Development of a Comprehensive Fouling Model for a Rotating Membrane Bioreactor System Treating Wastewater

Membrane Bioreactors for Produced Water Treatment: A Mini-Review

Environmentalists are prioritizing reuse, recycling, and recovery systems to meet rising water demand. Diving into produced water treatment to enable compliance by the petroleum industry to meet discharge limits has increased research into advanced treatment technologies. The integration of biological degradation of pollutants and membrane separation has been recognized as a versatile technology in dealing with produced water with strength of salts, minerals, and oils being produced during crude refining operation. This review article presents highlights on produced water, fundamental principles of membrane bioreactors (MBRs), advantages of MBRs over conventional technologies, and research progress in the application of MBRs in treating produced water. Having limited literature that specifically addresses MBRs for PW treatment, this review also attempts to elucidate the treatment efficiency of MBRs PW treatment, integrated MBR systems, general fouling, and fouling mitigation strategies.

Separation of bacteria Kocuria rhizophila BR-1 from its broth during synthesis of gold nanoparticles using ceramic membrane by shear-enhanced filtration process

In the present study, disc type ceramic membranes made from China clay, quartz and calcium carbonate were used for the separation of bacteria Kocuria rhizophila from its broth by shear-enhanced filtration process. Porosity, water permeability and average pore size of the membrane were 42%, 3.24 × 10^-4 L m^-2 h^-1 Pa^-1 and 180 nm, respectively. The membrane exhibited good chemical tolerance in acid, alkali and chlorine solutions. The effect of trans-membrane pressure and rotational speed on permeate flux and bacterial rejection was investigated. It was found that the permeate flux increased (40-163.5 L m^-2 h^-1) and bacterial rejection decreased (99.2-94.5%) with increasing pressure (69-345 kPa). With an increase in rotation (50-250 rpm), the permeate flux increased from 156.5 to 176.8 L m^-2 h^-1, while bacterial rejection decreased from 94.3 to 83.2%. The pressure of 345 kPa and rotational speed of 250 rpm with flux of 176.8 L m^-2 h^-1 and rejection of 83% was selected as an optimum process condition. The analysis of fouling models revealed that the cake filtration model provided the highest R² (0.89) value followed by intermediate pore blocking (0.87) which indicates that cake filtration model has the best fit with the experimental data. Henceforth, the shear enhanced filtration process used in this study can be considered as a pertinent filtration process for efficient recovery of biological products at industrial scale.

Advanced Wastewater Treatment Engineering-Investigating Membrane Fouling in both Rotational and Static Membrane Bioreactor Systems Using Empirical Modelling

Advanced wastewater treatment using membranes are popular environmental system processes since they allow reuse and recycling. However, fouling is a key limiting factor and so proprietary systems such as Avanti’s RPU-185 Flexidisks membrane bioreactor (MBR) use novel rotating membranes to assist in ameliorating it. In earlier research, this rotating process was studied by creating a simulation model based on first principles and traditional fouling mechanisms. In order to directly compare the potential benefits of this rotational system, this follow-up study was carried out using Avanti’s newly developed static (non-rotating) Flexidisks MBR system. The results from operating the static pilot unit were simulated and modelled using the rotational fouling model developed earlier however with rotational switching functions turned off and rotational parameters set to a static mode. The study concluded that a rotating MBR system could increase flux throughput when compared against a similar static system. It is thought that although the slowly rotating spindle induces a weak crossflow shear, it is still able to even out cake build up across the membrane surface, thus reducing the likelihood of localised critical flux being exceeded at the micro level and lessening the potential of rapid trans-membrane pressure increases at the macro level.