Metal Recycling Ebook
Given the high cost of moving and other critical variables that enter into decisions about corporate location, very few businesses will relocate solely to be part of an industrial symbiosis. In recognition of this, the model of Type 5 exchanges depends on virtual linkages rather than on co-location. While virtual eco-industrial parks are still place-based enterprises, Type 5 exchanges allow the benefits of industrial symbiosis to be expanded to encompass a regional economic community in which the potential for the identification of by-product exchanges is greatly increased owing simply to the number of firms that can be engaged. An additional attractive feature is the potential to include small outlying agricultural and other businesses, possibly by pipeline, as in Kalundborg, or by truck for those farther out. It could be argued that self-organized groups such as the network of scrap metal dealers, agglomerators and dismantlers who feed particular mills or subsystems such as...
In addition, residual management of plants with accumulated metals has not been sustainably optimized. Unless the multimedia transfer to one generation ofplants is sufficient to reduce soil or water concentrations to acceptable levels of risk, phytoextraction requires the harvest and disposal of plant materials. The rate of metal uptake per unit area, the target residual accumulation at harvest, the time available for cleanup on different parts of a contaminated site, and monitoring requirements are design variables selected to achieve economically and sustainably optimized solutions. The US state of the practice at this early stage requires metal-laden plants be disposed in expensive hazardous waste landfills. Metal recycling to smelters, established as feasible for nickel, and composing or incineration to reduce the volume disposed in landfills do not seem to have been rigorously explored.
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 recovery in boilers and industrial furnaces waste from which precious metals are reclaimed or spent lead-acid batteries being reclaimed. Wastes generally exempt from regulation are reclaimed industrial ethyl alcohol, used batteries or cells returned to a battery manufacturer for regeneration, scrap metal, and materials generated in a petroleum refining facility. Recycled used oil is subject to used oil management standards (Part 279 of RCRA).
Much of it is recycled from scrap metal, but it is normal to add at least 10 new steel to improve the strength. Steel reinforcement is in the form of bars of varying dimensions, or fibres of approximately 15 millimetres. The use of fibres can reduce the steel needed to half in concrete floors (Gielen, 1997). The distance between expansion joints can also be increased considerably, therefore reducing the use of plastic joint mastics. Other fibres have been introduced more recently in the form of glass and carbon. With carbon it is also possible to produce a reinforcing wire with far better strength properties than steel bars, reducing the climate impact in production by approximately 60 (Gielen, 1997).
Bottle bills, while having achieved partial success, should be integrated into overall recycling programs, which include office paper and newspaper recycling, cardboard collection from commercial establishments, curbside recycling, establishment of buy-back recycling centers, wood waste and metal recycling, glass and bottle collection from bars and restaurants, and composting programs. Advertising and public education are important elements in the overall recycling strategy. Street signs, door hangers, utility-bill inserts, and phone book, bus, and newspaper advertisements are all useful. The most effective longrange form of public education is to teach school-children the habits of recycling.
Generally speaking, metals have limited reserves. In certain cases scrap metal is used. Energy demand in production is high, and serious pollutants are emitted from the processes. It must be considered as an overinvestment of quality when using galvanized steel products in dry, indoor environments. Untreated steel products have a far better environmental profile.
If the amount of waste generated on-site is insufficient for a cost-effective recovery system, or if the recovered material cannot be reused on-site, off-site recovery is preferable. Materials commonly reprocessed off-site are oils, solvents, electroplating sludges and process baths, scrap metal, and lead-acid batteries. The cost of off-site recycling depends upon the purity of the waste and the market for the recovered materials.
Table 10.2.1 also shows generation rates for solid waste other than MSW. The quantity of other waste, most of which is bulky waste, is roughly half the quantity of MSW. The proportion of bulky and other waste varies, however, and is heavily influenced by the degree to which recycled bulky materials are counted as waste. The quantities of bulky waste shown for Atlantic and Cape May counties, New Jersey, include large amounts of recycled concrete, asphalt, and scrap metal. See also Component Composition of Bulky Waste in Section 10.3.