies in the area of mining, agriculture, construction, energy, industry, agroindustrial, etc.
Health companies, landfills and transfer stations, waste management and control.
Independent consultor.
Universities
Around the field of occupation, it is like a wide - ranging career also being economically well - paid career for professionals who perform their duties in any sector

Source from Wikipedia

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