Effect of dissolved oxygen and chemical oxygen demand to nitrogen ratios on the partial nitrification/denitrification process in moving bed biofilm reactors

Partial nitrification was reported to be technically feasible and economically favorable, especially for wastewater with high ammonium concentration or low C/N ratio. In this study, the effect of dissolved oxygen (DO) and influent ratio of chemical oxygen demand to nitrogen (COD/N) ratio on biological nitrogen removal from synthetic wastewater was investigated. Experiments were conducted in moving bed biofilm reactors (MBBRs) on partial nitrification process in pilot-plant configuration for 300 days. DO levels were changed from 0.04 to 0.12 and 0.42 to 3.4 mg/l in the anoxic (R1) and aerobic (R2) reactors, respectively. The optimum DO for partial nitrification was between 1-1.5 mg/l in the aerobic reactor (R2). Influent COD/N ratios between 20 and 2 g COD/g-N were tested by changing the nitrogen loading rate (NLR) supplied to the pilot plant. During operational conditions when the DO concentration in aerobic reactor was above 1 mg/l, near complete organic carbon removal occurred in the total MBBRs system. The effluent total nitrogen concentration in the operational conditions (1.7-2.1 mg O2/l and NH+ 4-N=35.7 mg N/l) was obtained in the range of 0.85-2 mg/l. The highest nitrite accumulation (50%- 52%) took place at the DO concentration of 1-1.5 mg/l and increased with decreasing COD/N ratio in aerobic reactor (R2). This study showed that the average nitrification rate at various COD/N ratios is about 0.96 gN/m2 per day while the maximum nitrification rate is about 2 gN/m2 per day at COD/N ratios lower than 6. The experimental COD/N ratio for denitrification was close to complete sum of NO2 - and NO3 - (NOx) removal efficiency (about 99%) at COD/N ratio equal 14 in the operational conditions in the anoxic reactor (R1)

Evaluation of bacteriological and chemical quality of dialysis water and fluid in Isfahan, central Iran

Background: Chemical and microbial quality of water used in hemodialysis play key roles in a number of dialysisrelated complications. In order to avoid the complications and to guarantee safety and health of patients therefore, vigorous control of water quality is essential. The objective of present study was to investigate the chemical and bacteriological characteristics of water used in dialysis centers of five hospitals in Isfahan, central Iran. Methods: A total of 30 water samples from the input of dialysis purification system and dialysis water were analyzed for chemical parameters. Heterotrophic plate count and endotoxin concentration of drinking water, dialysis water and dialysis fluid of 40 machines were also monitored over a 5-month period in 2011-2012. Results: Concentration of the determined chemicals (copper, zinc, sulfate, fluoride, chloramines and free chlorine) did not exceed the recommended concentration by the Association for the Advancement of Medical Instrumentation (AAMI) exclude lead, nitrate, aluminum and calcium. Furthermore, the magnesium; cadmium and chromium concentration exceeded the maximum level in some centers. No contamination with heterotrophic bacteria was observed in all samples, while the AMMI standard for endotoxin level in dialysis fluid (<2 EU/ml) was achieved in 95 of samples. Conclusion: Dialysis water and fluid failed to meet the all chemical and bacteriological requirements for hemodialysis. To minimize the risk of contaminants for hemodialysis patients therefore, a water quality management program including monitoring, maintenance and development of water treatment system in hemodialysis centers is extremely important. In addition, an appropriate disinfection program is needed to guarantee better control of bacterial growth and biofilm formation. © 2016, Iranian Journal of Public Health. All rights reserved

Multi-component adsorption of benzene, toluene, ethylbenzene, and xylene from aqueous solutions by montmorillonite modified with tetradecyl trimethyl ammonium bromide

Multicomponent adsorption of benzene, toluene, ethylbenzene, and xylene (BTEX) was assessed in aqueous solutions by montmorillonite modified with tetradecyl trimethyl ammonium bromide (TTAB-Mt). Batch experiments were conducted to determine the influences of parameters including loading rates of surfactant, contact time, pH, adsorbate concentration, and temperature on the adsorption efficiency. Scanning electron microscope (SEM) and X-ray diffractometer (XRD) were used to determine the adsorbent properties. Results showed that the modification of the adsorbent via the surfactant causes structural changes of the adsorbent. It was found that the optimum adsorption condition achieves with the surfactant loading rate of 200 of the cation exchange capacity (CEC) of the adsorbent for a period of 24 h. The sorption of BTEX by TTAB-Mt was in the order of B T E X. The experimental data were fitted by many kinetic and isotherm models. The results also showed that the pseudo-second-order kinetic model and Freundlich isotherm model could, respectively, be fitted to the experimental data better than other available kinetic and isotherm models. The thermodynamic study indicated that the sorption of BTEX with TTAB-Mt was achieved spontaneously and the adsorption process was endothermic as well as physical in nature. The regeneration results of the adsorbent also showed that the adsorption capacity of adsorbent after one use was 51 to 70 of original TTAB-Mt

INVESTIGATING THE STATE OF AMBUSH MARKETING IN FOOTBALL AND WRESTLING

One of the modern ways of investing in sports and advertising is through sports. Along with financial backers, the ambush marketing phenomenon has been around for three decades. In Iran, one of the weaknesses is the lack of rules and weakness in the implementation of marketing laws. Football and wrestling are popular sports in Iran and have significant sponsors. The purpose of this study was to investigate the situation of ambush marketing in football and wrestling. The present study is of qualitative type. The statistical population includes 12 professionals: professors of sports marketing, media officials, the Football Federation, and football wrestling and financial support. Research tools are semi-structured interviews and research methods, content analysis and thematic analysis using Nvivo8 software. The research results showed that the term hidden marketing should be used instead of ambush marketing, and strict legislation and heavy financial penalties are required by lawmakers. Although major sporting events such as the Olympics and the FIFA World Cup are more common in Western countries, we can also use their methods and rules to protect the rights of sponsors and prevent ambush marketing. Article visualizations

Effectiveness of chitosan as natural coagulant aid in removal of turbidity and bacteria from turbid waters

There has been considerable interest in the development of natural coagulants such as chitosan. By using natural coagulants, considerable savings in chemicals and sludge handling cost may be achieved. Chitosan, a natural linear biopolyaminosaccharide, is obtained by alkaline deacetylation of chitin. Present study is aimed to examine the effects of aluminium sulfate (alum) as coagulant in conjunction with chitosan as coagulant aid on removal of turbidity and bacteria from turbid waters. These tests were carried out using artificial water and kaoline as model suspensions to represent the wide range of natural turbid waters. A conventional jar test apparatus was employed for the tests. After determining of optimum mixing intensity and duration, alum suspensions were added to the samples and after one minute, the desired doses of natural chitosan were added. In optimum condition, residual Al+3 in treated water was less than 0.2 mg/l and meets the EPA guidelines. Turbidity removal efficiency was 74.3- 98.2% by chitosan at a pH 7.0-7.5 for all turbidities. In addition, chitosan significantly reduced the required dosage of primary coagulant 50-87.5%. Bacteria reduction of 2-4 log units (99 - 99.99%) was obtained within the first 1 to 2 h of treatment. Overall results indicate that E.coli was removed better than S. faecalis. The main effects of coagulation by chitosan on bacteria are enmeshment and stack on the microbial cell surface. We demonstrated that optimal design method is an efficient approach for optimization of coagulation-flocculation process and appropriate for raw water treatment

Amoxicillin degradation with electro-persulfate combined with H2O2 from aqueous solution using response surface methodology

Background: Discharging wastewaters containing antibiotic into the environment causes some adverse effects on the human health and other organisms. The present study investigated the efficiency of electropersulfate combined with hydrogen peroxide (H2O2) process as a chemical oxidation in amoxicillin (AMX) degradation. Methods: Optimization of the significant operational independent variables was explored for removal of AMX. Central composite design (CCD) was employed as a statistical tool for experimental design. High-performance liquid chromatography (HPLC) was used for measuring AMX concentration. The most effective factors of the electro-persulfate and H2O2 on the removal efficiency of AMX such as initial concentration of AMX, initial pH, PS/H2O2 molar ratio, and the current density were measured. Results: The optimum conditions for electro-persulfate removal efficiency of AMX to reach the degradation efficiency of higher than 95.28 ± 2.64% at reaction time of 60 minutes were obtained at pH = 4.23, AMX concentration = 31.9 mmol/L, current density = 39 mA/cm2, and PS/H2O2 molar ratio = 0.82. AMX degradation was satisfactorily predicted by the quadratic model with high possibility and confidence level of 95%. The quadratic model had high regression coefficients (R2 = 0.9964 and R2 adj = 0.9926), which was totally acceptable. The removal efficiency of AMX reduced from 87.3 ± 6.1 to 25.9 ± 9 as pH increased from 5.5 to 7. Conclusion: According to the results, the electro-persulfate and H2O2 process can be suggested as the most effective, high efficient, and in-situ chemical oxidation for degradation of AMX. Keywords: Amoxicillin, Hydrogen peroxide, Oxidation-reduction, Antibioti

Assessment of Spatial Variation of Groundwater Quality in a Mining Basin

Assessment of groundwater quality is vital for the sustainable safe use of this inimitable resource. However, describing the overall groundwater quality condition—particularly in a mining basin—is more complicated due to the spatial variability of multiple contaminants and the wide range of indicators found in these areas. This study applies a geographic information system (GIS)-based groundwater quality index (GQI) to assess water quality in a mining basin. The study synthesized nine different water quality parameters available—nitrate, sulphate, chloride, sodium, magnesium, calcium, dissolved mineral solids, potassium, and floride (NO−, SO2−, Cl−, Na+, Mg2+, Ca2+, DMS, 34 K+ and F−)—from 90 boreholes across the basin by indexing them numerically relative to the World Health Organization standards. The study compared data from 2006 and 2011. The produced map indicated a lower GQI of 67 in 2011 compared to 72 in 2006. The maximum GQI of 84.4 calculated using only three parameters (Mg2+, K+ and F−) compared well with the GQI of 84.6 obtained using all nine parameters. A noticeable declining groundwater quality trend was observed in most parts of the basin, especially in the south-western and the northern parts of the basin. The temporal variation between the GQIs for 2006 and 2011 indicated variable groundwater quality (coefficient of variation = 15–30%) in areas around the mining field, and even more variability (coefficient of variation >30%) in the south-western and eastern parts of the basin

The Effect of Wastewater Irrigation on the Activity of Soil Microorganisms

Introduction: The use of wastewater for irrigation in arid and semi-arid regions of the world is increasing. This study aimed to evaluate the effects of wastewater on the microbial activity of irrigated soils using the enzymatic activity of soil microorganisms. Materials and Methods: In this study, for soil irrigation, the secondary effluent of the Isfahan municipal wastewater treatment plant was used. As a control, tap water that has no microbial load was also used. Soil samples were collected in two stages, before and immediately after irrigation. All samples were collected in sterile bags, transferred immediately to the laboratory for physicochemical and microbiological tests. Soil samples were analyzed for the amounts of enzymatic activity (Fluorescein Diacetate (FDA) and dehydrogenase), electrical conductivity (EC), oxidation-reduction potential (ORP), and pH. Results: The EC levels before and after irrigation with tap water was 231.2 and 260.63 ps.cm-1, respectively, which was significantly different from levels of wastewater-irrigated soil (P [removed] 0.05). It was found that there is a significant relationship between bacterial density and FDA (P < 0.05). Conclusion: The results of the study showed that irrigation with wastewater has no significant effect on the microbial activity of irrigated soil. Because of the short-term wastewater irrigation in the present study, however, further investigation is needed to evaluate the effect of long-term wastewater irrigation on the microbial and physicochemical quality of soil