Interaction of acrylonitrile vapors on a bench scale biofilter treating styrene-polluted waste gas streams

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

[Giving alternatives for improvement of qualitative features of Mehran river in Tabriz for reuse]

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