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The accumulation of heavy metals in soil is a serious environmental problem. It is well known that heavy metals have an affinity for different compartments of soil. The risk associated with the presence of metals in soil is the ability of their transfer in water or plants. In the present research, batch extraction experiments were conducted using acetic acid (AA) as an extractant solution at various concentrations and contact times to determine the best conditions of soil washing process to achieve high heavy metal removal efficiencies. AA was investigated for its applicability for the removal of lead, cadmium and nickel from soil. Batch soil washing experiments were performed on 1.0 g portions of the spiked soil using different concentrations (0.001, 0.005, 0.01, 0.05, and 0.1 mol/L) of AA (CH3COOH) with solid: liquid ratio of 1:10. The results showed that AA extracted greater Pb than Cd and Ni. The extraction was carried out with shaking times from 15 to 180 min. The removal percentage of Pb varies from 42.2%-100% and Cd from 5.2%-31.1% with increasing concentration of AA, while the removal efficiency of Ni was not exceeded about 1%. Comparing with Pb and Cd, the removal efficiency of Ni was very low; this means that the solubility of Ni in AA was very low. It was found that 0.1 mol/L AA for soil washing was effective in removing absorbed Pb from contaminated soil (100% efficiency) at time 15 min. While the efficiency reaching 100% with washing solution of 0.05 and 0.01 mol/L at times 120 and 180 min, respectively. The efficiencies of Cd and Ni extraction were improved when 1 mol/L of AA solution was used (41.3% to 70.6% for Cd and 16.3% to 23.3% for Ni).

Owing to their toxicity, the existence of heavy metals in the environment has become a major global concern. In this study, the ability of albizia-lebbeck tree leaves (ALTL) as green and low cost adsorbent to remove Pb2+, Zn2+ and Cd2+ from Synthetic wastewater by adsorption was investigated. The initial metals’ concentrations of 10-80 mg/l, adsorbent dosage of 0.3-1.0 gm, pH of 3-8, contact time of 30-240 min, and shaking speed of 200 rpm, have been studied by batch adsorption technique. Four ranges of adsorbent particle size were tested: 75-150; 150-300; 300-600; 600-1000 μm. Five different temperatures (20, 30, 40, 50 and 60°C) were selected to demonstrate the influence of temperature on metals’ adsorption onto ALTL. Langmuir and Freundlich models were used to analyze the experimental data. Equilibrium data fitted well with the Freundlich isotherm model with maximum adsorption capacity of 9.124 mg/g at 20°C for metals’ concentration of 40 mg/L. Pseudo-first-order and pseudo-second-order equations were utilized for analysis of the kinetic data. The second-order model was fitting very well with the experimental data. Thermodynamic parameters like entropy, enthalpy and Gibbs free energy changes were estimated to determine the spontaneity of the sorption process. The results revealed that the ALTL adsorbent performed good removal of metals.

The CALPUFF atmospheric transport model was used to estimate ambient air concentrations of SO2, CO, NO2, and PM2.5, in a 256 km 2 region surrounding the Daura oil refinery in Baghdad, Iraq during a six-month period in the summer for 2013 and the winter of 2014. The CALPUFF modeling system includes a meteorological processor (CALMET), a Lagrangian puff atmospheric transport model (CALPUFF), and a post processor (CALPOST). Source term and meteorological data, including surface and upper air observations, were pre-processed and formatted for CALMET and CALPUFF using FORTRAN programs. Monthly emission rates and stack parameters for twelve stack sources were included in the model. Winds out of the northwest predominated, followed by winds out of the north and the west. The urban regions with the highest pollutant concentrations in the study domain were the Daura Express Highway located south and southeast of the facility, and the refinery employee residences located west of the facility. These areas were closest to the Daura oil refinery. Predicted pollutant concentrations showed that SO2 and CO were higher than NO2 and PM2.5, for the study period because emission rates of SO2 and CO were greater than NO2 and PM2.5. Monthly dispersion patterns were similar among the pollutants and exhibit plumes in the predominant wind direction. Winter generally had the highest predicted pollutant concentrations compared to the summer months.

The produced water considers as the largest waste stream in the oilfields and refineries, which has a high concentration of hydrocarbons, heavy metals besides other pollutants. As per the increase in the activity of industries, the generated produced water has increased all over the world and treating it for reusing becomes now important from the environmental point of view. Treatment of produced water can be achieved within different processes or methods including physical (filtration, adsorption, etc.), chemical (precipitation, oxidation), and biological (activated sludge, biological aerated filters and others) methods. The aim of this paper is to highlighting and discussing the characteristics of produced water in detail besides the physical, chemical, and biological techniques used for the treatment of the produced water.

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This research aims at presenting Moving Bed Biofilm Reactor (MBBR) technology as one of the alternatives and efficient methods for treating industrial wastewaters at a variety of conditions. In the last decade, this technology became more popular and widely utilized worldwide, due to the fact that the need for clean water keeps to rapidly increase with the increase in the population of the world grows year by year, which is why a high number of the waste-water treatment facilities are necessary expand, for the purpose of providing additional capacity with the minimal costs. The present study aimed at covering the most significant MBBR processes, like the fundamental process of the treatment, biofilm kinetics, and MBBR operation principles. This review includes as well a large number of the relevant researches that have been performed at the lab and pilot scales, in addition to cover the important procedures on the basic process of the treatment, which affects the influent types as well as the carrier type. None-the-less, this review concluded yet has been compiled herein and reported to be acquiring more sufficient insights and outlook upon the theme with a view to meet the new method. For that purpose, the most feasible technology may be the advanced biological process (i.e., the bio-reactor systems), which include the MBBR system