Environmental Engineering

Environmental engineering is defined as the branch of engineering that is concerned with protecting the environment from the potentially deleterious effects of human activity, protecting human population from the effects of adverse environmental factors and improving environmental quality for human health and well-being. The Environment * Global * Consists of the atmosphere, the hydrosphere and the lithosphere * Local * Constrained Life sustaining resources are withdrawn from the biosphere and wastes are discharged into the biosphere.

Waste discharge degrades the local environment and natural systems restore the degraded quality. When pollution load exceeds the assimilative capacity of biosphere, it shows the signs of stress. The Impact of Humans upon Environment Human population have thrived and flourished beyond natural constraints. Wastes generated by these increased number of human beings have upset the natural equilibrium. Natural needs * Needs human share in common with most of the higher mammals. Acquired needs * Needs associated with more advanced civilizations. Satisfying Natural Needs Natural needs are met by unprocessed resources and the wastes generated are generally compatible with, or readily assimilated by the environment. * Early civilization produced little pollution load and natural cleansing mechanisms easily restored the quality of the local environment. * Only as early peoples began to gather together in larger groupings did their impact upon their local environments begin to be significant. * Air pollution in 61 A. D. * Water pollution by the late eighteenth century in the river Rhine and Thames. * Solid waste problem from the middle ages.

Satisfying Acquired Needs * Industrial revolution enabled human to satisfy their natural needs easily. * Increasingly they turned their attention to other needs beyond those associated with survival. * Meeting the acquired needs had become a major thrust of modern industrial society. * Acquired needs are usually met by items that must be prepared or manufactured or refined and the production, distribution and use of such items usually results in more complex residuals, many of which are not compatible with or readily assimilated by the environment. Meeting the acquired needs of modern societies generates more residuals than meeting natural needs, and these residuals are likely to be less compatible with the environment and less likely to be readily assimilated into the biosphere. * As societies ascend the socio-economic ladder, the list of acquired needs or luxuries increases, as do the complexity of the production chain and the mass and complexity of the pollutants generated. The Impact of the Environment upon Human

Human populations generally manage to ignore their impact on the environment until the ill effects of a polluted environment upon their own health and well-being become evident. Health Concerns * A wide range of communicable diseases can be spread through elements of the environment by human and animal waste products. * Through immunization and environmental control programs, the major diseases transmitted via the environment have all been eliminated in developed countries. No country, however, is totally immune from outbreaks of environmentally transmitted disease. Pollution of the atmosphere has also posed severe health problems. * London smog of 1952 caused 4000 deaths. * New York inversion of 1963 claimed several hundred lives. * The widespread use of chemicals in agriculture and industry has introduced many new compounds posing a potential threat to all humans as they can be spread through air, water and soil as well as through the food chain. * Hazardous chemicals such as DDT, Dioxin have been widely used and their concentrations in the general environment are not currently known. * Residuals of hazardous chemicals in the environment are a cause of great concern.

Other Concerns * Polluted environment is aesthetically displeasing. * Our cultural and aesthetic heritage is being lost to pollution. * Pollution poses economic threats to human populations. Improvement of Environmental Quality * Environment management programs (EMP) are taken to improve environmental quality. * EMPs involve two different aspects * Environmental strategies * Environmental tactics * Environmental strategies are comprehensive plans that usually address a variety of problems that confront a single area. * Environmental strategies are usually worked in public and political arenas.

Economic, social and demographic factors must be considered. * The environmental engineer should be an important member of a management team that includes persons drawn from a wide variety of disciplines. * The major role of the environmental engineer in developing environmental strategies is to assess the likely response of the environment to various levels of contaminant loading and to weigh the various technical solutions that may be proposed. * Environmental tactics are the means for achieving the goals in a specific portion of a given environmental strategy. The engineer’s part primarily consists of the design, construction and operation of treatment facilities for water, air and solid wastes. The Role of the Environmental Engineer * They design treatment facilities to remove pollutants. * Engineered processes amplify and optimize natural processes to handle larger volume of pollutants and to treat them more rapidly. * Occasionally, the environmental engineer must design to reverse or counteract natural processes. * An understanding of natural and engineered purification processes requires an understanding of the biological and chemical reactions involved in these processes.

A fixture unit (F. U. ) is a quantity in terms of which the load producing effects on the plumbing systems of different kinds of plumbing fixtures are expressed on some arbitrarily chosen scale. Flush tank/Flushing cistern * A chamber in which water is accumulated and then discharged rapidly for flushing out water closets and urinals. Flushing valve * A flush valve is a device located at the bottom of a tank for the purpose of flushing water closets and similar fixtures and is closed by direct water pressure or some other mechanical means. * Water supply to buildings Purified water from public/private works is sent under pressure through pipes to the water service line that runs directly into building. * The pressure may vary from 55 to 100 psi. Measuring water pressure * Screw a water pressure gauge on to a cock outside of the house. * Turn on the faucet of the sill cock making certain that no other faucets in other parts of the house are open. * If the water pressure is low, underground reservoir tank, elevated house tank and pumping arrangement are to be provided. * In case of high water pressure, the pressure is reduced by installing and operating a pressure reducing valve below the sill cock.

House service It is that part of water supply system that runs from the street water main to the water meter that is usually inside the house. Corporation stop * A valve installed in the house service at the street water main. * Can be turned on or off by the authority. Goose tank * A curved pipe of a flexible material forming a flexible connection between the water main and the service line. Curb stop * A valve on the house service line. * Installed between the curb and the sidewalk. * To get at the valve a cast iron stop box is brought up to ground level equipped with an iron cover that can be lifted off. A long rod like wrench is used to turn the valve on and off. Service pipe * Usually a galvanized iron pipe which is connected to the water main through the goose neck. * Used to supply water to the building from the water main. Water meter