சிவில் மற்றும் சுற்றுச்சூழல் பொறியியல் இதழ்

According to the U.S. Environmental Protection Agency (EPA), in 2010 mobile sources in the U.S. contributed
58% of carbon monoxide (CO), 56% of nitrogen oxide (NOx), and 33% of Volatile Organic Compounds (VOCs). Onroad
sources also emit a variety of air toxics, including benzene, toluene, and xylenes. The case study presented here
determines a safe roadway buffer width to protect human health from nitrogen dioxide (NO2) exposure along an arterial
in Grand Prairie, Texas. NO2 health effects include eye, nose, throat, and lung irritation; cough; shortness of breath;
tiredness and nausea. In the Dallas Fort Worth region, where Grand Prairie is located, on-road vehicles contribute
about half of NOx emissions.
Vehicle NOx emission rates along Great Southwest Parkway were measured using a Horiba 1300 OBS onboard
emission measurement system, to determine a maximum g/mile emission factor for the corridor. Hourly DFW
meteorological data for a 5-year period was processed using CAL3QHCR to determine the 10 worst-case hourly
meteorological combinations. The maximum emission factor and worst-case meteorological conditions were input into
the line source dispersion model CALRoads View to determine worst-case NO2 concentrations at 5- m intervals away
from the roadway. CALRoads View output was post-processed in Arc View GIS to plot concentrations at receptor
locations.
Worst-case concentrations were compared to the 1-hour NO2 National Ambient Air Quality Standard (100 ppb). For
the current Great Southwest traffic volume, it was found that the standard would not be exceeded. Additional CALRoads
View runs were conducted to determine how much the traffic volume could increase, and still avoid exceedances
outside a 20-foot buffer width, which is a common setback distance in residential areas. It was determined that the
traffic volume could increase by a factor of 10 and still protect human health from NO2 impacts, using a 20-foot buffer.

Electrokinetic treatment uses low intensity direct electric current or a low electric potential difference, to improve the engineering properties of subsurface soils while having minimum disturbance to the surface. This study aims to investigate the effects of chemical-electrokinetic treatment on properties of two types of clay soils at different intervals under the coupled Chemical, Hydraulic and Electrical (CHE) gradient. “Chemical-electrokinetic treatment” refers to improvement of soil with electrokinetic together with addition of chemical enhancement solution. The enhancement solutions used in this study are hydrated lime and saline solution. The combined effects of these processes together with various electrochemical and geochemical reactions would change the chemical composition of the soil porous medium, hence modifies the properties of the soil. The experiments were conducted in the laboratory using stainless steel electrodes under total applied voltage of 30 V for period of 15 days. Two types of fine-grained soils, kaolinite and bentonite, were used as they possess different mineralogy and geotechnical properties. The cumulative electro-osmotic flow and electric current flow through the soil samples were measured for period of 15 treatment days. Subsequently the specimens were tested for moisture content, pH and Atterberg Limit variations and the results have been reported. Test results revealed that there is a potential of developing this technique to improve engineering properties of finegrained soils, in particular to stabilise and improve soft soils for infrastructure management and constructions.

The treatment of confectionary wastewaters by a biological aerobic treatment plant encountered strong failures when wastewaters concentration exceeded 30 g/l of chemical oxygen demand (COD), although the COD inlet flow remained under design specifications. Treatment performances stayed under 50%, and strong acid production and Hydrogen potential drop lead to heavy corrosion of equipments. During a laboratory scale study using the same organic load, with residence times ranging from 1 to 15 days, Hydrogen potential (pH) drop proved to be caused mainly by aerobic production of organic acids from sugars, leading thus to an auto-inhibiting process. The study demonstrated the influence of pH, acids and aeration rate upon key parameters as respiration rates and degradation kinetics. A reduction of 30 to 35 g/l of COD was obtained in laboratory scale reactors with pH and oxygen control. A comparison between the laboratory scale reactors and the full scale plant was made by measuring in the reactors the clean water oxygenation transfer rates and comparing its values to the data issuing from the plant. Compared to the data issuing from the full-scale wastewater treatment plant, the results of this study allowed giving recommendations for its upgrade.

In many cases, industry has main role in environmental crises especially in civil and energy projects. For example, more than 60 percent of annual greenhouse gas emissions are related to the industrial activities in the world (transportation fuels and distribution 25.3%, power stations 21.3%, industrial process 16.8%). Studding of air, water, and soil pollutions as separately may cause neglect from address to a comprehensive look in industrial pollution issue. In addition, without the exact information about quantity and quality of pollution sources, reduce or eliminate industrial pollutions are not possible. Environmental flow diagram (EFD) is made based on energy reference system (RES) and process flow diagram (PFD) for each industrial company or unit. In this paper, by coding in visual basic program environment, EFD designed for determining sources of pollutants, division sources of pollutants flows based on acceptor environment, and explaining impact of solutions to the energy optimization and reduce environmental pollutants. EFD is an user friendly software that can be used in all of the industrial companies and civil and energy projects for detailed knowledge of pollution level of the area to solution of environmental crises.

A vegetative filter strip (VFS) is designed to reduce transport of sediments and nutrients downstream mainly through settling, infiltration (into soil profile), adsorption (to soil and plant materials), and by plant uptake. However, the performance of a VFS greatly depends on a VFS design and climatic conditions of a region. In this paper, relative performance of three VFSs (hereafter Cass County-CC, Sargent County-SC, and Richland County-RC buffers) was evaluated and compared in the context of VFS design for feedlot runoff pollution control and management under agro-climatic condition of North Dakota. Buffer at CC feedlot was established with broadleaf or common cattail (Typha latifolia) grass filter, SC feedlot buffer had Garrison creeping foxtail (Alopecurus arundinaceus Poir.) and reed canary grass (Phalaris arundinaceus), and RC feedlot buffer had mixed grasses. Automatic samplers were installed to collect runoff samples at each inflow and outflow locations. Collected runoff samples were analyzed for total suspended solids (TSS), ortho-phosphorus (ortho-P), total phosphorus (TP), ammonium nitrogen (NH4-N), nitrate nitrogen (NO3-N), total Kjeldahl nitrogen (TKN), total nitrogen (TN), and potassium (K). Cass County (CC) VFS with cattails grass filter had the longest runoff-flow length (65 m) and resulted in better conducive environment for restricted TSS and TP transports reduction and better adsorption of ortho-P, NH4-N, and K compared to SC and RC feedlot buffers. Overall TSS, ortho-P, TP, NH4-N, and K removal efficacies were 88%, 90%, 89%, 91% , and 90%, respectively, at CC VFS. At SC feedlot VFS resulted in the highest NO3-N reduction. Relatively poor performance was observed for the RC feedlot which was due to smaller runoff-flow length (12 m). Overall, CC feedlot outperformed the SC and RC VFSs in respect of TSS, ortho-P, TP, NH4-N, TKN/TN transport reductions.