Ispectrum Magazine Ispectrum Magazine #09 | Page 28

Photo credit:The Ocean Cleanup count the number of particles of plastic that went through a strip of a certain length for a certain amount of time and that way we were able to calculate the speed of cleanup. That doesn’t mean that 42% is the maximum efficiency because if you make the array of floating barriers twice as long, you would collect about 70%. I believe that if you have a 100km long barrier deployed for 20 years the clean up efficiency is 75%, so the 42% is an arbitrary number; this is the efficiency you would get if you deploy the array for 10 years with 100km sides. be defined as below 5 mm in length and people sometimes erroneously refer to all ocean plastics as microplastics. Over 90% of the plastics are larger than microplastics and also removing larger plastics will prevent the increase of microplastics tenfold because a fundamental problem is that large plastics get eroded by the sun and waves into smaller bits that get eaten by fish and mammals and birds. We can collect the plastics over 2mm JK: The feasibility report said that you are unable to remove the smallest microplastics – millimetre sized plastic debris. Is that going to be a problem? Boyan: I don’t think so. Of course we would prefer to catch all plastics but we also ha ve to be realistic; we won’t collect every last kilo of plastic. It’s just about removing as much as possible. Microplastics can 27