Water disinfection using photocatalytic process with titanium dioxide nanoparticles

Background and purpose: Disinfection is one of the most important stages in water treatment. So far, various chemical disinfection methods such as chlorination have been widely used. However, these methods have serious disadvantages, like producing DBPs. The purpose of this research was to study the efficacy of nTiO2 photocatalyst process on removing E.Coli as a water microbial pollution index and effects of some parameters on its efficiency. Materials and methods: Water was artificially contaminated with E.Coli. Culture method and counting were performed according to standard methods for water and wastewater and was reported as CFU/ml. The size of nTiO2 was 20 nm that was used in the presence or absence of UV for disinfection. The Kolmogorov-Smirnov Test was used to check the normality of the data. The ANOVA and T-Test were used for analyzing the data. Results: The results indicated that the inactivation of Escherichia coli increased with increase of nTiO2 catalyst dose and contact time. However, the efficiency decreased when the number of colonies increased. Minimum, average and maximum percentage removal of nTiO2+UV process were 75.1, 88.9±12.7, and 100%, respectively, in 40 min contact time and 0.8 g/L catalyst dose. Conclusion: The bacteria mortality rate in the presence of UV alone was more than that of the nTiO2 alone process. However, the efficiency of the photocatalytic process (UV+nTiO2) was more than that of the UV alone or nTiO2 alone. © 2015, Mazandaran University of Medical Sciences. All rights reserved

Medical waste generation in gorgan hospitals, 2014

Background and purpose: Hospitals and health-care centers are the major sources of hazardous waste generation. Hospital wastes should be collected and disposed under certain conditions. The aim of this study was to investigate hospitals waste generation in Gorgan, Iran. Materials and methods: The study was performed in 8 hospitals including 3 educational hospitals and 5 non-educational hospitals in Gorgan, 2014. Waste generation was investigated in 4 consecutive months, three times a week. Weighting was performed 384 times (48 times in each hospital). Mann-Whitney and nonparametric correlation test were used for data analysis. Results: The results showed 40.27 hazardous and 59.73 general wastes were generated in hospitals. The mean rates of waste general and hazardous generation were 2.63 and 1.03 kg/bed/day, respectively. These rates in educational and non-educational hospitals were 3.75 and 1.96 kg/bed/day, respectively. Conclusion: Generation of hazardous waste was found to be high in Gorgan hospitals. Also, the educational hospitals generated more waste than non-educational hospitals. Therefore, necessary measures should be taken to reduce the generation of waste, especially hazardous waste. © 2015, Mazandaran University of Medical Sciences. All rights reserved

Methylene blue (cationic dye) adsorption into Salvadora persica stems ash

Methylene blue (MB) is the most commonly used substance for dyeing cotton, wood and silk. On inhalation, it can cause difficulty in breathing, while on direct contact, it may cause permanent injury of the eyes of human and animals, burning sensations, nausea, worming, profuse sweating, mental confusion and methemoglobinemia. In the present study, Salvadora persica stem ash was used as an adsorbent for the successful removal of methylene blue (MB) dye from aqueous solutions. The effect of various operating parameters such as initial concentration of dye (20 to 200 mg/L), contact time (5 to 270 min), adsorbent dosage (0.2 to 10 g/L) and pH (2 to 13) was investigated. The results of this study shows that the S. persica stem ash was able to remove up to 97% of MB dye from solutions with various initial dye concentrations at initial pH of 13. Also, the equilibrium data were also fitted to the Langmuir and Freundlich equilibrium isotherm models. It was found that the data fitted better to Freundlich (R2=0.9314) than Langmuir (R2=0.8836) model. Finally, it can be concluded that the S. persica stem ash can be used for textile industry wastewater treatment.Key words: Methylene blue (MB), adsorption, S. persica, natural adsorbent

Evaluation of microbiological and chemical parameters during wastewater Sludge and Sawdust Co-composting

Environmental specialists classified sewage sludge as a hazardous waste because of high organic compounds and pathogenic microorganisms. Therefore sewage sludge should be stabilized before disposal. Composting is an effective and economical method to stabilize sewage sludge. The object of this study is determining the optimum conditions of co- composting of dewatered sewage sludge and sawdust. Pilot scale studywas performed in Isfahan municipal wastewater treatment plant. To perform this study, the dewatered sewage sludge with humidity between 78-82 percent was mixed with sawdust. Turning over did once a week for aeration. Temperature was monitored at different depths daily. Other parameters such as N, C, organic matters, pH, heavy metals, total and fecal Coliform and Salmonella were determined three times a week. The results of this study showed that after about 15th days, temperature of the mixture reached up to 55 oC, and was stabled for fifteen days. Humidity, organic matter, organic carbon and C/N ratio of the mixture decreased during of the study, due to increasing the temperature. Also organic matter and humidity mainly decreased in thermophilic phase. The number of total and fecal coliforms and also Salmonella decreased to A class standards of U.S. EPA at the end of the operation. The result indicated that co-composting of sewage sludge with sawdust is a reliable and simple method to schedule, with high flexibility and low odor production. Organic compounds and pathogenic microorganisms reduced and EPA standards were met during this method. @ JASE

Evaluation of rapid purification of high concentrations of 2, 4-Dinitrophenol in wastewater using catalytic ozonation with carboneus nanocomposite

Background and purpose: 2, 4-dinitrophenol (DNP) are carcinogenic and non-biodegradable pollutants that exist at high concentration in wastewater of chemical industries. In this study, treatment and removal of organic materials (COD) in wastewater was carried out by catalytic ozonation process (COP) using carbon Nano-composite catalysts. Materials and methods: This study was conducted in cylindrical 250 mL semi-continuous reactor and the effects of several parameters including pH of the solution (4-10), the amount of catalyst concentrations (0 to 4 g/L), reaction time (0 to 60 min), and saturated catalyst was studied on treatment of high concentration of DNP and the COD removal efficiency. Also, the kinetics were compared with single ozonation (SOP). Results: Removal efficiency of high concentrations of DNP (1500 mg/L) and kinetics of the COP process catalyst concentration of 4 g/L was 83 (0.0241 min-1) while the results in SOP were 50 (0.0108 min-1). The optimum pH was 6 with the reaction time of 60 min. However, the removal efficiency of COD at initial concentration of 610 mg/L in the SOP process was 61 which increased to 92 after addition of the catalyst. The main mechanism of process was chemical oxidation and a small share (3) was due to adsorption. Conclusion: The results showed that COP and this new catalyst effectively and quickly removed high concentrations of DNP and COD. This method is believed to be economic due to the short time of ozonation, recovery and reuse of the catalyst. © 2016, AMazandaran University of Medical Sciences. All rights reserved

Phytodegradation potential of bisphenolA from aqueous solution by Azolla Filiculoides

Many organic hazardous pollutants such as bisphenolA (BPA) which are toxic and not easily biodegradable can concerns for environmental pollution worldwide. The objective of this study was to examine whether Azolla Filiculoides is able to remove BPA from aqueous solutions. In this study, the Azolla with different biomass (0.3, 0.6, 0.9, 1.2 g) has been cultured in solution that was contained 5, 10, 25 and 50 ppm BPA. Samples were collected every 2 days from all of containers. The analytical determination of BPA was performed by using of DR4000 uv-visible at λ(max) = 276 nm. The results indicated that Azolla has high ability to remove BPA from aqueous solutions. The BPA removal was 60-90%. The removal efficiency is increasing with decreasing of BPA concentration and increasing of biomass amount and vice versa. The removal efficiency was more than 90% when BPA concentration was 5 ppm and amount of biomass was 0.9gr. It is concluded that Azolla able remove BPA by Phytodegradation from the aqueous solutions. Since conventional methods of BPA removal need to high cost and energy, phytoremediation by Azolla as a natural treatment system can decrease those issues and it can be a useful and beneficial method to removal of BPA

The Quantity of Waste Produced at Mazandaran University of Medical Sciences and Evaluating the Possibility of Recycling

Background: The first step of solid waste management is identification of its composition and the amount of solid waste production per capita. The aim of this research was to estimate the quantity of solid waste production at Mazandaran University of Medical Sciences and the possibility of recycling. Methods: This study was a cross-sectional study. The quantity of solid waste production was measured at the student dormitories, self-service, caféteria and administrative sections of Mazandaran University of Medical Sciences. The solid waste produced during two consecutive weeks in one month was weighted and the weight and percent of its components were determined. The obtained data was statistically analyzed by using SPSS 16. Results: The results showed that putrescible waste was approximately 66.7% of the total solid waste produced. The share of other components of waste such as paper & cardboard, plastic, metals and glass was 19.2%, 10.8%, 0.15% and 0.14% respectively. Solid waste production rate was 144 grams per capita per day. Conclusion: As the main content of solid waste is putrescible, the best alternative for the University’s solid waste is to convert it into compost. Also better management in preparation and distribution of food can be one main strategy to reduce putrescible waste. Keywords: Waste, recycling, per capita production rate, Mazandara

Application of Moringa peregrina seed extract as a natural coagulant for phenol removal from aqueous solutions

Phenol and its derivatives are toxic pollutants frequently found in surface and tap waters, and in aqueous effluents from various manufacturing processes such as petroleum and petrochemical, coal conversion, synthetic rubber, plastics, paper, oil refineries and phenol-producing industries. In the present study, the ability of Moringa peregrina seed extract to remove phenol from aqueous solutions in a batch system was investigated. The effects of major operating variables such as coagulant dose (0.05 - 4 ml//L), initial phenol concentration (5, 10, 20, 50 and 100 mg/L) and pH (3-9) were investigated. The optimum pH for phenol removal by coagulation using M. peregrina seed extract was 5, with coagulant dose of 0.1 and 0.3 ml/L and the highest removal was found to be 95.16, 95.84, 97.91, 98.27 and 99.9% at initial phenol concentration of 5, 10, 20, 50 and 100 mg/L, respectively, as a result of precipitation, co-precipitation and adsorption mechanisms. According to these results, it was defined that M. peregrina seed extract is not only an inexpensive coagulant, but also quite an effective factor in the removal of phenol from aqueous environments.Key words: Phenol removal, Moringa peregrina, coagulation, natural coagulants

Quantity and Quality Analysis and Management of Dental Solid Waste Produced in Private Office in Urmia

Objective: Dental solid wastes often contain hazardous substances. The first step of management of dental solid wastes includes detection and classification of these substances. This study aimed to qualitatively and quantitatively assess the management of solid wastes by dental offices in Urmia  city in 2013.Methods: This descriptive study was conducted on all private dental offices in Urmia city and six samples were collected of the wastes of each office per season. Samples were manually searched, divided into 16 different categories and weighed by a digital scale. In the next step, the weighed components were classified according to their characteristics and hazardous potential.Results: The total amount of solid wastes produced by dental offices in Urmia city was 81 kg/day consisting of 28.3% infectious wastes, 59% domestic-like wastes, 9.6% chemical and  pharmaceutical wastes and 2.7% toxic wastes. Waste reduction and recycling programs were not performed in any office.Conclusion: Considering the type and quantity of generated dental solid wastes, especially the infectious wastes and their adverse effects on public health and the environment, a specific strategy must be designed for management of dental solid wastes

Survey on monthly variations of water quality in the Tajan River (Sari, Iran)

The aims of the study were to evaluate water quality of Tajan River in Sari in terms of chemical pollution and the impact of pollutant sources near the river by considering the climate, hydrological and hydraulic condition on it. In this study, 10 critical points of river were selected as sampling stations from dam to sea. Sampling was randomly done monthly from Apr 2009 to Mar 2010. Samples were analyzed in terms of chemical parameters after transferring to the laboratory according to standard methods. The results showed that the pH and temperature were within acceptable ranges of 6.5 to 8.5 and < 20°C, respectively. The minimum dissolved oxygen (DO) concentrations were above 6 mg/L along the river. Fish can survive because DO content was high. The maximum levels of biochemical oxygen demand (BOD), chemical oxygen demand (COD), phosphate (PO4) and nitrate (NO3) were at or below 30, 17, 0.5 and 0.7 mg/L, respectively. In general, the results showed that the physical and chemical qualities of water from Tajan River were within the acceptable limits for agricultural consumptions. In addition, Tajan River water can be classified in Class II.Keywords: Water quality, Tajan River, river pollution, water pollution.African Journal of Biotechnology Vol. 12(25), pp. 3984-399