MyCelx Bilge Water System Installed by International Shipping  Company
The Background
In early 2006, Environmental Management Committee of a major international shipping company was in the process of evaluating various marine products and filtration technologies to enhance the performance of the existing MEPC 60 (33) bilge water separators and to implement a fail-sate less maintenance intensive bilge treatment operation.
The shipping company services major oil and gas companies with product tankers of 8000-12000 GRT and an average bilge production capacity of 1-2 cubic meters per day per vessel.
The filtration technologies and units under evaluation were MyCelx Bilge Water Treatment and Polishing units, MEPC 107(49) bilge oil water separators (based on ultrafiltration membrane polishing), carbon/clay polishing and biological digestion units. About 40 ships in the fleet were identified for the bilge water treatment enhancement options due to unreliable and non-functional bilge oil water separators. The bilge water treatment and disposal costs incurred on the 40 ships range from $ 75,000 - $ 150,000 per vessel per year or $0.75-$1.0 per gallon of bilge water generated. The high costs were directly attributed to the inability to discharge bilge water overboard since the effluent from the existing bilge separators were much higher than 15 ppm, in some ships over 100 ppm.
The following considerations were adopted to identify the most rugged, reliable and economically viable bilge water treatment options for the 40 vessels:
The Problem
Based on the above operational considerations, MYCELX units and a ceramic ultrafiltration based MEPC 107(49) units were subjected to field trials on one of the most problematic ships experiencing heavy oil loading in bilge water. The MYCELX unit was retrofitted with the existing poorly performing separator between the Separator and the Oil Content Monitor.
The Results
After 2-3 months, the MyCelx unit did not require maintenance or supervision and the overboard discharge was consistently less than 15 ppm. The 4th Engineer on the ship claimed that they had never discharged so much bilge water ever before with almost no maintenance. The Chief Engineer stated that the unit worked great, was compact and cut down significantly on man-hours and maintenance time.
Meanwhile, the membrane filtration unit had high operational and cleaning time. (1:1 cleaning to operational time period). While the MyCelx unit processed about 85 cubic meters of bilge water, the membrane unit was able to discharge only 36 m3 during the time period requiring operator supervision of 1-2 hrs a day to maintain operation.
Based on the above operational characteristics of the MyCelx unit, the estimated cost savings in bilge treatment costs on the ship amounted to about $ 75,000 annually per ship.
The Solution
MyCelx Bilge Units were specified on the remaining 39 ships. To date the MyCelx units have been installed in 9 ships and are fully operational. The remaining 20 ships are in the process of acquisition of the equipment.
Field Data:
Influent to MYCELX unit post existing 60(33) Bilge Separator - ppm Effluent as per Oil Content Monitor - ppm
Nov’06 25 ppm 1.1 ppm
Dec’ 06 78 ppm 1.4 ppm
Jan’ 07 10 pm 0.8 ppm
Feb’ 07 5 ppm 0.3 ppm
Feb’ 07 129 ppm 1 ppm
Operational Characteristics:
- Bilge Processing Capacity: up to 5 m3/h
- Average oil loading: 5 – 150 ppm
- Average discharge from the unit: < 5 ppm
- Pressure drop across the unit: < 5 psig
- Particle pre-filter: 5/1 micron mechanical strainer
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