Unal Sen

An investigation of ultrasound effect on microalgal cell integrity and lipid extraction efficiency

In this study, different ultrasound power intensities (0.1-0.5 W mL(-1)) were applied at a frequency of 30 kHz and for durations of 5-60 min to mixed microalgal cultures, one cultivated in BG11 medium, and the other in secondary effluent wastewater. The ultrasonic effect on cell disruption was revealed by increased concentrations of protein and carbohydrate released into the solution, and a decreased concentration of total suspended solids in cell suspension. The highest intercellular material release was achieved at an ultrasonic energy intensity of 0.4 kWh L(-1), while the effect of ultrasound on cell disruption was reduced at higher energy intensities. Additionally, the ultrasonic effect on lipid extraction efficiency was studied in the presence of two different solvents, n-hexane and chloroform/methanol mixture. The application of ultrasound at 0.4 kWh L(-1), provided 1.5-2.0-fold increase in lipid extraction yields in the presence of the solvents.

Techno-economic investigation of water recovery and whey powder production from whey using UF/RO and FO/RO integrated membrane systems

AbstractAs a by-product of dairy industry with high pollutant capacity, uncontrolled discharges of cheese whey result in serious pollution problems in the environment. Besides, recovery of water and whey powder in a whey stream has come to the fore as an important one of whey control strategies in environmental pollution. In that sense, the feasibility of water recovery and whey powder production from whey using integrated membrane processes was techno-economically investigated in this study. The study was focused on three case studies including different process scenarios were executed with laboratory-scale experiments in order to determine the technical performances of processes. The process scenarios were selected as following: the ultrafiltration/reverse osmosis (UF/RO), the forward osmosis/reverse osmosis (FO/RO) with NaCl draw solution and forward osmosis/reverse osmosis including thermolysis (FO/T/RO) at 60°C for concentrating NH4HCO3 draw solution. The real-scale costs for the processes were estim...

Water recovery from treated urban wastewater by ultrafiltration and reverse osmosis for landscape irrigation

Techno-economic feasibility of water recovery from secondary effluents of an urban wastewater treatment plant (WWTP) for landscape irrigation was investigated considering two distinctive strategies: ultrafiltration (UF)/chlorination and UF/reverse osmosis (RO). Experimental performance evaluations were conducted separately for UF membranes and for different RO trans-membrane pressures. The quality of the effluent recovered by the UF/RO system was in accordance with the national and international guidelines. The produced reuse water was first class quality according to the national guideline for all parameters except sodium adsorption ratio (SAR), which can be eliminated readily by direct addition of KCl into the recovered water. Estimated field-scale costs indicated that UF/RO yielded a total cost of US

Combined effect of ozone and ultrasound on disruption of microalgal cells

12,500,000–13,600,000 with annual operating cost being US

Anhydrous proton conducting membranes for PEM fuel cells based on Nafion/Azole composites

482,000–533,000 at 5–20 bar. The economic estimations guaranteed reimbursement with US

Proton conducting membranes based on Poly(2,5-benzimidazole) (ABPBI)–Poly(vinylphosphonic acid) blends for fuel cells

7,600,000–7,400,000 net present value, 0.22–0.39 year payback time, US

Techno-economic analysis of textile dye bath wastewater treatment by integrated membrane processes under the zero liquid discharge approach

0.44–0.49/m3 treatment cost, and a benefit/cost ratio of 0.57.

Nafion/poly(1-vinyl-1,2,4-triazole) blends as proton conducting membranes for polymer electrolyte membrane fuel cells

ABSTRACT Among several disruption methods tested so far, ozonation and sonication were distinguished from others by their effective cell rupturing ability. In this study, these disruption methods were combined to enhance the retrieval of biofuel feedstock (carbohydrates and lipids) from microalgae. A mixed microalgal culture was subjected to first ozonation, followed by sonication. Compared to the extraction of 22% of total lipids and 47% of total carbohydrates by sole ozonation, the retrieval of algal metabolites reached 59% and 81% of total lipids and carbohydrates, respectively. The optimum process variables were found by means of a response surface modeling and quadratic programming.