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Among the emerging attached-growth biological treatment processes covered in this chapter are fluidized bed reactor (FBR), packed bed reactor (PBR), biological aerated filter (BAF), and hybrid biological-activated carbon systems including downflow conventional biological GAC systems and upflow fluidized bed biological GAC system (FBB-GAC). This chapter describes the above processes and explains their practice, limitations, process design, performance, energy requirements, process equipment, energy requirements, costs and case studies. [ABSTRACT FROM AUTHOR]

Man-made or produced fluids (liquids, gases or slurries) can move into the pores of rocks by the use of pumps or by gravity. Injection well technology can predict the capacity of rocks to contain fluids and the technical details to do so safely. Underground wastewater disposal and storage by well injection is being used by both industries and municipalities to help solve environmental problems. When wells are properly sited, constructed, and operated, underground injection is an effective and environmentally safe method to dispose of wastes. Issues discussed in this chapter include regulations for managing injection wells, basic well designs, evaluation of a proposed injection well site, ways to prevent, detect, and correct potential hazards, economic evaluation of a proposed injection well system, use of injection wells for wastewater management, use of injection wells for hazardous wastes management, protection of usable aquifers, case studies of deep well injection, and practical examples. [ABSTRACT FROM AUTHOR]

Among the emerging suspended-growth biological treatment processes covered in this chapter are powdered activated carbon treatment (PACT) process, carrier-activated sludge process (CAPTOR and CAST systems), activated bio-filter (ABF), vertical loop reactor (VLR), and phostrip process. This chapter describes the above processes and explains their practice, limitations, design criteria, energy requirements, process equipment, performance, and costs. [ABSTRACT FROM AUTHOR]

Aquaculture or the production of aquatic organisms (both flora and fauna) under controlled conditions has been practiced for centuries, primarily for the generation of food, fiber, and fertilizer. The water hyacinth and a host of other organisms like duckweed, seaweed, midge larvae, and alligator weeds are used for wastewater treatment. Water hyacinth system, wetland system, evapotranspiration system, rapid rate filtration, slow rate system, overland flow system, and subsurface infiltration have also been applied. This chapter describes the above applications and explains their practice, limitations, design criteria, performance, and costs. [ABSTRACT FROM AUTHOR]

Abstract Biosolids are essentially organic materials produced during wastewater treatment which may be put to beneficial use. A popular example of such use is the addition of biosolids to soil to supply nutrients and replenish soil organic matter. Biosolids can be applied on agricultural land, forests, rangelands, or on disturbed land in need of reclamation. Recycling biosolids through land application serves several purposes. It improves soil properties, such as texture and water holding capacity, which make conditions more favorable for root growth and increases the drought tolerance of vegetation. Biosolids application also supplies nutrients essential for plant growth, including nitrogen and phosphorous, as well as some essential micro nutrients such as nickel, zinc, and copper. In addition to describing the methods for land application of biosolids, the chapter covers its advantages and disadvantages, design criteria, performance, costs of recycling through land application, biosolids disposal on land (landfill), biosolids landfill methods, preliminary planning, facility design, operation and maintenance, site closure, costs of biosolids disposal on land (landfill) and application examples. [ABSTRACT FROM AUTHOR]

Three new biosolids treatment processes are introduced: vertical shaft digestion (VSD), vertical shaft floatation (VSF) thickening, and gas-phase biofiltration. The combination of these three major processes, and a few supplemental units (such as grit removal, dewatering and drying) provide complete biosolids treatment. The topics covered in this chapter include: biosolids treatment objectives, vertical shaft bioreactor, vertical shaft flotation, vertical shaft digestion, aerobic digestion, autothermal thermophillic aerobic digestion, anaerobic digestion, dewatering, air emission control by biofiltration, engineering design, and case histories. [ABSTRACT FROM AUTHOR]

The characteristics of the wastewater to be treated and site constraints will affect treatment performance and thus the selection of an effective process. The nature of the existing facilities will have an effect on the process selection when upgrading for nitrogen removal, especially when attempting to make maximum use of the existing facilities to reduce costs. Usually, a single-sludge system can be more easily retrofitted into an existing activated sludge plant than can a separate-stage system. In addition to the discussion of the factors that affect process selection, the chapter covers costs, design considerations, process design, and design examples. [ABSTRACT FROM AUTHOR]

In a conventional activated-sludge process, bio-oxidation, nitrification, and denitrification reactions occur in three separate bioreactors connected in series. Each bioreactor has its own type of micro-organisms (i.e., activated sludge), and each bioreactor has its own clarifier for micro-organisms–water separation. In a single sludge biological system, the mixed micro-organisms are used throughout the bioreactor, which is divided into aerobic and anoxic zones for nutrient removal. This chapter introduces the classification, stoichiometric principles, kinetic considerations, and system design of various single sludge biological systems. Specifically, the multistage single anoxic zone system, the multistage multiple anoxic zone system, and the multiphase cyclical aeration system are discussed in detail. Other biological systems covered in this chapter are: endogenous nitrate respiration, aerobic sludge synthesis, anoxic biosolids synthesis, and compartmentalized aeration tanks. [ABSTRACT FROM AUTHOR]

The sequencing batch reactor (SBR) is a fill-and-draw activated sludge system for wastewater treatment. SBR systems have been successfully used to treat both municipal and industrial wastewater. They are uniquely suited for wastewater treatment applications characterized by low or intermittent flow (IF) conditions. This chapter discusses the following aspects of the process: background and process description, proprietary SPR processes, description of a treatment plant using an SBR, applicability, advantages and disadvantages design criteria, process performance, operation and maintenance, cost, and packaged SBR for onsite systems. [ABSTRACT FROM AUTHOR]

The Vertical Shaft Bioreactor (VSB) treatment system is essentially a high rate activated sludge process capable of operating at food to microorganism ratios (F/M) of between 0.5 and 2.0 kg BOD5/kg MLVSS/d. These extremely high loadings are achievable because of the capability of the system to carry and maintain mixed liquor volatile suspended solids (MLVSS) concentration values between 5.000 and 10,000 mg/L. As a result, a much lower volume (aeration period) is required than in the conventional activated sludge process. The process consists of a vertical subsurface reactor shaft 0.75 to 6 m in diameter and 75 to 125 m deep, with hydraulic mean residence times in the order of 60 min. The following aspects of the VSB process are covered: Process description, technical development, vertical bioreactor system and its variations, process theory and design basis, process design, operation, and maintenance, comparison with equivalent technologies, and case studies. [ABSTRACT FROM AUTHOR]

Biological technologies can be used to treat a vast majority of organic wastewaters because all organics could be biologically degraded if the proper microbial communities are established, maintained, and controlled. Before environmental engineers design and operate biological treatment systems that create the environment necessary for the effective treatment of wastewater, a sound understanding of the fundamentals of microbial growth and substrate use kinetics is essential. This chapter covers the above including basic microbiology and kinetics, kinetics of activated sludge process, factors affecting the nitrification process, kinetics of the nitrification process, denitrification by suspended growth systems and design examples. [ABSTRACT FROM AUTHOR]

The purpose of this chapter is to provide the basic information on the use of membrane filtration and application of the technology in the design of potable water facilities. The main issues involved in the planning and design of membrane systems are covered: pilot testing; the considerations that influence system design and operation including operational unit processes, system design considerations, and residuals treatment and disposal; and the initial start-up phase which must be completed prior to placing the system into service and actual water production. The initial start-up phase is a critical step in the successful installation of a full-scale membrane filtration system and thus is an essential consideration in the facility planning and design process. This phase includes such tasks as initial system flushing and disinfection, system diagnostic checks, membrane module installation, integrity testing new equipment, and operator training, all of which must be completed prior to placing the system into service. [ABSTRACT FROM AUTHOR]

Membrane separation processes are based on the ability of semipermeable membranes of the appropriate physical and chemical nature to discriminate between molecules primarily on the basis of size and to a certain extent, on shape and chemical composition. A membrane΄s role is to act as a selective barrier, enriching certain components in a feed-stream, and depleting the others. One of the chief attractions of membrane technology is the low energy requirement compared to other food processing technologies. Since membrane processes are nonthermal and do not involve a change of phases, they are energy-efficient and do not change the nature of the foods during their process operation. This chapter presents the membrane process theory and case histories of various production applications in the food industry. Operational problems and recommended engineering solutions for membrane process optimization are presented and discussed. [ABSTRACT FROM AUTHOR]

Membrane filtration is considered as a simplified drinking water treatment process, which can remove organic impurities, as well as metal ions and other ions. Nowadays, membrane processes are increasingly employed for removal of bacteria and other microorganisms, particulate material and natural organic matter, which can impart color, tastes, and odors to the water and react with disinfectants to form disinfection by-products (DBPs). Recently, there have been several advanced technologies derived from the combination of biotechnology and filtration with application for potable water treatment. This chapter describes these techniques which includes biofiltration, membrane bioreactor, ion-exchange membrane bioreactor, and biological activated carbon adsorption-filtration. Several case studies in applying biofiltration for DBP control in bench- and pilot-scale are also demonstrated. [ABSTRACT FROM AUTHOR]

The United States Environmental Protection Agency (US EPA) promulgated the Long Term 2 Enhanced Surface Water Treatment Rule, which has identified membrane filtration as a treatment technology that may be used to achieve the required level of Cryptosporidium treatment. This rule, along with the companion: Stage 2 Disinfectants and Disinfection By-products Rule, constitutes the principal US regulations for the application of the membrane technology in potable water treatment. The primary elements of the regulatory requirements for membrane filtration including the definition of membrane filtration, as well as challenge testing, direct integrity testing, and continuous indirect integrity monitoring, are summarized in this chapter. The requirements and procedure for challenge testing, which is required to demonstrate the ability of the treatment process to remove a specific target organism, are explained in detail. The removal efficiency demonstrated during challenge testing establishes the log removal value (LRV) or removal credit that a membrane process would be eligible to receive. The core requirements of direct integrity testing and continuous indirect integrity monitoring are fully discussed. Design example and case studies are presented. Various water and wastewater physicochemical processes (such as, conventional sand filtration, direct filtration, contact filtration, slow sand filtration, cartridge filtration, diatomaceous earth filtration, dissolved air flotation, sedimentation, lime softening, coagulation, bank filtration, second stage filtration, continuous backwash upflow dual sand filtration, UV, chlorination, chloramination, ozonation, chlorine dioxide oxidation, etc.) are compared with membrane filtration for removal and/or inactivation of Cryptosporidium, Giardia, and virus. [ABSTRACT FROM AUTHOR]

Wet air oxidation (WAO) is a technology used to treat the waste streams which are too dilute to incinerate and too concentrated for biological treatment. The WAO process was originally developed by Zimmermann and its first industrial applications appeared in the late 1950s. It can be defined as the oxidation of organic and inorganic substances in an aqueous solution or suspension by means of oxygen or air at elevated temperatures and pressures either in the presence or absence of catalysts. According to this method, the dissolved or suspended organic matter is oxidized in the liquid phase by some gaseous source of oxygen, that may be either pure oxygen, or air. The usual temperature range, 150-320°C, requires high pressure to maintain a liquid phase. Typical conditions for WAO are 150-320°C for temperature, 2-15 MPa for pressure, and 15-120 min for residence time; the preferred chemical oxidation demand (COD) load ranges from 10 to 80 kg/m3 (1,2). WAO destroys toxics in industrial wastewater by breaking down complex molecular structures into simpler components such as water and carbon dioxide, without emissions of NOx SO2, HCl, dioxins, furans, and fly ash. It is reported that the WAO process is capable of a high degree of conversion of toxic organics with more than 99% destruction rate; however, some materials are not oxidized completely to carbon dioxide and water, instead, some intermediate compounds are formed, which represent a quarter of the original mass of organic matter. For example, small carboxylic acids: acetic acid and propionic acids, methanol, ethanol, and acetaldehyde. Removal of acetic is usually negligible at temperature less than 300°C. On the other hands, organic nitrogen compounds are easily transformed into ammonia, which is also very stable in WAO process. Therefore, WAO is pretreated of liquid wastes which requires additional treatment processes, for example, a bio-treatment is usually provided for final clean-up (3). [ABSTRACT FROM AUTHOR]

Lime is one of the most widely used and cheapest alkalizing agents employed worldwide. It is often applied in chemical processes in a slaked or calcium hydroxide or slurry form. The term "calcinations of limestone" refers to the process of thermal decomposition into quick lime and carbon dioxide. It is frequently referred to as "calcinations." Decomposition of limestone is characterized by very simple chemical reactions. Complexity is seen to arise when dealing with dolomite, which is believed to cause a change in crystallography and microstructure. Kinetics of decomposition of granular and lumped limestones has been found to be very complex. This has resulted in a limited validity to produce a unified theory on calcinations. This is controlled by many factors, which includes: [ABSTRACT FROM AUTHOR]

Generally, in a water treatment plant various number and kinds of chemicals are widely used. The required characteristic of water is the major factor for chemical selection. For example, activated carbon is used for taste and odor control, lime and alum are used for coagulation, chlorine is used for disinfection, and so on. Type of water plant is another factor to consider when choosing specific type of chemicals, for example, sodium hypochlorite in a single well system and gas chlorination in a large conventional treatment plant. List of most chemicals used in water treatment is shown in Table 1. To control the addition of these chemicals to water, chemical feeding systems are necessary. The design of a chemical feed system must consider whether the chemical form is solid, liquid, or gas. Other considerations are the desire for feeding, the physical and chemical characteristics of the chosen chemical, maximum and minimum water flows, and the dependability of the feeding devices. [ABSTRACT FROM AUTHOR]

There are about 54,367 community water systems in the United States, which serve about 253 million people. Approximately 93% of community water systems are small water systems serving fewer than 10,000 persons and serve just about 20% of the population served by community water systems (1). Ownership type and system size are closely related. Most water systems serving 500 or less people are ancillary or privately owned systems, whereas most of the larger systems are publicly owned systems. This chapter discusses the operating characteristics of small water systems and the effect of Safe Drinking Water Act (SDWA) amendments implementation on small systems. The main focus of the chapter is on the filtration systems of small water systems, which serve communities less than 10,000 persons. The application of sand filters for treatment of wastewater treatment effluents from septic tanks and lagoons for small communities is also discussed in this chapter. [ABSTRACT FROM AUTHOR]

Desalination technologies are intended for the removal of dissolved salts that cannot be removed by conventional treatment processes. Thermal distillation technologies have been used in some ships for more than 100 yr. Desalination was used on a limited scale for municipal water treatment in the late 1960s. The past four decades can be divided into three phases of development: (1) 1950s was the time for discovery; (2) 1960s was concerned with research; and (3) 1970s and 1980s has been the time for commercialization. In the beginning of the 1970s, the industry began to concentrate on commercially viable desalination applications and processes. [ABSTRACT FROM AUTHOR]

Endocrine disrupting compounds (EDCs) are defined as "chemicals that either mimic endogenous hormones, interfere with pharmacokinetics, or act by other mechanisms" (1). Adverse effects such as compromised reproductive fitness, functional or morphological birth defects, cancer, and altered immune functions, among others have been reported in the scientific literature (1-3). The term "endocrine disruptors" is used to describe substances that are not produced in the body but act by mimicking or antagonizing natural hormones. It is thought that EDCs may be responsible for some reproductive problems in both women and men as well as for the increases in the frequency of certain types of cancer. EDCs have also been linked to developmental deficiencies and learning disabilities in children. Because hormone receptor systems are similar in humans and animals, effects observed in wildlife species raise concerns of potential human health effects. During fetal development and early childhood, low-dose exposure to EDCs may have profound effects not observed in adults, such as reduced mental capacity and genital malformations. Evaluating potential low-dose effects of environmental estrogenic compounds has been identified as a major research priority. [ABSTRACT FROM AUTHOR]

This chapter introduces and reviews typical applications of improved air flotation clarifiers for groundwater decontamination, resources recovery, septic tank effluent treatment, industrial effluent treatment, oil-water separation, shidge thickening, and water purification. Treatment data, process efficiency, energy consumption, and construction costs of flotation process equipment are selectively presented. [ABSTRACT FROM AUTHOR]

The supply of oxygen for aeration is the single largest energy consumer at activated sludge wastewater treatment plants, representing 50-90% of total plant energy requirements (1,2). Replacement of less-efficient aeration systems with fine pore aeration devices can save up to 50% of aeration energy costs and has resulted in typical simple payback periods of 2-6 yr (3). As a result of these very impressive cost savings, a very large number, 1000-2000 municipal and industrial wastewater treatment facilities in the United States and Canada now use fine pore aeration. [ABSTRACT FROM AUTHOR]

In the last 20 yr, the water industry has been faced with a series of great challenges. Industries have discharged wastewater that contains various new compounds. In addition, the demand for high-quality water has been significantly increasing. As a result, new water treatment technologies have been developed. In this chapter, three novel technologies are introduced. The emerging technologies for the removal of heavy metals, disinfection byproducts, total organic carbons (TOC), and arsenic are illustrated. [ABSTRACT FROM AUTHOR]

Water is one of the scarce resources in the world. Naturally occurring freshwater sources are rainwater, surface water, and groundwater. After conventional treatment, most of the water can be directly used for various purposes. The demand for water to serve the world continues to increase; however, freshwater supplies are finite, it is becoming more difficult to develop them on a renewable basis. In addition, water pollution is becoming increasingly serious as a result of which water sources are greatly affected. [ABSTRACT FROM AUTHOR]

All substances change from solid to liquid, and from liquid to gas when energy or heat is added. This change is called phase change and occurs at constant temperature. When energy is added to the gas, electrons emerge from the neutral particles and become ions. The state in which many ions and electrons are intermingled is called "plasma" (Fig. 1) (1-4). The change from gas to plasma is based on an ionization reaction. The energy needed for the reaction is in the range of 1-50 eV, which is generally much more than latent heat energy in the phase change (0.01 eV). Therefore, the change from gas to plasma is not strictly classified into the phase change. However, plasma is often called the fourth state, whereas solid, liquid, and gas are the other states of substance. Plasma is generally defined as an ionization gas, which is electrically neutral macro-scopically (the local number density of ion ni is equal to the number density of electrons nnie). Both ion and electron particles in plasma are moved by the heat. In particular, the speed of electrons is much more than other particles because of their small mass and mobility. [ABSTRACT FROM AUTHOR]

Solid substances described in this chapter will include foods, wastewater sludges, and solid wastes. Disinfection is a process involving the destruction or inactivation of pathogenic organisms in the solid substances. The process is carried out principally to ensure sanitation or to minimize public health concerns. Destruction is the physical disruption or disintegration of a pathogenic organism, although inactivation, as used here, is the removal of a pathogen's ability to infect. An important but secondary concern may be to minimize the exposure of domestic animals to pathogens in the solid substances. At present in the United States, the use of procedures to reduce the number of pathogenic organisms is a requirement before sale of sludges or recycled byproducts to the public as a soil amendment, or before recycling the sludges/byproducts directly to croplands, forests, or parks. Because the final use or disposal of sludges/byproducts may differ greatly with respect to public health concerns, and because a great number of treatment options affecting various degrees of pathogen reduction are available, the system chosen for reduction of pathogens should be tailored to the demands of the particular situation (1,2). [ABSTRACT FROM AUTHOR]

Using electricity to treat water was first proposed in England in 1889 (1). The application of electrolysis in mineral beneficiation was patented by Elmore in 1904 (2). Electrocoagulation (EC) with aluminum and iron electrodes was patented in the United States in 1909. The EC of drinking water was first applied on a large scale in the United States in 1946 (3,4). Because of the relatively large capital investment and the expensive electricity supply, electrochemical water or wastewater technologies did not find wide application worldwide then. However, in the United States and the former USSR extensive research during the following half century has accumulated abundant amount of knowledge. With the ever increasing standard of drinking water supply and the stringent environmental regulations regarding the wastewater discharge, electrochemical technologies have regained their importance worldwide during the past two decades. There are companies supplying facilities for metal recoveries, for treating drinking water or process water, treating various wastewaters resulting from tannery, electroplating, diary, textile processing, oil and oil in water emulsion, and so on. Nowadays, electrochemical technologies have reached such a state that they are not only comparable with other technologies in terms of cost but also are more efficient and more compact. For some situations, electrochemical technologies may be the indispensable step in treating wastewaters containing refractory pollutants. In this chapter, the established technologies such as electrochemical reactors for metal recovery, EC, electroflotation (EF), and electro-oxidation (EO) will be examined. The emerging technologies such as electrophoto-oxidation, electro disinfection will not be discussed. Focus will be more on the technologies rather than analyzing the sciences or mechanisms behind them. For books dealing with environmentally related electrochemistry, the readers are referred to other publications (5-8). Before introducing the specific technologies, are reviewed few terminologies that are concerned by electrochemical process engineers. The most frequently referred terminology besides potential and current may be the current density (i) the current per area of electrode. It determines the rate of a process. The next parameter is current efficiency (CE) the ratio of current consumed in producing a target product to that of total consumption. Current efficiency indicates both the specificity of a process and also the performance of the electrocatalysis involving surface reaction as well as mass transfer. The space-time yield, Y ST, of a reactor is defined as the mass of product produced by the reactor volume in unit time with 1$$ Y_{ST} = \frac{{iaM}} {{1000zF}}CE $$ The space—time yield gives an overall index of a reactor performance, especially the influence of the specific electrode area (a). [ABSTRACT FROM AUTHOR]

Increasing population and improving standards of living are placing increasing burdens on water resources. The preservation of the limited natural water supplies and, in the near future, the necessity for direct recycling of water in some parts of the world will require improved technologies for the removal of contaminants from wastewater. [ABSTRACT FROM AUTHOR]

Vermicomposting is a novel municipal biosolids and solid waste treatment process that uses earthworms (Oligochaete annelids) for the biodegradation of the biosolids and/or solid waste. This system is alternately called earthworm conversion, vermicomposting, vermistabilization, worm composting, or annelidic consumption. The worms maintain aerobic conditions in the organic substances while accelerating and enhancing the biological decomposition of the organic substances. The main product of the vermicomposting (earthworm conversion) process is the worm's castings. In some process arrangements, there may be a net earthworm production. The excess earthworms may then be sold as fish bait or animal protein supplement. Earthworm marketing is a complex problem; for municipal biosolids applications, surplus earthworms might be considered as a byproduct, while the principal product is the castings, which can be a resource. [ABSTRACT FROM AUTHOR]

Biosolids are essentially organic materials produced during wastewater treatment, which might be put to beneficial use. A popular example of such use is the addition of biosolids to soil to supply nutrients and replenish soil organic matter. Biosolids can be applied on agricultural land, forests, rangelands, or on disturbed land in need of reclamation (1). The thrust of recent legislation has been to encourage such beneficial recycling of biosolids through land application (2). The establishment of the industrial waste pretreatment programs (3) with the objective of reducing toxic pollutant loadings to municipal treatment facilities rendered more municipal biosolids suitable for reuse. [ABSTRACT FROM AUTHOR]

Composting is one of several methods for treating biosolids to create a marketable end product that is easy to handle, store, and use. The end product is usually a class A, humus-like material without detectable levels of pathogens that can be applied as a soil conditioner and fertilizer to gardens, food and feed crops, and rangelands. This compost provides large quantities of organic matter and nutrients (such as nitrogen and potassium) to the soil, improves soil texture, and elevates soil cation exchange capacity (an indication of the soil's ability to hold nutrients), all characteristics of a good organic fertilizer. Biosolids compost is safe to use and generally has a high degree of acceptability by the public. Thus, it competes well with other bulk and bagged products available to homeowners, landscapers, farmers, and ranchers (1). [ABSTRACT FROM AUTHOR]

Since the early 1900s, high temperature processes have been used for combustion of municipal wastewater solids. The popularity of these processes has fluctuated greatly because of their adaptation from the industrial combustion field. In the past, combustion of wastewater solids was both practical and inexpensive. Solids were easily dewatered, and the fuel required for combustion was cheap and plentiful. In addition, air emission standards were virtually nonexistent. [ABSTRACT FROM AUTHOR]

Water removal from municipal and industrial effluent streams constitutes an important step in wastewater and sludge treatment. The purpose is to concentrate, separate, dispose, or utilize wastes and pollutants and to regenerate and return clean water to the environment. In this context, the discussion here will be limited only to industrial and municipal sludge dewatering, evaporation, and drying (1-5). [ABSTRACT FROM AUTHOR]

Pressure filter presses are used to remove water from liquid wastewater residuals and produce a nonliquid material referred to as "cake." Dewatered cake varies in consistency from that of custard (12-15% solids) to moist soil (20-40% solids) (1). Filter presses for dewatering were first developed for industrial applications and, until the development of diaphragm presses, were only slightly modified for municipal applications. [ABSTRACT FROM AUTHOR]

Belt filter presses are used to remove water from liquid wastewater residuals and produce a nonliquid material referred to as "cake." Dewatered residuals, or cake, vary in consistency from that of custard to moist soil. Dewatering serves the following purposes (1): a.Reducing the volume, thus reducing storage and transportation costs.b.Eliminating free liquids before landfill disposal.c.Reducing fuel requirements if residuals are to be incinerated or dried.d.Producing a material which will have sufficient void space and volatile solids for composting when blended with a bulking agent.e.Avoiding the potential of biosolids pooling and runoff associated with liquid land application.f.Optimizing subsequent processes such as thermal drying. [ABSTRACT FROM AUTHOR]

Filtration can be defined as the removal of solids from a liquid stream by passing the stream through a porous medium, which retains the solids. Figure 1 shows a flow diagram of a filtration system (1). [ABSTRACT FROM AUTHOR]

Solids processing represents about 40% of the overall costs at a wastewater treatment plant. Biosolids processing refers to the screening, grit removal, thickening, stabilization, dewatering, drying, and disinfection of sludge, and also air emission control, if the target waste contains toxic volatile organic compounds (VOCs), and odorous substances. [ABSTRACT FROM AUTHOR]

Although numerous techniques fulfill the basic functional definition of dewatering, they do so to widely varying degrees. It is important to keep this fact in mind when comparing different dewatering and/or drying devices. For example, sludge drying beds and evaporation lagoons can be used not only to dewater a particular sludge, but also to dry it to a solids concentration of more than 50-60%. Depending on the particular device involved, dewatered sludge from a mechanical device might vary from a wet, almost flowable form, to a harder and more friable form (1)-(5). [ABSTRACT FROM AUTHOR]

In many situations, it is necessary to pretreat agricultural waste before final treatment. The purpose of pretreatment is to reduce pollution potential of the waste through biological, physical, and chemical processes. These types of components reduce nutrients, destroy pathogens, and reduce total solids. Pretreatment also includes solids separation, drying, and dilution that prepare the waste for facilitating another function. By the nature, pretreatment facilities require a higher level of management than that of waste storage facilities. [ABSTRACT FROM AUTHOR]

Elutriation is described by Wang (1) as "A process of sludge conditioning whereby a sludge is washed either by fresh water or plant effluent, to reduce the sludge alkalinity and fine particles, thus decreasing the amount of required coagulant in further treatment steps, or in sludge dewatering," as shown in Fig. 1. Elutriation is the term commonly used to refer to the washing of anaerobically digested sludge before vacuum filtration, as shown in Fig. 2. Washing causes a dilution of the bicarbonate alkalinity in the sludge and therefore reduces the demand for acidic metal salt by as much as 50% (2)-(14). [ABSTRACT FROM AUTHOR]

Conditioning involves the chemical and/or physical treatment of biosolids to enhance water removal and improve solids capture. The three most common conditioning systems use inorganic chemicals, organic polymers (covered in another chapter), or heat. Table 1 shows and compares the effects of conditioning processes on a biosolids mixture of primary and waste-activated sludge (WAS). [ABSTRACT FROM AUTHOR]

Solid substances described in this chapter will include food, wastewater sludges and solid wastes. Disinfection is a process involving the destruction or inactivation of pathogenic organisms in the solid substances. The process is carried out principally to ensure sanitation or to minimize public health concerns. Destruction is the physical disruption or disintegration of a pathogenic organism, whereas inactivation, which is employed here, is the removal of a pathogen's ability to infect. An important but secondary concern may be to minimize the exposure of domestic animals to pathogens in solid substances. At the present time in the United States, the use of procedures to reduce the number of pathogenic organisms is a requirement before sale of sludges or recycled byproducts to the public as a soil amendment, or before recycling the sludges/byproducts directly to croplands, forests, or parks. Since the final use or disposal of sludges/byproducts may differ greatly with respect to public health concerns, and since a great number of treatment options effecting various degrees of pathogen reduction are available, the system chosen for reduction of pathogens should be tailored to the demands of a particular situation (1,2). [ABSTRACT FROM AUTHOR]

There are two kinds of thermal processes for sludge treatment: (a) heat conditioning: a conditioning process which prepares sludge (i.e., mainly biosolids) for dewatering on filter presses or vacuum filters without the use of chemicals and (b) heat-drying: a process which evaporates water from sludge by thermal means (1)-(11). Ambient air-drying processes are dealt with in another two chapters: "Evaporation processes" and "Drying beds." [ABSTRACT FROM AUTHOR]

Increasing populations and improving standards of living are placing increasing burdens on water resources. The preservation of our limited natural water supplies and, in the not too distant future, the necessity for direct recycling of water in some parts of the country will demand improved technology for the removal of contaminants from wastewater. The contaminants in wastewater are many and continually varying, and they are not well-characterized according to chemical species. Commonly the level of organic contamination is expressed by biochemical oxygen demand (BOD), chemical oxygen demand (COD), or total organic carbon (TOC). Ozone and oxygen are powerful oxidants, which can oxidize many contaminants in wastewater and sludge biosolids. Ozone is more powerful than oxygen, but it is an unstable material, which must be generated at the point of use. Ozone has been used for disinfecting drinking water in European countries for many years. It has also been used for treating some special industrial wastes, notably for removing cyanides and phenols. Since 1980, ozone started to be used for wastewater, industrial wastes, and sludge treatment on a large scale (1)-(6). Oxidative purification and disinfection with ozone as a tertiary wastewater treatment or sludge treatment has a number of inherent advantages which are as follows: a.Reduction in BOD and COD.b.Reduction of odor, color, turbidity, and surfactants.c.Pathogenic organisms are destroyed.d.The treatment products are beneficial.e.The effluent water has a high dissolved oxygen (DO) concentration. [ABSTRACT FROM AUTHOR]

Both aerobic and anaerobic digestion processes are being used in new designs for treating biological sludges; there are advantages and disadvantages to both systems. Before a specific choice can be made, waste characteristics, general climatic conditions, type of sludge handling equipment, and the capacity of the facility must be considered. In a large facility, it may be feasible or desirable to digest primary sludge anaerobically, and secondary sludge aerobically. Aerobic digestion is the biochemical oxidative stabilization of wastewater sludge in open or closed tanks that are separate from the liquid process system. This method of digestion is capable of handling waste activated, trickling filter, or primary sludges as well as mixtures of the same. The aerobic digester operates on the same principles as the activated sludge process. As food is depleted, the microbes enter the endogenous phase and the cell tissue is aerobically oxidized to CO2, H2O, NH4+, NO2−, and NO3−(1). [ABSTRACT FROM AUTHOR]

Alkaline or lime stabilization is a very simple process. Its principal advantages over other stabilization processes include low cost and simplicity of operation. However, lime stabilization accomplished at a pH of 10.0-11.0, may allow odors to return during storage owing to pH decay. To eliminate this problem and reduce pathogen levels, addition of sufficient quantities of lime to raise and maintain the biosolids pH to 12.0 for 2 h is required. The lime-stabilized biosolids readily dewaters with mechanical equipment and is generally suitable for application on an agricultural land or disposal in a sanitary landfill. [ABSTRACT FROM AUTHOR]