Waste continued plastic

The increase in the use of plastic materials in all sectors of industry and in everyday life, as well as the reduction in the lifetime of most plastic products, have led to a continuous increase in the generation of plastic wastes. Figure 1.7 illustrates the distribution of solid wastes by sector in Western Europe for 1996. The total volume of waste was 2.6 x 109 tonnes, although the total post-user plastics waste accounted for only 1.7 x 107 tonnes, i.e., only 0.6 wt% of the solid waste was plastic materials. 

Currently, only PET, high-density polyethylene (HOPE) and PP are being properly separated in municipal recycling streams in meaningful volumes across the developed world. However, it is predicted that innovations in continuous plastics detection and separation will eventually lead to materials such as PLA being easily redirected and reprocessed from domestic waste streams in the near future. 

An important newer use of fluorine is in the preparation of a polymer surface for adhesives (qv) or coatings (qv). In this apphcation the surfaces of a variety of polymers, eg, EPDM mbber, polyethylene—vinyl acetate foams, and mbber tine scrap, that are difficult or impossible to prepare by other methods are easily and quickly treated. Fluorine surface preparation, unlike wet-chemical surface treatment, does not generate large amounts of hazardous wastes and has been demonstrated to be much more effective than plasma or corona surface treatments. Figure 5 details the commercially available equipment for surface treating plastic components. Equipment to continuously treat fabrics, films, sheet foams, and other web materials is also available. 

The rate of decomposition in unmanaged landfills, as measured by gas production, reaches a peak within the first 2 years and then slowly tapers off, continuing in many cases for periods up to 25 years or more. The total volume of the gases released during anaerobic decomposition can be estimated in a number of ways. If all the organic constituents in the wastes (with the exception of plastics, rubber, and leather) are represented with a generahzed formula of the form QH O N, the total volume of gas can be estimated by using Eq. (25-27) with the assumption of completed conversion to carbon dioxide and methane. 

A pilot plant for the high temperature pyrolysis of polymers to recycle plastic waste to valuable products based on rotating cone reactor (RCR) technology. The RCR used in this pilot plant, the continuous RCR was an improved version of the bench-scale RCR previously used for the pyrolysis of biomass, PE and PP. 9 refs. 

This comprehensive article supplies details of a new catalytic process for the degradation of municipal waste plastics in a glass reactor. The degradation of plastics was carried out at atmospheric pressure and 410 degrees C in batch and continuous feed operation. The waste plastics and simulated mixed plastics are composed of polyethylene, polypropylene, polystyrene, polyvinyl chloride, acrylonitrile butadiene styrene, and polyethylene terephthalate. In the study, the degradation rate and yield of fuel oil recovery promoted by the use of silica alumina catalysts are compared with the non-catalytic thermal degradation. 9 refs. lAPAN... 

Pesticide containers were triple rinsed, crushed and disposed of as solid waste (Figure 3). Containment of liquid wastes by the newly constructed plastic lined pit was questionable after one year. There appeared to be some leakage or fluctuation of the liquid level. There is continual danger of rupture of such liners by mechanical Injury, chemical Interaction, rodents, etc., which could result in contamination... 

The disposal of low-value waste metals at hazardous dumpsites continues, principally because there are currently no economically viable alternatives. Conventional precipitation and filtration techniques are widely used by metal fabricators to remove and concentrate metals from their waste water streams. In some cases, the sludges are subsequently dried to reduce weight before transportation and disposal, or to comply with solids content regulations. The concentrated wastes are shipped in drums, dumpsters or heavy plastic bags to dumpsites. 

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