Effects of noise pollution on Samen district residents in Mashhad city

Background: Noise pollution is one of the most important environmental pollutions that affects human health in different dimensions. The current study aimed to survey the effects of noise pollution on residents of the Samen district in Mashhad

Methods: To understand the psychological effects that noise pollution caused by vehicles has on people, 400 questionnaires designed to gather demographic data and information on attitudes about noise pollution, its effects on people's activities, and noise source annoyance were randomly distributed among the people living in the Samen district of Mashhad city. SPSS software was used for statistical analysis

Results: According to the results of this study, the most important effects noise pollution had on the studied society were nervousness [29.1%], conversation problems [19.8%], amnesia [18.3%], and loss of concentration [12.8%]. Furthermore, 54.8% of the respondents considered the environmental noises annoying, and 32.5% reported it very annoying. In this study, traffic noise was reported as the most important source of noise pollution

Conclusion: Generally, the results showed that noise pollution is a serious issue in the Samen district, and the necessary actions should be taken to control noise and prevent the effects of noise pollution

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/m[2] per day while the maximum nitrification rate is about 2 gN/m[2] 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]

Biological phosphorus and nitrogen removal from wastewater using moving bed biofilm process

In this research, an experimental study to evaluate nutrient removal from synthetic wastewater by a lab-scale moving bed biofilm process was investigated. Also, kinetic analysis of the process with regard to phosphorus and nitrogen removal was studied with different mathematical models. For nutrient removal, the moving bed biofilm process was applied in series with anaerobic, anoxic and aerobic units in four separate reactors that were operated continuously at different loading rates of phosphorus and nitrogen and different hydraulic retention times. Under optimum conditions, almost complete nitrification with an average ammonium removal efficiency of 99.72% occurred in the aerobic reactor. In the aerobic reactor, the average specific nitrification rate was 1.92 g NOx-N [NOx-N=NO2-N +NO3-N] produced/kg volatile suspended solids. hour [VSS.h]. Denitrification rate increased with increasing NOx-N loading in the second anoxic reactor. The aerobic phosphate removal rate showed good correlation with the anaerobic phosphate release rate. Under optimum conditions, the average total nitrogen and phosphorus removal efficiencies were 80.9% and 95.8%, respectively. As a result of the moving bed biofilm process [MBBR] kinetic analysis, the Stover-Kincannon model was chosen for modeling studies and experimental data analysis. The Stover-Kincannon model gave high correlation coefficients for phosphorus and nitrogen removal, which were 0.9862 and 0.986, respectively. Therefore, this model could be used in predicting the behavior or design of the moving bed biofilm process

[Effectiveness of Moringa oleifera coagulant protein and chitosan as natural coagulant aids in removal of colloidal particles and bacteria from turbid waters]

In recent years, chitosan and Moringa oleifera Coagulant Protein a natural coagulant were used in order to reduce the problems occure from chemical coagulants. This investigation was done to determine effectiveness of Moringa Oleifera Coagulant Protein and Chitosan as natural coagulant aids in removal of colloidal particles and bacteria from turbid waters. In this interventional- quasi experimental study, the experiments were run by using synthetic water having low [10-20NTU], medium [100-120NTU] and high [200-220NTU] initial turbidities. In order to determine optimum pH and dosage of coagulant and coagulant aids, a conventional jar test apparatus was employed. Turbidity reading were carried out using a Hach model 2100P Turbidimeter. The samples were taken from the top four inch of the suspension for turbidity and bacteria removal measurement. Optimum dose of alum for waters with three different initial turbidities were 20, 40, and 20 mg/1, respectively. Optimum pH was between 7-7.5. Moringa oleifera Coagulant Protein and chitosan were reduced the required dosage of alum from 12.5% to 62.5% and from 50% to 87.5%, respectively, in different turbidities and residual aluminum was reduced to standard limit [0.2mg/l]. The bacteria removal efficiency were from 90% to 99.9999%. It was found when samples were stored during 24 hours; regrowth of E.coli was not observed. This study showed that natural coagulant aids can reduce the turbidity to below 5NTU without filtration in optimum condition

relationship of polycyclic aromatic hydrocarbons and heavy metals

Heavy metals and PAH [Polycyclic Aromatic Hydrocarbons], in flu gas have received considerable attention in recent years due to their mutagenic or carcinogenic properties. PAHs are products of incomplete combustion of carbonaceous compounds at high temperatures. Heavy metals are released into the ambient air from the same sources as those earlier mentioned for PAHs. The present study is carried out to investigate the influence of the quantity of heavy metals on PAHs formation in ambient air. In this study, air particulates were collected on glass fiber filters using a high-volume air sampler. Each filter was exactly cut into equal pieces. One piece was digested with HNO[3] as well as H[2]O[2] and used for determination of heavy metals. Another piece was extracted with DCM using Soxhlet method. The latter was used for the determination of PAHs. The concentrations of heavy metals [Cr, Cd, Cu, Pb, and Zn] were measured by using Perkin-Elmer atomic absorption spectrometer. The concentration of PAHs was measured by a PU4400 gas chromatograph equipped with FID detector. The concentrations of PAHs and heavy metals were determined in different seasons. The results showed that the concentration of PAHs was minimum in the weekend and holidays, but maximum in winter. The relationship between ambient air concentrations of PAHs and heavy metals was investigated and an excellent agreement was found. The general trend of variation in concentration of heavy metals was found very similar to PAHs, therefore it could be concluded that the source of pollution was the same for both the pollutants. The general trend of variation in concentration of heavy metals was found very similar to PAHs, therefore it could be concluded that the source of pollution was the same for both the pollutants