Biological treatment of synthetic wastewater containing 2,4 dichlorophenol (DCP) in an activated sludge unit

Chlorophenol compounds present in many chemical industry wastewaters are resistant to biological degradation because of the toxic effects of such compounds on microorganisms. Synthetic wastewater containing different concentrations of 2,4 dichlorophenol (DCP) was subjected to biological treatment in an activated sludge unit. Effects of feed DCP concentration on COD, DCP, and toxicity removals and on sludge volume index were investigated at a constant sludge age of 10 days and hydraulic residence time (HRT) of 25 h. The Resazurin method based on dehydrogenase activity was used for assessment of toxicity for the feed and effluent wastewater. Percent COD, DCP, and toxicity removals decreased and the effluent COD, DCP, and toxicity levels increased with increasing feed DCP concentrations above 150 mgl(-1) because of inhibitory effects of DCP. Biomass concentration in the aeration tank decreased and the sludge volume index (SVI) increased with feed DCP concentrations above 150 mgl(-1) resulting in lower COD and DCP removal rates. The system should be operated at feed DCP concentrations of less than 150 mgl(-1) in order to obtain high COD, DCP, and toxicity removals.     

Unsustainable urban development for Zonguldak metropolitan area (NW Turkey)

Since Turkey is located on a region that is prone to the risks of natural disasters like earthquake, flooding, and avalanche; a majority of the residential areas are facing these risks at various levels. Before determination of these risks, taking action in order to decrease the vulnerability levels of the residential areas will help keep the damage at the minimum level in case of a disaster. Urban planning decisions which are made in accordance with vulnerability studies aiming to determine natural disaster risks will not only help prevent loss of life but also help decrease negative social and economic effects of disasters. The Zonguldak city has been chosen as a case study area since Zonguldak metropolitan area has endured almost all kinds of threats that a city can face. In this study disaster-producing factors in the area are primarily considered which can be named as topography, destruction of forest lands, geological and karstic structure, mining activities, and misuse of the land, and later risk assessment is conducted with geographic information system (GIS). It has been assessed that more than half of the buildings within the study area were constructed in areas not suitable for housing. It is concluded that there is a need for urgent urban development plan for the city.     

Changes in some soil properties at different incubation periods after tobacco waste application

In this study changes in organic carbon (OC), basal soil respiration (BSR), nitrate nitrogen (NO3-N), electrical conductivity (EC) and aggregate stability (AS) of a clay loam soil due to tobacco waste (TOW) application were monitored for 240 days. After incorporating 5% TOW into soil according to oven dry weight basis, soil samples were incubated at field capacity for 20, 40, 80, 140 and 240 days under a greenhouse condition. TOW application significantly increased all soil properties over the control treatment Soil OC and AS values had significant positive correlations each other and with the other soil properties. Soil OC, BSR and AS values significantly increased from 0.12%, 0.03 microg CO2-C g(-1) dry soil 24 hr and 20.7% in control treatment to 1.13%, 3.7 microg CO2-C g(-1) dry soil 24 hr and 54.4% in TOW treatment, respectively in 20 days. While the highest NO3-N (1780 ppm) was found in 40 days, the highest EC (3.35 dS m(-1)) was in 240 days after TOW application. Disaggregation occurred in all treatments after 20 days of incubation due to probably the more substrate demands of microorganisms in soil.     

Electrospun Composite Nanofibers Based on Poly (ε-Caprolactone) and Styrax Liquidus (Liquidambar orientalis Miller) as a Wound Dressing: Preparation,Characterization, Biological and Cytocompatibility Results

Journal of Polymers and the Environment - In this study, styrax liquidus (sweet gum balsam) extracted from Liquidambar orientalis Mill. incorporated PCL fibrous scaffolds were prepared using the...