Organic matter, natural recycling

Figure 1 illustrates the different phases available for organic chemicals in the environment. These may include the original HWM, as well as water, air, soil, and other organic chemicals present in liquid or solid phases. As previously mentioned, the HWM may be recycled-asphalt pavement or shredded tires. Both the HWM and soil can be very complex. HWM may consist of different polymers, rocks and mineral fragments, and various HOPs. Soils consist of different types and amounts of natural organic matter, black carbon, and minerals. As discussed below, carbonaceous materials typically have the greatest affinity for HOPs. 

Jacques, G. (1983). Some ecophysiological aspects of Antarctic phytoplankton. Polar Biol. 2, 27-33. Jahnke, R., Reimers, C., and Raven, D. (1990). Intensification of recycling of organic matter at the sea floor near ocean margins. Nature 348, 50-54. 

This natural recycling of organic matter is an important process in terrestrial and aquatic ecosystems, but it becomes a serious problem when... 

DiGiano F.A, (1996), Evaluation of Natural Organic Matter Fouling in Bench-scale, Batch Recycle Tests of Nanofiltration, ICR Workshop on Bench-scale and Pilot-scale Evaluations, AWAVA, Cincinnati, Ohio, March 1996. 

Elevated lead contents were recorded in various species of plants from the vicinity of metal smelters, roadsides, soils heavily contaminated with lead, natural ore deposits, and lead recycling factories. Bioavailability of lead in soils to plants is limited, but is enhanced by reduced soil pH, reduced content of organic matter and inorganic colloids, reduced iron oxide and phosphorus content, and increased amounts of lead in soils. Lead, when available, becomes associated with plants by way of active transport through roots and by absorption of lead that adheres to foliage. Lead concentrations were always higher in the older parts of plants than in shoots or flowers. 

The products can also be recycled after use for second time and they can even be hydrolyzed back into lactic acid which is the basic monomer. Nevertheless, the recycled lactic acid can be re-introduced into the polymerization process of PLA. The last possibility is to introduce PLA into the natural life cycle of aU biomass where it degrades into carbon dioxide and water. Thus, the diversity of PLA becomes obvious as it can be recycled and also decomposed like all other organic matter. Besides that, it will do no harm if burned in an incineration plant or introduced into a classical waste management system (Jacobsen et al. [1]). The typical values of mechanical properties of PLA are displayed in Table 11.1. 

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