جستجوی مقالات مرتبط با کلیدواژه « dunaliella salina » در نشریات گروه « محیط زیست »

The use of microalgae is an effective path in the process of advanced wastewater treatment in order to remove nutrients. In this study, living microalgae, Dunaliella salina was cultivated and then used in a series of batch experiments for the removal of nitrate and phosphate from wastewater.

The effect of changes in NO3- and PO43- concentrations (2.5-13 mg/l) on the removal efficiency using D. salina was evaluated during the 12-day growth period in the laboratory of Offshore Fisheries Research Center, Chabahar, 2017.

Results indicated that the maximum nitrate and phosphate removal efficiency using D. salina were 51.5% and 93.4%, respectively. The range of initial nitrate and phosphate concentrations were 0, 2.5, 5, 7.5, 10 and 12 mg/l and among them, the highest efficiency of nutrients removal after the control sample was obtained in 2.5 mg / l concentration of nitrate and phosphate. Phosphate removal efficiency was higher than nitrate at all concentrations and this shows that living microalgae D. salina has a good compatibility for growth in phosphate-contaminated wastewater. However, nitrate removal percentage is also significant and applicable to wastewater treatment systems. The Langmuir and Freundlich equilibrium models were also investigated in absorption process from solutions by living microalgae and the results of experiments were more consistent with Langmuir equilibrium model with R2 levels of 0.87 and 0.56 for nitrate and phosphate, respectively.

The results of this investigation suggested that D. salina is suitable as a biosorbent material for recovery and biosorption of nitrate and phosphate ions from aqueous solutions and wastewaters.

Hypersaline ecosystems provide excellent conditions for ecological studies of aquatic ecosystems. Lipar Lagoon is an understudied hypersaline lagoon located in southeasternmost Iran (northern Gulf of Oman). Knowledge about the biotic and abiotic characteristics of this hypersaline water system is limited. This research thus investigated the plankton community composition and abundance, and also its variability under variable environmental conditions over one year.

Monthly (five replicates each month) water samplings were performed from 2017 to 2018, during pre-monsoon, monsoon, and post-monsoon seasons. Physicochemical properties of water were measured at the site using a portable multi-meter, while other parameters such as silicate, nitrate, and phosphate were analyzed by spectrophotometry. For plankton identification and density measurements, each sample was fixed by adding 3ml of acidic Lugol’s solution, and transferred to the laboratory for further analysis.

The plankton community observed during the study period included Fabrea salina, Dunaliella salina, Pseudo-nitzschia sp., and Spirulina sp. Temporal variations in plankton abundance were evident, mostly in September and November, most of which occurred due to the difference in the abundance of D. salina and F. salina. The impact of environmental parameters including salinity and the concentration of dissolved oxygen, nitrite, silicate, and phosphate on the community structure of planktons was significant.

The combination of high salinity, high evaporation rate, low freshwater input, and consequently, low nutrient levels may be the main factors behind the low biodiversity in the lagoon. Being under pronounced anthropogenic pressure due to salt extraction activities, it is evident that further hydrobiological monitoring is crucial for the long-term preservation of the lagoon