3.2.1 Point Source

Point source water pollution refers to contaminants that enter a waterway from a single, identifiable source, such as a pipe or ditch. Examples of sources in this category include discharges from a factory, a sewage treatment plant or a publicly owned treatment works (POTWs), or a city storm drain. The US Clean Water Act (CWA) defines point source for regulatory enforcement purposes (United States Code Clean Water Act Section 502 (14) 33 U.S.S 1362(14) 1999). The CWA definition of point source was amended in 1987 to include municipal storm sewer systems, as well as industrial storm water, such as from construction sites.

3.2.2 Nonpoint Source

Nonpoint source (NPS) pollution refers to diffuse contamination that does not originate from a single discrete source. NPS pollution is often the cumulative effect of small amounts of contaminants gathered from a large area. A common example is the leaching out of nitrogen compounds from fertilized agricultural lands (Moss 2008). Nutrient runoff in storm water from “sheet flow” over an agricultural field or a forest is also cited as examples of NPS pollution.

Contaminated storm water washed off of parking lots, roads and highways, called urban runoff, is sometimes included under the category of NPS pollution. However, because this runoff is typically channeled into storm drain systems and discharged through pipes to local surface waters, it becomes a point source.

Fugitive emissions are also NPS pollution in that the emissions of gases or vapors take place from pressurized equipment due to leaks and other unintended or irregular releases of gases, mostly from industrial activities. As well as the economic cost of lost commodities, fugitive emissions contribute to air pollution and climate change.

3.3.1 Physical Characteristics

The principal physical characteristics of wastewater include solids content, color, odor, and temperature.

3.3.2 Total Suspended Solids

The total solids in a wastewater consist of the insoluble or total suspended solids and the soluble compounds dissolved in water. The suspended solids content is found by drying and weighing the residue removed by the filtering of the sample. When this residue is ignited the volatile solids are burned off. Volatile solids are presumed to be organic matter, although some organic matter will not burn and some inorganic salts break down at high temperatures. The organic matter consists mainly of proteins, carbohydrates and fats. Between 40 and 65% of the solids in an average wastewater are suspended. Settleable solids, expressed as milligrams per liter (mg/l), are those that are removed by sedimentation. Usually about 60% of the suspended solids in a wastewater are settleable (Crites and Tchbanoglous 1998). Solids may be classified in another way as well: those that are volatilized at a high temperature (600 °C) and those that are not. The former are known as volatile solids, the latter as fixed solids. Usually, volatile solids are organic.

3.3.3 Color

Color is a qualitative characteristic that can be used to assess the general condition of wastewater. Wastewater that is light brown in color is less than six hours old, while a light‐to‐medium grey color is characteristic of wastewaters that have undergone some degree of decomposition or that have been in the collection system for some time. Lastly, if the color is dark grey or black, the wastewater is typically septic, having undergone extensive bacterial decomposition under anaerobic conditions. The blackening of wastewater is often due to the formation of various sulphides, particularly ferrous sulphide. This results when hydrogen sulphide produced under anaerobic conditions combines with divalent metal, such as iron, which may be present. Color is measured by comparison with standards.

3.3.4 Odor

The determination of odor has become increasingly important, as the general public has become more concerned with the proper operation of wastewater treatment facilities. The odor of fresh wastewater is usually not offensive, but a variety of odorous compounds are released when wastewater is decomposed biologically under anaerobic conditions. The different unpleasant odors produced by certain industrial wastewater are presented in Table 3.1.

3.3.5 Temperature

The temperature of wastewater is commonly higher than that of the water supply because warm municipal water has been added. The measurement of temperature is important because most wastewater‐treatment schemes include biological processes that are temperature dependent. The temperature of wastewater will vary from season to season and also with geographic location. In cold regions, the temperature will vary from about 7 to 18 °C, while in warmer regions the temperatures vary from 13 to 24 °C (Crites and Tchobanoglous 1998).

3.4.1 Inorganic Chemicals

The principal chemical tests include free ammonia, inorganic nitrogen as nitrate, nitrite, organic phosphorus, and inorganic phosphorus. Nitrogen and phosphorus are important because these two nutrients are responsible for the growth of aquatic plants. Other tests such as chloride, sulphate, pH, and alkalinity are performed to assess the suitability of reusing treated wastewater and in controlling the various treatment processes (Rouessac and Rouessac 2007).

Trace elements, which include some heavy metals, are not determined routinely, but trace elements may be a factor in the biological treatment of wastewater. All living organisms require varying amounts of some trace elements such as iron, copper, zinc, and cobalt for proper growth. Heavy metals can also produce toxic effects; therefore, determination of the amounts of heavy metals is especially important where the further use of treated effluent or sludge is to be evaluated. Many metals are also classified as priority pollutants such as arsenic, cadmium, chromium, mercury, etc.

Measurements of gases such as hydrogen sulphide, oxygen, methane, and carbon dioxide are made to help the system to operate. The presence of hydrogen sulphide needs to be determined not only because it is an odorous and very toxic gas but also because it can affect the maintenance of long sewers on flat slopes, since it can cause corrosion. Measurements of dissolved oxygen are made in order to monitor and control aerobic biological treatment processes. Methane and carbon dioxide measurements are used in connection with the operation of anaerobic digesters.

3.4.2 Organic Chemicals

Over the years, a number of different tests have been developed to determine the organic content of wastewaters. In general, the tests may be divided into those used to measure gross concentrations of organic matter greater than about 1 mg/l and those used to measure trace concentrations in the range of 10⁻¹²–10⁻³ mg/l. Laboratory methods commonly used today to measure gross amounts of organic matter (>1 mg/l) in wastewater include (i) BOD, (ii) COD, and (iii) total organic carbon (TOC). Trace organics in the range of 10⁻¹²–10⁻³ mg/l are determined using instrumental methods including gas mass spectroscopy and chromatography. Specific organic compounds are determined to assess the presence of priority pollutants (Metcalf & Eddy 2003). The BOD, COD, and TOC tests are gross measures of organic content and as such do not reflect the response of the wastewater to various types of biological treatment technologies.

3.4.3 Volatile Organic Compounds

Volatile organic compounds (VOCs), such as benzene, toluene, xylenes, trichloroethane, dichloromethane, and trichloroethylene (TCE), are common soil pollutants in industrialized and commercialized areas. One of the more common sources of these contaminants is leaking underground storage tanks. Improperly discarded solvents and landfills, built before the introduction of current stringent regulations, are also significant sources of soil VOCs. Many of organic substances are classified as priority pollutants such as PCBs, polycyclic aromatic, acetaldehyde, formaldehyde, 1,3‐butadiene, 1,2‐dichloroethane, dichloromethane, hexachlorobenzene, etc. In Table 3.2, a list of typical inorganic and organic substances present in industrial effluents is presented.

3.4.4 Heavy Metal Discharges

Several industries discharge heavy metals, it can be seen that of all of the heavy metals, chromium is the most widely used and discharged to the environment from different sources. As shown in Figure 3.1, many of the pollutants entering aquatic ecosystems (e.g. mercury lead, pesticides, and herbicides) are very toxic to living organisms. They can lower reproductive success, prevent proper growth and development, and even cause death.

However, chromium is not the metal that is most dangerous to living organisms. Much more toxic are cadmium, lead, and mercury. These have a tremendous affinity for sulfur and disrupt enzyme function by forming bonds with sulfur groups in enzymes. Protein carboxylic acid (–CO₂H) and amino (–NH₂) groups are also chemically bound by heavy metals. Cadmium, copper, lead, and mercury ions bind to cell membranes, hindering transport processes through the cell wall. Heavy metals may also precipitate phosphate bio‐compounds or catalyze their decomposition.

3.4.5 Some Inorganic Pollutants of Concern

Cyanide ion, CN‐, is probably the most important of the various inorganic species in wastewater. Cyanide, a deadly poisonous substance, exists in water as HCN which is a weak acid. The cyanide ion has a strong affinity for many metal ions, forming relatively less toxic ferrocyanide, Fe(CN)₆⁴⁻, with iron (II), for example. Volatile HCN is very toxic and has been used in gas chamber executions in the United States. Cyanide is widely used in industry, especially for metal cleaning and electroplating. It is also one of the main gas and coke scrubber effluent pollutants from gas works and coke ovens. Cyanide is widely used in certain mineral processing operations.

Ammonia is the initial product of the decay of nitrogenous organic wastes, and its presence frequently indicates the presence of such wastes. It is a normal constituent of some sources of groundwater and is sometimes added to drinking water to remove the taste and odor of free chlorine. Since the pK_a (the negative log of the acid ionization constant) of the ammonium ion, NH₄⁺, is 9.26, most ammonia in water is present as NH₄⁺ rather than NH₃.

Hydrogen sulphide, H₂S, is a product of the anaerobic decay of organic matter containing sulfur. It is also produced in the anaerobic reduction of sulphate by microorganisms and is developed as a gaseous pollutant from geothermal waters. Wastes from chemical plants, paper mills, textile mills, and tanneries may also contain H₂S. Nitrite ion, NO²⁻, occur in water as an intermediate oxidation state of nitrogen. Nitrite is added to some industrial processes to inhibit corrosion; it is rarely found in drinking water at levels over 0.1 mg/l. Sulphite ion, SO₃²⁻, is found in some industrial wastewaters. Sodium sulphite is commonly added to boiler feed‐waters as an oxygen scavenger:

3.4.6 Organic Pollutants of Concern

Effluent from industrial sources contains a wide variety of pollutants, including organic pollutants. Primary and secondary sewage treatment processes remove some of these pollutants, particularly oxygen‐demanding substances, oil, grease, and solids. Others, such as refractory (degradation‐resistant) organics (organochlorides, nitro compounds, etc.), salts, and heavy metals, are not efficiently removed. Soaps, detergents, and associated chemicals are potential sources of organic pollutants. Most of the environmental problems currently attributed to detergents do not arise from the surface‐active agents which basically improve the wetting qualities of water. The greatest concern among environmental pollutants has been caused by polyphosphates added to complex calcium functioning as a builder.

Bio‐refractory organics are poorly biodegradable substances, prominent among which are aromatic or chlorinated hydrocarbons (benzene, bornyl alcohol, bromobenzene, chloroform, camphor, dinitrotoluene, nitrobenzene, styrene, etc.). Many of these compounds have also been found in drinking water. Water contaminated with these compounds must be treated using physical and chemical methods, including air stripping, solvent extraction, ozonation, and carbon adsorption.

First discovered as environmental pollutants in 1966, polychlorinated biphenyls (PCB compounds) have been found throughout the world in water, sediments, and in bird and fish tissues. They are made by substituting between 1 and 10 Cl atoms onto the biphenyl aromatic structure. This substitution can produce 209 different compounds (Rouessac and Rouessac 2007).

3.4.7 Thermal Pollution

Considerable time has elapsed since the scientific community and regulatory agencies officially recognized that the addition of large quantities of heat to a recipient possesses the potential of causing ecological harm. The really significant heat loads result from the discharge of condenser cooling water from the ever‐increasing number of steam electrical generating plants and equivalent‐sized nuclear power reactors. Large numbers of power plants currently require approximately 50% more cooling water for a given temperature rise than that required of fossil‐fuel plants of an equal size. The degree of thermal pollution depends on thermal efficiency, which is determined by the amount of heat rejected into the cooling water. Thermodynamically, heat should be added at the highest possible temperature and rejected at the lowest possible temperature if the greatest amount of effect is to be gained and the best thermal efficiency realized. The current and generally accepted maximum operating conditions for conventional thermal stations are about 500 °C and 24 MPa, with a corresponding heat rate of 2.5 kWh, 1.0 kWh resulting in power production and 1.5 kWh being wasted. Plants have been designed for 680 °C and 34 MPa; however, metallurgical problems have kept operating conditions at lower levels.

Nuclear power plants operate at temperatures from 250 to 300 °C and pressures of up to 7 MPa, resulting in a heat rate of approximately 3.1 kWh. Thus, for nuclear plants, 1.0 kWh may be used for useful production, whereas 2.1 kWh is wasted. Most steam‐powered electrical generating plants are operated at varying load factors, and consequently the heated discharges demonstrate wide variation with time. Thus, the biota is not only subjected to increased or decreased temperature, but also to a sudden or “shock,” temperature change. Increased temperature will cause remarkable reduction in the self‐purification capacity of a receiving water body and cause the growth of undesirable algae (Krenkel and Novotny 1980). The addition of heated water to the receiving water can be considered equivalent to the addition of sewage or other organic waste material, since both pollutants may cause a reduction in the oxygen resources of the receiving waters. Also, elevated temperatures in the receiving water could cause undesirable algae bloom (Hauser 2018; USEPA 2018).

3.5.1 Pollution Load and Concentration

In most industries, wastewater effluents result from the following water uses:

1. Sanitary wastewater (from washing, drinking, etc.)
2. Cooling (from disposing of excess heat to the environment)
3. Process wastewater (including both water used for making and washing products and for removal and transport of waste and by‐products)
4. Cleaning (including wastewater from cleaning and maintenance of industrial areas)

Excluding the large volumes of cooling water discharged by the electric power industry, the wastewater production from urban areas is about evenly divided between industrial and municipal sources. Therefore, the use of water by industry can significantly affect the water quality of receiving waters. The level of wastewater loading from industrial sources varies markedly with the water quality objectives enforced by the regulatory agencies. There are many possible in‐plant changes, process modifications, and water‐saving measures through which industrial wastewater loads can be significantly reduced. Up to 90% of recent wastewater reductions have been achieved by industries employing such methods as recirculation, operation modifications, effluent reuse, or more efficient operation. As a rule, treatment of an industrial effluent is much more expensive without water‐saving measures than the total cost of in‐plant modifications and residual effluent treatment. Industrial wastewater effluents are usually highly variable, with quantity and quality variations brought about by bath discharges, operation start‐ups and shutdowns, working‐hour distribution, and so on. A long‐term detailed survey is usually necessary before a conclusion on the pollution impact from an industry can be reached. Because of the wide variety of industries and levels of pollutants, we can present a snapshot view of the characteristics. The values of typical concentration of conventional pollutants (BOD₅, COD, TSS) and pH for different industrial effluents are given in Table 3.3. A similar sampling for nonconventional pollutants is given in Table 3.4.

3.5.2 Industrial Pretreatment

Industrial wastewater may contain pollutants which cannot be removed by conventional sewage treatment. Also, variable flow of industrial waste associated with production cycles may upset the population dynamics of biological treatment units, such as the activated sludge process. Thus, industrial wastewaters can pose serious hazardous to municipal systems because the collection and treatment systems have not been designed to carry or treat them.

Highly regulated industrial effluent usually receives at least pretreatment, if not full treatment, at the factories themselves to reduce the pollutant load, before discharge to the sewer. Using proven treatment technologies and manufacturing practices that promote recycling, industries can remove or eliminate pollutants before discharge of wastewater. This practice is called industrial wastewater treatment or pretreatment.

The pretreatment program is a component of the USEPA (United States Environmental Protection Agency) national NPDES (National Pollutant Discharge Elimination System) program. It is a cooperative effort of federal, state, and local environmental regulatory agencies established to protect water quality. Similar to how USEPA authorizes the NPDES permit program to state, tribal, and territorial governments to perform permitting, administrative, and enforcement tasks for discharges to surface waters (NPDES program), EPA and authorized NPDES state pretreatment programs approve local municipalities to perform permitting, administrative, and enforcement tasks for discharges into the municipalities' POTWs. A treatment works (as defined by CWA section 212) is owned by a state or municipality [as defined by CWA section 502(4)]. This definition includes any devices or systems used in the storage, treatment, recycling, and reclamation of municipal sewage or industrial wastes of a liquid nature. It also includes sewers, pipes, or other conveyances only if they convey wastewater to a POTW treatment plant.

The national pretreatment program identifies specific discharge standards and requirements that apply to sources of nondomestic wastewater discharged to a POTW. By reducing or eliminating waste at the industries (“source reduction”), fewer toxic pollutants are discharged to and treated by the POTW, providing benefits to both the POTWs and the industrial users. Oversight of the program is by the POTW, state, or the EPA. The control authority issues permits for discharge of industrial wastewaters to the POTW. The permits contain numerical limits for controlled pollutants and requirements for sampling, flow measurements, laboratory testing, and reporting.

3.6.1 Dilute Solutions

The discharges from continuous manufacturing processes are normally dilute solutions of compatible and sometimes nonconventional pollutants. They may be discharged to the industry's pretreatment system or directly to the POTW without any pretreatment. Manufacturing processes such as plating bath rinses, raw food cleaning, and crude oil dewatering are all examples of dilute solutions of pollutants that may be discharged directly to a POTW sanitary sewer. If a problem occurs in the manufacturing process, a probable result is that the quality of wastewater will change; it may be more laden with pollutants. Some wastestreams from utility services, such as cooling tower and boiler blowdown, are continuous and represent the discharge of dilute solutions.

Another low‐strength wastewater is storm water runoff from chemical handling and storage areas. Products which may have spilled on the industry's grounds are washed off during a rainstorm or during the spring thaw. The pollutant concentration is usually too dilute to require pretreatment before discharge to the sewer, but it exceeds the discharge standards for discharge to surface waters. While the strength of the storm runoff may be low, the volume that must be treated in addition to normal flow to the pretreatment system or to the POTW can cause hydraulic capacity problems. Excessive flows can be diverted to storage reservoirs or basins and then gradually discharged to the pretreatment system. A great deal of attention is presently focused on cleaning up groundwater sources that have been contaminated by leaking underground storage tanks. Cleanup projects of this nature typically involve large quantities of wastes that may contain high concentrations of solvents, fuels, heavy metals, and pesticides. Because of the public attention surrounding groundwater cleanup projects, pretreatment of the contaminated water is almost always required and the result is usually a “high‐ quality” industrial wastewater.

3.6.2 Concentrated Solutions

Typically, concentrated solutions are batch‐generated and the frequency of generation is usually not daily but weekly, monthly, annually, or even longer. These solutions are process chemicals or products that cannot be reconditioned or reused in the same manufacturing process. Concentrated solutions such as spent plating baths, acids, alkalies, static drag out solutions, and reject product may have concentrations of pollutants hundreds or thousands of times higher than the discharge limits of the POTW or higher than can be adequately treated by the pretreatment system if discharged all at once. Time has to be taken to examine and understand each manufacturing process, then identify these concentrated solutions and take the necessary steps to prevent damage to the treatment facilities.

Some wastes may be considered concentrated by the POTW but not by the industry. For example, the 10% sulfuric acid solution used for pickling parts is considered “dilute” by comparison to the 98% or 505 stock solution that the industry uses to make up the pickling solution. When this solution is spent or can no longer be used as a pickling solution, proper treatment and disposal are required. From the industrial manufacturer's point of view, the solution is spent and no longer concentrated. However, from a wastewater treatment point of view, the solution is concentrated since it contains high concentrations of acid (pH < 1.0) and heavy metals (1000 mg/l) compared to the normal pH of 1.0–4.0 and heavy metal concentrations of less than 100 mg/l (IWT 1999). Another source of concentrated solutions is the wastewater from equipment cleanup. While the amount of material in the process chemical bath may be considered dilute by industry standards, it forms a concentrated wastestream when discharged during the cleanup of manufacturing equipment. Cleanup wastestreams contain a high concentration of the product during the first washing of the tank, pipe, or pump. This discharge of concentrated waste is followed by successive rinses which contain less and less pollutants. If cleanup flow concentrations are not equalized, the cleanup cycle can cause problems in the industrial waste treatment system (IWTS). Spills of process chemicals to the floor, if not contained, can flow directly to the floor drain and the pretreatment or sewer system. The adverse effects on the pretreatment system and POTW are the same as those of any other concentrated solutions. This is why chemical containment areas must not have drains.

3.7.1 Frequency of Generation and Discharge

Important to both the operation of the industry's pretreatment system and the POTW's collection, treatment, and disposal systems is the frequency of industrial waste generation and discharge. Wastewater sampling to investigate process problems and to determine compliance with the discharge limits are also affected by the hours of discharge.

3.7.2 Hours of Operation vs. Discharge

Normally, the hours of operation are also the hours of discharge to the IWTS. Thus, the operator can generally expect to receive flow for treatment during the hours of operation. If the production is constant, the discharge volume and chemical constituents will also be constant. Several common situations where an industrial waste must be treated after the normal production hours are described below:

1. The “wet” processes run for one shift, but the “dry” processes run for two. The dry processes may require utilities such as compressed air or a boiler, each having a wastewater discharge.
2. In industries with long collection systems, production and wastewater flow to the system may stop, but the IWTS may continue to operate and discharge until the wastewater in the collection system has been processed.
3. Spills, accidental discharges, or storm water flow that goes to the IWTS may cause the IWTS to operate outside of the normal production hours.
4. A food‐processing plant operates for one or two shifts, generating some wastewater, but most of the equipment cleaning operations occur on an off shift. The cleaning generates most of the wastewater volume.
5. The IWTS has an equalization tank either at the beginning of the IWTS or at the end of the manufacturing system. Discharge from the equalization tank to the rest of the IWTS may continue after production stops because it is programmed to pump to the next unit process until it reaches its low level.

Equalization of the wastewater is an important factor affecting the actual hours of wastewater discharge to the IWTS and sewer. In order to deliver a relatively constant flow and concentration of pollutants to the IWTS, large wastewater collection sumps, equalization tanks, or storage tanks may be used. As noted above, these equalization devices may also lengthen the time of discharge beyond the actual hours of operation of the manufacturing facility. Equalization of industrial wastewater flows can also be beneficial to the POTW. By lengthening the hours of discharge from the industry, there is an effective increase in the available hydraulic capacity of the POTW collection system because of the decreased industrial flow rates. Due to the normal diurnal variation in domestic wastewater flows (peak flows usually occur between 8 : 00 a.m. and 6 : 00 p.m.), the hydraulic capacity of a sewer may be exceeded if a large industrial flow is allowed to be discharged to the sewer during a short period. Therefore, it may be necessary for the industry to discharge only at night. Sampling of this discharge would then be shifted to the night‐time hours.

3.7.3 Discharge Variations

Industries that have daily, weekly, or seasonal manufacturing cycles will show variations in wastewater generation. Business cycles for each of the various segments of the industrial community will have an effect on production; therefore, on the generation of wastewater. The food‐processing industry provides a good example of daily, weekly, and seasonal variations in discharge quantity and quality. For example, an industry that processes citrus peel to make pectin is dependent on when the peel arrives at the industry's plant. This may mean anywhere from three to six days per week. As the season progresses, the type of peel changes from orange to lemon and the sugar content changes yielding a slightly different type of wastewater. After the citrus season, the plant is completely shut down. In certain industries, variations in the quantity of wastewater reflect the nature of the business or the business cycle of the particular business segment. In a small shop producing printed circuit boards, it is typical to have a 30‐day turnaround with sales, ordering, and development taking place during the first part of the month. Production is slow while making test boards, but once the board is developed, production proceeds at a rapid pace to produce the boards for shipment in the last week of the month. The printed circuit board industry is subject to both downturns and upturns in the market. The major pollutant from the industry is copper, consequently, the quantity of copper discharged to the industrial sewer fluctuates according to market and production cycles.

Variations in the quality of industrial waste can also occur due to market forces or environmental concerns requiring a different type of product. In the metal‐finishing industry, for example, companies are moving from cadmium‐plated metal, an environmentally more hazardous substance with more stringent discharge limitations, to zinc‐plated parts. Knowledge of the industry, the manufacturing processes, and market forces are valuable tools needed by the industrial waste treatment plant operator to anticipate variations in industrial discharges.

3.7.4 Continuous and Intermittent Discharges

Discharges from manufacturing facilities usually reflect the type of manufacturing process used at the facility. Processes which are continuous tend to produce wastewater on a continuous basis with relatively constant volume and quality. Batch processes or activities that occur once per shift, per day, or per week tend to produce an intermittent discharge. Also, as a general rule‐of‐thumb, the larger the manufacturing process, the more likelihood there is of a continuous discharge. Examples of manufacturing processes that have continuous discharges include rinsing or cleaning of parts or food, processing of crude oil, either at the well head or refinery, air or fume scrubbing, papermaking, and leather tanning. Intermittent discharges of wastewater are characterized by discharges of a volume of wastewater separated by a time period between discharges.

These typically occur at the beginning or ending of a manufacturing process or during equipment cleanup, a spill, replacement of spent solution, or disposal of a rejected product. Intermittent discharges also tend to be more concentrated and of smaller volume than the wastewater normally discharged. For an industrial pretreatment facility, the intermittent discharges and the variations in waste generation determine the design capacity of the system.

3.7.5 Industrial Effluents

Whereas the nature domestic wastewater is relatively constant, the extreme diversity of industrial effluents calls for an individual investigation for each type of industry and often entails the use of specific treatment processes. Therefore, a thorough understanding of the production processes and the system organization is fundamental.

There are four types of industrial effluents to be considered:

1. General manufacturing effluents: Most processes give rise to polluting effluents resulting from the contact of water with gases, liquids, or solids. The effluents are either continuous or intermittent. They even might only be produced several months a year (campaigns in the agriculture and food industry, two months for beet sugar production, for example). Usually, if production is regular, pollution flows are known. However, for industries working in specific campaigns (synthetic chemistry, pharmaceutical and allied chemical industries), it is more difficult to analyze the effluents as they are always changing.
2. Specific effluents: Some effluents are likely to be separated either for specific treatment after which they are recovered, or to be kept in a storage tank ready to be reinjected at a weighted flow rate into the treatment line, such as pickling and electroplating baths, or spent caustic soda.
3. General service effluents: These effluents may include wastewater (canteens, etc.), water used for heating (boiler blowdown, spent resin regenerants), etc.
4. Intermittent effluents: These must not be forgotten; they may occur from accidental leaks of products during handling or storage, from floor wash water and from polluted water, of which storm water may also give rise to a hydraulic overload.

For the correct design of an industrial effluent treatment plant, the following parameters must be carefully established (IWT 1999):

1. Types of production, capacities and cycles, raw materials used
2. Composition of the make‐up water used by the industrial plant
3. Possibility of separating effluents and/or recycling them
4. Daily volume of effluents per type
5. Average and maximum hourly flows (duration and frequency by, type)
6. Average and maximum pollution flow (frequency and duration) per type of waste and for the specific type of pollution coming from the industry under consideration, since it can seriously disturb the working of certain parts of the treatment facilities (glues, tars, fibers, oils, sands, etc.)

In the starch industry, starch is extracted from tubers of manioc and potatoes. A wet process is used to extract starch from the richest cereals (wheat, rice, corn). The general pollution of this process is shown in Table 3.5. The nature of the effluents depends on the specific treatments used on the raw materials after common washing.

The effluents are rather acidic which is due to lactic fermentation or to sulphitation process in white sugar manufacture (pH 4–5). When a wet technique is used to extract starch, the pollution comes from the evaporation of water and it is made up of volatile organic acids. A notably soluble protein‐rich pollution may come from the glucose shop. The general wastes of potatoes processing is presented in Table 3.6.

3.7.6 Wastewater Quality Indicators: Selected Pollution Parameters

3.7.6.2 Oxygen

Most aquatic habitats are occupied by fish or other animals requiring certain minimum dissolved oxygen concentrations to survive. Dissolved oxygen concentrations may be measured directly in wastewater, but the amount of oxygen potentially required by other chemicals in the wastewater is termed as oxygen demand. Dissolved or suspended oxidizable organic material in wastewater will be used as a food source. Finely divided material is readily available to microorganisms whose populations will increase to digest the amount of food available. Digestion of this food requires oxygen, so the oxygen content of the water will ultimately be decreased by the amount required to digest the dissolved or suspended food. Oxygen concentrations may fall below the minimum required by aquatic animals if the rate of oxygen utilization exceeds replacement by atmospheric oxygen.

Basically, the reaction for biochemical oxidation may be written as

Oxygen consumption by reducing chemicals such as sulfides and nitrites is typified as follows:

3.7.6.7 Pollutant Concentration and Loading in Wastewater

Loadings on wastewater treatment units are often expressed in terms of pounds of BOD or TSS per day or pounds of solids per day, as well as quantity of flow per day. The relationship between the parameters of concentration and flow is based on the following conversion factors: 1.0 mg/l, which is also 1.0 parts per million (ppm) by weight, equals 8.34 or 62.4 lb/million gal (MG), since 1 gal of water weighs 8.34 lb.

Conversion of mg/l (ppm) to lb/MG

(3.1)

or

(3.2)

where

• A = BOD, TSS, or other constituents (mg/l)
• Q = volume of wastewater (MG or million ft³)
• 8.34 = (lb/MG)/(mg/l)
• 62.4 = (lb/million ft³)/(mg/l)

3.8.1 Variation in Industrial Wastewaters

The composition of wastewater from industry operations varies widely depending on the function and activity of the particular industry (Tables 3.3 and 3.4). From these examples, it can be observed that the daily average concentration of both BOD and TSS can vary significantly. Problems with high short‐term loadings most commonly occur in small treatment plants that have limited reserve capacity to handle “shock loadings.” If industrial wastes are to be discharged to the collection system for treatment in a POTW, it will be necessary to characterize the wastes adequately to identify the ranges in constituent concentrations and mass loadings. Such characterization is also needed to determine if pretreatment is required before the waste is permitted to be discharged into the POTW collection system. If pretreatment is needed, the effluent from the pretreatment facilities must also be characterized. Further, any proposed future process changes should also be assessed to determine what effects they might have on the wastes to be discharged.

3.8.2 Pretreatment Program Purpose

The purpose of the USEPA National Pretreatment Program is to protect POTWs and the environment from the adverse impacts that may occur when “shock loadings” of criteria pollutants or hazardous or toxic wastes are discharged into a POTW system. This is achieved mainly by regulating nondomestic (industrial) users of POTWs that discharge toxic wastes or unusually strong conventional wastes. The Federal Water Pollution Control Act, known as the Clean Water Act (CWA), was passed in 1972 to maintain and improve the quality of ambient waters. Its goal was to eliminate the introduction of pollutants into navigable waters and to achieve fishable and swimmable water quality. The NPDES and its permit programs establish requirements for point source direct dischargers to the water environment. The National Pretreatment Program, a component of NPDES, requires indirect industrial and commercial waste dischargers, or those that discharge wastewater to a POTW, to obtain permits that specify the effluent quality to be obtained by pretreatment or other controls before discharge to POTW systems. Thus, the CWA gives the EPA the authority to establish and enforce pretreatment standards for discharge of industrial wastewaters into POTW facilities.

3.8.3 Dental Waste Pretreatment Management

Dental offices create a variety of wastes, which need to be pretreated or managed correctly to protect our health and the environment. This guide explains the Best Management Practices (BMPs) that will help dentists follow environmental laws and prevent pollution. Note that this guidance is only for dental offices on a POTW. Operatory waste should never go to a septic system or POTW, even with an amalgam separator.

Dental amalgam waste is a significant source of mercury received by POTWs and they can't treat the mercury in waste, so it pollutes natural water bodies and the land the solids are applied to. For more information, consult the American Dental Association's Dental Amalgam BMPs.

On 15 December 2016, EPA Administrator signed the final rule related to dental categorical standards, and the EPA submitted the rule for publication in the Federal Register. The official version of the rule for purposes of compliance has been presented in a Federal Register publication. The publication rule can be found at https://www.epa.gov/eg/dental‐effluent‐guidelines‐documents.

3.9.1 The Atmosphere

On a mesoscale (Figure 3.2) as temperature varies with altitude, so does density. In general, the air grows progressively less dense as we move upward from the troposphere through the stratosphere and the chemosphere to ionosphere. In the upper reaches of the ionosphere, the gaseous molecules are few and far between as compared with the troposphere.

The ionosphere and chemosphere are of interest to space scientists because they must be traversed by space vehicles en route to or from the moon or the planets, and they are regions in which satellites travel in the Earth's orbit. These regions are of interest to communications scientists because of their influence on radio communications and they are of interest to air pollution scientists primarily because of their absorption and scattering of solar energy, which influences the amount and spectral distribution of solar energy and cosmic rays reaching the stratosphere and troposphere.

The stratosphere is of interest to aeronautical scientists because it is traversed by airplanes; to communications scientists because of radio and television communications; and to air pollution scientists because global transport of pollution, particularly the debris of aboveground atomic bomb tests and volcanic eruptions occur in this region and because absorption and scattering of solar energy also occur there. The lower portion of this region contains the stratospheric ozone layer which absorbs harmful UV solar radiation. Global change scientists are interested in modifications of this layer by long‐term accumulation of chlorofluorocarbons and other gases released at the Earth's surface or by high‐altitude aircraft.

The troposphere is the region in which we live and is the primary focus of this book.

3.9.2 Unpolluted Air

The gaseous composition of unpolluted tropospheric air is given in Table 3.7. Unpolluted air is a concept, i.e., what the composition of the air would be if humans and their works were not on Earth. We will never know the precise composition of unpolluted air because by the time we had the means and the desire to determine its composition, humans had been polluting the air for thousands of years. Now even at the most remote locations at sea, at the poles, and in the deserts and mountains, the air may be best described as dilute polluted air. It closely approximates unpolluted air, but differs from it to the extent that it contains vestiges of diffused and aged human‐made pollution.

The real atmosphere is more than a dry mixture of permanent gases. It has other constituents‐vapor of both water and organic liquids and particulate matter held in suspension. Above their temperature of condensation, vapor molecules act just like permanent gas molecules in the air. The predominant vapor in the air is water vapor. Below its condensation temperature, if the air is saturated, water changes from vapor to liquid. We are all familiar with this phenomenon because it appears as fog or mist in the air and as condensed liquid water on windows and other cold surfaces exposed to air. The quantity of water vapor in the air varies greatly from almost complete dryness to super‐saturation, i.e., between 0 and 4% by weight. Gaseous composition in Table 3.7 is expressed as parts per million by volume – ppm (vol) (when a concentration is expressed simply as ppm).

3.9.3 Mobile Sources and Emission Inventory

Generally, mobile sources imply transportation, but sources such as construction, equipment, gasoline‐powered lawn mowers, and gasoline‐powered tools are included in the category. Mobile sources, therefore, consists of many different types of vehicles powered by engines using different cycles, fueled by a variety of products and emitting varying amounts of both simple and complex pollutants. The emissions from a gasoline‐powered vehicle come from many sources. With most of today's automobiles using unleaded gasoline, lead emissions are no longer a major concern.

An emission inventory is a list of the amount of pollutants from all sources entering the air in a given time period. The boundaries of the area are fixed. The emission inventories are very useful to control agencies as well as planning and zoning agencies. They can point out the major sources whose control can lead to a considerable reduction of pollution in the area. They can be used with appropriate mathematical models to determine the degree of overall control necessary to meet ambient air quality standards. They can be used to indicate the type of sampling network and the locations of individual sampling stations if the areas chosen are small enough. For example, if an area uses very small amounts of sulfur‐bearing fuels, establishing an extensive SO₂ monitoring network in the area would not be an optimum use of public funds. Emission inventories can be used for publicity and political purposes: “If natural gas cannot meet the demands of our area, we will have to burn more high‐sulfur fuel, and the SO₂ emissions will increase by 8 tons per year.”

The method used to develop the emission inventory does have some elements of error, but the other two alternatives are expensive and subject to their own errors. The first alternative would be to monitor continually every major source in the area. The second method would be to monitor continually the pollutants in the ambient air at many points and apply appropriate diffusion equations to calculate the emissions. In practice, the most informative system would be a combination of all three, knowledgeably applied.

The US Clean Air Act Amendments of 1990 (CAAA) strengthened the emission inventory requirements for plans and permits in non‐attainment areas. The amendments state:

INVENTORY – Such plan provisions shall include a comprehensive, accurate, current inventory of actual emissions from all sources of the relevant pollutant or pollutants in such area, including such periodic revisions as the Administrator may determine necessary to assure that the requirements of this part are met.

IDENTIFICATION AND QUANTIFICATION – Such plan provisions shall expressly identify and quantify the emissions, if any, of any such pollutant or pollutants which will be allowed, from the construction and operation of major new or modified stationary sources in each such area. The plan shall demonstrate to the satisfaction of the Administrator that the emissions quantified for this purpose will be consistent with the achievement of reasonable further progress and will not interfere with the attainment of the applicable national ambient air quality standard by the applicable attainment date.

3.9.4 Inventory Techniques

To develop an emission inventory for an area, one must (i) list the types of sources for the area, such as furnaces, automobiles, and home fireplaces; (ii) determine the type of air pollutant emission from each of the listed sources, such as particulates and SO₂; (iii) examine the literature to find valid emission factors for each of the pollutants of concern (e.g. “particulate emissions for open burning of waste wood or sawdust are 10 kg per ton of residue consumed”); (iv) through an actual count, or by means of some estimating technique, determine the number and size of specific sources in the area (the number of steelmaking furnaces can be counted, but the number of home fireplaces will probably have to be estimated); and (v) multiply the appropriate numbers from (iii) and (iv) to obtain the total emissions and then sum the similar emissions to obtain the total for the area.

A typical example will illustrate the procedure. Suppose we wish to determine the amount of carbon monoxide from oil furnaces emitted per day, during the heating season, in a small city of 50 000 population:

1. The source is oil furnaces within the boundary area of the city.
2. The pollutant of concern is carbon monoxide.
3. Emission factors for carbon monoxide are listed in various ways (240 gm/1000 l of fuel oil, 50 gm/day/burner, 1½% by volume of exhaust gas, etc.). For this example, use 240 gm/1000 l of fuel oil.

   Fuel oil sales figures, obtained from the local dealers association, average 40 000 l/day.

3.9.5 Data Reduction and Compilation

The final emission inventory can be prepared on a computer. This will enable the information to be stored on magnetic tape or disk so that it can be updated rapidly and economically as new data or new sources appear. The computer program can be written so that changes can easily be made. There will be times when major changes occur and the inventory must be completely changed. Imagine the change that would take place when natural gas first becomes available in a commercial‐residential area which previously used oil and coal for heating.

To determine emission data, as well as the effect that fuel changes would produce, it is necessary to use the appropriate thermal conversion factor from one fuel to another. Table 3.2 lists these factors for fuels in common use.

A major change in the emissions for an area will occur if control equipment is installed. This can be shown in the emission inventory to illustrate the effect on the community.

By keeping the emission inventory current and updating it at least yearly as fuel uses change, industrial and population changes occur and control equipment is added, a realistic record for the area is obtained.

3.9.6 Major Sources of Air Emissions

3.9.7 1990 Clean Air Act Amendments

On 15 November 1990, the President signed the amendments to the CAA, referred to as the 1990 CAAA. Embodied in these amendments were several progressive and creative new themes deemed appropriate for effectively achieving the air quality goals and for reforming the air quality control regulatory process (USEPA 1990). Specifically, the amendments:

1. Encouraged the use of market‐based principles and other innovative approaches similar to performance‐based standards and emission banking and trading.
2. Promoted the use of clean low‐sulfur coal and natural gas, as well as innovative technologies to clean high‐sulfur coal through the acid rain program.
3. Reduced energy waste and created enough of a market for clean fuels derived from grain and natural gas to cut dependency on oil imports by over million barrels per day.
4. Promoted energy conservation through an acid rain program that gave utilities flexibility to obtain needed emission reductions through programs that encouraged customers to conserve energy.

3.9.8 Introduction to Air Pollution Control and Estimating Air Emission Rates

Air pollution control has become an essential part of operations for many industries particularly the chemical process industries. In developed countries, air quality problems are attributable to the by‐products of combustion processes used in the private and public transportation sectors of the economy, as well.

Frequently; however, planners fail to acknowledge that control systems themselves are industrial processes that consume energy and can emit significant amounts of pollutants into the atmosphere. Regulators have tended to pursue the control of each target pollutant independently with little consideration of secondary pollutants.

In the United States, for example, regulation of air pollution started with the largest sources because they had the most potential for immediate environmental improvement and because the major corporations responsible for these sources could reasonably be asked to assimilate the costs of added controls. The next regulatory phase saw a progressive tightening of standards and application of limits to more and smaller sources, with priority pollutants targeted as separate and distinct entities to be controlled.

3.9.8.3 What Is an AP‐42 Emission Factor?

An emission factor is a representative value that attempts to relate the quantity of a pollutant released to the atmosphere with an activity associated with the release of that pollutant. These factors are usually expressed as the weight of pollutant divided by a unit weight, volume, distance, or duration of the activity emitting the pollutant (e.g. kilograms of particulate emitted per megagram of coal burned). Such factors facilitate estimation of emissions from various sources of air pollution. In most cases, these factors are simply averages of all available data of acceptable quality and are generally assumed to be representative of long‐term averages for all facilities in the source category (i.e. a population average).

The general equation for emission estimation is

(3.3)

where

• E = emissions,
• A = activity rate,
• EF = emission factor, and
• ER = overall emission reduction efficiency, %.

ER is further defined as the product of the control device destruction or removal efficiency and the capture efficiency of the control system. When estimating emissions for a long time period (e.g. one year) both the device and the capture efficiency terms should account for upset periods as well as routine operations.

3.9.8.10 Methods for Estimating Fugitive Emissions

The USEPA has established a number of methods for estimating fugitive emissions (USEPA 1988, 1995). The methods vary in the time and expense they require and as would be expected, the more time‐consuming and costly methods result in a more accurate estimate of emissions. The least accurate and least costly method for estimating fugitive emissions is to count all the potential sources of releases and apply an average “emission factor,” according to the formula:

(3.4)

where E is the emission rate of VOCs from a component, m_voc is the mass fraction of VOC in the stream serviced by the component, and f_av is the average emission factor.

Portable gas leak imaging cameras are also a new technology that can be used to improve leak detection and repair, leading to reduced fugitive emissions. The cameras use infrared imaging technology to produce video images in which invisible gases escaping from leak sources can be clearly identified. The average emission factors for fugitive emissions from synthetic organic chemical manufacturing industry (SOCMI), including petroleum refining and natural gas plants, are given in Table 3.11.

			Emission factors (kg/h/source)
Equipment	Service	SOCMIa	Refineryb	Gas plantc
Valves	Hydrocarbon gas	0.005 97	0.027	—
	Light liquid	0.004 03	0.011	—
	Heavy liquid	0.000 23	0.000 2	—
	Hydrogen gas	—	0.008 3	—
	All	—	—	0.020
Pump seals	Light liquidd	0.019 9	0.11	—
	Heavy liquid	0.008 62	0.021	—
	Liquidd	—	—	0.063
Compressor seals	Hydrocarbon gas	0.228	0.63	—
	Hydrogen gas	—	0.050	—
	All	—	—	0.204
Pressure‐relief valves	Hydrocarbon gas	0.104	0.16	—
	Liquid	0.007 0e	0.007 0e	—
	All	—	—	0.188
Flanges and other
Connectors	All	0.001 83	0.000 25	0.001 1
Open‐ended lines	All	0.001 7	0.002	0.022
Sampling connections	All	0.015	—	—

^a SOCMI: Synthetic Organic Chemical Manufacturing Industry.

^b USEPA (1985a) except as noted.

^c USEPA (1993) except noted.

^d This factor can be used to estimate the leak rate from agitator seals.

^e USEPA (1985b).

Equipment type	Emissions (lb/year)	Percent of emissions by equipment type
Valves	100 250	47.52
Flanges	93 717	44.42
Pumps	9 027	4.28
Pressure‐relief valves	2 352	1.11
Open‐ended lines	600	0.28
Sampling connections	5 040	2.38
Total	211 000	100

3.19.1 Industrial Wastes Management Approach

In this section, we will focus on the best available industrial processes, techniques, and technologies that treat wastestreams, including sold and hazardous wastes, as well as innovative and emerging processes that have better potential for achieving the highest standards in pollution prevention at the plant level, leading to zero effect and zero defect (ZED). To move toward ZED via “process pollution prevention” (P3), industries must use processes that deploy materials and energy efficiently enough to neutralize contaminants in the waste stream. The ultimate goal is to remove pollutants from the waste streams and convert them into products or feeds for other processes. Logically then, P3 refers to industrial processes by which materials and energy are efficiently utilized to achieve the end product(s) while reducing or eliminating the creation of pollutants or waste at the source.

Industrial waste is the waste produced by industrial activity which includes any material that is rendered useless during a manufacturing process such as that of factories, industries, mills, mining operations, and thermal and nuclear power plant. Some examples of industrial wastes are chemical solvents, pigments, sludge, metals, ash, paints, sandpaper, paper products, industrial by‐products, metals, and radioactive wastes.

Toxic waste, chemical waste, industrial solid waste, and municipal solid waste (i.e. primary and secondary sludge from POTWs) are designations of industrial wastes. Wastewater treatment plants can treat some industrial wastes, i.e. those consisting of conventional pollutants such as BOD, COD, and TSS). Industrial wastes containing toxic pollutants require specialized treatment systems.

3.19.2 Waste as Pollution

A waste is defined as an unwanted by‐product or damaged, defective, or superfluous material of a manufacturing process. Most often, in its current state, it has or is perceived to have no value. It may or may not be harmful or toxic if released to the environment. Pollution is any release of waste to environment (i.e. any routine or accidental emission, effluent, spill, discharge or disposal to the air, land, or water) that contaminates or degrades the environment.

In 2010, Americans generated about 270 million T of municipal solid waste (MSW), an increase of 16% over 2000 and 53% over 1980 (USEPA 2012). Thus, management of MSW continues to be an important challenge facing the United States and other highly industrialized nations in the twenty‐first century. Solid waste management is critical in the developed world, and developing world as well, where age‐old traditions of wasting nothing (recycle and reuse) are often followed without regard to the significance and implications of the ZED concept.

3.19.3 Why Recycle?

Each ton of solid waste diverted from disposal, whether reused, recycled, converted in a waste‐to‐energy (WtE) program or composted is one less ton of solid waste requiring disposal. To see the value of reusing, recycling, and composting solid waste, one need to simply consider the amount of disposal space required to accept that material. By implementing environmentally benign waste management strategies (as well as resource‐management strategies), a population can reduce its dependence on incinerators and landfills. And when recycled materials are substituted for virgin plastics, metal ores, minerals, glass, paper and trees, there is less pressure to expand the chemical, mining, and forestry industries. Supplying industry with recycled materials is preferable to extracting virgin resources from mines and forests not only because it conserves scarce natural resources but because it reduces dangerous air and water pollutants, such as greenhouse‐gas emissions and saves energy.

Saving energy is an important environmental benefit of recycling because generating energy usually requires fossil‐fuel consumption and results in emissions that pollute the air and water. The energy required to manufacture paper, plastics, glass, and metal from recycled materials is generally less than the energy required to produce them from virgin materials. Additionally, the collection, processing, and transportation of recycled materials typically uses less energy than the extraction, refinement, transportation, and processing steps to which virgin materials must be subjected before industry can use them.

As is well known, a great amount of energy used in industrial processes and in transportation comes from the burning of fossil fuels. Recycling helps stem the dangers of global climate change by reducing the amount of energy used by industry, thus reducing greenhouse‐gas emissions as well.

3.19.4 Chemical Waste

Chemical waste is a waste that is made from harmful chemicals (mostly produced by large factories). Chemical waste may fall under regulations such as COSHH in the United Kingdom, or the CWA and Resource Conservation and Recovery Act (RCRA) in the United States. In the United States, the EPA and the Occupational Safety and Health Administration (OSHA), as well as state and local regulations also regulate chemical use and disposal (Hallam 2010). Chemical waste may or may not be classed as hazardous waste. A chemical hazardous waste is a solid, liquid, or gaseous material that displays either a “hazardous characteristic” or is specifically “listed” by name as a hazardous waste (for HAPs, see Appendix C.1). There are four characteristics chemical wastes may have to be considered as hazardous. These are ignitability, corrosivity, reactivity, and toxicity. This type of hazardous waste must be categorized as to its identity, constituents, and hazards so that it may be safely handled and managed (University of Pennsylvania 2016). Chemical waste is a broad term and encompasses many types of materials. Consult the Material Safety Data Sheet, Product Data Sheet, or Label for a list of constituents. These sources should state whether this chemical waste is a waste that needs special disposal (University of Pennsylvania 2016).

3.19.5 Electronic Waste

Electronic waste in the United States have become an ever‐growing problem in the United States. Each year, over 3.2 million T of electronic waste is put in US landfills. A large portion of this electronic waste is computers, monitors, and televisions. Over 100 million computers, monitors, and televisions are disposed of yearly in the United States (Weidenhamer and Clement 2007). Although there is an enormous amount of electronic waste in the United States, the EPA found that in 2009 approximately only about 25% of all electronic waste is recycled in the United States. About 70% of metals that are found in the United States landfills come from electronic devices. The disposal of all this electronic waste has a detrimental effect on the environment, as well as the global economy.

Electronic waste has become serious issue for the environmental stability in the United States. Over the years, the government has become increasingly more involved in this issue. As described in the USEPA office of RCRA report of 2009, after the electronic products are purchased and used, they are separated into two groups. One group of electronics is collected for recycling, while the other is disposal. After this, the products that are at disposal mainly are put into landfills, and the rest of the electronics that were collected for recycling are either refurbished, reused, or used for material (Stephenson 2008). Hans Tammemagi, the author of The Waste Crisis, talks about the detrimental effect the waste has on the environment. Nearly 20% of all waste in the United States is being incinerated, while the rest of it is being put into landfills (Tammemagi 1999). That leaves almost 80% of the waste consumed in the United States being placed into landfills. Out of this 80% of the waste, the majority of this waste is primarily electronic.

3.20.1 Hazardous Wastes in the United States of America

A US facility that treats, stores, or disposes of hazardous waste must obtain a permit for doing so under the RCRA. Generators and transporters of hazardous waste must meet specific requirements for handling, managing, and tracking waste. Through the RCRA, Congress directed the EPA to create regulations to manage hazardous waste. Under this mandate, the EPA developed strict requirements for all aspects of hazardous waste management including the treatment, storage, and disposal of hazardous waste. In addition to these federal requirements, states may develop more stringent requirements that are broader in scope than the federal regulations. Furthermore, RCRA allows states to develop regulatory programs that are at least as stringent as RCRA and, after review by EPA, the states may take over responsibility for the implementation of the requirements under RCRA. Most states take advantage of this authority, implementing their own hazardous waste programs that are at least as stringent, and in some cases are more stringent than the federal program.

3.20.2 Hazardous Waste Mapping Systems

The US government provides several tools for mapping hazardous wastes to particular locations. These tools also allow the user to view additional information.

1. TOXMAP is a Geographic Information System from the Division of Specialized Information Services of the United States National Library of Medicine (NLM) that uses maps of the United States to help users visually explore data from the USEPA's Toxics Release Inventory and Superfund Basic Research Programs. This is a resource funded by the US federal government. TOXMAP's chemical and environmental health information is taken from NLM's Toxicology Data Network and PubMed, and from other authoritative sources.
2. The USEPA “Where You Live” (Chaudhary and Rachana 2006) allows users to select a region from a map to find information about Superfund sites in that region.

3.20.3 Universal Wastes

Universal wastes are a special category of hazardous wastes that (in the United States):

• generally pose a lower threat relative to other hazardous wastes that are ubiquitous and produced in very large quantities by a large number of generators.

Some of the most common “universal wastes” are fluorescent light bulbs, some specialty batteries (e.g. lithium‐ or lead‐containing batteries), cathode ray tubes, and mercury‐containing devices.

Universal wastes are subject to somewhat less stringent regulatory requirements. Small quantity generators of universal wastes may be classified as “conditionally exempt small quantity generators” which release them from some of the regulatory requirements for the handling and storage of hazardous wastes. Universal wastes must still be disposed of properly at a regional or county landfill facility.

3.20.4 Final Disposal of Hazardous Waste

Historically, some hazardous wastes were disposed of in regular landfills. This resulted in unfavorable amounts of hazardous materials seeping into the ground. These chemicals eventually entered to natural hydrologic systems. Many landfills now require countermeasures against groundwater contamination. For example, a barrier has to be installed along the foundation of the landfill to contain the hazardous substances that may remain in the disposed waste. Currently, hazardous wastes must often be stabilized and solidified in order to enter a landfill and must undergo different treatments in order to stabilize and dispose them. Most flammable materials can be recycled into industrial fuel. Some materials with hazardous constituents can be recycled, such as lead acid batteries.

3.20.5 Recycling

Some hazardous wastes can be recycled into new products. Examples may include lead‐acid batteries or electronic circuit boards. When heavy metals in these types of ashes go through the proper treatment, they could bind to other pollutants and convert them into easier‐to‐dispose solids, or they could be used as pavement filling. Such treatments reduce the level of threat of harmful chemicals, like fly and bottom, while also recycling the safe product.

3.20.6 Portland Cement

Another commonly used treatment is cement‐based solidification and stabilization. Cement is used because it can treat a range of hazardous wastes by improving physical characteristics and decreasing the toxicity and transmission of contaminants. The cement produced is categorized into five different divisions, depending on its strength and components. This process of converting sludge into cement might include the addition of pH adjustment agents, phosphates, or sulfur reagents to reduce the settling or curing time, increase the compressive strength, or reduce the leach ability of contaminants.

3.22.1 Pyrolysis

Some hazardous waste types may be eliminated using pyrolysis in an ultrahigh temperature electrical arc, in inert conditions to avoid combustion. This treatment method may be preferable to high‐temperature incineration in some circumstances such as in the destruction of concentrated organic waste types, including PCBs, pesticides, and other persistent organic pollutants (RCRA, USEPA, Title 40 CFR 261).

3.23.1 Sources

Radioactive waste comes from a number of sources. In countries with nuclear power plants, nuclear armament or nuclear fuel treatment plants, the majority of waste originates from the nuclear fuel cycle and nuclear weapons reprocessing. Other sources include medical and industrial wastes as well as naturally occurring radioactive materials (NORM) that can be concentrated as a result of the processing or consumption of coal, oil, and gas and some minerals as discussed below.

3.23.2 Nuclear Fuel Cycle

3.24.1 Oil and Gas

Residues from the oil and gas industry often contain radium and its decay products. The sulfate scale from an oil well can be very radium rich, while the water, oil, and gas from a well often contain radon. The radon decays to form solid radioisotopes which form coatings on the inside of pipe‐work. In an oil‐processing plant, the area of the plant where propane is processed is often one of the more contaminated areas of the plant as radon has a similar boiling point to propane.

3.25.1 Intermediate‐Level Waste

Intermediate‐level waste (ILW) contains higher amounts of radioactivity and in general require shielding, but not cooling (USNRC, April 3 2017). ILWs includes resins, chemical sludge, and metal nuclear fuel cladding, as well as contaminated materials from reactor decommissioning. It may be solidified in concrete or bitumen for disposal. As a general rule, short‐lived waste (mainly nonfuel materials from reactors) is buried in shallow repositories, while LLW (from fuel and fuel reprocessing) is deposited in geological repository. US regulations do not define this category of waste; the term is used in Europe and elsewhere.

3.25.2 High‐Level Waste

High‐level waste (HLW) is produced by nuclear reactors. The exact definition of HLW differs internationally. After a nuclear fuel rod serves one fuel cycle and is removed from the core, it is considered HLW (Janicki 2013). Fuel rods contain fission products and transuranic elements generated in the reactor core. Spent fuel is highly radioactive and often hot. HLW accounts for over 95% of the total radioactivity produced in the process of nuclear electricity generation. The amount of HLW worldwide is currently increasing by about 12 000 MT every year, which is the equivalent to about 100 double‐decker buses or a two‐story structure with a footprint the size of a basketball court (Rogner 2010). A 1000‐MW nuclear power plant produces about 27 T of spent nuclear fuel (unreprocessed) every year (Myths and Realities of Radioactive Waste, Feb. 2017). In 2010, there was very roughly estimated to be stored some 250 000 T of nuclear HLW (World Nuclear Association, July 2015) that does not include amounts that have escaped into the environment from accidents or tests. Japan estimated to hold 17 000 T of HLW in storage in 2015 (Geere 2010). HLWs have been shipped to other countries to be stored or reprocessed, and in some cases, shipped back as active fuel.

The ongoing controversy over high‐level radioactive waste disposal is a major constraint on the nuclear power's global expansion (Humber 2015). Most scientists agree (Findlay 2010) that the main proposed long‐term solution is deep geological burial, either in a mine or a deep borehole. However, almost six decades after commercial nuclear energy began, no government has succeeded in opening such a repository for civilian high‐level nuclear waste (Humber 2015), although Finland is in the advanced stage of the construction of such facility, the Onkalo spent nuclear fuel repository. Reprocessing or recycling spent nuclear fuel options already available or under active development still generate waste and so are not a total solution, but it can reduce the sheer quantity of waste, and there are many such active programs worldwide. Deep geological burial remains the only responsible way to deal with high‐level nuclear waste (World Nuclear Association 2015). The Morris Operation is currently the only de facto high‐level radioactive waste storage site in the United States.

3.25.3 Transuranic Waste

Transuranic waste (TRUW) as defined by US regulations is, without regard to form or origin, waste that is contaminated with alpha‐emitting transuranic radionuclides with half‐lives greater than 20 years and concentrations greater than 100 nCi/g (3.7 MBq/kg), excluding HLW. Elements that have an atomic number greater than uranium are called transuranic (“beyond uranium”). Because of their long half‐lives, TRUW is disposed more cautiously than either low‐ or intermediate‐level waste. In the United States, it arises mainly from weapons production and consists of clothing, tools, rags, residues, debris, and other items contaminated with small amounts of radioactive elements (mainly plutonium).

Under US law, transuranic waste is further categorized into “contact‐handled” (CH) and “remote‐handled” (RH) on the basis of the radiation dose rate measured at the surface of the waste container. CH TRUW has a surface dose rate not greater than 200 mrem/h (2 mSv/h), whereas RH TRUW has a surface dose rate of 200 mrem/h (2 mSv/h) or greater. CH TRUW does not have the very high radioactivity of HLW nor its high heat generation, but RH TRUW can be highly radioactive, with surface dose rates up to 1 000 000 mrem/h (10 000 mSv/h). The United States currently disposes of TRUW generated from military facilities at the Waste Isolation Pilot Plant in a deep salt formation in New Mexico (Biello 2011).

3.26.1 Initial Treatment