End-of-pipe and recycling technologies

Note Other = Patents from countries different from USA, Europe and Japan. 

Note Share of end-of-pipe patents on the total number of patents by countries. 

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Table 2. Patent applications in end-of-pipe and recycling technologies (1993-97)...

Within the first two groups we then made a distinction between mother companies and subsidiaries. In order to distinguish firms t) ology and sector, the Who Owns Whom 1997 directory (WOW, Dun Bradstreet) was used. Table 7 shows the results related to the USPTO patents (end-of-pipe and recycling technologies, respectively), while table 8 refers to EPO patents. 

The sample was composed of 10 percent of end-of-pipe and recycling patents identified in the previous analyses. They were proportionally subdivided among countries, and between recycling and end-of-pipe technological classes. 

Various treatment technologies are used at the iron and steel plant for recycle system water treatment prior to recycle and reuse, or end-of-pipe wastewater treatment prior to discharge to surface water or a POTW. The physical/chemical treatment technologies extensively used include equalization, tar removal, free and fixed ammonia stripping, cooling technologies, cyanide treatment technologies,... 

The first approach may involve cleaner synthesis processes, improved technology, recycling of residues, improved use of catalysts, and generally, every technique integrated into the process that leads to less waste whereas the second one is an end-of-pipe treatment of the waste that is inevitably produced by a chemical process. Both approaches have to be combined so that our releases into the environment are as minimal and harmless as possible. 

Portable water supply and wastewater treatment costs, coupled with water availability concerns, are causing the industry to look at internal and end-of-pipe recycle options. These projects could not have been justified and/or the technology was not readily available 10 years ago. This situation is addressed further in the next section. 

Different techniques are available to cut VOC emissions. End-of-pipe technologies of course were the first solution introduced by the industry, and still are the most common (Interview, 1999). Various filtration, destruction and recycling techniques continue to be applied in decorative paints manufacturing plants. Akehurst (1997) discussed in detail the various techniques available to destroy VOCs. First, he considered thermal oxidation and catalytic incineration. 

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