Energy Relationships In Sound

The magnitudes most used to describe the energy involved in sound or noise are sound pressure and sound power. Pressure, either static (barometric) or dynamic (sound vibrations), is the magnitude most easily observed. Sound pressure is usually measured as an RMS value whether this value is specified or not but peak values are sometimes also used. From the threshold of hearing to the threshold of pain, sound pressure values range from 0.0002 to 1000 or more dynes per square centimeter (Table...

Removal Mechanisms

The predominant mechanisms responsible for removing SS in granular filtration systems have been previously discussed. As shown in Figure 7.33.5, surface screening is not a predominant removal mechanism in this type of system, and solids are retained deep within the voids of the media. This system requires intensive backwashing (see Figure 7.33.6) to dislodge the entrapped solids that accumulate during the filtration process. Surface wash systems are acceptable only if screening is the...

285

Source Council on Environmental Quality, 1993, Environmental quality, 23rd Annual Report (Washington, D.C. U.S. Government Printing Office January ). Notes PMSA Primary Metropolitan Statistical Area. PSI Pollutant Standards Index. na not applicable. The PSI index integrates information from many pollutants across an entire monitoring network into a single number which represents the worst daily air quality experienced in the urban area. Only carbon monoxide and ozone monitoring sites with...

Info

FIG. 3.8.15 Continuous emulsion liquid membrane extraction. (Reprinted, with permission from R. Marr, H. Lackner, and J. Draxler, 1989, VTT Symposium 102. Vol. 1, 345.) ial transfer takes place. In the sedimentation stage, the continuous phase is separated from the emulsion by gravity. In the emulsion-breaking stage, the W O emulsion is broken, and the organic inner phase is separated. Compared to LLE, liquid membrane extraction, has the following advantages Is more compact because the...

Noiselevel Specifications

The best way of controlling noise at its source is to buy quieter machines. Buying quieter machines is almost always more economical than trying to reduce noise by modifying the machine after purchase. Everyone profits from quieter machines the employees' hearing is better protected, work is performed more efficiently, and the employer gains from increased production and product quality. The purchase order should specify the maximum permissible noise levels for equipment as listed in the Table...

Flocculants

Flocculants are water-soluble, organic polyelectrolytes that are used alone or in conjunction with inorganic coagulants or coagulant aids to agglomerate solids suspended in aqueous systems. The large dense flocs resulting from this process permit more rapid and efficient solids-liquid separation. Separating SS from raw water and wastewater for purification generally involves gravity settling in large clari-fiers operating at low velocity gradients prior to a secondary biological process, a...

Mechanical Bar Screen And Grit Collector

A combined mechanical screen and grit collector is available for small- and medium-sized plants (see Figure 7.14.4). The unit is similar to a frontcleaned mechanical screen except that the rakes are attached to one or more perforated buckets and a steep hopper to collect the grit is ahead of the screen. The buckets travel downward, and the grit is dewatered on upward travel by perforations in the buckets. The disadvantage of this combined solution, however, is that the screenings and grit are...

Elimination Of Water

Eliminating water in certain operations eliminates attendant wastewater treatment problems. Wherever possible, food should be handled by either a mechanical belt or pneumatic dry conveying system. If possible, the food should be cooled in an air system. Recent studies by the National Canners Association in comparing hot air blanching of vegetables with conventional hot water blanching show that both product and environmental quality were improved by using air. Blanching, used to deactivate...

Conventional Sewage Treatment Plants

This section describes a conventional sewage treatment plant, emphasizing the total plant concept. Conventional plants are best identified by what they do not achieve, namely nutrient removal, demineralization, and the removal of trace organics. Therefore, the conventional plant's performance is usually measured by reductions in suspended matter, BOD, and bacteria. The processes in conventional plants include 1) pre-treatment, 2) settling, 3) chemical treatment, 4) biological oxidation, 5)...

Radon Detection

The two most common radon testing devices are the charcoal canister and the alpha-check detector. Alpha-check detectors are ideal for making long-term measurements but are not suited for quick results (Lafavore 1987). A charcoal-adsorbent detector is the most practical approach for most. This test method is low-cost the price for a single unit ranges from 10 to 50 (Cohen 1987). However, a disadvantage of charcoal is its sensitivity to temperature and humidity. Charcoal-adsorbent detectors...

10

Note This rate is lower than the solids rate obtained from slurry flow because of solids passing through cloth. Note This rate is lower than the solids rate obtained from slurry flow because of solids passing through cloth. and a pH of 7. Therefore, as the proportion of industrial waste in a system increases, the ratio of total BOD (dissolved and suspended) to SS increases. High polymers in industrial waste forms colloidal suspensions or solutions.

Pollution Control Laws

Specific Provisions Other Features Summary Resource Conservation and Recovery Act Comprehensive Environmental Response, Compensation, and Liability Act Specific Provisions Summary Noise Control Act Statutory Roadmap Purpose Specific Provisions Summary Safe Drinking Water Act Statutory Roadmap Purpose Specific Provisions Summary Federal Water Pollution Control Act Statutory Roadmap Purpose Summary Toxic Substances Control Act Statutory Roadmap Purpose Specific Provisions TSCA's Limited...

Electrical Properties

Since oil is an insulator, o w emulsions conduct an electrical current, whereas w o emulsions ordinarily do not. Researchers have studied the conductivity of emulsions by measuring the current flowing between two fixed platinum electrodes immersed in the emulsion. The dielectric properties of emulsion systems are different from the average of the individual phases. The dielectric constant is important because of its intimate relationship to emulsion stability. The dielectric properties of an...

ISO 14000 Environmental Standards

ISO 14000 is a different kind of environmental standard than others discussed in this chapter. It is a series of process standards developed by the International Organization for Standardization (ISO). They consist of a family of voluntary environmental management standards and guidelines. The purpose of the standards is to establish an organizational environmental ethic and enhance an organization's ability to measure and attain standards of environmental performance. As such, it has the...

Leak Detection

Release detection requirements differ between petroleum USTs and hazardous waste USTs. Petroleum UST systems may choose from among five primary release detection methods, for example 1) automatic tank gauging that tests for product loss and conducts inventory control 2) testing or monitoring for vapor within the soil gas of the tank area and 3) testing or monitoring for liquids in the ground-water. Hazardous substance tanks must use secondary containment systems such as double-walled tanks or...

Sources

Most dry processing operations generate dust. Generation points include the following Screening or classifying of materials Generally, these materials are finely divided products that are easily airborne, resulting in sanitation problems and possibly fire or explosions.

Analyzing Air Emissions

The technologies for sampling air are many and varied. The choice of the air sampling and analysis method de- A. 2 ports, 90 apart with diameter less than 10 ft + port length 4 ports, 90 apart with diameter over 10 ft + port length At least two stack diameters above stack exit 115-V, 15-A, single phase, 60-Hz AC located on platform At least eight stack diameters below last obstruction A. At least 3 ft wide (4 ft wide for stacks with 10 ft or greater I.D.) and capable of supporting three people...

Afbr

The AFBR is an expanded-bed reactor that retains media in suspension from drag forces exerted by upflowing wastewater. Part D in Figure 7.28.2 shows the process schematic. Fluidization of the media particles provides a large surface area where biofilm formation and growth can occur. The media particles have a high density resulting in a settling velocity that is high enough so that high-liquid-velocity conditions can be maintained in the reactor. However, the media particles' overall density...

Waste Minimization

Figure 3.11.10 summarizes a suggested approach for applying pinch technology to environmental problems (Spriggs, Smith, and Petela 1990). Waste minimization is clearly the place to start. Solving environmental problems at the source is not always the simplest solution, but it is usually the most satisfactory solution in the long term. Reducing the problem at the source by modifications to the process reaction and separation technology has the dual benefit of reducing raw material and effluent...

O

Pesticides, Herbicides, Insecticidesa Manufacturing of ethylbenzene (for styrene monomer) dodecylbenzene (for detergents) cyclohexane (for nylon) phenol nitrobenzene (for aniline) maleic anhydride chlorobenzene hexachloride benzene sulfonic acid and as a solvent Intermediate in the production of styrene and as a solvent Aviation gasoline and high-octane blending stock benzene, phenol, and caprolactam solvent for paints and coatings, gums, resins, most oils, rubber, vinyl organosols diluent and...

Table 334 Maintenancebased Strategies

Existing Preventive Maintenance (PM) Program Include centrifuges, dryers, and other process equipment in the PM program. Include conveyors and other material handling equipment in the PM program. Minimize pipe and connector stresses caused by vibration of pumps and compressors. Minimize air leaks into VOC-containing equipment operating under vacuum. Minimize steam leaks into process equipment. Adjust burners to optimize the air-to-fuel ratio. Implement a computerized inventory tracking system...

Table 331 Engineering Designbased Pollution Prevention Strategies

Install geodesic domes for external floating-roof tanks. Store VOCs in floating-roof tanks instead of fixed-roof tanks. Store VOCs in low-pressure vessels instead of atmospheric storage tanks. Use onsite boilers instead of wet scrubbers for air pollution control. Select vessels with smooth internals for batch tanks requiring frequent cleaning. Install curbs around tank truck unloading racks and other equipment located outdoors. Load VOC-containing vessels via dip pipes instead of splash...

Bibliography

American Society for Testing and Materials (ASTM). 1989. Standard specifications for waste glass as a raw material for the manufacture of glass containers. E708-79 (Reapproved 1988). Vol. 11.04 in 1989 Annual book of standards, 299-300, Philadelphia ASTM. Bagchi, A. 1990. Design, construction and monitoring of sanitary landfill. New York John Wiley & Sons. Baillie, R.C. and M. Ishida. 1971. Gasification of solid waste materials in fluidized beds. 69thNationalA.I.Ch.E. Meeting, Cincinnati,...

R F T

The potential under standard conditions of unit activity referred to the SHE the gas constant, 1.986 cal per mol degree Faraday's constant temperature in K number of electrons exchanged in the reaction Table 7.7.5 shows how the n values change from reaction to reaction. These changes, plus the fact that a given ORP reaction can encompass side reactions, reveal why it is difficult, if not impossible, to temperature-compensate an ORP reaction. In the Nernstian representation of pH, n always...

Analytical Methods Gross Alpha Beta

A proportional counter with heavy shielding is recommended for this method. The instrument is calibrated by adding radionuclide standards to a matrix similar to the sample. A standard solution of cesium 137 or strontium 90 certified by the National Institute of Standards and Technology (NIST) is suitable for gross beta analysis. A solution of natural uranium, thorium, plutonium 239 or americium 241 is recommended for gross alpha analysis. Gross alpha-beta results are always reported in...

Electrostatic Precipitation

Particulate matter can be quantitatively removed from air by ESPs. Devices that operate on the same principal but are much larger are frequently used to remove particulate matter from stack gases prior to discharging into the atmosphere. Several commercially available ESPs can be used for air sampling, and all operate on the same general principle of passing the air between charged surfaces, imparting a charge to particles in the air, and collecting the particles on an oppositely charged...

Feature Summary

Type of Process Biological treatment of liquid hazardous wastewaters. Type of Reactor Sequencing Batch Reactor (SBR), a fill-and-draw, activated sludge-type system where aeration and settling occur in the same tank. Type of Aeration and Mixing Systems Jet-aeration systems are common and allow mixing either with or without aeration however, other aeration and mixing systems are used. Type of Decanters Most decanters, including some which are patented, float or otherwise maintain inlet orifices...

Typical Range of Noise Levels

In rural areas, ambient noise can be as low as 30 dB even in residential areas in or near cities, this low level is seldom achieved. In urban areas, the noise level can be 70 dB or higher for eighteen hours of each day. Near freeways, 90 to 100 dB levels are not unusual. Many industries have high noise levels. Heavy industries such as iron and steel production and fabricating and mining display high levels so do refineries and chemical plants, though in the...

003

Hoak, 1950, Sewage and Ind. Wastes 22 212. Notes aCa(OH)2 waste product. From CaC2 + 2H2O d C2H2+ + Ca(OH)2 Source R.D. Hoak, 1950, Sewage and Ind. Wastes 22 212. Notes aCa(OH)2 waste product. From CaC2 + 2H2O d C2H2+ + Ca(OH)2 priate control equipment to protect against freezing during winter. As with lime, neutralization reactions depend on the acid or acids being neutralized as follows 2NaOH + H2SO4 Na2SO4 + 2H2O 7.39(9) NaOH + HCl NaCl + H2O 7.39(10) For the reactions described...

Wave Action

Waves cause cross-coupled surge, heave, and roll of the boom. If wave surge and current tension loads are taken through an independent bridle, they will have a minimum tendency to constrain the boom's heave response. Minimizing boom mass tends to increase the natural heave frequency and minimize the lag in heave response. Thus, ballasting for stability or even adding weight for flotation can be critical to heave. Flotation placement away from the faces of the boom yields stability and decreased...

Specific Speed

The impeller's rotational speed affects the capacity, efficiency, and extent of cavitation. Even if the suction lift is within permissible limits, cavitation can be a problem and should be checked. The specific speed of the pump is determined with the following equation Charts are available showing the upper limits of specific speed for various suction lifts. FIG. 7.12.4 Role played by NPSH in determining allowable suction lift. A. Pump with suction lift. B. Pump with submerged FIG. 7.12.3...

Reduced Material Intensiveness

Resource conservation can reduce waste and directly lower environmental impact. A less material-intensive product may also be lighter, thus saving energy in distribution or use. When reduction is simple, benefits can be determined with a vigorous LCA. For example, a fast-food franchise reduced material input and solid waste generation by decreasing the paper napkin weight by 21 . Two store tests revealed no change in the number of new napkins used compared to the old design. Attempts to reduce...

Table 731 Summary Of The Origin And Characteristics Of Selected Industrial Wastewater

Cooking of fibers and desizing of fabric Unhairing, soaking, deliming, and bating of hides blanching of fruits and vegetables Dilutions of whole milk, separated milk, buttermilk, and whey Steeping and pressing of grain residue from distillation of alcohol and condensate from stillage evaporation Stockyards slaughtering of animals rendering of bones and fats residues in condensates grease and wash water and picking of chickens Transfer, screening, and juicing waters drainings from lime sludge...

Turbidity Units

Different turbidity instruments detect light intensity differently. The three main techniques are perpendicular scattering (nephelometry), backscattering, and forward scattering. Different turbidity units have evolved in connection with different designs. The JTU is a purely optical scale and correlates with forward scattering measurements. The value of one JTU corresponds to the turbidity of a liter of distilled water with 1 mg (1 ppm) of suspended diatoma-ceous fullers earth (an inert...

Combustion Chambers

Many hazardous wastes are incinerated in industrial boilers and furnaces. However, hazardous waste combustion in boilers is limited by the amount of chlorine in the waste stream, because most industrial boilers do not use scrubbers for hydrogen chloride. The physical form of the waste and its ash content determine the type of combustion chamber selected. Table 11.14.3 provides selection considerations for the four major combustion chamber designs as a function of different forms of waste (EPA...

Chemical Oxidation

Water and wastewater are treated by chemical oxidation in specific cases when the contaminant can be destroyed, its chemical properties altered, or its physical form changed. Examples of chemicals that can be destroyed are cyanides and phenol. Sulfides can be oxidized to sulfates, thus changing their characteristics completely. Iron and manganese can be oxidized from the soluble ferrous or manganous state to the insoluble ferric or manganic state, respectively, permitting their removal by...

Wastewater Treatment Preprocessing

Proper management of food processing wastes requires consideration of individual operations from harvest through waste disposal as integrated subunits of the total process. Every effort should be made to eliminate wastes and to avoid bringing wastes from the farm into the processing plant. Where possible, preprocessing should occur in the field, returning the organic materials to the land. In the processing plant, wastewater volume and strength should be reduced at each step. This principle...

Liquid Injection Incinerators

Liquid injection incinerators are applicable for pumpable liquid waste. These units (Figure 11.14.2) are usually simple, refractory-lined cylinders (either horizontally or vertically aligned) equipped with one or more waste burners. Liquid wastes are injected through the burner(s), atomized to fine droplets and burned in suspension. Burners, as well as separate injection nozzles, may be oriented for axial, radial or tangential firing. Improved use of combustion space and higher heat release...

Applications

Municipal sewage plants can use the conveyor centrifuge for raw primary and raw mixed or cosettled primary plus biological sludges, anaerobically digested primary or mixed sludges, and heat-treated or limed chemical sludges. It can be applied, (sometimes at high coagulant costs) to dewatering whole, mixed, or secondary waste biological (excess activated) sludges, aerobic digested sludges, and alum or ferric chemical sludges. In water treatment plants, it is excellent on water-softening lime...

Technologybased Strategies

Use different types or physical forms of catalysts. Use water-based coatings instead of VOC-based coatings. Use pure oxygen instead of air for oxidation reactions. Use pigments, fluxes, solders, and biocides without heavy metals or other hazardous components. Use terpene or citric-acid-based solvents instead of chlorinated or flammable solvents. Use supercritical carbon dioxide instead of chlorinated or flammable solvents. Use plastic blasting media or dry ice pellets instead of sand blasting....

Inaccuracy

For standard industrial units 0.5 to 5 of full scale. Full-traversing Pitot Venturis under National-Bureau-of-Standards-type laboratory conditions can give 0.5 of the actual flow error. Industrial Pitot Venturis must be individually calibrated to obtain 1 of range performance. Inaccuracy of individually calibrated multiple-opening averaging pitot tubes is claimed to be 2 of the range when the Reynolds numbers exceed 50,000. Area-averaging duct units are claimed to be between 0.5 and 2 of the...

Multiflash Evaporators

In a 2.5 million gpd plant designed for OSW as a standard or Universal Desalination Plant (Othmer 1970) (Figure 8.6.6), seawater at 85 F is first sent to the heat rejection stages (Figure 8.6.3) where it is heated to 97.7 F. Part of this seawater is discharged, while the other part is treated for scale, corrosion, and foam prevention. The FIG. 8.6.6 Universal desalination plant (2.5 million GPD). FIG. 8.6.6 Universal desalination plant (2.5 million GPD). treated seawater joins the discharge...

Well Development

The purpose of well development is to remove the residues of drilling fluids and fine particles of filter packs so that subsequent sampling is representative of the groundwater. The development should be performed as soon as possible after the well is installed and the annular seal is cured. Development methods include bailing, overpumping, air surging, and high-velocity jetting. In bailing, a bailer is dropped and retrieved in and out of the well causing an outward surge of water through the...

Filtration Theory

The basis of this theory is the capture of particles by a single fiber. The single-fiber efficiency iber is defined as the ratio of the number of particles striking the fiber to the number of particles that would strike the fiber if streamlines were not diverted around the fiber. If a fiber of diameter df collects all particles contained in a layer of thickness y, then the single-fiber efficiency is y df (see Figure 5.16.9). The general approach involves finding the velocity field around an...

Hydrolysis

Hydrolysis is a chemical reaction in which an organic chemical (RX) reacts with water or a hydroxide ion (OH) as follows R - X + H2O R - OH + H+ + X 9.12(1) During these reactions, a leaving group (X) is replaced by a hydroxyl ion (OH), and a new carbon-oxygen bond is formed. The R represents the carbonium ion and the X the leaving group. Common leaving groups include halides (Cl-, Br-), alcohols (R O-), and amines (R1R2N-). The acquisition of a new polar functional group increases the water...

So2

Sax, Dangerous properties of industrial materials, 2d ed. (New York Rhinhold.) To obtain efficient gas dispersion in large vessels requires concentric draft tubes and turbine-type blades, while a single draft tube (if any) and axial flow blades are used to efficiently blend waste and reagent for neutralization. Figure 7.39.5 shows the alkali requirements for neutralizing various acids and the acid requirements for neutralizing various alkalis.

Fluctuations in Solid Waste Quantities

Weakness in the economy generally reduces the quantity of solid waste generated. This reduction is particularly true for commercial and industrial MSW and construction and demolition debris. Data quantifying the effect of economic downturns on solid waste quantity are not readily available. The generation of solid waste is usually greater in warm weather than in cold weather. Figure 10.3.1 shows two month-to-month patterns of MSW generation. The less variable pattern is a composite of data from...

Effluent Recycling Pump

FIG. 7.35.9 Schematic diagram of two fluidized-bed reactors in series for biological wastewater treatment. (Reprinted, with permission, from E.T. Oppelt and J.M. Smith, 1981, U.S. Environmental Protection Agency research and current thinking on fluidised-bed biological treatment, in Biological fluidised bed treatment of water and waste water, edited by P.F. Cooper and B. Atkinson, Chichester Ellis Horwood Ltd., Publishers.) to 4.8 kg m3 day for a standard oxygen-activated sludge process. The...

Caliper Gamma Lithology Neutron Velocity Resistivity

FIG. 9.14.5 Well log suites in sedimentary and fractured rocks. (Reprinted from U.S. Environmental Protection Agency, 1993, Subsurface characterization and monitoring techniques, a desk reference guide, U.S. EPA 625 R-93 003a May U.S. EPA.) FIG. 9.14.5 Well log suites in sedimentary and fractured rocks. (Reprinted from U.S. Environmental Protection Agency, 1993, Subsurface characterization and monitoring techniques, a desk reference guide, U.S. EPA 625 R-93 003a May U.S. EPA.) acterization of...

Recyclable Materials 40 Cfr 2616

Recycled hazardous wastes are known as recyclable materials. These materials remain hazardous, and their identification as recyclable materials does not exempt them from regulation. With certain exceptions, recyclable materials are subject to the requirements for generators, transporters, and storage facilities. The exceptions are wastes regulated by other sections of the regulations and wastes that are exempt, including waste recycled in a manner constituting disposal waste burned for energy...

Characteristics of Grit

Grit is the heavy mineral material in raw sewage, and may contain sand, gravel, silt, cinders, broken glass, seeds, small fragments of metal, and other small inorganic solids. It is generally nonputrescible. Grit settles more rapidly than organic or putrescible material in sewage, allowing a reasonably clean separation from the waste stream under normal conditions. Grit is an inert material. Once drained of most of its water, it can be spread on the ground and used on roadways and sand drying...

Shear Rate

FIG. 7.19.2 Typical rheogram for a sludge. Projecting the straight line portion of the pseudoplastic curve to the zero shear rate gives the apparent yield stress. FIG. 7.19.1 Shear diagram of Newtonian and nonNewtonian fluids. ply standard hydraulic formulas for fluid friction without correction. The viscosity term is meaningful for pseudoplastic materials only at a known and fixed shear rate. For light sludges, such as activated sludge, errors occur when the viscosity is assumed to be that of...

References

Eckenfelder. 1974. Process design techniques for industrial waste treatment. Nashville, Tenn. Enviro Press. Adams, J.Q., and R.M. Clark. 1991. Evaluating the cost of packed-tower aeration and GAC for controlling selected organics. Journal AWWA 1 49-57. Bass, D.H., and T.E. Sylvia. 1992. Heated air stripping for the removal of MTBE from recovered groundwater. Proceedings for the 1992 Petroleum Hydrocarbons and Organic Chemicals in Groundwater, 4-6 November, Houston, Tex....

Methylation Of Inorganic Mercury

Certain microorganisms present in sediments convert inorganic mercury to methyl mercury, which is soluble (5 gpl), readily assimilated by aquatic life, and also more toxic than inorganic forms of mercury (Royal Society of Canada 1971). It also becomes more concentrated as it passes up the food chain. This biological conversion process was regarded as an anaerobic process but was later found to occur even more efficiently under aerobic conditions. The process was first identified with...

Extractive Or Ex Situ Analysis

In extractive or ex situ systems, process material is transferred from the sample point to an external analyzer. Because the analyzer (e.g., process gas chromatograph) is installed away from the process, maintenance is more manageable than for inline devices (see Figure 3.12.2). Like inline analyzers, extractive samplers can be located at several different points in a process. However, calibration and reference streams can also be routed to the analyzer with the process samples, something not...

Flash Distillation Systems

Multistage flash evaporation systems have been used commercially in desalination for many years. Conceptual designs for 1000-mgd plants are based on the flash principle. In the multistage flash process (see Figure 7.37.1), after the influent water has the SS removed and is deaerated, it is pumped through heat transfer units in several stages of FIG. 7.37.1 Multistage flash process. FIG. 7.37.1 Multistage flash process. the distillation system. Evaporating influent water condenses on the outside...

Hydrocarbons

A bulk oil handling terminal stores and tranships petroleum products, petrochemicals, animal fats, greases and food grade vegetable oils. In addition they often accept and dispose of ballast wastewaters from marine tankers that deliver to the terminal or pick up cargo for transhipment. A biological treatment system is appropriate because of the wide range of physical and chemical characteristics of the various types of oils and petrochemicals mechanical and or chemical means of separation and...

Process Design

The design of a completely mixed, activated-sludge process illustrates the general procedures involved (Metcalf and Eddy, Inc. 1991). When a BOD5 (5-day BOD) is used and the effluent produced is to have < 20 mg l BOD5, the following equation applies where aXe the biodegradable portion of effluent biological solids. An a 0.63 is generally applicable (Metcalf and Eddy, Inc. 1991). Furthermore, the values of the following parameters in the design exercise that follows are Si (influent BOD5), Q...

Percent Of Panel Exhibiting Correct Response

5.26.1 where a 50 panel response occurs at 235 D T for one sample and 344 D T for the other sample. Over the years, many terms have been used to express the concentration of odor including the following ODOR UNIT one volume of odorous air at the odor threshold often the volume is defined in terms of cubic feet as follows odor units volume of sample diluted to threshold (cu ft) ODORANT QUOTIENT Expressed by the following equation. The Z is for Zwaardermaker who was the earliest investigator to...

Source And Effects

Radon gas is produced by the decay of naturally occurring uranium found in almost all soils and rocks. Figure 5.28.1 shows the decay chain that transforms uranium into radon and its progeny. Radon is also found in soils contaminated with certain types of industrial waste, such as the by-products of uranium mining. Phosphate rock is a source of radon because deposits of phosphate often contain high levels of uranium, approximately 50 to 150 ppm. A significant amount of radon is present in wells...

Air Drying

LAND AREA REQUIRED 1 to 2 ft2 per capita LAYER THICKNESS ON SAND BEDS 7 to 8 in of digested primary sludge with 6 to 8 solids MOISTURE CONTENT OF DRIED SLUDGE 60 to 70 SALE PRICE OF DRIED SLUDGE Usually free For a small community, air drying digested sludge is the accepted, most common, and most economic process for sludge treatment and disposal. The advantages of simplicity and economy overshadow the disadvantages of potential nuisance, susceptibility to adverse weather, residual pathogens,...

Continuousfeed Incinerator

Furnace temperature at furnace sidewall near outlet, range 38 to 1250 C Stoker compartment temperature, range 38 to 1250 C Dust collector inlet temperature, range 38 to 500 C Furnace outlet temperature controlled by regulating total air from forced draft fan set point in 800 to 1000 C range Dust collector inlet temperature controlled by regulating water spray into flue gas set point in 300 to 400 C range Forced-draft-fan outlet duct Induced-draft-fan inlet duct Furnace outlet Stoker...

Continuous Cyanide Destruction

Continuous flow-through systems have the advantage of reduced space requirements but require additional process equipment. In the system shown in Figure 7.42.4, the two reaction steps are separated. In the first step, the ORP controller setpoint is approximately + 300 mV. It controls the addition of chlorine to oxidize the cyanide into cyanate. The pH is maintained at approximately 10. The reaction time is approximately 5 min. Since the second step (oxidation of the cyanates) requires an...

Four Stage Bardenpho Process

The Bardenpho process provides a TN removal capability that cannot be obtained in the MLE process. The four-stage Bardenpho process subjects the nitrate that was not recycled from the primary aerobic zone to anoxic conditions in a secondary anoxic zone (see Part e in Figure 7.38.7). Although biological denitrification is occurring in both anoxic reactors, the carbon source is different the carbon source of the primary anoxic zones is supplied by influent wastewater, whereas endogenous...

Static Mixed And Aerated Fill

Developing an operating strategy for the fill period is a complex problem for designers of hazardous wastewater SBR systems. Domestic wastewater treatment systems seldom require laboratory treatability studies, because these systems follow conservative design approaches and municipal wastewater flow rates and characteristic variations are predictable. Laboratory treatability studies are almost always needed to design SBRs and to select the appropriate fill policy for hazardous wastes. The...

Static Fill

Static fill introduces influent wastewater into the SBR with little or no mixing and contact with the settled biomass, resulting in a high substrate concentration when mixing first begins. High substrate concentrations result in high reaction rates. In addition, such concentrates control sludge bulking because they favor organisms that form more dense floc particles over filament forming organisms. Bulking sludge is a common problem in continuous flow systems where substrate concentrations are...

Physical Factors

In addition to the preceding chemical factors, a number of physical factors have an important bearing on the chemical reaction. The most important of these are Most reactions occur under atmospheric pressure while oxidation, hydrogenation, and some polymerization occur at higher pressures. The effects of pressure and temperature on equilibrium and the reaction rate are discussed in Section 3.7. For capacity, feeding the reactants in their stoichio-metric ratio and at a maximum concentration is...

Strontium

Strontium is an alkaline-earth element with a chemistry similar to that of calcium and other divalent cations in Group IIa of the periodic table of the elements. The metal is used in some alloys of tin and lead various strontium salts are used in pyrotechnics, refining beet sugar, glass, paints, ceramics, and some medicines and strontium radioisotopes are generated from fission reactions at nuclear installations (McKee and Wolf 1963). The major liquid industrial wastes containing strontium are...

Selection Of Centrifuge

The operating curves in Figure 7.48.11 show one aspect of centrifuge selection. For example, if a wastewater treatment facility thickens municipal excess activated sludge at 90 recovery to limit the return of solids with the recirculated centrifuge liquid discharge (centrate), the feed flow rate must be large enough to require one or more of the largest units of any centrifuge type. The conveyor centrifuge without polymer addition cannot reach 90 recovery and cannot be considered in this...

Pdl

Integrating from 0 to Vf and from 0 to Tf gives the following equations where Vf and Tf are the filtrate volume and time, respectively, for one batch of a batch filter. For one cycle of a small area A on a continuous filter, if n cycles per minute and Tc minutes per cycle, then n 1 Tc. Also, Tf BTc when 0 < B < 1.00. B is the fraction of total area that is filtering at any given time. The cycles per hour 60n. On a continuously rotating drum, the following equation gives the continuous...

Batch Controller Tuning

For batch control, the offset from setpoint can be made smaller than the peak error for continuous pH control if the sequential requirements of batch pH control are recognized and addressed. Batch pH control is analogous to the titration done in chemistry lab. If the student has enough patience to use sequentially smaller doses and to wait longer as the pH approaches the endpoint, the final pH can end up within the measurement error of the endpoint. The increased difficulty of continuous pH...

Cake Washing

Cake washing, which is unimportant in large municipal-industrial treatment plants, can be beneficial in industrial pretreatment when a valuable material dissolved in the filtrate is separated from waste solids. Better washing can be obtained on batch filters than on continuous filters. A thorough theoretical and experimental study of cake washing concludes that removing 80 of a solute dissolved in the filtrate left in the void spaces of the filter cake requires at least six void volumes of wash...

Demineralization

Demineralization by Distillation Distillation Processes Corrosion and Scaling Flash Distillation Systems Vertical Tube Evaporators Vapor Compression Evaporators Demineralization by Electrodialysis Principles of Electrodialysis Electrodialysis Processes Sizing of Electrodialysis Units Membranes Applications Demineralization by Freezing Energy Requirements Indirect-Contact Freezing Process Direct-Contact Freezing Process Hydrate Process Costs Demineralization by Reverse Osmosis Pretreatment...

Earthmounded Concrete Bunkers

Earth-mounded concrete bunkers (EMCB), a combination of trenches and vaults, are being strongly considered by many of the new state disposal sites mandated by Congress. EMCB disposal technology involves isolating low-level radioactive waste in an engineered vault located above or below the natural grade of the site. A multilayer, engineered earthen cover is positioned over the vault to provide an additional barrier. Depending on the design, Class A, B, or C wastes can be stored in these...

Permeable Treatment Beds

Permeable treatment beds are also in situ treatment techniques used at sites with relatively shallow groundwater tables. The concept of a permeable treatment bed involves excavating a trench, filling the trench with a permeable treatment material, and allowing the plume to flow through the bed thus physically removing or chemically altering the contaminants. The function of a permeable treatment bed is to reduce the quantities of contaminants in the plume to acceptable levels. Potential...

Nonlinear Controllers

Special controllers have been developed to compensate for the nonlinearity of most pH neutralization processes. These nonlinear controllers change their gain characteristics proportionally to the ion load (pH) of the process. The characteristics of the controller are as shown in Figure 7.40.3. The diagonal line represents the error-output relationship for the controller (in response to an error, a cor FIG. 7.40.3 Nonlinear controller characteristics. FIG. 7.40.3 Nonlinear controller...

Horizontalflow Clarifiers

In horizontal-flow clarifiers, sedimentation occurs in specially designed basins. These basins are known as settling tanks, settling basins, sedimentation tanks, sedimentation basins, or clarifiers. They can be rectangular, square, or circular. The most common basins are rectangular tanks and circular basins with a center feed. In rectangular basins (see part A in Figure 7.17.1), the flow is in one direction and is parallel to the basin's length. This is called rectilinear flow. In center-feed...

Co2

Carbon dioxide Calcium carbonate Water In contrast with the softening reaction, this process is suited to automatic pH control. Figure 7.42.11 shows this control system. The carbon dioxide feeder has two operators one controlled by feedforward on the influent flow and the other by feedback on the effluent pH. The setpoint is about 9.5 pH. Electrode fouling occurs as a result of the precipitation of crystallized calcium carbonate. Daily maintenance is required unless automated cleaners are used....

Slipstream And Bypass Filters

To minimize transportation lag, the flow rate system takes a large slipstream from the process and tubes it to the analyzer. Because the sample flow to the analyzer is small, the analyzer uses only a small portion of this stream and returns the bulk to the process (see Figure 7.8.1). This arrangement permits the high-flow rate system to continuously sweep the main volume of the filter, minimizing lag time at the same time, only the low-flow stream to the analyzer is filtered, maximizing filter...

Choice Of Reagents

In oxidations, potassium dichromate or permanganate, or lead tetraacetate, is used in the laboratory. However, these stoichiometric reactions involve mole-for-mole amounts of high-molecular-weight oxidants. Therefore, the oxidants must be used in large, absolute quantities. Such reactions are costly and generate large volumes of an effluent, pos- sibly containing toxic metal salts that must be treated in the scaled-up process (Stinson 1993). Hydrogen peroxide, peracetic acid, or tert-butyl...

Precision And Accuracy

One of the objectives of the QA or QC plan is to ensure that there is no contamination from initial sampling through final analysis. For this reason, duplicate, field blank, and travel blank samples should be prepared and analyzed. Duplicate sampling requires splitting one field sample into two aliquots for laboratory analysis. Typically, 10 of the samples should be collected in duplicate. Duplicates demonstrate the reproducibility of the sampling procedure. A travel blank is a contaminant-free...

Anaerobic Digester Design Example

In this example, high-rate, primary digesters (heated and completely mixed) followed by secondary digesters (un-heated and unmixed) provide anaerobic digestion of primary and excess activated sludge from a 10 mgd waste-water treatment plant. Secondary digesters provide a maximum 30-day detention time and are intended mainly for solids-liquid separation, sludge thickening, and sludge storage. The daily loading of solids to the primary digesters is as follows 1. Primary (raw) sludge 12,010 lb per...

Sludge Thickening

Gravity thickening in a deep, circular, open tank is frequently used before anaerobic digestion. Some wastewater treatment facilities also use polyelectrolytes to improve gravity thickening, but their use for this purpose is not widespread. Air flotation thickening of activated sludge is an alternative. This process uses dissolved or diffused air and sometimes a coagulant to float the sludge to the surface where it is removed by a mechanically driven skimmer. The effluent drawn near the bottom...

Ocean Dumping

Dumping waste in the ocean, seas, estuaries, or inland lakes is regulated by emission standards for abating pollution of the oceans. The concept of an infinite ocean (a mile and a half deep on the average around the world) has given way to the reality that the ocean is a limited and valuable resource. This resource must be protected, otherwise it can become like Lake Erie and the Baltic Sea, and irreversible oceanic life systems may create an uninhabitable environment for people as well as for...

Table 1095 Advantages And Disadvantages Of Fabric Filter Systems

High particulate (coarse to submicron) collection efficiencies Dry collection and solids disposal Relatively insensitive to gas stream fluctuations. Efficiency and pressure drop are unaffected by large changes in inlet dust loading for continually cleaned filters Corrosion and rusting of components usually not a problem No hazard of high voltage, simplifying maintenance and repair and permitting the collection of flammable dust Use of selected fibrous or granular filter aids (precoating) which...

Aerobic Fluidized Bed Treatment of Municipal Wastewater

From 1970 to 1973, the EPA used supported microbial cultures in expanded or fluidized-bed reactors to study municipal wastewater treatment at its Lebanon Research Pilot Plant near Cincinnati, Ohio (Oppelt and Smith 1981). Fine 0.5 mm sand particles, like those used in sand filters, supported a 0.25 mm biomass film. The total COD removal was 26 at 16 min and 65 at 47 min residence time. A COD removal of 65 was the best that the two-column system could do. The minimum upflow rate in the columns...

170

Notes Other sizes and capacity ranges are available. 00 Smallest particle size removed design is based on 95 removal of 150-mesh or larger grit. Notes Other sizes and capacity ranges are available. 00 Smallest particle size removed design is based on 95 removal of 150-mesh or larger grit. FIG. 7.15.4 Hydrocyclone grit separator. FIG. 7.15.4 Hydrocyclone grit separator.

Reactor Selection

As shown in the two sets of parallel reactions in Table 3.7.1, the feed material can react either to the PRODUCT or in parallel to the WASTE BY-PRODUCT. By looking at the ratio of the rates of the secondary and primary reactions in Table 3.7.1, the chemical engineer can choose conditions to minimize that ratio. For some two-feed reaction systems (as shown in Table 3.7.1), semibatch and semiplug-flow processes can be used. In a semibatch process, the reactor is charged with one of the feeds at...

Pathogens

Wastewater sludge is known to contain pathogens including bacteria, viruses, parasites, and helminths. Epstein and Donovan (1992) note that pathogens can be grouped under three major headings primary pathogens, secondary or opportunistic pathogens, and endotoxins. They further note that the major concerns with pathogens related to composting wastewater sludge are product disinfection, worker health, and public health as impacted by facility location. The U.S. EPA (1979 1993) in the previous 40...

Golden Carrot Program

The Golden Carrot Program, promoted by the EPA's Office of Air and Radiation, encourages manufacturers to design superefficient refrigerators that use no CFCs for cooling or insulation. Refrigerators and freezers use about 20 of the nation's electricity and vary in efficiency. To stimulate manufacturers to develop more efficient CFC-free units, twenty-three electric utilities have pooled their resources to offer a 30 million incentive (the golden carrot) to the winner of a product design...

Liquid Membranes

Liquid membrane technology offers a novel membrane separation method in which the separation is affected by the solubility of the component to be separated rather than by its permeation through pores, as in conventional membrane processes. The component to be separated is extracted from the continuous phase to the surface of the liquid membrane, through which it diffuses into the interior liquid phase. The liquid membrane can be created in an emulsion or on a stabilizing surface of a permeable...

Community Action

The public, as consumers and disposers of toxic-chemical-containing products, is a major source of toxic pollution. It must and has become involved in toxic pollution prevention. Public involvement has resulted from state-wide initiatives, the action of interest groups, and individual initiatives. Environmentalists concerned with pollution control advocate source reduction over waste treatment as the preferred environmental option. However, the lack of public information about industrial...

Annoyance

Annoyance by noise is a response to auditory experience. Annoyance has its base in the unpleasant nature of some sounds, in the activities that are disturbed or disrupted by noise, in the physiological reactions to noise, and in the responses to the meaning of the messages carried by the noise. For example, a sound heard at night can be more annoying than one heard by day, just as one that fluctuates can be more annoying than one that does not. A sound that resembles another unpleasant sound...

Sizing Of Electrodialysis Units

The following equations approximate the inorganic salt removal capacity and the power consumption of electro-dialysis units Energy consumption, kWh lb-equivalent weight Membrane area, ft2 Current density, amps per ft2 Total number of cell pairs Membrane resistance of one cell pair, ohm-ft2 Rs Solution resistance, ohm-ft2 Current efficiency, a fraction Tp Plant capacity, lb equivalent per hr Energy consumption, kWh lb-equivalent weight Membrane area, ft2 Current density, amps per ft2 Total...

Development of a Decision Matrix

The final step in multicriteria decision making is to develop a decision matrix displaying the products of the importance weights (or ranks) and the alternative scales (or ranks). Table 2.5.4 shows a simple weighting-rating checklist used in an environmental impact study of sites for a wastewater treatment plant (Wilson 1980). Two groups of importance weights are used, with factors assigned an importance weight of 2 being more important than factors assigned an importance weight of 1. Each of...

Flow Regime

A-c intermittent mixing d mixed (surface layer) e no mixing and f completely mixed a < 10 b 0.5-2 c 2-10 d 2-10 e 0.5-2 and f 2-10 a 3-4 b 1-1.5 c 3-5 d 4-8 e 8-16 and f 6-20 LRT (days) a 10-40 b 4-6 c 5-20 d 5-30 e 20-50 and f 3-10 BOD5 LOADING (lb acre-day) a 60-120 b 80-160 c < 15 d 50-180 and e 200-500 BOD5 REMOVAL ) a, b, d, & f 80-95 c 60-80 and e 50-85 a 40-100 b 100-260 c 5-10 d 5-20 and e 0-5 a 80-140 b 150-300 c 10-30 d 40-60 e 80-160 and f 80-250

Wind Rose

Wind speed determines the travel time of a pollutant from its source to a receptor and accounts for the amount of pollutant diffusion in the windward direction. Therefore, the concentration of pollutant at any receptor is inversely proportional to the wind speed. Wind direction determines in what direction a pollutant travels and what receptor is affected at a given time. Wind direction is normally defined by a wind rose, a graphic display of the distribution of wind direction at a location...

Lowlevel Radioactive Waste

Low-level radioactive waste is a general term for a wide range of materials contaminated with radioisotopes (Gershey, Klein, Party & Wilkerson 1990 Burns 1988). Industries and hospitals, medical, educational and research institutions, private and government laboratories, and nuclear fuel cycle facilities using radioactive materials generate low-level radioactive wastes as part of normal operations. These wastes are generated in many physical and chemical forms, and at many levels of...

R

And the drawdown s at any point is given by Radial Flow in a Semiconfined Aquifer Radial flow in a semiconfined aquifer occurs when the flow is towards a well in an aquifer such as the one shown in Figure 9.3.4. When leakage through the confining layer is considered, Equation 9.3(4) becomes The general solution of this equation is where A and B are arbitrary constants, and Io and Ko are modified Bessel functions of zero order and of the first and second kind, respectively. Table 9.3.1 is a...

2

FIG. 9.4.4 Unconfined flow with rainfall. FIG. 9.4.4 Unconfined flow with rainfall. FIG. 9.4.5 One-dimensional unconfined flow with rainfall. (Reprinted from A. Verrjuit, 1982, Theory of groundwater flow, Macmillan Pub. Co.) FIG. 9.4.5 One-dimensional unconfined flow with rainfall. (Reprinted from A. Verrjuit, 1982, Theory of groundwater flow, Macmillan Pub. Co.) Hence, the differential equation for the potential becomes In terms of tf> , this equation reads One-Dimensional Flow with...