Determination of total Cr in wastewaters of Cr electroplating factories in the I.organize industry region (Kayseri, Turkey) by ICP-AES

The wastewater pollution in industrial areas is one of the most important environmental problems. Heavy metal pollution, especially chromium pollution in the wastewater sources from electroplating, dyeing, and tannery, has affected the life on earth. This pollution can affect on all ecosystems and human health directly or by food chain. Therefore, the determination of total chromium in this study is of great importance. In this study, accurate, rapid, sensitive, selective, simple, and low-cost technique for the direct determination of total Cr in wastewater samples collected from the some Cr electroplating factories in March 2008 by inductively coupled plasma-atomic emission spectrometry has been developed. The analysis of a given sample is completed in about 15 min by this technique applied. As the result of the chromium analysis, the limit of quantification for the total Cr were founded to be over the limit value (0.05 mg L^???1; WHO, EPA, TSE 266, and inland water quality classification) as 1,898.78 ± 0.34 mg/L at station 1 and 3,189.02 ± 0.56 mg/L at station 2. The found concentration of total Cr has been determined to be IV class quality water according to the inland water classification. In order to validate the applied method, recovery studies were performed.     

The hydrochemistry of groundwater in the Densu River Basin, Ghana

Hydrochemical analyses of groundwater samples were used to establish the hydrochemistry of groundwater in the Densu River Basin. The groundwater was weakly acidic, moderately mineralized, fresh to brackish with conductivity ranging from of 96.6 μS cm^???1 in the North to 10,070 μS cm^???1 in the South. Densu River basin have special economic significance, representing the countries greatest hydrostructure with freshwater. Chemical constituents are generally low in the North and high in the South. The order of relative abundance of major cations in the groundwater is Na^?+??> Ca^2?+??> Mg^2?+??> K^?+? while that of anions is Cl^????> HCO $_{3}^{-} >$ SO $_{4}^{2-} >$ NO $_{3}^{-}$ . Four main chemical water types were delineated in the Basin. These include Ca–Mg–HCO₃, Mg–Ca–Cl, Na–Cl, and mixed waters in which neither a particular cation nor anion dominates. Silicate weathering and ion exchange are probably the main processes through which major ions enter the groundwater system. Anthropogenic activities were found to have greatly impacted negatively on the quality of the groundwater.     

Pilot installation for the thermo-chemical characterisation of solid wastes

The increasing production and the large variety of wastes require operators of thermal treatment units to continuously adapt the installations or the functioning parameters to the different physical and chemical properties of the wastes. Usually, the treated waste is encountered in the form of heterogeneous mixtures. The classical tests such as thermogravimetry and calorimetric bomb operate component by component, separately. In addition to this, they can analyse only small quantities of waste at a time (a few grams). These common tests are necessary but insufficient in the global waste analysis in the view further thermal treatment. This paper presents an experimental installation, which was designed and built at the CNRS Science Division, Department of Industrial Methods, Compiègne University of Technology, France. It allows the determination of waste thermal and chemical properties by means of thermal treatment. Also, it is capable of continuously analysing significant quantities of waste (up to 50kg/h) as compared to the classical tests and it can work under various conditions: The installation reproduces the process conditions from incinerators or pyrolysis reactors. It also provides complete information on the kinetics of the waste thermal degradation and on the pollutant emissions. Using different mixtures of components present in the municipal solid waste and also in the reconstituted MSW samples, we defined a series of criteria for characterising waste behaviour during the stages of the main treatment process such as: feeding, devolatilisation/oxidation, advancement, solid residue evacuation, and pollutants emission.     

Review of state of the art methods for measuring water in landfills

In recent years several types of sensors and measurement techniques have been developed for measuring the moisture content, water saturation, or the volumetric water content of landfilled wastes. In this work, we review several of the most promising techniques. The basic principles behind each technique are discussed and field applications of the techniques are presented, including cost estimates. For several sensors, previously unpublished data are given. Neutron probes, electrical resistivity (impedance) sensors, time domain reflectometry (TDR) sensors, and the partitioning gas tracer technique (PGTT) were field tested with results compared to gravimetric measurements or estimates of the volumetric water content or moisture content. Neutron probes were not able to accurately measure the volumetric water content, but could track changes in moisture conditions. Electrical resistivity and TDR sensors tended to provide biased estimates, with instrument-determined moisture contents larger than independent estimates. While the PGTT resulted in relatively accurate measurements, electrical resistivity and TDR sensors provide more rapid results and are better suited for tracking infiltration fronts. Fiber optic sensors and electrical resistivity tomography hold promise for measuring water distributions in situ, particularly during infiltration events, but have not been tested with independent measurements to quantify their accuracy. Additional work is recommended to advance the development of some of these instruments and to acquire an improved understanding of liquid movement in landfills by application of the most promising techniques in the field.     

Use of inert C&D materials for seawall foundation: quality control measures

The technical viability of using inert construction and demolition (C&D) materials for the construction of seawall and breakwater foundations has been established by laboratory testing of the materials, numerical analysis of foundation stability, and a pilot field-scale engineering performance evaluation. However, quality control measures are still required so that only suitable materials are used for seawall and breakwater foundation construction. The development of different quality control measures for different site conditions is presented in this paper. The rationale, practicality, and implementation of these quality control measures are also discussed.     

Ignition and burning rates of segregated waste combustion in packed beds

Recent developments in national recycling and re-use programmes for municipal waste have led to segregation of an increasing proportion of waste to enhance material recovery. Several of the segregated streams contain materials that can not viably be re-used or recycled but can be used for energy recovery. In this study, the combustion of cardboard and waste wood was investigated in a small-scale packed bed reactor in order to provide fundamental data for the design/operation of moving bed furnaces. Key parameters of combustion including the ignition and burning rates were evaluated for various air flowrates and compared to the modelling results. Two successive stages of combustion were identified for both samples: the propagation of ignition front into the bed and combustion of the fuel above the ignition front. The burning rate of cardboard reached a peak of about 300 kg/m(2)h at the air flowrate of 936 kg/m(2)h and decreased at higher air flowrates. For waste wood, both the ignition and burning rates increased in the tested range of the air flowrate up to 702 kg/m(2)h, of which the values were very close to those for the cardboard. The model prediction was in good agreement with the test results for waste wood. However, the burning rate for cardboard was under-predicted due to strongly irregular shapes of the fuel.     

Waste polyvinylchloride derived pitch as a precursor to develop carbon fibers and activated carbon fibers

Polyvinylchloride (PVC) was successfully recycled through the solvent extraction from waste pipe with an extraction yield of ca. 86%. The extracted PVC was pyrolyzed by a two-stage process (260 and 410 degrees C) to obtain free-chlorine PVC based pitch through an effective removal of chlorine from PVC during the heat-treatment. As-prepared pitch (softening point: 220 degrees C) was spun, stabilized, carbonized into carbon fibers (CFs), and further activated into activated carbon fibers (ACFs) in a flow of CO2. As-prepared CFs show comparable mechanical properties to commercial CFs, whose maximum tensile strength and modulus are 862 MPa and 62 GPa, respectively. The resultant ACFs exhibit a high surface area of 1200 m2/g, narrow pore size distribution and a low oxygen content of 3%. The study provides an effective insight to recycle PVC from waste PVC and develop a carbon precursor for high performance carbon materials such as CFs and ACFs.     

Leachate recirculation effects on waste degradation: study on columns

The purpose of this study is to determine the impact of leachate recirculation on the degradation of municipal solid wastes (bioreactor concept). The study was carried out using columns containing approximately 50 kg of waste, in order to follow waste degradation over a limited time. Three types of waste were studied: fresh waste of standard composition, fresh waste of fermentable composition and some 8-yr-old waste extracted from a site in France. Measurement of the global parameters, such as chemical oxygen demand (COD), volatile acidity, alkalinity, leachate conductivity, methane potential of the wastes and biogas production monitoring (volume of CO2 and CH4 produced), were carried out. The quantity of oxydizable matter and biogas production was increased by the leachate recirculation, and the duration of the first degradation phases was reduced in all cases. Chloride, ammonium and organic pollution accumulation was observed according to the duration of recirculation. After 400 days of degradation, waste stabilization seemed to be reached for all of the recirculated columns (COD<300 mg/L O2, and methane potential reached).     

Assessment of pesticide contamination in three Mississippi Delta oxbow lakes using Hyalella azteca

Three oxbow lakes in northwestern Mississippi, USA, an area of intensive agriculture, were assessed for biological impairment from historic and current-use pesticide contamination using the amphipod, Hyalella azteca. Surface water and sediment samples from three sites in each lake were collected from Deep Hollow, Beasley, and Thighman Lakes from September 2000 to February 2001. Samples were analyzed for 17 historic and current-use pesticides and selected metabolites. Ten-day H. azteca survival and growth (as length and dry weight) were measured to determine the degree of biological impairment. Maximum number of detectable pesticides in surface water from Deep Hollow, Beasley and Thighman Lakes was 10, 11, and 17, respectively. Maximum number of detectable pesticides in lake sediments was 17, 17, and 15, respectively. Bioassay results indicated no observable survival effects on H. azteca exposed to surface water or sediment from any lake examined and no growth impairment in animals exposed to lake sediments. However, growth was significantly impaired in surface water exposures from Deep Hollow Lake (2 sites) and Beasley Lake (1 site). Statistically significant relationships between growth impairment (length) and cyanazine, methyl parathion, λ-cyhalothrin, chlorfenapyr, and pp′DDE surface water concentrations in Deep Hollow Lake as well as trifluralin, atrazine, and methyl parathion in Beasley Lake were observed. Although pesticide frequency and concentrations were typically greater in sediment than surface water, bioassay results indicated decreased availability of these pesticides in sediment due to the presence of clay and organic carbon. Growth impairment observed in surface water exposures was likely due to complex interaction of pesticide mixtures that were present.     

Catalytic activity of Ru/Al2O3 for ozonation of dimethyl phthalate in aqueous solution

With dimethyl phthalate as the model pollutant and Ru/Al(2)O(3) as catalyst, this paper systemically investigates the removal of total organic carbon (TOC) of system. Our results have confirmed that Ru/Al(2)O(3) can significantly increase the effect of ozonation. TOC removal in 120 min can reach 72% while only 24% with ozone alone. The optimal catalyst preparing condition was 0.1 wt% Ru content, 600 degrees C calcination temperature, 0.5-1.0mm particle diameter, which is characterized by a high surface area and a large population of surface active sites. The contrasting experiments of ozone alone, catalyst adsorption after ozonation, and catalytic ozonation confirmed that catalytic reaction was the most important process to TOC removal in system with Ru/Al(2)O(3) as catalyst.