Growing populations, high-technology applications and the energy transition raise the demand for rare earth elements. As a secure supply in the future is all but certain, opportunities arise for deep-sea mining. Polymetallic nodules
that are located on the vast, sediment-covered ocean floors, are one of the more promising deep-sea mineral occurrences. Large amounts of unwanted surrounding water and sediment are collected along with the nodules in the
harvesting process. Separating the sediment and excessive water from the nodules before transportation toward the surface could mitigate sediment plumes and be beneficial for energy consumption. In this research, the feasibility of a hydrocyclone inspired machine is investigated for this process. With model experimentation, the key performance parameters are studied using varying particle fractions, adjusting split ratio and conical angle. Timescale ratios are
used for particle scaling, and to describe their behaviour. The cyclones’ separation shows great potential. However, large particles can be problematic, and the energy consumption is too high for deep-sea operation. Therefore, topside utilisation is recommended.


Keywords: Polymetallic nodules, separation, hydrocylone, performance parameters, topside.

Every year large quantities of plastic waste accumulate in Bali’s environment. This has a negative impact on Bali’s environment, local society and its tourist driven economy. With lacking waste management facilities and local awareness plastic waste enters Bali’s rivers, through which the waste ends up in the ocean. A concept small-scale recycling business, aiming to improve local waste management and awareness, is proposed to solve the problem at the source. The goal of this research is to investigate the technological, social and financial feasibility of the concept recycling business and to find a target location. The research first aims to choose three potential locations with different social-demographics through a literature study on Bali’s regional social-demographics and the results of previous ”Pantai” Project researches. Based on this three locations are chosen: Denpasar, Canggu and Pulukan. For better understanding of the areas of interest, the crucial steps for setting up a business on Bali and its local waste management are investigated. A detailed stakeholder analysis is therefore also conducted. This is researched through participatory observation, literature study and interviews with local inhabitants, local businesses and governmental institutions. Surveys are conducted in the areas of interest to analyze how to Balinese handles their plastic waste, their mentality towards the plastic problem and their willingness to participate in the concept recycling plan. The results of the survey show enthusiasm of the local people towards the concept recycling business in the target areas. However, not all stakeholders are represented in conducted surveys, thus care must be taken when concluding the social feasibility. To investigate the technological feasibility literature study is done on plastics and different techniques in all steps of the recycling chain. Through this, feasible techniques for all steps of the recycling chain are chosen, regarding the concept recycling business. Plastic waste is to be sorted by hand and processed by easy operable machinery based on the open-source designs of Precious Plastic. A conceptual model of the small-scale recycling business is introduced for better understanding of the plastic and money streams involved in the concept recycling facility. To investigate the financial feasibility, first the plastic stream is evaluated. In each location households separated and collected all their plastic from the rest of their waste for one week to estimate the composition and quantity of their weekly plastic waste production. From this result the plastic input per location is estimated through calculations. A model is presented to evaluate financial stability of the concept recycling business. Input values for the model are the results from own waste collection measurements and the values acquired from connected parties. Calculations show, although being a rough estimate, financial feasibility. However more in-depth market study has to be performed for more detailed results. Taking everything into account it can be concluded that it is indeed feasible to start a small-scaled recycle business on Bali in Pulukan or similar areas, which is determined by a multi criteria trade-off. However close consideration of local conditions should always be taken into account.