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

Alternative Disinfection Methods Use to Control of Microbial Quality and Shelf-life of Raw Eaten Vegetables (Case Study)

Background:&nbsp;Fresh-cut vegetables are particularly susceptible to microbial growth and, therefore, the use of an effective sanitizer on this product is great importance. Method: The common vegetable &nbsp;types obtained from a local wholesale market in Isfahan and washed with different common disinfectants such as edible salt, sodium hypochlorite, electrolyzed water (EW), complex disinfectant, calcium hypochlorite, and dishwashing liquid. Disinfection time and concentration select according to the Official Protocol in Iran. A total of 126 samples including Mint, Savory, parsley, Garden cress, Common Purslane, Chives, Basil, Radish, and mixed vegetables were analyzed for total bacteria, total coliform bacteria, and E. coli. Result: Results demonstrated that calcium hypochlorite has the best efficiency for total coliforms in separate vegetable of parsley, Garden cress, Common Purslane, Chives, Radish, with100% efficacy. For total coliforms BGB (Brilliant Green Broth) test, complex disinfectant and calcium hypochlorite have 100% removal for all of the vegetables. E.coli test result showed in four vegetables not E.coli but for another vegetable except Dishwashing Liquid efficiency was 100%. Among all disinfectants, EW has a high efficiency for mixed vegetables. For Basil disinfected with edible salt and mint washing with complex disinfectant, Eimeria parasite and in savory disinfected with calcium hypochlorite Hook worm parasitic was found. Shelf-life was between 1 to 5 days. Conclusion:&nbsp;Our research suggested that EW has a good effect for total coliforms, fecal coliforms, E.Coli, and helmet eggs removal, also save the vegetable shelf life

Alternative Disinfection Methods Use to Control of Microbial Quality and Shelf-life of Raw Eaten Vegetables (Case Study)

Background:&nbsp;Fresh-cut vegetables are particularly susceptible to microbial growth and, therefore, the use of an effective sanitizer on this product is great importance. Method: The common vegetable &nbsp;types obtained from a local wholesale market in Isfahan and washed with different common disinfectants such as edible salt, sodium hypochlorite, electrolyzed water (EW), complex disinfectant, calcium hypochlorite, and dishwashing liquid. Disinfection time and concentration select according to the Official Protocol in Iran. A total of 126 samples including Mint, Savory, parsley, Garden cress, Common Purslane, Chives, Basil, Radish, and mixed vegetables were analyzed for total bacteria, total coliform bacteria, and E. coli. Result: Results demonstrated that calcium hypochlorite has the best efficiency for total coliforms in separate vegetable of parsley, Garden cress, Common Purslane, Chives, Radish, with100% efficacy. For total coliforms BGB (Brilliant Green Broth) test, complex disinfectant and calcium hypochlorite have 100% removal for all of the vegetables. E.coli test result showed in four vegetables not E.coli but for another vegetable except Dishwashing Liquid efficiency was 100%. Among all disinfectants, EW has a high efficiency for mixed vegetables. For Basil disinfected with edible salt and mint washing with complex disinfectant, Eimeria parasite and in savory disinfected with calcium hypochlorite Hook worm parasitic was found. Shelf-life was between 1 to 5 days. Conclusion:&nbsp;Our research suggested that EW has a good effect for total coliforms, fecal coliforms, E.Coli, and helmet eggs removal, also save the vegetable shelf life

Effect of zinc oxide nanoparticles synthesis precursor in hydrothermal method on structure and physical properties of poplar wood

In this research, effect of the alkaline precursors of soda and ammonia as reagent deposition of zinc oxide nanoparticles using hydrothermal method in structure and physical properties of poplar wood were investigated. The samples of physical test were prepared with dimensions of 2*2*2 cm3 according to ASTM-D4446-05, and divided to three levels; control, Zncl2/NH3 and Zncl2/Naoh at 0.05M concentration and pH=10. Test samples were impregnated with salty precursor in the experimental cylinder using vacuum-pressure method, and in order to adjust the pH, soda and ammonia added. Due to the electron microscope images, change the type of precursor deposition, caused the different structure of ZnO nanoparticle. Retention of zinc oxide nanoparticles, density changes, water absorption, swelling and anti-swelling efficiency (ASE) were determined after synthesis. Retention of zinc chloride precursor with ammonia and soda acidity regulator was determined 4.43 and 1.71kg/m3 respectively. Water absorption increased at first hours of immersion, and then decreased. These treatments increased water absorption of wood. Least swelling and water absorption, and maximum ASE were measured in Zncl2/NH3 level

Effect of insitu synthesis of zinc oxide nanoparticles on the mechanical and biological properties of a wood-polymer composite

The current research work was planned to investigate the possibility of zinc oxide nanoparticles synthesis using hydrothermal method in wood structure and its effect on mechanical and biological properties of wood-polymer composite. Test samples were divided to control and treated with styrene, zinc oxide nanoparticles, nanocomposite and nano/Styrene. Mechanical and biological tests samples according toASTM-D143 and EN113 respectively were treated by vacuum- pressure method using cylinder experimental. The mechanical tests were considered for each level 5 repeat and for biological test for each level 10 repeat. The presence of zinc oxide nanoparticles on cell wall and styrene in the cell cavities were confirmed by Scanning electron microscopy. According to the results, bending strength, bending modulus, hardness and pressure parallel to grain for nano/styrene samples with highest improvement were increased 36.74, 40.23, 60.58 and 25.07 in comparison with control respectively. Also, decay resistance of treated samples increased, so that maximum and least weight loss were recorded for control and nano/styrene samples with 25.81 and 3.37% weight loss

The Effect of Lignosulfunate on Rooting of Micropropagated Walnut

Introduction: Tissue culture is an effective technique for mass propagation of walnut that has many advantages. Plants were obtainedby in vitro techniques in comparison with in vivotechniques areableto producet fruitearlier. However one of the major problems in walnut micropropagation is the difficulty of rooting. Auxin protection against auxin-oxidase system can make a major contribution to rooting. Among all the compounds that can play the synergistic role with auxin, they will probably have the ability of auxin protection against enzymes. In this experiment, the effect of lignosulfunate on rooting of micropropagated walnut was investigated for the first time. Materials and Methods: In this experiment, Hartley cultivar of walnut was used. At first, explants were washed under running water for 1 hour then explants were placed in 70% alcohol for 1 minute and after that in 10% bleach for 10 minutes. After sterilization, under laminar air flow hood, explants were washed three times with distilled water and werecultured on Driverand Kuniyuki, 1984(DKW) medium supplemented with 2.2 g l-1phytagel, 2 mg l-1 BA, 0.01 mg l-1 IBA and 30 gl-1 sucrose (establishment stage). In multiplication stage, plantlets were subcultured every 25 days. All of the plantlets were placed in jars and were kept inside a growth chamber in photoperiod of 16 hours of light. All the multiplicated shoots were used as explants for the trails. Twodifferenttestswere usedto induceroot in explants. At the first trial, explants were transferred to induction medium containing IBA (3, 5, 7 and 10 mg l-1) and treatmentswere placedin thedark for 3, 5and7 days. Treatments related to theconcentrations of5and7 mg l-1IBAand7 daysof darknesshadthe highestpercentage ofrooting. In the next experiment, thecombination ofthree levels oflignosulfunate (1, 2 and 3 g l-1), and two concentration of 5and7mg l-1IBAwere used. Treatmentswere placedindarknessfor 7 days. After root induction,shootlets were transferred to root development medium. Rootdevelopmentmedium includesa quarteroftheDKWand vermiculite. Results and Discussion:The aim of the first trial was to determine the concentration of IBA which produced the highest percentage of rooting. Among all the auxins, it was shown in other experiments that IBA has the best results in rooting of walnut. Due to this, we chose IBA as root induction hormone. With increasing of IBA concentrations and the induction period, rooting increased. Because the higher amount of exogenous auxin will induce the higher amount of endogenous auxin (IAAsp). However, rooting increased to a certain level and then began to decrease. With increasing concentrations above 10 mgl-1 IBA rooting reduced and formation of callus in the shoot end increased which is not good for rooting because callus would not let the cells form roots. It seems that accumulation of IAAsp induces self-productive cells in root area to grow and duplicate abnormally and maybe root formation stops because of this accumulation and also because of the inadequacy of the IAAsp to transfer to neighboring cells. Also with increasing concentration, defoliation and wilting happens. A lower concentration of IBA (about3 mgl-1) caused loss of rooting. The highest percentage of rooting for the first treatment with IBA was with 5 mgl-1 IBA and 7 days of darkness and 7 mgl-1 IBA and 7 days of darkness. The treatments were placed in darkness due to degradation of auxin under light condition. The induction time was related to auxin concentration. If the auxin concentration is less, the exposure time in the dark will be more. Root induction in the dark had better results than induction in light. The capacity of rooting in walnut is related to the amount of endogenous (IAAsp) and exogenous auxin. The amount of endogenous auxin is completely related to the cultivar and thatis why some cultivars respond really well to the amount of exogenous hormones in rooting stage. Exogenous auxin induces the production of endogenous auxin (IAAsp). These two concentrations were chosen for next treatment with lignosulfunate. Rootingratedecreaseswith increasinglignosulfunate. However, the highest root induction among all the treatments wasachieved on medium containing 1 g l-1lignosulfunate. The reason of transferring all explants after root induction to root development medium was changing the hormone and salts concentrations. At this stage, the ¼ DKW was used as a medium. This is due to the reduction of salts, root induction and rooting accelerate. Conclusions: In this study, the effect of lignosulfunate (auxin synergist) on rooting stage of Hartley cultivar of walnut was investigated. For this goal, two trials were done. The first trial was to determine the best concentration of IBA for rooting. Two concentrations were chosen and another trial was the effect of the combination of lignosulfunate with IBA on rooting. For the first time in this study, we showed that lignosulfunatecan improve rooting of walnut

Microbial quality of water in dental unit waterlines

&lt;ul&gt;&lt;li&gt;&lt;strong&gt;BACKGROUND&lt;/strong&gt;: Dental unit waterlines (DUWLs) are ideal nvironment for development of microbial biofilms. Microbial contamination of water in DUWLs is thought to be the result of biofilm formation as it could serves as a haven for pathogens. The aim of this study was to assess microbial quality of water in dental unit waterlines of dental units located at the dental school of Isfahan University of Medical Sciences.&lt;/li&gt;&lt;li&gt;&lt;strong&gt;METHODS&lt;/strong&gt;: Water samples were collected from air/water syringe and high-speed handpiece. Generally, 100-200 ml water samples were collected aseptically in sterile containers with sodium thiosulfate at the beginning of the day after a 2 minute purge. Samples were transferred to the laboratory in insulated box with cooling packs and examined for total viable heterotrophic bacteria and fungi.&lt;/li&gt;&lt;li&gt;&lt;strong&gt;RESULTS&lt;/strong&gt;: The heterotrophic plate count levels were significantly exceeded the American Dental Association recommendations for DUWL water quality (&amp;lt; 200 CFU/ml), in both air/water syringe (84%, CFU/ml: 500-20000) and highspeed handpiece (96%, CFU/ml: 710-36800) samples. However, there was no significant difference between the level of contamination in the air/water syringe and high-speed handpiece. Fungi were found in 28% and 36% of air/water syringe and high-speed handpiece samples, respectively; and filamentous fungi were the most frequently isolated fungi.&lt;/li&gt;&lt;li&gt;&lt;strong&gt;CONCLUSIONS&lt;/strong&gt;: DUWLs should be subjected to routine microbial monitoring and to a decontamination protocol in order to minimize the risk of exposure to potential pathogens from dental units.&lt;/li&gt;&lt;li&gt;&lt;strong&gt;KEYWORDS&lt;/strong&gt;: Biofilm, Dental Unit Waterlines, Microbial Quality, Water.&lt;/li&gt;&lt;/ul&gt

The role of Hospital Wastewaters in Dissemination of Antibiotic Resistant Bacteria and Resistance Genes to the Environment

Background: Antibiotic resistance Genies causes many problems in hospitals. Dissemination of these agents to the environment is a great concern worldwide. The aim of this study was to investigate the concentration of antibiotic resistant bacteria (ARB) and presence of antibiotic resistance genes(ARGs) in hospital wastewaters. Methods: in present work, 33 sample from raw hospital wastewater were taken from three hospitals. Heterotrophic plate counts (HPC) method was used to assess the concentration of ARB in hospital wastewater samples. Six conventional antibiotics were selected. Presence of six resistance genes regarding to the selected antibiotics were surveyed in wastewater samples and isolated ARB by PCR method. Results: Average concentration of ARB in raw hospital wastewater was 3.81 &times;107 CFU/100mL. Frequency pattern of ARB in raw hospital wastewater was as follows: ceftazidim(CAZ)> tetracycline(TE)> sulfomethoxazol (STX)> chloramphenicol (CHL)> erythromycin (ER)> and gentamicin(GM), respectively. ARGs in raw wastewater samples were detected more than isolated bacteria. ARGs frequency pattern in wastewater samples were as follows: sul1>cmlA1>ermB>tetW>aac3-1>ctx-m-32. Conclusion: The results of this study revealed that there are high concentration of ARB and ARGs in hospital wastewaters. Therefore, hospital wastewaters could play an important role in dissemination of ARB and ARGs into the natural environment and therefore, may pose serious public health risks

Disinfection of Water and Wastewater Using Gamma Irradiation in Isfahan Water and Wastewater Treatment Plants

To investigate the effect of gamma irradiation on the disinfection of water and wastewater, water samples were collected from raw and filtered water and wastewater samples were taken from the effluent of the secondary sedimentation, polished effluent (1-day retention time), and also from filtered (rapid sand filter) effluent. The samples were irradiated with gamma collimated beam in a batch system using a Co-60 therapeutic gamma radiation machine with a radioactive source emission rate of 405.38CGy/min at different doses of 20-160 Gy and 80-240 Gy, respectively. The samples were analyzed before and after irradiation for total and fecal coliforms. It was observed that nearly 100% reduction was achieved in total and fecal coliforms in water samples treated with a dose of 160 Gy. Depending on effluent quality, disinfection efficiencies achieved using 240 Gy gamma irradiation for inactivation of total coliforms in wastewater samples were 83, 64, and 56 percent for filtered, clarified, and secondary effluents, respectively. The same values were nearly 81, 58, and 46 percent, respectively, for inactivation of fecal coliforms. At lower doses of 120-240Gy, the coliform bacteria were successfully inactivated. It was concluded that a linear correlation holds between the dose delivered and the inactivation of microorganisms, so that inactivation increases with increasing irradiation time