Infusion of combustion gases into ballast water preferably under less than atmospheric pressure to synergistically kill harmful aquatic nuisance species by simultaneous hypercapnia, hypoxia and acidic ph level

Abstract

Aquatic nuisance species (ANS) in ship's ballast water are killed by permeating to equilibrium a gaseous mixture consisting essentially of, preferably, ≧84% nitrogen, ≧11% carbon dioxide and ≦4% oxygen through ship's ballast water until the ballast water itself becomes (i) hypercapnic to ≧20 ppm carbon dioxide, and, by association, (ii) acidic to pH≦7, while preferably further, and also, being rendered (iii) hypoxic to ≦1 ppm oxygen. The permeating is preferably realized by bubbling the gaseous mixture preferably obtained from an inert gas generator through the ballast water over the course of 2+ days while the ballast water is continually maintained a pressure less than atmosphere, preferably −2 p.s.i. or less. The (i) hypercapnic, (ii) acidic and (iii) hypoxic conditions—each of which can be independently realized—synergistically cooperate to kill a broad range of ANS in the ballast water without deleterious effect on the environment when, and if, the ballast water in which the balance of dissolved gases has been changed is discharged.

Description

RELATION TO A RELATED PATENT APPLICATION[0001]The present patent application is related as a Continuation-in-Part to U.S. patent application Ser. No. 10 / 120,339 filed on Apr. 9, 2002, for CLOSED LOOP CONTROL OF BOTH PRESSURE AND CONTENT OF BALLAST WATER TANK GASES TO AT DIFFERENT TIMES KILL BOTH AEROBIC AND ANAEROBIC ORGANISMS WITHIN BALLAST WATER to inventor Henry Hunter assigning to the same MH Systems, San Diego, Calif., that is the assignee of the present invention. That application is itself a Continuation-In-Part (C-I-P) of U.S. patent application Ser. No. 09 / 865,414 filed May 25, 2001 now U.S. Pat. No. 6,539,884, for CLOSED LOOP CONTROL OF VOLATILE ORGANIC COMPOUND EMISSIONS FROM THE TANKS OF OIL TANKERS, INCLUDING AS MAY BE SIMULTANEOUSLY SAFEGUARDED FROM SPILLAGE OF OIL BY AN UNDERPRESSURE SYSTEM, now issued as U.S. Pat. No. 6,539,884. The contents of the related predecessor patent applications are incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field o...

AI Technical Summary

Benefits of technology

[0073]This is achieved at a rate that will, most preferably, permit the entire maximum ballast water of a ship to be treated to these levels in a period less than, most preferably, one-half the normal voyage duration of the ship minus the required time for aquatic nuisance species to die to the 90% level. This is only to say that the shipboard ballast water gaseous infusion system is sized to (i) the task at hand, (ii) the time available for the completion of the task, and (iii) the resilience to die off (from hypercapnia, anoxia and acidic conditions) of the ANS to hand, all at an adequate safety margin. Most typically all the ballast water on a ship will be treated so as to reach desi

Problems solved by technology

Aquatic marine organisms—at least of the aerobic types—can scarcely tolerate these noxious gases any better than can air-breathing animals, a

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