Reduction of ballast tank sediment: Evaluating the effect of minor structural changes and developing a pneumatic cleaning system

Abstract

Ballast tank sediments host organisms that pose invasion risk even if the ships are installed with ballast treatment systems. The bottom sediments also contribute to corrosion and cause cumulative deadweight loss over the years.This study presents the outcomes of the project “Conceptual Ballast Tank Design for Reducing Sediment Accumulation” (TUBITAK, Grant No: 115Y740). In the published first phase of the project, sediment accumulation pattern was determined and the center girder was found to be critical.In this study, the findings of the second and third phases are presented. In the second phase, the tank model design was revised aiming to reduce total sediment accumulation. The contribution of this revision was found to be is numerically insignificant. However, this revision drove more sediment towards the center girder. Thus, in the third phase, a pneumatic cleaning system targeting the center girder was designed to mobilize water to suspend sediment and facilitate discharge from the tank. The pneumatic cleaning system reduced the total sediment deposition in the ballast tank up to 45%. Operating the pneumatic system before de-ballasting operations on a regular basis would decrease the amount of sediment to be managed; reduce the invasion risk, tank corrosion, and cumulative deadweight loss.