Fouling in membrane technology for produced water treatment: Assessing mechanisms, mitigation, and CFD Analysis

Due to environmental discharge regulations and compliance, the need for oily wastewater treatment and reuse for sustainability has become a pressing reality. Membrane-based technologies for oily wastewater separation have grown in popularity due to their energy efficiency, chemical/thermal resistance, and low cost. The membrane can separate a wide range of oily wastewater effluents and deliver good permeate quality. While the membrane technology witnessed many improvements, membrane fouling continues to be a major drawback and is the downside of the large-scale adoption of this technology. To improve membrane performance, understanding membrane fouling development is the final objective of many researchers. In this work, we assess the laws and the mechanisms used by the researchers to explain the fouling development. We used computational fluid dynamics (CFD) to prove the limitation of these blocking laws/Hermia’s models, originally developed for solid-liquid separation in pressure-driven system and extended them to cover the modeling approach of crossflow filtration. First, a comprehensive study using experimental work and microfluid analysis was used to elucidate the effect of the oil in the membrane pores on the behavior of the oil droplets during the oily wastewater filtration. In this study, in-situ visualization is used alongside experiments. The CFD and experimental results refuted the ability of the blocking laws to explain the membrane fouling mechanism during oily wastewater membrane filtration. Second, a cross-flow ultrafiltration ceramic membrane is used to mitigate membrane fouling. The results showed the limitation of the crossflow to combat fouling development, where the permeate flux declined by up to 80% in the first 10 minutes of filtration time. In addition to the crossflow field pretreatment method, reverse backwashing and backpulsing cleaning methods were used their efficiencies were investigated. Given the operational limits of backwashing and pulsatile physical antifouling approaches, we suggested a novel physical antifouling technique called the Periodic Transmembrane Pressure Technique (PTMP) to mitigate membrane fouling and enhance performance. The new approach involves a controlled membrane fouling via pressure variation, creating induced shear stress at the membrane surface, resulting in the displacement of oil droplets and their transport by the crossflow field. The mechanistic and physics behind the novel technique were elucidated, and the technique was implemented in a series of experiments. The total filtration system performance including the flux recovery and the state of the membrane after each cycle was quantified, leading to the investigation of fouling mitigation. Several PTMP scenarios were explored, and their performances were compared. Finally, a comparison between all the physical antifouling techniques (backwashing, pulsatile flow, and the novel PTMP approach) was performed according to the fouling control and membrane performance. Fouling development, in all scenarios, was studied using static and dynamic resistance modelling analysis alongside an in-situ membrane internal channel surface visualization to understand the extent of the fouling mitigation in each case. The membrane performance was measured based on the collected permeate volume during each scenario. PTMP studies show that the implementation of the technique will significantly reduce operating costs by allowing for more frequent cyclic cleanings in the crossflow membrane water filtration system.

Name thesis:degree_name

Doctor of Philosophy (PhD)

Discipline thesis:degree_discipline

Engineering - Industrial Systems

Grantor dc:publisher

Faculty of Graduate Studies and Research, University of Regina

Year dc:date.issued

2023

Author dc:creator

• Echakouri, Mohamed

Advisors dc:contributor.advisor

• Henni, Amr
• Salama, Amgad

Committee members dc:contributor.committeemember

• Ibrahim, Hussameldin
• Kabir, Golam
• Shirif, Ezeddin
• Hersi, Osman Salad

Language dc:language.iso

en

DOI

https://doi.org/10.82465/5011

OAI identifier oai:identifier

oai:uregina.scholaris.ca:10294/16402