For some years, the massive spreading of technically complex products as well as the shortening of product life cycles have led to a constantly rising return flow of discarded technical devices. The removal of these devices today occurs mostly through disposal-oriented strategies, i.e. used products are shredded and finally stored in dumps or eliminated thermally in domestic refuse combustion plants. For a long time, the product flow was a one-way street. Public and legal pressure have led to an increase in the importance of environmentally-oriented aspects in both the industrial and private sector. This leads to a rising demand for the establishment of a cycle-oriented economy. The cycle-oriented economy aims to keep materials and products in economic circulation as long as possible. The objective of the cycle-oriented economy is motivated by the shortage of resources (energy and raw materials) and the shrinking of disposal areas (air, water, soil), as well as the realization that economically usable potentials are currently being thrown away (Gupta and Veerakamolmal, 1999). Disposal, as central component of the cycle-oriented economy, includes recycling. Recycling includes disassembly as a type of treatment. In contrast to other types of treatment, disassembly permits a higher maintenance of value of old products; however, it usually requires a higher expenditure as well. In contrast to alternative types of treatment (i.e. shredding), the recovery of functional components and assemblies for reuse (product recycling) and the possibility of the recovery of materials (material recycling) are possible advantages of conducting a disassembly process (Seliger and Kriwet, 1993). In general, disassembly follows the same objectives as production; thus remanufacturing is often spoken of (Rautenstrauch, 1999).
The Effect of Dichloromethane on Product Separation during Continuous Hydrothermal Liquefaction of Chlorella vulgaris and Aqueous Product Recycling for Algae Cultivation
