ABSTRACT
Over the last three decades environmental pollutions became a more noticeable problem in all around of the world. In many countries, noise pollution as a basic problem has a great importance.Development of the city, increasing of industrial centers, increasing vehicles, other annoying noise resources and also little information about the noise pollution of Tabriz city, has led to the doing of this research. Sampling and measuring of noise pressure levels was done 180 times According to the EPA standards, measuring was done simultaneously in two stations [commercial-residential areas], three times a day [morning 7:30 -9:30 am, midday 12:30-14:30 pm and night 19:00-21:00 pm] and 30 days in month. Sound pressure level in both stations was higher than the standards and the highest average level with 71.4 db was recorded in Raste-koche station at midday. Also lowest calculated average value with 68.5 db was measured in Golbad station at the morning time that is 8.5 db higher than the standards. Average measured sound pressure level in two stations was higher than the standards. The results show that Tabriz has a noise pollution in commercial and residential - commercial areas. It is suggested that other noise pollution resources identified and the proper management actions for its reduction be done
ABSTRACT
Particular importance of hazardous wastes is due to having characteristics such as toxicity, flammability, corrosively and reactivity. Some of the chemical wastes due to having hazardous materials must be collected and managed in a proper manner, since they are potentially harmful to the environment. Owing to the fact that educational centers have important roles in developing countries, so the main objective of the present study was to investigate, hazardous waste management in chemistry laboratories of Ministry of Science universities, in Tehran, Iran. Study area of this research includes all chemistry laboratories in Tehran universities which were covered by Ministry of Science. To obtain the number of samples, based on Scientific Principles and identification formula, 64 samples were calculated. In addition, sampling was done by Stratified sampling. Validated checklists were used for data gathering. Data analysis were done by Descriptive statistics [mean, frequency and etc.] and inferential statistics [kruskal-wallis test]. results obtained in this study indicate that Sharif University by obtaining the mean score of 60.5 and Tehran University by obtaining the mean score of 4.5-6 are placed in best and worst rank, respectively. Beheshty, Alzahra and Tarbiat Moallem univesities by acquiring the mean score of 20-28.5 have a same position in ranking table. Results show that most of the studied laboratories do not have any collection program and only 26.5 percent of them have acceptable programs.The separation and storing program observed in about 12.5 percent. Hazardous wastes* management in chemistry laboratory of Tehran Universities was not in good status. And from the standpoint of management, only 12.5 percent of studied cases are in good status, while 75 percent was in undesirable status
ABSTRACT
Considering concurrent use of styrene and acrylonitrile as raw materials in the production of synthetic resins and plastic and their associated differences in physiochemical properties and biodegradability, our experiments were conducted in a three-stage downflow bench-scale biofilter to study the potential suppressive effects of acrylonitrile on styrene removal. A Mixture of yard waste compost and shredded plastics and activated sludge was used as bed media. Gas phase concentration of styrene and acrylonitrile was determined via gas chromatographic analysis. Under steady-state conditions, maximum elimination capacity of styrene and acrylonitrile was 44 and 120 g/m[3] h, respectively. The effect of moisture was very significant in reducing the specific adsorptive capacity [microg/g of bed media] of styrene and acrylonitrile. The bed media with 60% moisture content lost styrene absorption capacities by more than one order of magnitude when compared to dry media. The existence of water increased the absorption capacity of medium for acrylonitrile about 95%. Styrene elimination capacity of the biofilter during co-treatment was less as compared to pure styrene biodegradation indicating the likelihood of inhibitory kinetics. Introduction of acrylonitrile into the air stream reduced elimination capacity of styrene to 103 g/m[3] h. The adverse impact on removal rate of acrylonitrile due to the presence of styrene in the gas stream was minimal. Carbonequivalent removal for the system amounted to about 85 g C/m[3] h at empty bed retention time of 120 s
Subject(s)
Volatilization , Styrene , Gases , Sewage , Chromatography, Gas , Biodegradation, Environmental , SoilABSTRACT
Shortage of available water resource and deficiency of rainfall, increasing in population growth and industrial development, suitable use of water resources and pollution prevention is an essential issue in accord with sustainable development and environmental protection. Present study shows the qualitative status of Mehran River and determines its pollution or non pollution to municipal wastewater and to assess qualitative characteristics of the water according to international water quality index. Padding strand of MEHRAN River from source to end has been done for wistful determination of branches, runoff and wastewater entrances, etc. Necessary decisions were made for determining sampling points and critical and effective points on water quality then water samples were analyzed to determine chemical and microbiological characteristics. Results showed the average of BOD5, COD, TSS, NO3, DO, pH, Turbidity and color are about 80 +/- 30, 155 +/- 58, 1013 +/- 637, 7.3 +/- 2, 4.5 +/- 3.5 mg/l, 7.2 +/- 1, 385 +/- 238 NTU, 122 +/- 70 TCU respectively. It could be concluded that the Mehran River is completely polluted with municipal sewage and is unsanitary. Water quality index varies in the range of 41-52 and the water is classified as number 4. At present the river is in a dangerous ore toxic state and could not be considered as drinking water resource or needs more advanced water treatment units