Scope of environmental engineering

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Classification of organic compounds

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In most of its compounds carbon exhibits a constant covalency of four. Probably owing again to its peculiar position in the Periodic Table the carbon atoms has the property of combining with other carbon atoms by means of one or more of its covalent linkages to from chains of atoms. Thus, one hydrogen atom of methane can be regarded as being replaced by a CH3 grop in ethane.

Similarly chains of three, four, five, etc. carbon atoms may be obtained producing propane, butane, pentane, and the higher hydrocarbons respectively. Compounds which contain straight chains of carbon atom are called aliphatic compounds. Introducing each carbon atom removes one hydrogen atom and replaces it by one carbon atom and three hydrogen atoms, the net increase being one atom of carbon and two of hydrogen. In this way a series of compounds is obtained, each number of which differs in formula from the member above or below it by a constant difference, namely CH₂.

Such a series is called a homologue series. Every member of the series can be expressed by the general formula: CnH₂n+2. The simplest homologue series begins with methane, CH₄, and is as follows: methane, ethane, butane, pentane. In a large number of organic compounds the carbon atoms instead of being straight chains form closed rings containing six carbon atoms. Such substances are called aromatic compounds and if they contain in the ring atoms other than carbon, they are called heterocyclic, for example, pyridine.

The hydrocarbon methane with its four covalent linkages can not undergo chemical reactions to form a covalent compound except by removing one or more hydrogen atoms and their replacement by other atoms or groups A compound such as methane is called saturated. Compounds which can react merely by adding on other elements or groups of elements are called unsaturated and form addition products.

Vocabulary List

peculiar position – особое положение

covalent linkages – ковалентные связи

to replace – замещать

to react -реагировать

Pollutants may be chemical, biological, thermal, radioactive, or even mechanical. Environmental engineering emphasizes several areas: process engineering, environmental chemistry, water and sewage treatment (sanitary engineering), waste reduction/management, and pollution prevention/cleanup. Environmental engineering is a synthesis of various disciplines, incorporating elements from the following:

Environmental engineering is the application of science and engineering principles to the environment. Some consider environmental engineering to include the development of sustainable processes. There are several divisions of the field of environmental engineering.

Environmental impact assessment and mitigation

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 to water quality, air quality, habitat q uality, 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.

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