Shipboard biomechanical oil water separator

Details Shipboard biomechanical oil water separator Shipboard biomechanical oil water separator

2000-04-27

2002-01-29

Simmons, David A. (Department: 1724)

Liquid purification or separation

Processes

Treatment by living organism

C210S614000, C210S615000, C210S620000, C210S150000, C210S195100, C210S201000, C210S221100, C210S242100, C435S262500

Reexamination Certificate

active

06342159

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a method and biomechanical apparatus for treating ship bilge wastes contaminated with petroleum or biodegradable materials. More particularly, the invention relates to a method and apparatus for the physical separation of petroleum hydrocarbons from bilgewater and the subsequent microbiological remediation of the petroleum and biodegradable materials in the ship bilgewater.
BACKGROUND
The shipping industry and military generate millions of gallons per year of bilgewater contaminated with petroleum hydrocarbon and/or hazardous pollutants. The direct discharge of this contaminated bilgewater from commercial and non-commercial shipping vessels into the world's oceans and lakes is a universal environmental problem. Currently, the majority of such bilge wastes is processed through on-board oil/water phase separators. The separated oil is either stored in containers or pumped back to the bilge. The separated water is either sent overboard or back in the bilge area. However, the water that is processed by such separators often exceeds international and domestic regulatory standards for legal discharge. Local and international laws impose severe fines and/or imprisonment if ships discharge bilge waste while in harbor areas. Ship owners must dispose of the contaminated bilgewater by costly and inconvenient methods such as pump, haul, and incineration.
On shore, the storage and transportation of such bilge wastes requires countless tanks and pipelines. Substances typically processed and stored at these facilities include petroleum distillates, industrial solvents, and oily bilge wastes. Due to the dangers presented by storing and transporting concentrated solutions of these materials, engineers and government agencies conduct extensive research and development to insure the tanks and pipelines used will effectively and safely contain these materials. Weathering and unforeseen engineering limitations, however, often cause the facilities to fail, resulting in the release of chemicals into the environment from on-shore storage facilities.
The release of concentrated bilge wastes typically cause extensive damage to the local ecosystem by contaminating or killing indigenous plant and animal life. More remote ecosystems may be affected if the contamination migrates away from the site of ship discharge.
U.S. Pat. Nos. 4,072,614, 4,426,293, 5,277,794, 5,609,760, and 5,965,015 disclose methods to process oily water whereby oil is physically separated and removed prior to the discharge of the water phase from the separator system. Commercially available separators typically consist of a tank containing oleophobic filters, coalescing resin beads or hollow fiber membranes. These agents, combined with gravitational forces, separate oil from water. The various filters and beads components can be used individually or in combination to separate petroleum products from the bilgewater thereby insuring the overboard discharge of oil-free water into surrounding waters.
A major problem with these separator technologies is that concentrations of petroleum hydrocarbon contaminants remaining in the water phase often exceed the regulatory-allowed limits for discharge into open waters. The reasons for poor separator performance vary but include the typical presence of engine-cleaning detergents and other substances that emulsify oil into water, thereby allowing a higher percentage of oil to become associated with the aqueous phase. Ship agitation and inefficient phase separators allow significant amounts of petroleum to enter the aqueous phase as well. Also, under circumstances where filter technologies have been employed, these filters typically contain a significant volume of oil; consequently they are not typically capable of providing lengthy unattended service such that oil leakage from the filters can become a significant problem resulting in the overall poor performance of the oil water separator. In general, the operation and maintenance costs associated with oil water separators that utilize filter or coalescing bead technologies can be significant over the life of the unit. The net effect of these events is that relatively high amounts of petroleum can be, and are, discharged directly into the surrounding waters, thereby posing significant environmental risks as cited earlier.
U.S. Pat. Nos. 3,846,290, 4,385,121, 4,765,902, 4,992,174, and 5,080,782 disclose methods for reducing the amount of petroleum hydrocarbons in a solution. Although these methods achieve remediation in soil and groundwater environments, the methods are disadvantageous for cleanup of bilge wastes for a number of reasons. First, the equipment used is often large and cumbersome. This type of equipment would not be appropriate for ship environments because of space constraints often encountered in ships. A second reason pertains to the hydrocarbon-degrading microorganisms used to degrade the contaminants associated with bilgewater. Although indigenous microbial populations may be sufficient in terrestrial environments to biodegrade petroleum hydrocarbons that may have contaminated it, such microorganisms may not be present in the bilge environment. Because the oil/water mixture is periodically removed from the ship as a normal part of cleaning operations, any hydrocarbon-degrading microorganisms, which may be present, would also be removed in the process. Thirdly, terrestrial/groundwater bioreactor systems are not designed to treat oil contaminated with surfactants and cleansers often associated with bilge wastes. And fourthly, hydrocarbon-degrading microorganisms associated with terrestrial environments are typically not efficient degraders in surface water environments (i.e., saltwater).
U.S. Pat. No. 5,248,253 to Behmann describes the use of an onboard-activated sludge bioreactor combined with nutrients obtained from raw sewage (“black water” from toilets) and wastewater from showers, sinks, and kitchen facilities (“grey water”) to biodegrade bilge oils. Although the method achieves some reductions of petroleum hydrocarbons, there are several drawbacks of this approach. First, the mixing of “black” and “grey” water to achieve optimal nutrient concentrations in the activated sludge bioreactor is not practical due to the inconsistent amount of nitrogen present in these materials. Second, appropriate concentrations of phosphate are not found in these “black” and “grey” waters to allow complete metabolism of petroleum hydrocarbons to occur. Third, activated sludge systems generate considerable sludge material (i.e., solids) which are cumbersome to deal with and expensive to dispose. Fourth, pathogenic microorganisms are often associated with “black” water wastes which present a risk to both humans and the environment when such water is discharged to open waters.
U.S. Pat. No. 3,938,692 whereby Gutnick et al. describes the application of microorganisms and nutrients to biodegrade residual oil in the emptied cargo compartments. This method involves the addition of microbes rather than the utilization of an on-site bioreactor. There are several limitations of this approach. First, the absence of a bioreactor limits the amount of dissolved oxygen required to complete metabolism of petroleum hydrocarbons. The method of the '692 patent is essentially an activated sludge batch reactor which is less efficient than continuous flow fixed-film bioreactors for the reasons cited earlier. In addition, the method does not allow control of the amount of hydrocarbon present in any given cargo compartment. High levels of petroleum hydrocarbons may be toxic or indigestible to microorganisms introduced into these compartments, whereas the current invention allows for the control of petroleum hydrocarbon concentrations being treated. Thirdly, there are no provisions for accurately maintaining the required nutrients within the cargo compartment in the method of the '692 patent.
U.S. Pat. No. 5,807,485 to Caplan and Kelemen addressed the need for a method and apparatus for the bioremedia

Affiliated with

Also associated with

Rating

Shipboard biomechanical oil water separator does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Shipboard biomechanical oil water separator, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Shipboard biomechanical oil water separator will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2821721