جستجوی مقالات مرتبط با کلیدواژه « wastewater treatment » در نشریات گروه « شیلات »

The aim of this study was to investigate the possibility of improving the quality of aquaculture wastewater by magnetic copper nano oxide (CuO) with iron nanoparticles. For this research, after preparing magnetized copper nano oxide (Fe3O4 @ CuO), the research was conducted in two parts. In the first part of the study, five treatments of magnetized copper nano oxide including zero (control), 10, 20, 30 and 40 mg / l in experimental units of 5 liters of aquaculture wastewater were considered with three replications for each treatment. After 12 hours from adding nanomaterials to the wastewater, the magnetized nanomaterials were separated from the aquaculture wastewater using a magnet, then the effect of nanomaterials on wastewater quality indicators including nitrate, phosphate, soluble solids (TDS) and bacterial load in aquaculture wastewater was studied. In the first part of the study, a concentration of 20 mg/l of magnetized copper nano oxide showed the best performance; in this treatment, the nitrate was reduced by 45%, phosphate by 55% and bacterial load in aquaculture wastewater by 40% and no significant effect was observed in TDS. As the second part of the research, an experiment was conducted under the title of confidence test, during which a concentration of nanomaterials that showed the best results in the first part of the research i.e. 20 mg/l, was selected and the same amount of copper oxide and iron oxide (as single) treatments applied to three replications in aquaculture wastewater and after 12 hours, the above indicators were measured and Were compared with control treatment. The results showed a positive effect of the first part was due to the application of copper nano oxide (CuO) on aquaculture wastewater. This experiment showed that the use of magnetized copper nano oxide at a concentration of 20 mg/l as the best high efficiency concentration can improve the quality indicators of aquaculture wastewater.

Wastewater has been the biggest problem for the surimi industry. Thus, it is essential to have long-term strategies for surimi wastewater treatment, including recovery / reduction of the proteinous compounds, as well as the costs of such an operation. In the meantime, the recovery of myofibrillar proteins from surimi wastewater that is then put back into primary products has been an economic gain for the industry. There has also been a gradual shift in the strategies to incorporate other proteins such as sarcoplasmic proteins and bioactive compounds into the surimi product. However, the recovery of these compounds from wastewater is not profitable yet. It is necessary to clearly define goals for by-product recovery, as they directly determine the technology to be employed and the costs for operation and maintenance. A technology that is adopted to recover solids for human consumption will be more expensive than the one developed for producing animal feeds or landfills. One strategy may include a combination of different technologies for achieving different goals in order to develop the most cost-effective and profitable surimi byproduct utilization operations as well as reducing the amount of various organic compounds.

Phytoremediation is a sustainable and inexpensive technology and has become popular as an alternative solution to traditional wastewater treatment methods. The aim of this study was to use fish farm effluent as a culture medium for the Azolla and also to improve the effluent. For this purpose, the initial amount of 60 g of Azolla was dvided in two treatments with three replications, including Azolla in the wastewater of Beluga sturgeon farm (SW) and Azolla in the water of Anzali wetland (AL) which were grown in-vitro for 30 days. Sampling of water was performed to evaluate some water quality parameters at 10, 20 and 30 days. At the end of the experiment, the plant growth performance, fatty acid profile, and approximate composition were measured. The results showed that maximum amount of biomass (295.22 g) and plant width (9.64 mm) were observed in SW treatment (p <0.05). Also, the results of fatty acid composition showed that saturated fatty acids in SW treatment had a significant increase compared to AL treatment. However, unsaturated fatty acids in SW treatment showed a significant decrease compared to AL (p <0.05). In addition, a significant downward trend in the water quality parameters (phosphate, nitrate, and nitrite) was observed in SW treatment on day 30. The highest and lowest contents of fat and moisture were observed in SW treatment (p <0.05). Therefore, the production of Azolla in Beluga farm effluent can be an effective and cost-effective method due to the rapid growth rate, high ability to absorb the amount of phosphorus and nitrogen in water, as well high nutritional values (protein and lipid contents) and high diversity of fatty acids.

Chlorination is a common method of water disinfection in the world, especially in developing countries. But this process can cause harmful compounds such as trihalomethanes. In this investigation, the importance of different levels of chlorination on aquaculture effluent (cold fish) to produce trihalomethane compounds (THMs) was determined. In this experiment, 400 liters of rainbow trout farm sevage were collected and transferred to Laboratory and divided into 15 containers with 20-liter capacity as experimental treatment. Then different concentrations of chlorine (sodium hypochlorite) were added to the containers, including five treatments (control), 10, 20, 30 and 40 mg / l. each treatment had 3 replications and shaker for ventilation. Experiment duration was 24 hours. The experiment result showed that the amount of trihalomethane increased with chlorination increasing. So that in the 40 mg / l chlorination treatment, the total trihalomethane concentration was 4 ± 82 μg / l but in the control treatment, was 15.2 μg / l. Also, although the mean of produced chloride-bromomethane did not show a significant difference between the experimental treatments (p> 0.05), the experimental treatments were significantly different compare with control treatment. Also, with increasing chlorination concentration, the compounds of dichlorobromethane and chloroform formed an increasing trend and the difference between treatments were significant, while different levels of chlorination had no effect on increasing the concentration of bromoform and the difference between treatments were not significant. The production of trihalomethanes in the process of aquaculture wastewater treatment due to the high level of organic matter in these effluents is higher than the global health standards, except in the 10 mg / l treatment. Therefore, due to the experiment results the maximum allowable concentration for process of aquaculture wastewater (cold-water fish), 10 mg per liter of liquid chlorine is recommended.

Aquaculture development during the last decades has led to an increase in aquaculture effluents into water bodies. Treatment of these effluents and reusing them in culture systems can decrease the level of destructive impacts on aquatic ecosystems. The present study was conducted to investigate the possibility of using phyto- and zooplankton microorganisms to treat and reuse fish culture wastewater in an integrated culture system. The Nile tilapia (Oreochromis niloticus) and Chlorella vulgaris were used as fish and microalgae species. The main zooplankton classes were composed of artemia (Artemia franciscana) and rotifer (Brachionus sp.). Measured and calculated parameters were: nitrate (NO3), nitrite (NO2), ammonium (NH4), phosphate (PO4), dissolved oxygen (DO), pH, electrical conductivity (EC), total dissolved solids (TDS), total suspended solids (TSS), number of microalgae cells and zooplankton counts, and fish growth performance parameters include weight gain (WG), specific growth rate (SGR) and condition factor (CF). The results showed that nutrient levels (NO2, NO3, and PO4) were significantly (P < 0.05) lower at the system outlet than control condition during the study period. The DO and pH levels were observed at their optimum ranges (DO > 6 mg.l-1; pH = 7 - 8) during the study period. The levels of EC, TDS and TSS of the integrated system were significantly (P < 0.05) lower than the control condition. The growth performance (i.e. weight gain) of fish was significantly (P < 0.05) better in the integrated system compared to the control condition. It can be said, based on the obtained results, simultaneous use of microalgae, zooplankton, and fish in an integrated tilapia culture system was led to the appropriate treatment of fish culture effluent and significant improvement of water quality to reuse in the system without any undesirable effect on fish growth compared to the control condition.