Reuse Recycling and Resource Recovery

Finding new sources of energy and materials is becoming increasingly difficult. Concurrently, we are finding it more and more difficult to locate solid waste disposal sites, and the cost of disposal is escalating exponentially. As a result, society's interest in reuse, recycling, and recovery of materials from refuse has grown. Reuse of materials involves either the voluntary continued use of a product for a purpose for which it may not have been originally intended, such as the reuse of coffee...

Radiation

X-rays were discovered by Wilhelm Roentgen toward the end of the year 1895. Almost immediately thereafter, Henri Becquerel observed radiation similar to X-rays emanating from certain uranium salts. In 1898, Marie and Pierre Curie studied radiation from two uranium ores, pitchblende and chalcolite, and isolated two additional elements that exhibited radiation similar to that of uranium but considerably stronger. These two elements were named radium and polonium. The discovery and isolation of...

Control of Nitrogen Oxides

Wet scrubbers absorb N02 as well as S02, but are usually not installed primarily for N02 control. An effective method often used on fossil fuel burning power plants is off-stoichiometric burning. This method controls NO formation by limiting the amount of air (or oxygen) in the combustion process to just a bit more than is needed to burn the hydrocarbon fuel in question. For example, the reaction for burning natural gas competes favorably with the high-temperature combination of nitrogen in the...

Financing of Capital Expenditures

A municipality's or industry's inability to finance large capital expenditures will necessarily affect choice among alternatives and possibly affect their ability to comply with environmental regulations. Traditional economic impact assessments examine the amortized capital, operation and maintenance (O& M) costs of a project, and the community's ability to pay, but the analyses typically overlook the problems involved in raising the initial capital funds required for implementation....

Precipitation

Precipitation removes contaminants from the air by two methods. Rainout is an in-cloud process in which very small pollutant particles become nuclei for the formation of rain droplets that grow and eventually fall as precipitation. Washout is a below-cloud process in which rain falls through the pollutant particles and molecules, which are entrained by the impinging rain droplets or which actually dissolve in the rainwater. The relative importance of these removal mechanisms was illustrated by...

100

Draw wind roses and pollution roses, and determine which plant is most guilty of the measured air pollution. 18.5 Using Eq. (18.7), derive an expression for the maximum ground level concentration in terms of the wind speed u and the dispersion constants ay and az. 18.6 A power plant burns 1000 tons of coal per day, 2 of which is sulfur. All of the sulfur is burned completely and emitted into the air from a stack with an effective height of 100 m. For a wind speed of 6 m s, calculate (a) the...

Vertical Dispersion Of Pollutants

Civil Environmental Engineering

As a parcel of air in the earth's atmosphere rises through the atmosphere, it experiences decreasing pressure and thus expands. This expansion lowers the temperature of the air parcel, and therefore the air cools as it rises. The rate at which dry air cools as it rises is called the dry adiabatic lapse rate and is independent of the ambient air temperature. The term adiabatic means that there is no heat exchange between the rising parcel of air under consideration and the surrounding air. The...

D

Class, wind speed, and sunshine conditions. Class A is the least stable Class F is the most stable. In terms of ambient lapse rates, Classes A, B, and C are associated with superadiabatic conditions Class D with neutral conditions and Classes E and F with subadiabatic conditions. A seventh, Class G, indicates conditions of extremely severe temperature inversion, but in considering frequency of occurrence is usually combined with Class F. Urban and suburban populated areas rarely achieve...

Nonhazardous Solid Waste

The most significant solid waste disposal regulations were developed under the Resource Conservation and Recovery Act (RCRA) of 1976. This federal statute, which amended the elementary Solid Waste Disposal Act of 1965, reflected the concerns of the public in general and Congress in particular about (1) protecting public health and the environment from solid waste disposal, (2) filling the loopholes in existing surface water and air quality laws, (3) ensuring adequate land disposal of residues...

2

These equivalents are in terms of X-ray dose, which is defined as 1.00. These equivalents are in terms of X-ray dose, which is defined as 1.00. Molecules along the path of the ionizing radiation are damaged in the process, as chemical bonds are broken and electrons are ejected (ionization). Resulting biological effects are due mainly to the interactions of these electrons with molecules of tissue. The energy transferred through these collisions and interactions per unit path length through the...

Civil Engineering

Throughout western civilization settled agriculture and the development of agricultural skills created a cooperative social fabric and spawned the growth of communities, as well as changed the face of the earth with its overriding impact on the natural environment. As farming efficiency increased, a division of labor became possible, and communities began to build public and private structures that engineered solutions to specific public problems. Defense of these structures and of the land...

Sources Of Water Pollution

Water pollutants are categorized as point source or nonpoint source, the former being identified as all dry weather pollutants that enter watercourses through pipes or channels. Storm drainage, even though the water may enter watercourses by way of pipes or channels, is considered nonpoint source pollution. Other nonpoint source pollution comes from agricultural runoff, construction sites, and other land disturbances, as discussed in Chap. 11. Point source pollution comes mainly from industrial...

The Hydrologic Cycle And Water Availability

The hydrologic cycle is a useful starting point for the study of water supply. This cycle, illustrated in Fig. 6-1, includes precipitation of water from clouds, infiltration into the ground or runoff into surface water, followed by evaporation and transpiration of the water back into the atmosphere. The rates of precipitation and evaporation transpiration help define the baseline quantity of water available for human consumption. Precipitation is the term applied to all forms of moisture...

Ultimate Disposal

Even after treatment, we are left with a large volume of sludge that needs a final resting place. The choices for ultimate disposal of sludge are limited to air, water, and land. Until quite recently, incineration (air disposal) was viewed as an effective sludge reduction method, if not exactly an ultimate sludge disposal method (the residual ash still required disposal). However, strict controls on air pollution and increasing concern over global warming are making incineration an increasingly...

Prevention And Mitigation Of Nonpoint Source Pollution

There has been a growing emphasis on prevention and mitigation of nonpoint source pollution during the past decade. Many counties now require agricultural farm plans that provide site-specific guidance for minimizing agricultural nonpoint source pollution. Similarly, many cities are now required to have discharge permits for storm drains that empty into natural water bodies. The following section will describe current practices for preventing and mitigating nonpoint source pollution from three...

Aerobic And Anaerobic Decomposition

Decomposition or biod gradation may take place in one of two distinctly different ways aerobic (using free oxygen) and anaerobic (in the absence of free oxygen). The basic equation for aerobic decomposition of complex organic compounds is The biological respiration or decomposition of glucose (the reverse of Eq. (4.1)) under aerobic conditions would result in the release of CO2, H2O, and energy that can be used for metabolism Carbon dioxide and water are always two of the end products of...

Environmental Impact

On January 1,1970, President Richard Nixon signed NEPA into law, setting a national policy to encourage productive and enjoyable harmony between people and their environment. This law established the Council on Environmental Quality (CEQ), which monitors the environmental effects of all federal activities, assists the President in evaluating environmental problems, and determines solutions to these problems. However, few people realized in 1970 that NEPA contained a sleeper, Section 102(2)(C),...

Ecosystem Risk Assessment

Regulation of toxic or hazardous substances often requires an assessment of hazard or risk to some living species other than homo sapiens, or assessment of risk to an entire ecosystem. Methods for ecosystem risk assessment are now being developed by Suter and others (Suter 1990). Ecosystem risk assessment is done in the same general way as human health risk assessment, except that identification of the species at risk and the exposure pathway is a far more complex process than in human health...

Expression Of Risk

In order to use risks in determining pollution standards, as EPA does, it is necessary to develop quantitative expressions for risk. The quantitative expressions reflect both the proportionality of the risk factor to the adverse effect and the statistical significance of the effect. Risk is defined as the product of probability and consequence, and is expressed as the probability or frequency of occurrence of an undesirable event. For example, if 10 of the students in a course were randomly...

180

Viessman, and m. j. Hammer, Water Supply and Pollution Control, 3rd ed., Thomas Crowell, New York, 1977. 148 ENVIRONMENTAL ENGINEERING Column 2 From Eq. (7.7) Columns 3 and 4 For the first size, x 1.10 and d 3.28 x 10-3 The last column is summed f(x d) 113,977, and from Eq. (7.14), we have 2 ( -0.4 (8.9 x 10 3)2 - 0 (w) ( 32.2 ) < U3'977) - 5'78 The deposition of material during the filtering process increases the head loss through the filter. A method of...

Surface Water Supplies

Surface water supplies are not as reliable as groundwater sources since quantities often fluctuate widely during the course of a year or even a week, and water quality is affected by pollution sources. If a river has an average flow of 10 cubic feet per second (cfs), this does not mean that a community using the water supply can depend on having 10 cfs available at all times. The variation in flow may be so great that even a small demand cannot be met during dry periods, and storage facilities...

Elements Of Aquatic Ecology

Plants and animals in their physical and chemical environment make up an ecosystem. The study of ecosystems is termed ecology. Although we often draw lines around a specific ecosystem to be able to study it more fully (e.g., a farm pond) and thereby assume that the system is completely self-contained, this is obviously not true. One of the tenets of ecology is that everything is connected with everything else. Three categories of organisms make up an ecosystem. The producers use energy from the...

Disposal Of Unprocessed Refuse In Sanitary Landfills

Area Method Landfill

The only two realistic options for disposal are in the oceans and on land. Because the environmental damage done by ocean disposal is now understood, the United States prohibits such disposal by federal law, and many developed nations are following suit. This chapter is therefore devoted to a discussion of land disposal. Until the mid-1970s, a solid waste disposal facilities was usually a dump in the United States and a tip (as in tipping) in Great Britain. The operation of a dump was simple...