Starch waste management

National Solid Waste Management Association (NSWMA), 279 National Starch Chemical Co., 210 National Starch and Chemical Company, 240 National Technical Infomiation Service hiformation Center (NTIS), 303 Natural Gas, 96... 

Figure 23 shows the result of comparisons of life cycle CO2 emission of Bionolle, starch-Bionolle compound, LDPE, and polystyrene. Data for producing LDPE and polystyrene are taken from a report of the Plastic Waste Management Institute [17]. The disposal method assumed is incineration. CO2 emissions from both Bionolle and starch-Bionolle compound are lower than those of LDPE or polystyrene. 

Breslin VT, Swanson RL (1993) Deterioration of starch-plastic composite in the environment. J Air Waste Manag Assoc 43 325-335 Breslin CB, Chen C, Mansfeld F (1997) The electrochemical behaviour of stainless steels following surface modification in cerium-containing solutions. Corrosion Sci 39 1061-1073... 

Modified starch-based polymers are promoted as potential solutions to the current litter/ municipal solid-waste management problems in as much as they serve two purposes ... 

In the first step, various options of production, use and waste management are evaluated sequentially first, the effects of variations in production are studied while the assumptions made for the use phase and for waste management remain unchanged. This is followed by similar sensitivity analyses for the use phase and for waste management. All these analyses are prepared both for starch polymer (Table 13.3) and EPS loose fill (not reported here). 

For starch polymer loose fill, the first column of Table 13.3 provides a ranking of the various options studied in production, in the use phase and in waste management. Twenty enviromental parameters were determined. The ranking shown in Table 13.3 has been determined by comparing for how many impact categories the environmental damage is lower in one case compared to the other without normalisation and valuation. Similar comparisons were also made for EPS loose fill (results not given). 

For starch polymer pellets energy requirements are mostly 35%-70% below those for PE and GHG emissions are 30%-80% lower (disregarding differences that result from differences in waste management). Starch polymers also score better than PE for all the other indicators listed in the table with eutrophication being the sole exception. The lower the share of petrochemical copolymers, the smaller the environmental impact of starch polymers generally is. However, the application areas for pure starch polymers and blends with small amounts of copolymers are limited due to inferior material properties. Hence, blending can extend the applicability of starch polymers and thus lower the overall environmental impact at the macroeconomic level. 

Waste management Composting of starch polymers, incineration of EPS. Collection after use is excluded. Sensitivity analyses for disposal via waste water. The following options are distinguished for starch polymers and EPS ... 

Biopolymers generally have lower heating values than most petrochemical bulk polymers (Table 7). In some cases the difference is negligible (e.g., PH3HB versus PET), while in other cases it is substantial (starch polymers versus PE). In practice, the difference in recoverable heat may be even larger than indicated by Table 7 due to the feature of most biopolymers to absorb water rather easily. The choice of the waste management system may therefore have a considerable impact on the... 

Environmental comparisons including recycling as a waste management option are rarely made. Moreover, most of the biopolymers except starch can be processed by mechanical or even feedstock recycling (back to monomer). Mechanical recycling is in principle possible even for thermoplastic polymers reinforced with natural fibres. More attention must be paid to these options in future studies. 

Of all studied bio-based plastics (pellets), starch polymers are considered to perform best in environmental terms under the current state of the art -with some differences among the various types of starch polymers. Compared to starch polymers, the environmental benefits seem to be smaller for PLA (LCA results only available for energy and CO2). For PHA, the environmental advantage currently seems to be very small compared to conventional polymers (LCA results only available for energy use). For both PLA and PHA, the production method, the scale of production, and the type of waste management treatment can influence decisively the ultimate conclusion about the overall environmental balance. 

One market which may provide potential for biodegradable polymers includes institutions such as theme parks or special events that must manage their own solid wastes. This concept was showcased at the Sydney Olympic Games in 2000 where 40 million food service items made of starch-based polymers were collected after use and composted [97]. Disposable cutlery and dishes used at the Sydney Olympic Games were supplied by Biocorp Inc., Novamont s North American distributor. 

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