WASTE SORTING

Recycling is the process of collecting waste, sorting it, and reclaiming raw materials that can be sold to produce products. From our household waste, glass and metals have been recycled for decades in many parts of the United States. Automobiles have been extensively recycled in North America for many years. Approximately 75% of the mass of an average scrap car is recycled. Clearly this is a profitable business with an extensive infrastruc-... 

Tertiary recycling involves chemical breakdown of nylon or PET for repolymerisation. This requires either clean, sorted pre-consumer waste or post-consumer waste, sorted by fibre type, as a feedstock. In quaternary recycling, the embedded energy of textiles can be reclaimed through incineration (Wang, 2010). This final approach is not addressed in this chapter. 

Is the waste sorted with respect to colour and polymers contained in it ... 

Waste sorting has been instructed and trained and containers for different sections of waste exist. Sorting know-how is included in the orientation. 

There is at least one indicator for societal results and it is locally compared. (Theses, internships, work hours of externals, environmental goals set by the customer, development of the amounts of waste, functionality of waste sorting or amounts of harmful substances). 

Functionality of waste sorting is checked (e.g. from the waste containers), maximum of one error per container is accepted. 

FIG. 5. Representation of the concept of maximum allowable concentration of radionuclides in a repository and of the RNC profile of a waste sort. 

Separation processes utilize these differences in properties directly, in the sorting processes the relevant property is measured and decision is made in which stream to place a given component of the waste. Sorting can be done manually or automatically. 

Waste sorting should be done to the extent possible at the place of waste generation. If this is not possible the incineration facility shall have a sorting area where material not suitable for incineration can be removed. Depending on the radioactivity level of the wastes and the potential for airborne contamination, the wastes may or may not be sorted by hand. Alpha bearing wastes shall be sorted in a sealed glove box. 

Viegas, S., Almeida-Silva, M. Viegas, C. (forthcoming 2014). Occupational exposure to particulate matter in two Portuguese waste sorting units. International Journal of Occupational Medicine and Environmental Health. 

Principles and Characteristics Industry requires both technically sound and economic waste sorting processes. According to EC directives polymers containing cadmium e.g. as CdS pigments) or bromine (e.g. PBDE) need to be eliminated from the recycling process. 

It would appear that the use of laser-aided polymer waste sorting [137] (eventually in combination with LIBS) and fluorescent tracer systems (cfr. Chp. 1.4.2) [152] are technologically the most attractive, with the latter technology more geared towards the identification of polymers than additives. 

Practical application of plastic waste sorting is greatly determined by legislation. 

Miniature spectrometers find useful applications in plastics waste sorting. Chemiluminescence is used for the continuous determination of nitrogen oxides. 

Automatic polymer waste sorting plants based on NIR identification are operative (c/r. Chp. 1.2.2). For identification and sorting of carpets a portable NIR spectroscopic system - CarPID - was developed [139]. Other reported NIRS applications are to be found in the quantitative analysis of copolymers or blends the near-IR range allows for accurately monitoring of the monomer ratio and residual monomer content. Ikeda [140] used near-IR spec-trochemical analysis in controlled manufacture of polyester plasticisers. Jones et al. [141] similarly described the use of NIR analysis for controlling plasticiser ester formation the esterification of phthalic anhydride by isodecyl alcohol was exemplified. 

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