Electrocoagulation process for the treatment of metal-plating wastewater: Kinetic modeling and energy consumption

The wastewater from industrial area was treated by EC via Fe and Al electrodes. Cu, Ni, Cr and Zn were highly removed at the first minutes, simultaneously. Pseudo-2nd-order was found to be more suitable for kinetics. Adsorption capacities based on kinetic modeling were observed as Cr>Cu>Ni>Zn. The chemical cost in the case of pH adjustment after EC was less as 3.83 $/m³. It is known that wastewater produced by the metal-plating industry contains several heavy metals, which are acidic in nature and therefore toxic for the environment and for living creatures. In particular, heavy metals enter the food chain and accumulate in vital organs and cause serious illness. The precipitation of these metals is mostly achieved by pH adjustment, but as an alternative to this method, the electrocoagulation process has investigated in this study using iron and aluminum electrodes. The effects of the pH adjustment on removal before and after the electrocoagulation process were investigated, and cost analyses were also compared. It was observed that a high proportion of removal was obtained during the first minutes of the electrocoagulation process; thus, the current density did not have a great effect. In addition, the pH adjustment after the electrocoagulation process using iron electrodes, which are 10% more effective than aluminum electrodes, was found to be much more efficient than before the electrocoagulation process. In the process where kinetic modeling was applied, it was observed that the heavy metal removal mechanism was not solely due to the collapse of heavy metals at high pH values, and with this modeling, it was seen that this mechanism involved adsorption by iron and aluminum hydroxides formed during the electrocoagulation process. When comparing the ability of heavy metals to be adsorbed, the sequence was observed to be Cr>Cu>Ni>Zn, respectively.     

Determination of heavy metals in fresh water fish species of the River Ravi, Pakistan compared to farmed fish varieties

The untreated industrial and sewage wastes arising from industries and metropolitan activities make their passage to the River Ravi, Pakistan, where Balloki Headworks is one of the major sites of effluent concentration. This study was designed to evaluate the concentration of various toxic elements in fishes of that area compared to a nearby fish farm. The concentrations of heavy metals, such as As, Cd, Cu, Pb, Hg, and Zn, and electrolytes Ca, K, and Na were determined in different edible and non-edible fresh water fish varieties. Fish samples were collected from two selected sites and were analyzed for aforementioned elements. Higher levels of As (35.74–45.33 ppm), Cd (0.35–0.45 ppm), Pb (2.1–3.0 ppm), Hg (83.03–92.35 ppm) while normal levels of Zn (37.85–40.74 ppm) and Cu (1.39–2.93 ppm) were observed. Mercury, higher levels of which trigger cough, impairment of pulmonary function, and psychotic reactions, was significantly higher in all studied categories. At the sites under study, there has been observed alarming levels of toxic metals which are needed to be monitored regularly.     

Impacts of land use conversion on soil properties and soil erodibility

Land use conversion can affect natural ecological processes such as surface runoff and erosion. Therefore, it has potential to change soil stability To investigate this process in depth, Iskalan creek catchment in the Black sea region, where excessive land use applications and erosion events have often occured, was selected as the study area. The objective was to determine the effects of land use conversion on soil properties, soil erodibility and the relationships among soil properties and some erodibility indices. Duplicate topsoil samples were taken by using steel cylinders at 100 different sampling points from three different land use types; 34 of them are in farmlands, 34 in rangelands and 32 in forestlands. Soil particle size distribution, loss of ignition, pH, electrical conductivity skeleton percentage and three erodibility indices were determined. Data were analysed by using Pearson correlation analysis (at 95% and 99% significance level), ANOVA and Tukey's test at 95 % significance level. According to study results, land use conversion affects some properties of soils significantly Loss of ignition of soils in forests was significantly higher than soils in farmlands and rangelands. Soil skeleton percentage in rangelands and farmlands were significantly different. The study results showed that there was significant difference between pH of soils in forests and farmlands (p < 0.05). Pearson correlation analysis results showed significant correlations among erodibility indices and certain soil properties such as clay and sand fraction of soils (p < 0.05 and p < 0.01). Topsoils of the study area were sensitive to erosion according to all three erodibility indices. The most sensitive soils were in farmlands.     

Radiochemical characterization of mineral waters in the Eastern Black Sea Region, Turkey

This study has evaluated the levels of natural radionuclides and chemical components of mineral waters in the Eastern Black Sea Region (Turkey). The mean activity concentrations of (226)Ra, (232)Th, (137)Cs, (40)K, gross alpha and gross beta were found as 129, 33, 28, 714, 125 and 170 mBq L(-1), respectively. Due to consumption of mineral waters, the radiological impact of them on the inhabitants was calculated by taking the annual intake into account through ingestion of aforementioned radionuclides. The estimated effective doses from mineral water were found to be 13.20 μSv year(-1) ((226)Ra), 2.74 μSv year(-1) ((232)Th), 0.13 μSv year(-1) ((137)Cs) and 1.62 μSv year(-1) ((40)K). The overall contribution of these radionuclides to the committed effective dose from a year's consumption of mineral water in the region is therefore estimated to be only 17.69%, which is in concordance with the recommended WHO value (100 μSv year(-1)). The chemical analysis results showed that these waters contain Na, Al, P, Cl, K, Ca, V, Mn, Fe, Ni, Cu and Zn elements. These values were evaluated and compared with the internationally verified values. This study provides important information for consumers and authorities because of their internal radiochemical exposure risk from mineral water intake.     

Decolorization of Blue CL-BR dye by AOPs using bleach wastewater as source of H2O2

This research was focused on the investigation of the efficacy of advanced oxidation processes (Fenton,ozonation and UV/H_2O_2) for decolorization of reactive azo dye (Blue CL-BR) using bleach wastewater as possible source of H_2O_2.All the experiments were performed on the laboratory scale set-up.The results showed that colour removal efficiencies by UV or bleach (H_2O_2) alone were not so efficient.Fenton process with bleach wastewater was found to be the most effective at process conditions such as pH of 3 and H_2O_2/Fe~(2 ) ratio of 24:1,resulting in 64% colour removal.Almost complete colour removal,i.e.,99% and 95% were achieved by UV/H_2O_2 and UVfoleach wastewater in 30 and 60 min,respectively.Ozonation proved an efficient method for decolorization of Blue CL-BR dye at alkaline pH.It was possible to achieve 98% colour removal with 30 min of ozonation at pH 9.The colour removal of dye was found to follow first order kinetics.     

Assessing spatio-temporal trend of vector breeding and dengue fever incidence in association with meteorological conditions

Th aim of this study is to investigate spatio-temporal trends of dengue vector breeding and epidemic (disease incidence) influenced by climatic factors. The spatio-temporal (low-, medium-, and high-intensity periods) evaluation of entomological and epidemiological investigations along with climatic factors like rainfall (RF), temperature (T_max), relative humidity (RH), and larval indexing was conducted to develop correlations in the area of Lahore, Pakistan. The vector abundance and disease transmission trend was geo-tagged for spatial insight. The sufficient rainfall events and optimum temperature and relative humidity supported dengue vector breeding with high larval indices for water-related containers (27–37%). Among temporal analysis, the high-intensity period exponentially projected disease incidence followed by post-rainfall impacts. The high larval incidence that was observed in early high-intensity periods effected the dengue incidence. The disease incidence had a strong association with RF (r = 0.940, α = 0.01). The vector larva occurrence (r = 0.017, α = 0.05) influenced the disease incidence. Similarly, RH (r = 0.674, α = 0.05) and average T_max (r = 0.307, α = 0.05) also induced impact on the disease incidence. In this study, the vulnerability to dengue fever highly correlates with meteorological factors during high-intensity period. It provides area-specific understanding of vector behavior, key containers, and seasonal patterns of dengue vector breeding and disease transmission which is essential for preparing an effective prevention plan against the vector.     

Recent Years Status of Sediment Bed of Golden Horn (Istanbul) After Year 1999

Golden Horn is an estuary in Istanbul. It has connection with Marmara Sea directly and with Black Sea via Bosphorus, and was polluted by different kinds of industrial plants up to 1999. In addition to this, municipal wastewater of around one million people has been discharged to here. Greater part of the estuary was almost blocked off by sediment islands. Extensive effort was spent to dredge sediment in 1999. This created quite a convenient condition for aquatic medium in the estuary.In this research, the variations of chemical compositions of sediment bed were investigated to get clue about ecological conditions of the estuary. For that purpose, sediment samples were taken from 6 stations along the estuary in 2001, 2003 and 2004. The sediment samples were analyzed for inorganic and organic constituents. Meanwhile, water samples (from the surface and just above benthic mass) were also taken from the same 6 places and they were analyzed to verify the data from sediment samples. By this way, correlations between sediment mass and water body were determined.     

Bird's‐eye view of the environmental attitude types in the sustainable consumption context

Environmental attitudes are considered to be important factors that influence sustainable consumption. Typically, attitudes fall into two main types: a general environmental attitude (GEA) and a specific environmental attitude (SEA). This study found that the effect of the SEA is stronger than the GEA in regard to sustainable consumption behavior. Also, when analyzing the purchasing behavior of green products, the SEA is a more appropriate and consistent predictor of behavior than the GEA. The study suggests a more operationalized and salient definition of the intended meaning of the term “environmental attitude,” and also advises researchers and marketing professionals to use a framework that contains both types of environmental attitudes in order to better understand what drives the attitude–behavior gap in green consumer behavior.     

Chemical transformation and flux of different forms of arsenic in the carb Carcinusmaenas

The amount of ingested arsenic assimilated and eliminated by the crab appeared to depend on chemical form of arsenic present in the food. Arsenic-74 was translocated rapidly with a high percentage located in hepatopancreas and exoskeleton. The speciation of radioarsenic determined by sequential extraction of experimental food, feces, muscle and hepatopancreas showed that there is no efficient mechanism within the crab which can covert lipid and water soluble arsenic to arsenite and residual arsenic or vice-versa. The biological mechanism in crab selectively and effectively excretes soluble form of arsenite and residual arsenic much more readily than organic arsenic.     

Treatability of water-based paint wastewater with Fenton process in different reactor types

Water-based paint wastewater which is formed during the coating step of metal surfaces performed with various spray processes include binders, pigments and additives. Binders and other additives may also affect the toxicity of the paint depending on the specific characteristics of the paint. This study deals with Water-based paint wastewater, which is hard to treat. Fenton oxidation process was principally used to treat the wastewater. Treatability runs were carried out by using rust (oxidized iron) particles obtained as a waste of the metal rolling process, as the Fenton's catalyst. In order to change the variables such as dimensions of the column, packing material size, reactive dosage, pH value and reaction time, the experiments on the basis of packed columns and mixed reactors were carried out to increase the COD removal. COD eliminations with pH adjustment were about 20%. With the contribution of Fenton process in both column and mixed-reactor studies, the COD removal was improved by about 80%.