Membrane photobioreactor as a device to increase CO2 mitigation by microalgae

The integration of a membrane contactor with a photobioreactor serves two major purposes for the mitigation of CO₂ by microalgae, i.e., to enhance the mass transfer and interfacial contact between two different phases and to increase the exchange process of CO₂-O₂ by microalgae in the photobioreactor. The membrane integrated with a photobioreactor for CO₂ mitigation by microalgae can be considered as a relatively new field, and only four or five related research efforts have been published in the literature, suggesting that a significant amount of work remains to be done in this field. In addition, all of the authors agreed that a membrane contactor is capable of achieving better mass transfer than the conventional approach of using a separation column in the gas-liquid separation process. One significant problem associated with using a membrane as a CO₂-O₂ gas exchanger is its susceptibility to pore fouling due to the micron-size cells of the microalgae. However, pore fouling can be prevented by using a hydrophobic membrane contactor and appropriate operating conditions, both of which are discussed in detail in this work

Critical micelle concentration and the effect of solution age on drag reduction performance of anionic surfactants

In the present study, Ammonium lauryl sulfate was introduced as new drag reducing agent in aqueous media flowing through pipelines. A built-up rig with ratio of pipe length to diameter (L/D) is equal to 59 was used to achieve the purpose of this work which to test the critical micelle concentration and the effect of using different ages of solution for 300ppm (wt) of anionic surfactants. The drag reduction performance of the surfactant under investigation was also analyzed for different concentrations and flow rate of anionic surfactants, which 200ppm, 300ppm, 400ppm, 500ppm and 600ppm, respectively. It was found that the starting point of critical micelle concentration of ammonium sulfate lauryl was detected within range 140 to 200 ppm. The highest drag reduction was achieved is 50% at Re equal to 11235 for 600ppm of solution and the fresh solution gave better drag reduction compared to other ages of solution. The drag reduction decreases as the age of solution increases. After 4 days, the ammonium lauryl sulfate increases the drag in pipes

Polishing of POME by Chlorella sp. in suspended and immobilized system

The effect of using suspended and immobilized growth of Chlorella sp. to treat POME was studied. Cotton and nylon ropes were used as the immobilization material in a rotating microalgae biofilm reactor. The result showed that POME treated in suspended growth system was able to remove 81.9% and 55.5% of the total nitrogen (TN) and total phosphorus (TP) respectively. Whereas the immobilized system showed lower removal of 77.22% and 53.02% for TN and TP. Lower performance of immobilized microalgae is due to the limited light penetration and supply of CO2 inside the immobilization materials. The rotating microalgae biofilm reactor was able to reduce the biochemical oxygen demand (BOD) to 90 mg/L and chemical oxygen demand (COD) to 720 mg/L. Higher BOD and COD reading were obtained in suspended growth due to the presence of small number of microalgae cell in the samples. This study shows that suspended growth system is able to remove higher percentages of nitrogen and phosphorus. However, an efficient separation method such as membrane filtration is required to harvest the cultivated microalgae cell to avoid organic matter release into water bodies

Membrane processes for microalgae in carbonation and wastewater treatment

The objective of this work is to present the integration of membrane processes in the field of bioenergy resource and wastewater treatment using microalgae. There are two main processes involved: carbonation and separation, which were conducted and reported as a separated work within this chapter. The chapter begins with the introduction of membrane processes, followed by carbonation of microalgae and separation of biomass from the wastewater effluent. The experimental work on the carbonation aims to evaluate the effectiveness of hydrophobic hollow fibre membrane in transporting CO2 into microalgae culture and microalgae accumulation within the membrane. The experimental work on the separation process of microalgae biomass from the wastewater effluent on the other hand, aims to evaluate Ultrafiltration (UF) membrane capability in removing BOD and COD as well as its ability to retain microalgae biomass which were used by the turbidity reading of the membrane permeate. The application of hydrophobic membrane in the carbonation process has increased the carbonation efficiency up to 83% in comparison with the carbonation without membrane and only a small amount of mirage was accumulated within the membrane. The experimental result also shows that, the carbonised microalgae can be further used for wastewater treatment. Based on the result of separation process of microalgae biomass of wastewater effluent, the UF membrane utilization shows high separation efficiency in turbidity to lower than 5 Fau, and was able to facilitate in nutrient removal for less time required compared to the biological treatment without application of the membrane

Synthesis and characterization of metal oxide promoted alumina catalyst for biofuel production

Alumina has been widely used as a support in catalysis process which owing to its extremely thermal and mechanical stability, high surface area, large pore size and pore volume. The aim of this study was to synthesize calcium oxide-supported basic alumina catalysts (CaO/Al2O3) by impregnation method and to characterize the properties of the catalyst based on its surface area and porosity, functional group, surface morphology and particle size. Impregnation method was chosen for the synthesization of catalyst which involved contacting the support with the impregnating solution for a particular period of time, drying the support to remove the imbibed liquid and calcination process. In the preparation of catalyst, catalytic performance of CaO/Al2O3 catalyst was measured at different calcined temperatures (650°C, 750°C and 800°C). Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Mercury intrusion porosimetry (MIP), and particle size analyzer (Zetasizer) was used to characterize the catalyst. The highest total specific area and the total porosity of the catalyst was obtained at 750oC. FTIR analysis basically studied on the functional groups present in each catalyst synthesized, while SEM analysis was observed to have pores on its surface. Moreover, CaO/Al2O3 catalysts at 650°C produced the smallest particle size (396.1 mn), while at 750°C produced the largest particle size (712.4 mn). Thus it can be concluded that CaO/Al2O3 catalysts has great potential coimnercialization since CaO has attracted many attentions compared to other alkali earth metal oxides especially on the transesterification reaction

Copper oxide anti-wax coating for petroleum pipelines

Background/Objectives: This research aims to study the efficacy of copper oxide as an anti-wax coating for petroleum pipelines. Methods/Statistical Analysis: Stainless steel was dipped into copper chloride and methanol solution before heating at 300 ᴼC. The performance of anti-wax deposition was determined using a self-fabricated wax deposition test. Reduction of wax deposition was determined by weight of wax deposited onto substrate. The surface morphology of the coating was studied to determine the factors of anti-wax deposition. Findings: The analyzed wax deposition reduction shows a maximum of 100% reduction of wax deposition, indicating that the copper oxide coating was able to act as an anti-wax coating. SEM analysis shows that the surface morphology of coating has a microstructure that plays an important role in improving the anti-wax performance of stainless steel surfaces. Application: Copper oxide coatings have shown potential for use in pipeline interiors in the petroleum industry to prevent wax deposition, which leads to pipeline blockage

Anti-wax nickel-based coating for stainless steel pipeline

This study aims to determine the efficacy of nickel-based coating as wax repellent for stainless steel pipelines. Two variables for nickel-based coating were studied namely nickel sulphate and sodium hypophosphate. Results show that 100% and 50% reduction of wax deposition for coating with sodium hypophosphate and coating with nickel sulphate respectively. These values indicate that nickel-based coating can reduce wax deposition on the pipe surface. It also depicts that coating with more sodium hypophosphate serve better anti-wax coating compared to nickel-based coating with more nickel sulphate. SEM analysis shows good surface morphology for the coating and displays a microstructure that plays an important role in protecting stainless steel surfaces

Composting and anaerobic digestion of food waste and sewage sludge for campus sustainability: A review

Composting and anaerobic digestion have emerged as better options for managing food waste and sewage sludge at the campus level. This review highlights the characteristics of food waste and sewage sludge from various global higher education institutions. The composting and anaerobic digestion processes of food waste and sewage sludge will be reviewed and evaluated. Also, the adoption of composting and anaerobic digestion at various campus levels has been reviewed. The challenges and future direction, focusing on managing university campus composting and anaerobic digestion, are discussed as well. This review paper will significantly contribute to the understanding of the potential for managing and handling campus waste in a natural-friendly manner