Final answer:
In a no-discharge zone, marine vessels must manage ballast water to meet US discharge standards. This typically requires BW treatment systems or ballast water exchange conducted far from shore. No BWTS had received USCG type approval as of December 2014, but ballast water exchange remains the primary management method.
Step-by-step explanation:
In a no-discharge zone or sole state waters, the requirements for the marine sanitary device, commonly known as ballast water (BW) management, are quite stringent. In the US, the Coast Guard (USCG) and the Environmental Protection Agency (EPA) regulate the discharge of BW to prevent the introduction of nonindigenous species and protect marine environments. As per regulations effective 21 June 2012, all ships approved as seagoing vessels including those operating in sole state waters must manage their BW.
It is mandatory for any discharged ballast water to meet US discharge standards for maximum allowed concentrations of organisms, which necessitates the use of BW treatment systems (BWTS) that often include filtration combined with advanced treatment methods like oxidation, de-oxygenation, ozone, or ultra-violet light. Although as of December 2014, no BWTS had received type approval from the USCG, ballast water exchange (BWE) is still widely used as the primary method of BW management in the absence of approved BWTS. The majority of overseas arrivals to the US do not discharge BW, particularly because ships must manage it appropriately before discharge, such as by conducting BWE, which often occurs more than 200 nautical miles from shore.
Another method to protect local waters includes the public taking action, such as cleaning boats and equipment to prevent the introduction of foreign species into the environment. Actions such as removing visible plants and mud, draining and rinsing live wells, and rinsing fishing equipment are also recommended.