Returning the shells to the beach

Abstract

This thesis consist of the graduation project executed in cooperation with the municipality of the Hague, at design studio DIDID in the Hague. The beaches of the Hague are cleaned by so called beach cleaners. Beach cleaners are large tractor pulled screening machines that effectively screen/rake garbage from the beach. There is however a problem with these machines. Together with the garbage, large quantities of shells are taken in. This is in-desirable for three reasons. 1: Shells are materials that belong to a natural beach and should therefor not be taken away. 2: Shells help prevent beach erosion because of their sand-clinching characteristics. More shells mean less beach erosion. 3: Shells form a large weight fraction of the material collected by the beach cleaners and therefor account for a large part of the disposal costs. Leaving them on the beach will significantly decrease these costs. This thesis shows the development of the ShellSaver. The ShellSaver is an add on to the current Beach cleaners, It is situated within the large collection container on top of the beach cleaner and separates the shells from the collected garbage in three separation steps. A disc screen separates large garbage from small garbage and shells. The first zigzag wind sifter separates glass and iron from shells and plastics. In the second zigzag wind sifter the shells are separated from the plastics and are returned to the beach. A prototype of the concept was developed and tested on a sample taken from one of the beach cleaners. The chosen combination of separation techniques proved to be capable of executing the desired separation.