Keywords

bilgewater, electric field, Electric field forward osmosis (EFFO), emulsion, Forward Osmosis (FO), fouling, reverse salt flux, water flux

Abstract

Bilgewater discharge needs to meet the existing regulations with an oil concentration of less than 15 ppm. Among many treatment options, forward osmosis (FO) can be an economic-environmental method utilizing an osmotic pressure gradient between feed solution (FS) and draw solution (DS) which are separated via a semipermeable membrane. However, FO membrane foundling is still challenging. The main objective of this study was to evaluate the effect of electric field forward osmosis (EFFO) to mitigate membrane fouling and thus improve oil-in-water emulsion separation. Standard bilge mix (SBM) was used as representative bilgewater and mineral oil (MO) was used as control. Two different surfactants/detergents, sodium dodecyl sulfate (SDS) as an anionic surfactant and Type 1 as a non-ionic cleaner, were selected for 36 hours of EFFO operation (0, -0.1, and -1.0 V of electric field). 1% MO+SDS at -0.1 and -1.0 V improved the water flux (Jw) by approximately 12.1% to 52.6% compared to FO-only mode (0 V), showing that the negative electric field effectively increased Jw in the presence of anionic surfactant, unlike Type 1 emulsion FO. 1% SBM+SDS emulsion FO at -0.1 and -1.0 V also improved Jw by approximately 26.3% to 48.6% compared to FO-only mode (0 V). The results found that the electric field may play a significant role in mitigating flux decrease caused by the unknown oil additive in SBM, however, increasing the electric potential did not increase Jw recovery for 1%SBM+SDS. Reverse salt flux (RSF) (Js) was monitored during the experiments and the effect of surfactant/detergent was also evaluated by determining Js/Jw (g L-1). During the tests, the physical cleaning only could recover Jw for every cycle. This study demonstrated the feasibility of employing an electric field to mitigate fouling and improve the water flux inherent in traditional FO systems.

Completion Date

2024

Semester

Spring

Committee Chair

Lee, Woo Hyoung

Degree

Master of Science in Environmental Engineering (M.S.Env.E.)

College

College of Engineering and Computer Science

Department

Civil, Environmental and Construction Engineering

Degree Program

Environmental Engineering

Format

application/pdf

Language

English

Rights

In copyright

Release Date

November 2024

Length of Campus-only Access

None

Access Status

Masters Thesis (Open Access)

Campus Location

Orlando (Main) Campus

Accessibility Status

Meets minimum standards for ETDs/HUTs

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