PERFORMANCE OF MAIN DESIGN PARAMETERS FOR AEROBIC DIGESTION OF ISFAHAN MUNICIPAL WASTEWATER MIXED SLUDGE

Introduction. Sludge is a broad term used to describe the various aqueous suspensions of solids produced during wastewater treatment. Raw sludge can be broadly classified as primary sludge, secondary sludge and mixed sludge (mixtures of these two sludge). Raw sludge contains a variety of pollutants creating potentials for environmental pollution and must be treated and disposed properly. Sludge produced in Isfahan South Wastewater Treatment Plant is treated by anaerobic digestion. This method generates nuisance odors and has many operational problems.
 Aerobic digestion is an alternative process for stabilizing sludge. Because the operational control of aerobic digesters is simple and many other advantages, it appears that aerobic digestion will increase in popularity.
 Methods. Aerobic digestion was carried out in a 7.5 liters bioreactor (rectangular glass tank 23*16*21 Cm) that was loaded with 5 liters mixed sludge from this plant. This experimental research was conducted at the Environmental Health Laboratory of Isfahan Faculty of Health. Aeration of bioreactor content provided through three air stones that each of them connected with one aquarium air pump (RENA101). The aeration rate was set to maintain a minimum residual dissolved oxygen concentration of 1.5 mg/I and aeration was sufficient to keep the solids in suspension. This research was continued for 5 period from autumn and winter 1998 through end of spring 1999. In each period the sludge was aerated for three weeks and in each week two times samplings are accomplished and were analyzed.
 Results. The measurements of TS, TSS, TVS, VSS, and COD concentration and percent reduction of them were performed to monitor the progress of aerobic digestion process and determination of design parameters. Standard Methods (APHA, 1992) were used for all analytical procedures. After the 18 days of detention time of aerobic digestion the decrease in TS, TSS, TVS. VSS, and COD reached 45.22, 49.30, 52.36, 52.28, and 43.03 percent respectively of its primary value.
 Discussion. The results of this study were shown that mixed sludge from Isfahan South Wastewater Treatment Plant were stabilized effectively by aerobic digestion and during of these process significant decreases in any form solids and organic matters were occurred. Determining endpoints in digestion of sludge is carried out by determining the TVS reduction. A 40 percent TVS reduction (EPA's regulations) was achieved with a minimum hydraulic detention time of 11 days at maximum TVS loading rate of 1.45KgTVsm-3d-1

Cataract Surgery in Patients with Ocular Surface Disease: An Update in Clinical Diagnosis and Treatment.

In this article we review essentials of diagnosis and management of ocular surface disease in patients who undergo cataract surgery. It is clearly shown that dry eye disease worsens following the cataract surgery in patients with prior history of ocular surface disease, Also new cases of dry eye might appear The current strategies for timely diagnosis and proper management of dry eye syndrome in the face of cataract surgery patients is mainly emphasized. To achieve the best outcome in cataract surgery, a healthy ocular surface is crucial. While ocular surface preparation is indispensable in patients with established ocular surface disease, it is also helpful in those with minimal signs or symptoms of surface disease. The current approach begins with early diagnosis and drastic management of ocular surface disease before cataract surgery using a stepwise regimen customized to the individual patient and disease severity. These considerations are typically sustained throughout and following the surgery

Long-term Management of Severe Ocular Surface Injury Due to Methamphetamine Production Accidents.

Purpose: The aim of this study was to report the clinical features and management of patients with ocular surface damage during methamphetamine production accidents. Methods: This is a retrospective noncomparative interventional case series of 5 patients with methamphetamine production–related ocular injuries referred to the Cincinnati Eye Institute between 1999 and 2014. Results: Four of 5 cases were white young men with severe bilateral ocular injury and extremely poor vision. All except 1 eye (9 of 10) were diagnosed with total or near-total ocular surface failure. Limbal stem cell transplantation was performed in 8 of 10 eyes. Keratolimbal allograft was followed by penetrating keratoplasty in 7 of 10 eyes. Ocular surface stability was achieved in 7 of 10 eyes after keratolimabl allograft. Postoperative visual acuity was better than 20/200 in 4 of 10 of eyes. Keratolimbal graft rejection occurred in 3 of 10 eyes; the rate of rejection of penetrating keratoplasty was also 3 out of 10 eyes. Conclusions: Methamphetamine-related accidents can lead to severe bilateral ocular injuries. Although stem cell transplantation procedure success is guarded in most of these patients because of severe conjunctival inflammation and accompanying ocular comorbidities, as well as personality issues, compliant patients can achieve good visual function with ocular surface transplantation and subsequent keratoplasty

Late Acute Rejection After Allograft Limbal Stem Cell Transplantation: Evidence for Long-Term Donor Survival.

Purpose: To describe the clinical presentation and management of late (>3.0 years) acute graft rejection in keratolimbal allograft (KLAL) recipients. Methods: This was a multicenter, retrospective observational case series. Six eyes of 6 patients with ocular surface transplant at a mean age of 36.2 years were seen at 3 tertiary referral centers for acute graft rejection between 2007 and 2013. Main outcome measures included strength of systemic immunosuppression (SI) at the time of rejection, time to rejection, and clinical presentation of rejection. Results: Preoperative diagnoses included total limbal stem cell deficiency because of aniridia (n = 2) or chemical injury (n = 4). After an initially successful outcome, patients experienced late acute graft rejection at a mean time of 67.8 ± 24.1 months (range: 41-98) after KLAL while receiving suboptimal levels of SI because of medication taper (n = 5) or noncompliance (n = 1). Objective findings included an epithelial rejection line (n = 6), edema (n = 2), corneal epithelial irregularities (n = 2), and neovascularization (n = 1). Antirejection management consisted of topical corticosteroids (n = 6) and augmentation of SI therapy (n = 5). Conclusions: These cases of late acute graft rejection in KLAL patients support the notion that allodonor cells can persist over the long run and remain at risk for immunologic rejection. It further underscores the fact that long-term success with KLAL may require extension of SI beyond the first few years, albeit at lower levels individualized to each patient