Environmental risk of waste and its management - Environmental Deterioration and Contamination: Problems and their Management - page 157

Figure 6.8 Risk assessment and control for chemicals in wastes.

rubber is used as a filler material of permeable reactive barriers since its sorption
potential toward dissolved organic contaminants is similar or better than that of
activated carbon. It is also beneficial for fixing the biodegrading microflora (Park
et al., 1996; Tim et al., 1997).

• Plastic waste, e.g., PET (polyethylene terephthalate) chips from PET bottles that

are 12 4 mm in size can amend soil texture and soil's load bearing capacity. It

also works against soil compaction (Babu et al., 2011; Consoli et al., 2002).

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• Used vegetable oil is utilized mainly for biodiesel production, but 10% is applied

directly as soil amendment in Hawaii (Kovaleski, 2012).

Assessment of the risk of chemicals present in the waste is always a key issue in
environmental management. If maximum waste utilization is aimed at either by reuse
or recycling, the waste materials shall be handled as any other material or product.
The integration of the concept of material streaming from the waste sources to final
utilization requires that waste materials are handled as chemical substances and prod-
ucts, and therefore, any hazard associated with waste constituents has to be assessed
and controlled in a proper way by waste treatment and utilization (Figure 6.8).
Managing chemicals contained in waste similar to other hazardous and nonhaz-
ardous chemical substances involves the control of risk. The hazardous material/waste
can be used only if the risks can be controlled and accepted based on a risk-benefit
comparison and socio-economic evaluation.
Waste utilizing technologies should be evaluated carefully. To make the right
selection of a waste management option and waste treating or utilizing technology,
they must be comparatively evaluated with regard to their technological, envi-
ronmental, and socio-economic efficiency. Figure 6.9 shows the uniform elements
of the comparative evaluation of the alternatives and verification of the selected
waste management option. After implementing the selected waste treatment/utilizing