Uses of Solid Wastes

Asphalt concrete Aggregate - Hot mix asphalt - Cold mix asphalt - Seal coat or surface treatment Asphalt cement modifier Mineral filler 

Portland cement concrete Aggregate Supplementary cementitious materials 

Stabilized base Aggregate Cementitious materials - Pozzolan - Pozzolan activator Self-cementing material 

Asphalt concrete - aggregate Blast furnace slag 

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Kirso, U., Teinemaa, E. Irha, N. 2002. Environmental problems of use of solid wastes in agriculture. Abstracts of the Symposium on Oil Shale, 18-21 November 2002, Tallinn, Estonia, 72-73. 

As a result of the Clean Air Act, the Water Pollution Control Act, and other federal and state laws respecting public health and the environment, greater amounts of solid waste, in the form of sludge and other pollution treatment residues, have been created. Similarly, inadequate and environmentally unsound practices for the disposal or use of solid waste have created increased amounts of air and water pollution and other problems for the environment and health. 

Table 18 Highway applications and uses of solid waste materials... 

Use of specific forms of radiant energy, infrared, ultraviolet, dielectric heating, etc., can allow specific separations to be made. The separation of clear and colored grains of glass and the separation of different metals are possible apphcations of the thermoadhesive method being considered in the field of solid-waste processing. 

Types of Solid Wastes The term solid wastes is aU-inchisive and encompasses all sources, types of classifications, compositions, and properties. As a basis for subsequent discussions, it will be helpful to define the various types of solid wastes that are generated. It is important to note that the definitions of solid-waste terms and the classifications vary greatly in prac tice and in literature. Consequently, the use of published data requires considerable care, judgment, and common sense. The following definitions are intended to serve as a guide. 

Density. Typical densities for various wastes as found in containers are reported oy source in Table 25-50. Because the densities of solid wastes vaiy markedly with geographical location, season of the year, and length of time in storage, great care should be used in select-ing typical values. 

On-Site Storage Factors that must be considered in the on-site storage of solid wastes include (1) the type of container to be used, (2) the container location, (3) public health and aesthetics, (4) the collection methods to be used, and (5) future transport method. 

TABLE 25-55 Data on the Types and Sizes of Containers Used for On-Site Storage of Solid Wastes... 

Processing Techniques for Solid Wastes Processing techniques are used in solid-waste-management systems to (I) improve the efficiency of the systems, (2) to recover resources (usable materials), and (3) to prepare materials for recoveiy of conversion produc ts and energy. The more important techniques used for processing solid wastes are summarized in Tables 25-61 and 25-62. 

Equipment used to reduce the size of solid waste including hammer mills, shredders, roll crushers, grinders, chippers, jaw crushers, rasp mills, and hydropulpers briquettes... 

Incineration with Heat Recovery Heat contained in the gases produced from the incineration of solid wastes can be recovered as steam. The low-level heat remaining in the gases after heat recoveiy can also be used to preheat the combustion air, boiler makeup water, or solid-waste fuel. 

Landfilling Methods and Operations To use the available area at a landfill site effectively, a plan of operation for the placement of solid wastes must be prepared. Various operational methods have been developed primarily on the basis of field experience. The principal methods used for landfilling dry areas may be classified as (1) area, and (2) depression. 

USATHAMA) completed a trial burn of explosive, contaminated soil in a rotary kiln (Noland, 1984). Soil contaminated from red and pink water lagoons was successfully burned. A transportable rotary kiln yrstem was set up. The technology by Therm-All, Inc., had been used in industry for destruction of solid wastes. The normal screw feed system was not used, due to fear of a soil explosion during the extruded plug feed process. Therefore, the soil was placed in combustible buckets and individually fed by a ram into the incinerator. The feed rate was 300 to 400 Ib/hr and the operational temperature was 1200° to 1600°F in the kiln and 1600° to 2000°F in the secondary chamber. 

Bacteria, yeast and algae are produced in massive quantities of protein sources as food for animals and humans.1 SCP is considered a major source of feed for animals. The production of valuable biological products from industrial and agricultural wastes is considered through the bioconversion of solid wastes to added-value fermented product, which is easily marketable as animal feedstock. The waste streams that otherwise would cause pollution and threaten the environment can be considered raw material for CSP production using suitable strains of microorganisms. 

Another major cause of waste is the use of mineral acids (H2SO4, H3PO4, etc.) and Lewis acids (AICI3, ZnCL), often in stoichiometric amounts, which cannot be recovered and recycled. A typical example is the HNO3/H2SO4 mixture used in aromatic nitrations. Consequently, there is a discernible trend towards the use of solid, recyclable Brpnsted and Lewis acids, e.g. zeolites, acidic clays, etc. (see later) as alternatives to conventional mineral and Lewis acids. 

The TS-1 catalysed hydroxylation of phenol to a 1 1 mixture of catechol and hydroquinone (Fig. 2.16) was commercialized by Enichem (Romano et ai, 1990). This process offers definite advantages, such as higher selectivities at higher phenol conversions, compared to other catalytic systems. It also illustrates another interesting development the use of solid, recyclable catalysts for liquid phase (oxidation) processes to minimize waste production even further. 

Conventional structural design and construction procedures for a construction are generally applicable to a construction incorporating foundry solid wastes. The same production methods and equipment used for conventional manufacture can be used for production of manufacture using foundry solid waste. 

Hazardous waste identification begins with an obvious point in order for any material to be a hazardous waste, it must first be a waste. However, deciding whether an item is or is not a waste is not always easy. For example, a material (like an aluminum can) that one person discards could seem valuable to another person who recycles that material. U.S. EPA therefore developed a set of regulations to assist in determining whether a material is a waste. RCRA uses the term solid waste in place of the common term waste. Under RCRA, the term solid waste means any waste, whether it is a solid, semisolid, or liquid. The first section of the RCRA hazardous waste identification regulations focuses on the definition of solid waste. For this chapter, you need only understand in general terms the role that the definition of solid waste plays in the RCRA hazardous waste identification process. 

Wastes used as a product substitute. If a material is directly used as an effective substitute for a commercial product (without first being reclaimed), it is exempt from the definition of solid waste. 

Dioxin-containing wastes considered inherently waste-like. Dioxin-containing wastes are considered inherently waste-like because they pose significant threats to human health and the environment if released or mismanaged. As a result, RCRA does not exempt such wastes from the definition of solid waste even if they are recycled through direct use or reuse without prior reclamation. This is to ensure that such wastes are subject to the most protective regulatory controls. 

Pulping liquors. Pulping liquor, also called black liquor, is a corrosive material used to dissolve wood chips for the manufacturing of paper and other materials. To promote waste minimization and recycling, U.S. EPA excluded pulping liquors from the definition of solid waste if they are reclaimed in a recovery furnace and then reused in the pulping process. If the liquors are recycled in another way, or are accumulated speculatively, they are not excluded. 

Coke byproduct wastes. Coke, used in the production of iron, is made by heating coal in high-temperature ovens. Throughout the production process many byproducts are created. The refinement of these coke byproducts generates several listed and characteristic wastestreams. However, to promote recycling of these wastes, U.S. EPA provided an exclusion from the definition of solid waste for certain coke byproduct wastes that are recycled into new products. 

Processed scrap metal. Scrap metal includes, but is not limited to, pipes, containers, equipment, wire, and other metal items that are no longer of use. To facilitate recycling, scrap metal that has been processed to make it easier to handle or transport and is sent for metals recovery is excluded from the definition of solid waste. Unprocessed scrap metal is still eligible for an exemption from hazardous waste regulation when recycled. 

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