Application To Subsurface Treatment

The application of adsorption to contaminated groundwater remediation is not only an important subject, but one we could expand upon into several volumes unto itself. At best, all we can do is try to provide a concise overview in this volume. When we discuss this subject, we cannot separate groundwater treatment from subsurface soil treatment, as the two often go hand in hand. Furthermore, carbon adsorption is not the only technology applicable to subsurface (soil and water) remediation, but it...

Applications

Applications of carbon adsorption go far beyond conventional water treatment applications which we will discuss in a general sense shortly. Table 8 provides a summary of the key applications of carbon adsorption systems for liquid phase applications. Table 8. Liquid Phase Applications of Carbon Adsorption. Table 8. Liquid Phase Applications of Carbon Adsorption. Granular activated carbons (GAC) installed in rapid gravity filters Removal of dissolved organic contaminants, control of taste and...

Biosolids Regulations

EPA has developed comprehensive federal biosolids use and disposal regulations , which are organized in five parts. These parts are general provisions, land application, surface disposal, pathogens and vector attraction reduction, and incineration. Parts of the regulations which address standards for land application, surface disposal, and incineration practices consist of general requirements, pollutant limits, operational requirements, management practices, frequency of monitoring,...

Cone Of Flowing Solids

Illustrates angle of internal friction. Figure 4. Illustrates angle of internal friction. The angle of repose is sensitive to the conditions of the supporting surface the smoother the surface, the smaller the angle. The angle may also be reduced by vibrating the supporting surface. When handling slow moving materials having large angles of repose, well-designed, bunkers and hoppers are provided with highly polished internal surfaces and low amplitude vibrators. The angle is also...

Equipment And Operation

Ion exchange processing can be accomplished by either a batch method or a column method. In the first method, the resin and solution are mixed in a batch tank, the exchange is allowed to come to equilibrium, then the resin is separated from solution. The degree to which the exchange takes place is limited by the preference the resin exhibits for the ion in solution. Consequently, the use of the resins exchange capacity will be limited unless the selectivity for the ion in solution is far...

Filter Media Selection Criteria

Due to the wide variety of filter media, filter designs, suspension properties, conditions for separation and cost, selection of the optimum filter medium is complex. Filter media selection should be guided by the following rule a filter medium must incorporate a maximum size of pores while at the same time providing a sufficiently pure filtrate. Fulfilment of this rule invokes difficulties because the increase or decrease in pore size acts in opposite ways on the filtration rate and solids...

Filtration Dynamics

When a suspension of solids passes through a porous media, the solid particles are collected on the feed side of the plate while the filtrate is forced through the media and carried away on the leeward side. A filter medium is, by nature, inhomogeneous, with pores nonuniform in size, irregular in geometry and unevenly distributed over the surface. Since flow through the medium takes place through the pores only, the micro-rate of liquid flow may result in large differences over the filter...

Flocculation And Filtration Together

The sand filtration process is normally comprised of a clarification chain including other unit operations which precede filtration in the treatment sequence and can not be conceived of completely independent of the filtration stage. The conventional treatment scheme consists of coagulation-flocculation-settling followed by filtration. When the preceding process, in this case flocculation and or settling, becomes insufficient, subsequent rapid filtration can be used to ensure a high quality of...

Granular Media Filtration

Granular media filtration is used for treating aqueous waste streams. The filter media consists of a bed of granular particles (typically sand or sand with anthracite or coal). The anthracite has adsorptive characteristics and hence can be beneficial in removing some biological and chemical contaminants in the wastewater. This material may also be substituted for activated charcoal. The bed is contained within a basin and is supported by an underdrain system which allows the filtered liquid to...

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Ftt t Si,> cct Ce.ll lAdiilh 7 5' 0 j -3jc tria ------ 1. J -kWU'TIJ Mfii Figure 6. Range of common particle sizes (diameter) over range of UF pore size. The retention efficiency of membranes is dependent on particle size and concentration, pore size and length, porosity, and flow rate. Large particles that are smaller than the pore size have sufficient inertial mass to be captured by inertial impaction. In liquids the same mechanisms are at work. Increased velocity, however, diminishes the...

Importing Biosolids From New York Case Studyl

Y., have been imported into southeastern Colorado for application to dry land wheat, grassland, and reclamation sites. The Colorado Department of Health and the EPA have issued land application permits for about 7700 ha (19,000 ac). Annual precipitation in the area averages 36 cm. Biosolids from this project were used to reclaim a 104 ha (258 ac) sand blowout on private land near Granada, Colorado. The sandy dunes began as a 12 ha (30 ac) area subject to wind...

Industrial Water And Wastewater Treatment

The markets for ozone in industrial water and wastewater treatment are quite small. Industrial applications for ozone could grow. The use of ozone for treating photoprocessing solutions is a novel application that has been limited, but might grow. In this process, silver is recovered electrolytically then the spent bleach baths of iron ferrocyanide complexes are ozonated. Iron cyanide complexes are stable to ozonation so that the ferrous iron is merely oxidized to ferric, which is its original...

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LrijsJsaV cr Trssfcd Water Eaura Miartg Charter ifitc dt Charrfcw .v Water with Replaceable Turnci lrijsJsaV cr Trssfcd Water Eaura Miartg Charter Figure 13.Example of a municipal water treatment plant for taste and odor control. Nonpotable water treatment is also well within the economical applications of liquid phase adsorption systems. There in fact are so many unique examples of process water treatment throughout the chemical industry that we could go on for days discussing speicif systems....

Introducing The Physical Treatment Methods

The following technologies are among the most commonly used physical methods of purifying water Heat Treatment - Boiling is one way to purify water of all pathogens. Most experts feel that if the water reaches a rolling boil it is safe. A few still hold out for maintaining the boiling for some length of time, commonly 5 or 10 minutes, plus an extra minute for every 1000 feet of elevation. One reason for the long period of boiling is to inactivate bacterial spores (which can survive boiling),...

Ion Exchange And Carbon Adsorption

Ion exchange and carbon adsorption are unrelated technologies, and often have different objectives. They are however oftentimes used in compliment to achieve Ion exchange is a reversible chemical reaction wherein an ion (an atom or molecule that has lost or gained an electron and thus acquired an electrical charge) from solution is exchanged for a similarly charged ion attached to an immobile solid particle. These solid ion exchange particles are either naturally occurring inorganic zeolites or...

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Frictional drag on particles in compressible cakes. The terra ps is a fictitious pressure, because the cross-sectional area A is not equal to either the surface area of the particles nor the actual contact areas In actual cakes, there is a small area of contact Ac whereby the pressure exerted on the solids may be defined as Fs Ac. Taking differentials with respect to x, in the interior of the cake, we obtain This expression implies that drag pressure increases and hydraulic pressure...

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NPDES Permit National Pollutant Discharge Elimination System permit is the regulatory agency document issued by either a federal or state agency which is designated to control all discharges of pollutants from point sources into U.S. waterways. NPDES permits regulate discharges into navigable waters from all point sources of pollution, including industries, municipal wastewater treatment plants, sanitary landfills, large agricultural feed lots and return irrigation flows. Nitrification An...

Principles Of Ozone Effluent Treatment

Ozone was first discovered by the Dutch philosopher Van Marun in 1785. In 1840, Schonbein reported and named ozone from the Greek word ozein, meaning to smell. The earliest use of ozone as a germicide occurred in France in 1886, when de Meritens demonstrated that diluted ozonized air could sterilize polluted water. In 1893, the first drinking water treatment plant to use ozone was constructed in Oudshorrn, Holland. Other plants quickly followed at Wiesbaden (1901) and Paderborn (1902) in...

Questions For Thinking And Discussing

Go to the proper U.S. environmental legislation and obtain the MCLs for the chemicals listed in Table 9. 2. Complete the following reactions that take place with hydrogen cation-exchange resins Na2(HC03)2 + H2 Z CaS04 + H2Z MgZ + H2S04 3. Complete the following reactions that take place for anion exchange reactions (weakly basis and strongly basis) R3N + H2S04 R3N + 2HC1 R3N-H2S04 + Na2C03 R4NOH + H2Si03 (R,N)2S04 + 2NaOH The symbol R3N represents the complex weakly basic anion-exchanger...

Rapid Sand Filtration

Rapid filtration is performed either in open gravitational flow filters or in closed pressure filters. Rapid pressure filters have the advantage of being able to be inserted in the pumping system, thus allowing use of a higher effective loading. Note that pressure filters are not subject to development of negative pressure in a lower layer of the filter. These filters generally support higher speeds, as the available pressure allows a more rapid flow through the porous medium made up by the...

Recommended Resources For The Reader

Vigneswaran, S. and Ben Aim, R., Water, Wastewater and Sludge Filtration, CRC Press, Boca Raton, FL, pp 139-224, (1989). 2. Paulson, David J. Wilson, Richard L. and Spatz, D. Dean, Crossflow Membrane Technology and Its Applications, Food Technology 38 (12) 77-87,& 111(1984). 3. Mohr, C.M. Leeper, S.A. Engelgau, D.E. and Charboneau, B.L., Membrane Applications and Research in Food Processing, (Noyes Data Corporation, Park Ridge, NJ) p. 305 (1989). 4. Morr, C.V., Current Status of Soy Protein...

Sludge Lagoons

This is a technique that relies both on the settling characteristics of sludge and solar evaporation. The considerable labor involved in sludge drying bed operation may be avoided by the use of sludge lagoons. These lagoons are nothing but excavated areas in which digested sludge is allowed to drain and dry over a period of months or even a year or more (refer to Figure 22 for an example). They are usually dug out by bulldozers, or other dirt-moving equipment, with the excavated material used...

Some Case Studies For You To Ponder

Studies have shown that the biosolids application reduce runoff from treated rangeland. Results were attributed to increase increased ground surface roughness and water adsorption by the dry biosolids. Over time, the biosolids should decompose and have a less direct effect on surface runoff. However, the increase in vegetative cover in response to the fertilizer effect of the biosolids should further improve the surface hydrology of the treated rangeland. Potential surface water contamination...

Stabilization Via Anaerobic Digestion

The purpose of digestion is to attain both of the objectives of sludge treatment a reduction in volume and the decomposition of highly putrescible organic matter to relatively stable or inert organic and inorganic compounds. Additionally, anaerobic sludge digestion produces a valuable by-product in the form of methane gas (the primary constituent of natural gas, which we can burn for heat or convert to electricity). Sludge digestion is carried out in the absence of free oxygen by anaerobic...

Sterilization Using Ozone

Ozone (03) is a powerful oxidant, and application to effluent treatment has developed slowly because of relatively high capital and energy costs compared to chlorine. Energy requirements for ozone are in the range of 10 to 13 kWh lb generated from air, 4 kWh lb from oxygen, and 5.5 kWh lb from oxygen-recycling systems. Operating costs for air systems are essentially the electric power costs for oxygen systems the cost of oxygen (2 to 30 lb) must be added to the electrical cost. Capital costs of...

Strongly Acidic Cation Resins

Strongly acidic cation resins derive their exchange activity from sulfonic functional groups (HSO). The major cations in water are calcium, magnesium, sodium, and potassium and they are exchanged for hydrogen in the strong acid cation exchanger when operated in the hydrogen cycle. The following stoichiometric equation represents the exhaustion phase, and is written in the molecular form (as if the salts present were undissociated). It shows the cations in combination with the major anions, the...

The Final Touches To Water

< > Disinfection - water completely free of suspended sediment, is treated with a powerful oxidizing agent usually chlorine, chlorine and ammonia (chloramine), or ozone. A residual disinfectant is left in the water to prevent reinfection. Chlorine can form harmful byproducts and has suspected links to stomach cancer and miscarriages. < > pH adjustment - so that treated water leaves the plant in the desired range of 6.5 to 8.5pH units. conditioner, as well as a some fertilizer value....

The Plateandframe Filter Press

This type of filter allows pressurized filtration of a slurry mixture to remove solids. A set of filter plates is sandwiched together in series with a configuration similar to the plates on a plate-and-frame heat exchanger. After the plates are compressed together hydraulically, a channel throughout all the plates allows the slurry to be pumped into one side of each of the plates. The filtrate goes through the filter media on the plate leaving the solid cake on the media. Filtrate on the other...

The Tilting Pan Filter

The Tilting Pan Filter is predominantly employed in the phosphoric acid industry and, to some extent, in the washing of phosphate rock. There was a traditional rivalry over the years between the Pan and Belt Filter which now, owing to the substantial progress in rubber technology, swings in the favor of the later. The operation of Tilting Pan Filters is based on a series of horizontal independent trapezoidal pans mounted on a circular supporting structure that rotates under vacuum during the...

Wash Water

I NO. 2 NO. 3 Figure 5. Flow scheme for three-stage CDD. THICKENER THICKENER THICKENER NO. I NO. 2 NO. 3 Figure 5. Flow scheme for three-stage CDD. The diameters on these machines are over 400ft., with operating torques to 2,400,000ft.-Lbs. The stationary center pier supports the drive and rake mechanisms. The truss extends from the center pier to the tank periphery supports walkway, power lines and feed asunder. (,Diameters are up to 600ft with operating...

Wastewater Treatment Plant Operations

Before getting into the subject of sand filtration, we should first attempt to put the technologies of municipal wastewater treatment into some perspective. Wastewater treatment plants can be divided into two major types biological and physical chemical. Biological plants are more commonly used to treat domestic or combined domestic and industrial wastewater from a municipality. They use basically the same processes that would occur naturally in the receiving water, but give them a place to...

Water Quality Test Methods

Determination of the bacteriological quality of water is not a straightforward analysis. The testing for a specific pathogenic bacteria can often lead to erroneous conclusions. Analyses for pathogenic bacteria are difficult to perform. In general, data are not quantitatively reproducible. As an example, if Salmonella was found to be absent from a water sample, this does not exclude the possible presence of Shigella, Vibrio, or disease-producing viruses. The bacteriological quality of water is...

Water Treatment In General

Water must have eye appeal and taste appeal before we will drink it with much relish. Instinctively we draw back from the idea of drinking dirty, smelly water. Actually far more important to our well-being is whether or not a water is safe to drink. If it holds disease bacteria, regardless of its clarity and sparkle, we should avoid it. Let's consider these two highly important aspects of water potability and palatability. Regardless of any other factors, water piped into the home must be...

Wet Air Oxidation

When the organic sludge is heated, heat causes water to escape from the sludge. Thermal treatment systems release water that is bound within the cell structure of the sludge and thereby improves the dewatering and thickening characteristics of the sludge. The oxidation process further reduces the sludge to ash by wet incineration (oxidation). Sludge is ground to a controlled particle size and pumped to a pressure of about 300 psi. Compressed air is added to the sludge (wet air oxidation only),...

What Eletcrodialysis Is

The principle behind electrodialysis is that electrical potential gradients will make charged molecules diffuse in a given medium at rates far greater than attainable by chemical potentials between two liquids as in conventional dialysis. When a DC electric current is transmitted through a saline solution, the cations migrate toward the negative terminal, or cathode, and the anions toward the positive terminal, the anode. By adjusting the potential between the terminals or plates, the electric...

What Sludge Is

When we think of sludge, what automatically comes to mind is sewerage. Water carriage systems of sewerage provide a simple and economical means for removing offensive and potentially dangerous wastes from household and industry. The solution and suspension of solids in the transporting of water produces sewage. Thus, the role of solids and sludge removal at Sewage Treatment Plants is apparent. Sludge removal is complicated by the fact that some of the waste matters go into solution while others...

The Rotary Drum Filter

This continuous filter is used when the solids in the slurry can be easily suspended in solution and remain there. In this filter a cylindrical drum sets horizontally half submerged in a trough holding the filtration slurry. The drum is coated with a filter media and a vacuum is pulled on the inside of it. The filtrate passes through the filter media leaving the solids on the outside of the drum. The drum is rotated continuously allowing the solids to be washed and dried before they are removed...

Carbon Adsorption In Water Treatment How Adsorption Works

Activated carbon is a crude form of graphite, the substance used for pencil leads. It differs from graphite by having a random imperfect structure which is highly porous over a broad range of pore sizes from visible cracks and crevices to molecular dimensions. The graphite structure gives the carbon it's very large surface area which allows the carbon to adsorb a wide range of compounds. Activated carbon can have a surface of greater than 1000 m2 g. This means 5g of activated carbon can have...

Sample pointSample point

Configuration of column scale-up tests. It is also preferred where suspended solids create a high pressure drop, or dissolved gases create bubbles in the carbon bed. For a downflow or percolation system, an influent line should be installed at the top of the column, with an effluent at the bottom. To prevent the column from draining during operation, the effluent line from the last column should extend from the bottom of the column to above the top of the column. This will keep the...

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Ecology The study of all aspects of how organisms interact with each other and or their environment. Ecosystem Groupings of various organisms interacting with each other and their environment. E-coli Escherichia coli - one of the non-pathogenic coliform organisms used to indicate the presence of pathogenic bacteria in water. Effective area The total area of the porous medium exposed to flow in a filter element. Efficiency The ability, expressed as a percent, of a filter to remove specified...

The Sludge Pasteurization Process

Filter Press Sludge Treatment

This process is really sludge disinfection. Its aim is the destruction or inactivation of pathogenic organisms in the sludge. Destruction is defined as the physical disruption or disintegration of a pathogenic organism, while Inactivation is defined as the removal of a pathogen's ability to infect. In the United States procedures to reduce the number of pathogenic organisms are a requirement before sale of sludge or sludge-containing products to the public as a soil conditioner, or before...

The Pressure Leaf Filter

Diagram Agitated Nutsche Filter Dryer

This device is similar to a plate-and-frame filter press but the whole plate assembly is also housed in a tank or pressure vessel. This design allows higher pressures to be used, and also allows the filtration operation to be done more efficiently in many applications. There are two basic configurations, namely a horizontal plate and a vertical pressure leaf filter. Horizontal plate pressure filters were commonly applied to the fine chemical process industries such as antibiotics , pesticides...

Vacuum Filtration

We have already discussed this important technology in Chapter 5, but a review may be helpful in placing its importance to sludge processing into perspective. The vacuum filter for dewatering sludge is a drum over which is laid the filtering medium consisting of a cloth of cotton, wool, nylon, dynel, fiber glass or plastic, or a stainless steel mesh, or a double layer of stainless steel coil springs. The drum with horizontal axis is set in a tank with about one quarter of the drum submerged in...

An Alternative Analysis The Forgotten Method Of Dimensional Analysis

I often refer to dimensional analysis as lost art - because it is usually not heavily emphasized in engineering education today. However, for well over 100 years its has provided simply a wealth of practical design correlations that are still relied upon in virtually all aspects of chemical engineering, ranging from classes of problems dealing with heat and mass transfer, reaction kinetics, momentum exchanges in flow dynamics. Much of sedimentation theory, and indeed the basis for more...

Ozonated Water

Lowther Plate Ozone

A high level of gas preparation usually air is needed before ozone generation. The air must be dried to retard the formation of nitric acid and to increase the efficiency of the generation. Moisture accelerates the decomposition of ozone. Nitric acid is formed when nitrogen combines with moisture in the corona discharge. Since nitric acid will chemically attack the equipment, introduction of moist air into the unit must be avoided. Selection of the air-preparation system depends on the type of...

Introduction Of Physical Methods Of Waste Treatment

We may organize water treatment technologies into three general areas Physical Methods, Chemical Methods, and Energy Intensive Methods. Physical methods of wastewater treatment represent a body of technologies that we refer largely to as solid-liquid separations techniques, of which filtration plays a dominant role. Filtration technology can be broken into two general categories - conventional and non-conventional. This technology is an integral component of drinking water and wastewater...

Air Flotation Systems

Air flotation is one of the oldest methods for the removal of solids, oil amp grease and fibrous materials from wastewater. Suspended solids and oil amp grease removals as high as 99 can be attained with these processes. Air flotation is simply the production of microscopic air bubbles, which enhance the natural tendency of some materials to float by carrying wastewater contaminants to the surface of the tank for removal by mechanical skimming. Many commercially available units are packaged...

It Makes Sense To Select A Filter Press

Of When a very low moisture content is required for thermal cake drying or incineration. rar When high f ltrate clarity is required for polishing applications. rar When good cake release assisted by squeezing is required. y When the cake is disposed as land fill for spreading with a bulldozer provided it is hard enough to carry its weight. When large filtration areas are required in a limited space. The shuttle shifter moves the plates one by one towards the follower and the cake discharges....