In the present study, the removal performance of phenol and Chemical Oxygen Demand (COD) from a petroleum refinery wastewater (PRW) in a Rotating Biological Contactor (RBC) was investigated. The impact of temperature of wastewater (T) (35-45ºC), rotational speed (ω) (2-14 rpm) and disc submergence (Ω) (30-50%) on phenol and COD removal was examined. The response surface methodology (RSM) was applied to minimize the number of runs and investigate the optimum operating conditions. Seventeen runs were carried out and the optimum conditions for phenol and COD removals were statistically obtained at temperature of 35°C, rotational speed of 11 rpm and disc submergence of 46%. These predicted data were in good agreement with the observed ones, as well. The result indicated that, the removal efficiency of phenol, cyanide, ammonia nitrogen, hydrogen sulfide, COD, biological oxygen demand (BOD 5), total dissolved solid (TDS), total suspended solid (TSS), total organic carbon (TOC) and turbidity respectively were under the 99%, 82%, 40%, 93%, 89%, 87%, 76%, 85%, 55% and 58%, in the optimum conditions that mentioned above. The major group of microbes (for the phenol microbial treatment) isolated from effluent of American Petroleum Institute (API) separator identified as Bacillus and Pseudomonas species. Furthermore, indigenous bacteria no need to acclimate. It also produced low sludge compared with the activated sludge in the RBC. Therefore, this type of bacteria was successfully applied in this research.

Backgrounds: Abnormal vaginal discharge is a common problem among pregnant women. The most common cause of these discharges is bacterial vaginosis (BV), which has numerous complications and causes problems for pregnant mothers and their fetuses. The purpose of this study was to determine the BV frequency among pregnant women referring to a gynecology clinic in Arak city using Amsel and Nugent criteria, Alberta guideline, and PCR. Materials & Methods: This descriptive study was performed on 70 vaginal samples of pregnant women in Arak to investigate the most common causes of vaginal discharge according to Amsel and Nugent criteria and polymerase chain reaction (PCR) method using specific primers targeted towards three bacteria: Gardnerella vaginalis, Atopobium vaginae, Mobiluncus curtisii. Data were analyzed using SPSS software and Chi-square test. Findings: In this study, ten (14.28%) out of 70 pregnant women had positive bacterial vaginosis according to Amsel criteria. According to Nugent criteria and Alberta guideline, three (4.29%) cases were diagnosed with definite BV, 20 (32.26%) cases with intermediate BV with clue cells, 42 (67.74%) cases with intermediate BV without clue cells, and finally five (4.29%) cases with negative BV. Also, according to PCR, the frequency of G. vaginalis, M. curtisii, and A. vaginae in vaginal samples was 71.42% (50 cases), 64.28% (45 cases), and 30% (21 cases), respectively. Conclusion: According to the obtained results, the prevalence of definite bacterial vaginosis was lower than that of vaginitis, and most patients suffered from nonspecific vaginitis.

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