In this research, the efficiency of the integrated fixed‐film activated sludge‐oxic settling anoxic (IFAS‐OSA) system in biological nutrient removal was studied. The oxic‐settling anoxic (OSA) process is known as a cost effective way to reduce the nutrients (nitrogen and Phosphorus). According to the results, the percentages of total nitrogen removal efficiency in the IFAS, IFAS‐OSA2h and IFAS‐OSA4h systems were 78.56 ± 2.46, 83.60 ± 0.92 and 85.03 ± 1.69, respectively, while the percentages of phosphorus removal efficiency in these systems were 32.69 ± 8.25, 36.35 ± 6.73 and 39.87 ± 3.61, respectively. The PCR‐RFLP method showed that C. albicans had the greatest prevalence (n = 36, 90%). Moreover, Vorticella convallaria was identified as the most abundant species of protozoa. The current research demonstrated that the efficiency of the modified IFAS‐OSA process was higher than that of IFAS in the removal of nutrients (TN and PO43–P) and can be a suitable method for upgrading the wastewater treatment plants worldwide.
An upgraded integrated fixed-film activated sludge-oxic settling anoxic (IFAS-OSA) system is a new technology for reducing nutrients and excess sludge. The results showed that the average TN removal efficiency of the IFAS-OSA system was gradually increased up to 7.5%, while the PO4–3-P removal efficiency increased up-to 27%, compared with that of the IFAS system. The COD removal efficiency of the IFAS-OSA system was slightly increased up-to 5.4% and TSS removal efficiency increased up to 10.5% compared with the control system. Biomass yield coefficient (Yobs) in the IFAS and IFAS-OSA systems were 0.44 and 0.24 (gr MLSS/ gr COD). Hence, sludge production decreased by 45%. The average SVI was decreased by 48% in IFAS-OSA system compared with IFAS. This study demonstrated the better performance of the IFAS-OSA system compared to that of the IFAS system.
Background: Food-borne pathogens are one of the most important problems in less developed and developed countries. Commercial refrigerators are a potential source of fungal contamination that causes food spoilage, food-borne intestinal infectious diseases or mycotoxin diseases. Objectives: The purpose of this study was to determine the distribution of psychotropic fungi in food storage refrigerators (n = 50) with temperatures above and below 0ºC at selected restaurants (n = 25) located in the city of Ahvaz, Iran. Methods: Samples were collected from the surfaces of the refrigerators by using sterile swab sticks pre-moistened with sterile distilled water, and then each collected sample was plated out on Sabouraud dextrose agar medium. Finally, all fungi were counted and identified based on macroscopic and microscopic characteristics. Results: According to our results, 100% of the sample refrigerators showed fungal contamination. Cladosporium sp. (42.34%) and Mucor sp. (0.06%) had the highest and the lowest frequency of fungi recovered from our research, respectively. Furthermore, the P value calculated indicated a significant correlation between refrigerators above 0ºC and refrigerators below 0ºC (P < 0.00001). Conclusions: The presence of fungi in commercial refrigerators could be an indicator of a potential source of food spoilage and food-borne diseases. Therefore increased education, and proper packaging and refrigerator management are recommended since regular cleaning of these refrigerators is important in order to prevent food-borne diseases and other health risks.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.