## 2 Searching for an Open Technology Strategy for Marine Plastic Recycling
### CircularSeas Project and Main Results of Plastic Waste Survey
The most relevant objects for the introduction of recycled plastic products found from the surveys were the following: to manufacture short runs; to replace products that frequently break; to gain marketing advantages or new business opportunities; to obtain a distinctive seal to \begin{table}
\begin{tabular}{c c c} \hline \hline
**Waste** & **Quantity (Tn)** & **Plastic Type** & **Current Waste Management** \\ \hline Nets & 1681.34 & HDPE, PP & Sale to plastic recycling company \\ \hline Containers & 454.10 & PET, HDPE, PP, LDPE & Contract with private company for collection, transport and management of the waste \\ \hline Films & 135.73 & LDPE & MSW 1 or sale to plastic recycling company \\ \hline Bags & 130.00 & LDPE & Compacted and managed as MSW 1 \\ \hline Ropes & 100.00 & HDPE, PP & Sale to company for reuse \\ \hline Fragile packaging & 31.28 & EPS (Expanded PolyStyrene) & Collection by the port manager \\ \hline Strapping tapes & 29.56 & PP & MSW 1 or sale to plastic recycling company \\ \hline \hline \end{tabular}  
* MSW = Municipal Solid Waste.  
\end{table} 
Table 1: Summary of the main plastic waste data. \begin{table}
\begin{tabular}{c c} \hline \hline
**Plastic Type** & **Quantity (Tn)** \\ \hline HDPE & 1429.04 \\ \hline PP & 365.83 \\ \hline LDPE & 265.73 \\ \hline PET & 62.04 \\ \hline EPS & 31.28 \\ \hline \hline \end{tabular}  
\end{table} 
Table 2: Quantity of waste identified by type of plastic. support their environmental involvement; to avoid having physical stock to store certain spare parts. Table 3 highlights the products that have been found to be in high demand, some of which need a considerable amount of material (plastic) to be produced. However, mass production and big parts lay outside the application scenario of 3D printing. Nevertheless, considering the contributions of all business agents, especially in a big port area such as Vigo, the number of different products and the demanded number of items to be produced by 3D printing may be relevant, as may be the amount of plastic used. The last part of the survey focused on 3D printing technology in maritime industries, the results of which are presented below. The stakeholders gave their view on employing 3D printing technology to support their business. They were also asked about their actual resources (hardware, software and qualified personnel). Finally, they gave their opinion on the use of recycled plastic or commercial plastic to manufacture parts in their particular environment. The results are presented below. These industries, traditionally reluctant to change [45], welcome the introduction of 3D printing to support their business. In fact, 70% of the companies surveyed agree with this emerging technology; however, they are sceptical and consider that certain products and technologies, such as injection moulding, are much more appropriate and widely used, for example, to manufacture containers, bottles, etc. [46]. These industries were also asked about their current readiness to manage the manufacturing chain of a product using 3D printing, from design to manufacturing on the printer. In general, the responses highlighted a need for an external service to manage the manufacturing process, since they do not have qualified personnel in additive manufacturing. However, 80% of respondents said that, in the case of printing parts by themselves, they would need a cheap and user-friendly infrastructure. This fact facilitates the direct introduction of 3D printing in the activity of maritime companies. Therefore, from these surveys it can be identified that 3D printing could be an enabling technology to decrease the use of plastic that comes from outside the maritime industry, encouraging plastic recycling as well as the Circular Economy. In the genesis of the project, the choice of 3D printing as the technology to be used was specified because it is more economical compared to many other manufacturing technologies using plastic materials. A cost study (associated to geometry, material and