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Soft drinks are industrial intermediate chemicals found in wastewater and are among the most significant environmental pollutants. Up-flow anaerobic sludge blanket (UASB) reactors are used to treat soft drink wastewater, offering high-volume loading capacity, optimal grain deposition, and the ability to bear impact loads. The use of support materials can enhance biological productivity and expedite the UASB start-up period. In this study, bone powder was utilized as a support material in a UASB reactor to remove contaminants from wastewater. During the 70-day sludge adaptation period, the treatment reactor achieved a 93% reduction in COD, while the control reactor achieved a 65% reduction. Biogas production was higher in the bone powder UASB reactor (1750 mL/d) compared to the control UASB reactor (1100 mL/d), and the bone powder UASB reactor demonstrated greater resistance to shock loading. The improvement in sludge settling, shear strength, and higher biological activity in the bone powder UASB reactor was attributed to the formation of large granular sludge. The size of the granular sludge increased further with the colonization of filamentous bacteria at the irregular levels of bone powder. [ABSTRACT FROM AUTHOR]

Biological reactors are the most energy-consuming facilities of conventional wastewater treatment plant (WWTP). Therefore, adjustment of aerators installation angles inside the aeration tank seems to be an effective way to ensure efficient biological performance. In this work, the biological treatment performance of Kermanshah's municipal WWTP (Kermanshah, Iran) was surveyed via varying angles of the aerators installation relative to the perpendicular. Two different aeration configurations in terms of installation angles of aerators, 30° and 45°, were considered. Effect of the aerators installation angles on variations of some operating and process parameters such as dissolved oxygen (DO), oxidation reduction potential (ORP), nitrogenous compounds, and phosphorus were pursued. From results, more DO and ORP amounts were found at the 30° angle compared to the 45° angle. However, changes trends in the DO and ORP amounts were similar at both angles. As the main conclusion, no prominent effect on remediation of carbon, nitrogenous compounds, and phosphorus was reported in these two angles. These results were justified by low influent organic loading, and also not to have appropriate conditions for nitrogen and phosphorus removal. In addition, in this study kinetic evaluation was conducted, and obtained findings were in a good agreement with literature. [ABSTRACT FROM AUTHOR]

Purpose: To report the indications and techniques of corneal transplantation at a tertiary referral center in Tehran over a 3-year period. Methods: Records of patients who had undergone any kind of corneal transplantation at Labbafinejad Medical Center, Tehran, Iran from March 2004 to March 2007 were reviewed to determine the indications and types of corneal transplantation. Results: During this period, 776 eyes of 756 patients (including 504 male subjects) with mean age of 41.3±21.3 years underwent corneal transplantation. The most common indication was keratoconus (n=317, 40.8%) followed by bullous keratopathy (n=90, 11.6%), non-herpetic corneal scars (n=62, 8.0%), infectious corneal ulcers (n=61, 7.9%), previously failed grafts (n=61, 7.9%), endothelial and stromal corneal dystrophies (n=28, 3.6%), and trachoma keratopathy (n=26, 3.3%). Other indications including Terrien's marginal degeneration, post-LASIK keratectasia, trauma, chemical burns, and peripheral ulcerative keratitis constituted the rest of cases. Techniques of corneal transplantation included penetrating keratoplasty (n=607, 78.2%), deep anterior lamellar keratoplasty (n=108, 13.9%), conventional lamellar keratoplasty (n=44, 5.7%), automated lamellar therapeutic keratoplasty (n=8, 1.0%), and Descemet stripping endothelial keratoplasty (n=6, 0.8%) in descending order. The remaining cases were endothelial keratoplasty and sclerokeratoplasty. Conclusion: In this study, keratoconus was the most common indication for penetrating keratoplasty which was the most prevalent technique of corneal transplantation. However, deep anterior lamellar keratoplasty is emerging as a growing alternative for corneal pathologies not involving the endothelium. [ABSTRACT FROM AUTHOR]