Technology for-profit initiatives can help save marine life and water pollution

The ocean pollution puts marine life at risk. People keep shipping shit, pollute the oceans and things seem to get worse year over year. What technology initiatives that are potentially attractive for investors could help improve this situation? Now I am not talking reinventing the shipping industry with solar powered ships, as this would be extremely expensive to set up, but perhaps something more plausible for a start up? I am trying to think of something that doesn't require hundreds of millions of dollars or tens of years to start showing profit AND also something that can help improve the pollution situation, ecology and water quality in the oceans. My apologies, English is not my first language.