Envisaging a ballast water treatment system from shipboard waste heat

Abstract

Non-native alien species cause harm to the environment. Epidemics to economic erosion of value resources are the harmfuleffects that are being experienced. Ballast water Management Convention of 2004 requires effective treatment replacing the currentshipboard practice of ballast water exchanges. With full ratification of the Convention nearing, treatment systems are being approved forcommercial availability. One of the treatment methods is by heat, which sterilises the water from typical marine species. A systemharnessing shipboard waste heat would provide an economic solution for ballast water treatment. Based on an analysis of waste heatavailable onboard an existing crude oil tanker, though heat availability is seen, a complementing treatment method is necessary to treathigh volumes. So, a heat-filtration combination system is proposed. The sea water circulating as secondary coolant in machineries isfiltered and heated by harvesting heat from machinery systems, steam heat rejections and exhaust gases. The treatment protocols areextended during sailing also at no extra cost. The combination promises to overcome sediment retention problems as also improvespecies mortalities. Alternative arrangement instead of back flushing of filters is projected. The system layout is presented as a promisingsolution which could possibly optimise ballast water management. Further analyses are suggested for other vessel types.