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US 7,018,539 B2Granted
Treatment of shipboard-generated oily wastewaters
AssigneeMembrane Technology and Research, Inc.
InventorsAnurag P. Mairal, Alvin Ng, Johannes G. Wijmans, Ingo Pinnau, Jennifer H. Ly
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Abstract
A process and apparatus for treating oily wastewater, such as bilge water or ballast water, generated on a ship. The process uses a combination of a centrifugal separation step and a membrane separation step, such as an ultrafiltration step. The membrane separation step uses a dense, non-porous filtration membrane. The process is able to remove both emulsified oil and dissolved oil from the wastewater to low levels.
Claims37
A process for treating oily wastewater generated on a ship, comprising:
- (a) carrying out a centrifugal separation step, comprising:
- (i) providing a centrifugal separator;
- (ii) treating the oily wastewater in the centrifugal separator, thereby dividing the oily wastewater into a light oil-rich phase and a heavy oil-depleted phase;
- (iii) withdrawing the light oil-rich phase as a concentrate stream;
- (iv) withdrawing the heavy oil-depleted phase as a water stream;
- (b) carrying out a membrane separation step, comprising:
- (i) providing a membrane separation unit containing a membrane having a feed side and a permeate side, the membrane being characterized in that the feed side comprises a dense, non-porous membrane capable of permeating water and rejecting both emulsified oil and dissolved oil under ultrafiltration conditions;
- (ii) passing the water stream across the feed side;
- (iii) withdrawing from the feed side a residue stream enriched in oil compared to the water stream;
- (iv) withdrawing from the permeate side a treated water permeate stream.
7 more elements
Dependencies are inferred from the claim text.