جستجوی مقالات مرتبط با کلیدواژه « فاضلاب شهری » در نشریات گروه « عمران »

Microalgae have the potential to produce valuable substances for pharmaceutical purposes as well as serve as a food source, providing bioactive compounds and ingredients for cosmetics. However, harvesting microalgae is a crucial step in the mass production of various high-value products derived from microalgae. This process often becomes a major bottleneck in downstream processing. It is essential to find effective and cost-effective harvesting methods for industrial applications. Among several harvesting methods, magnetic flocculation offers the benefits of modest operation, energy savings, and quick separation. This study investigates the harvesting process of Chlorella sorokiniana pa.91 microalgae using a novel flocculation process involving nano-Fe3O4 coated with PACl. In this research, we have used the chemical co-precipitation method to prepare nanoparticles. Using the response surface method to optimize the most important parameters of the magnetic flocculation harvesting process to check the microalgae removal efficiency, three variables of time, concentration of nanomaterials, and pH in the culture medium obtained from municipal wastewater have been investigated. The results demonstrated that the highest harvesting efficiency, nearly 90%, was achieved under the conditions of 3.5 g/L Fe3O4, a constant concentration of 0.075 g/L PACl, a harvesting duration of 40 minutes, and a pH level of 4. On the other hand, the lowest microalgae harvesting efficiency was observed under specific conditions: a composite nanoparticle concentration of 0.5 g/L per liter, a harvesting time of 27.5 minutes, and a pH of 6.5 resulting in a mere 22% efficiency. The rate of microalgal removal increased from 53% in the most alkaline condition to 75% in the most acidic environment. The highest harvesting efficiency, reaching 80%, was achieved under neutral pH conditions with a settling time of 53 minutes. Furthermore, the investigated combined method investigated enhances the flocculation effectiveness of microalgae. Based on the findings, it can be inferred that the efficiency of microalgae harvesting rises with longer duration, higher nanoparticle concentrations, and lower pH levels

Due to considerable carbon removal, high on-site biomass, and lipid production compared to traditional agriculture, and a wide range of final products, recent research has focused on the facile commercialization of Microalgae by increasing productivity and cost-effectiveness. Nowadays, wastewater is used as an inexpensive and easy-accessible culture medium rather than expensive culture medium synthesis on large scale, therefore, simultaneous wastewater treatment and production of biodiesel from microalgae can be considered sustainable, cost-effective, and environmentally friendly approach. In this regard, the present study is aimed to optimize the growth and biomass quality of Chlorella sorokiniana pa.91 microalgae from Sari wastewater culture medium using Magnesium Aminoclay nanomaterial (MgAC). In this study by application of the surface response method - central design, the effect of temperature, light intensity, and nanomaterial concentration was investigated on the parameters including the dry weight of biomass on the seventh day, specific growth rate, chlorophyll, and carotenoids in wastewater after 12 h exposure to visible light. Under 37 μmol photons, m-2 s-1 radiation intensity, and in the presence of 0.05 g/L of magnesium aminoclay NM at 20 °C, the optimal condition including biomass dry weight, specific growth rate, chlorophyll, and carotenoids increased by 47.13, 30.26, 81.33 and 36.47% respectively compared to the control sample. Also, to make the present study feasible, the test conditions were performed in real wastewater.

Today, with the increase in population and the development of cities, urban wastewater collection lines are of great importance. Given the high cost of implementing wastewater collection facilities, it is important to provide any method that can reduce costs used. First, using data related to the study area such as climate, population density, etc., and then by determining the per capita consumption of household, public, commercial and area covered by sewers, etc., the sewerage network has been designed. After performing the calculations with the help of software and manual, longitudinal profiles and ground level, pipe length, diameter, slope and direction will be drawn. The results related to pipe specifications and control of manual results are explained by the results obtained from the software.