Research Journal of Chemistry and Environment

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Vol. 13(4) December 2009

Characteristics of Heavy Metals in Cement-treated and Cement/Sodium Silicate-treated Sewage Sludges

Lo Shang-Lien and Hsiau Ping-Chin

Characteristics of heavy metals in cement-treated and cement/sodium silicate-treated sewage sludges were studied by bench processes. The results indicate that sodium silicate addition promotes the drying of alkaline sludge due to the formation of silica/silicate gels that hold free water in sewage sludge. The CaCO3 equivalencies of cement-treated and cement/sodium silicate-treated sludges were 33.1% and 32.6% respectively. The CaCO3 peaks shown in XRD graphs for both alkaline sludges indicated the occurrence of carbonation, particularly for cement/sodium silicate-treated sludge. The micrograph of cement/sodium silicate-treated sludge shows the absence of needle-like ettringite, which commonly appears in Portland cement hydration. Heavy metals (e.g. Cu) with higher affinity organics in sewage sludge become unstable in the sludge after chemical treatment. This explains why the order of the percentages of exchangeable metals in chemically treated sludges was the same as that of organically bound metals in untreated sludge. Some metals (e.g. Zn), however, become more stable in the sludge after chemical fixation, resulting from a lower affinity for organics.

Utilisation of Flyash as Gainful Resource Material for Green Brick Making

Chaulia P.K., Ruj Biswajit and Maity S.N.

Coal based thermal power station during the process of burning of coal generates huge quantity of burnt solid residue ash and constitutes the biggest source of environmental degradation. The problem is likely to aggravate at a much faster rate in coming years as many more numbers of coal based thermal power stations are expected to be installed in the near future in India. It is estimated that the current annual production of flyash in the world is of the order 600 million tons and in India, it is approximately 112 million tons. It is fact that the huge quantity of flyash can be only utilized, if the application is wide spread. Also, the application of the ash should be such that it should compete on cost economics with the conventional material being used for similar applications. The present study of the flyash brick has been carried out for four cases with the variation of cement percentage and with other constituent materials like fine sand, course sand, stone dust and blast furnace slag. The brick and paver block samples have been prepared and tested for compressive strength and water absorption. The cost effectiveness of the flyash brick over the conventional burnt clay brick has been made and it is observed that there is almost a saving of 30%. A comparative study of flyasah brick has been made for dry density, crushing strength and water absorption value with that of burnt clay brick. It is observed from this study that flyash bricks exhibit higher strength, lighter weight and lower water absorption than that of common burnt clay brick.

Adsorption of Cr (VI) by Attapulgite-Zeolite Composite Ceramisite from Aqueous Solution

Wang Zheng, Jing Zhao-qian, Cheng Li-li, Shen Wei and Kong Yu

The adsorption of Cr (VI) from aqueous solution by batch experiments using attapulgite-zeolite composite ceramisite was investigated. After SEM characterization of this ceramisite, the influences of pH, contact time, temperature, ceramisite dosage and initial Cr (VI) concentration on the removal percentage were investigated. Results showed that adsorption process was highly pH dependent. The optimum pH range for adsorption of Cr (VI) was found to be<1. Adsorption equilibrium attained within 2 h time. The sorption of Cr (VI) increased with rise of temperature because adsorption process was endothermic. Increase in ceramisite dosage led to increase in Cr (VI) adsorption due to increased number of adsorption sites. The removal percentage of Cr (VI) from aqueous solution decreased with increasing concentration of Cr (VI). Both the Langmuir and the Freundlich isotherms were suitable for describing the sorption of Cr (VI) onto attapulgite-zeolite composite ceramisite with the correlation coefficients over 0.984.The attapulgite-zeolite composite ceramisite in this study shows very good promise for practical applicability of Cr (VI) removal from aqueous solution.

Oxidation of Oilfield Sludge in Supercritical Water

Guolin Jing, Shaopeng Qin, Baochen Cui, Ming Li, Lijie Xing and Shulin Li

Oilfield sludge was selected and its oxidation in supercritical water was investigated. The experimental results showed that carbon monoxide (CO) and acetic acid (CH3COOH) are the intermediate products and carbon dioxide (CO2) is the ultimate product. When the reaction temperature is 713K, pressure is 24MPa, the residence time is 10 min, then the crude oil removal of oilfield sludge could reach 95%. The residence time and reaction temperature are the main factors for crude oil removal of oilfield sludge. The removal increases with the rise of reaction temperature and residence time. Reaction pressure and original concentration of oxygen are also important, but when the reaction pressure and oxidant concentration reach a certain value, the crude oil removal changes little.

Heavy Metals Contamination and its potential Health Risk with special reference to Narmada River at Nimar Region of Madhya Pradesh

Ayachit Bhavana, Shrivastava Vibha, Tiwari Chitra Rekha and Jain Praveen

In the present work, water samples were collected monthly from October 2007 to August 2008 in triplicate, totaling 165 water samples. The five sampling locations were: the Omkareshwar Ghat (OG), Maheshwar Ghat (MG1); Mandleshwar Ghat (MG2); Navda Todi (NT), and Punasa Dam (PD). The levels of As, Be, Ca, Cd, Co, Cu, Cr, Fe, Li, Mg, Mn, Mo, Ni, Pb, Sb, Se, Sr, Ti, Ta, V and Zn were measured by using atomic absorption spectroscopy. In addition, temperature, pH, electrical conductivity and total and fecal coliformes were determined. The statistical analysis considered a factorial treatment design; where factor A was the location point and factor B was sampling date. In addition, a multivariate technique looking for principal components was performed. Overall, the results confirmed that this stretch of the Narmada river is contaminated with heavy metals and other contaminants that might affect human health as well as the health of the ecosystem.

Study on Quick Cultivation of Granular Sludge and Its Characteristicsin Acidogenic UASB

Xu Zhonghui, Li Dongwei, Wang Kehao and Xiao Zuju

The start-up of two-phase UASB reactor designed for experiment is investigated in this paper, so as to seek the rapid start-up method. Glucose and starch are used as the organic-carbon source of the synthetic wastewater in the experiment. Starting up at low organic loading, the influent COD is increased quickly and HRT is shortened by stages, so that acidogenic phase can work in acidic optimal condition as soon as quickly. After 36 days of operation, 69% of total bioparticles are more than 1.0 mm, and most of the granular diameter is between 2 mm to 3 mm in acidogenic reactor. So acidogenic phase achieves rapid start-up successfully.

La(III) Sorption Studies on Poly[dibenzo-18-crown-6] for the Sequential Separation of La(III), Th(IV) and U(VI) in L-arginine

Sabale Sandip R., Jadhav Deepali V. and Mohite Baburao S.

Poly[dibenzo-18-crown-6] is used as a stationary phase to study the sorption behavior of La(III) in L-arginine medium. The quantitative adsorption of La(III) was found at 1×10-4 to 1×10-6 M L-arginine. 1.0-8.0 M hydrochloric acid, 0.5-8.0 M hydrobromic acid and perchloric acid were found to be efficient eluents for La(III). The capacity of crown polymer for La(III) was found to be 1.37±0.01 mmol/g. The tolerance limit of various cations and anions for La(III) was determined. La(III) was quantitatively separated from other metal ions in binary as well as multicomponent mixtures. The study was extended to sequential separation of La(III), U(VI) and Th(IV). The good separation yields were obtained and have good reproducibility (±2%). The method incorporates the determination of La(III) in real sample. The method is simple, rapid and selective.

Statistical Sampling and Sludge Characterization at Tehran Oil Refinery

Heidarzadeh Nima, Gitipour Saeid and Abdoli Mohammad Ali

Oily sludge samples generated from Tehran oil refinery (Pond 1) were evaluated for their contami-nation levels and an adequate remediation technique was proposed for the wastes. A simple random sampling method was used to collect the samples. The samples were analyzed to measure TPHs, PAHs and heavy metals concentrations in the sludge. Statistical analysis showed that seven samples were adequate to assess the sludge characterization with respect to TPHs analyses. The mean concentration of TPHs in the samples was measured to be 265594 ppm. A composite sample prepared from a mix of the seven samples was used to determine the sludge’s additional characteristics. The composite sample analysis showed that there were not detectable amounts of PAHs in the sludge. In addition, mean concentrations of selected heavy metals including Ni, Pb, Cd and Zn were 2700, 850, 100 and 6100 ppm respectively. In order to assess the sludge contamination level, the results from the analysis were compared with soil cleanup levels. Due to a lack of national standards for soil cleanup levels in Iran, sludge pollutant concentrations were compared with standards set in developed countries to evaluate if the treatment of the sludge was required. According to the cleanup standards, the sludge was highly polluted with petroleum hydrocarbons. The results of the study indicated that incineration, biological treatment and solidification/stabilization (S/S) treatments would be the most appropriate methods for treatment of the sludges. In the case of S/S, due to high organic content of the sludge, it is recommended to use organophilic clays prior to treatment of the wastes.

A Geospatial Modelling – based Assessment of Water Quality in and around Kaliveli Watershed

Abbasi Tasneem, Chari K. B. and Abbasi S. A.

Ground water has been catering to the ever-increasing demands of domestic, industrial and irrigation sectors world-wide. Its role in providing water for drinking and irrigation in the regions such as the southern peninsular India has been particularly crucial due to the absence of perennial rivers in these regions. The quality of ground water in an area is essentially a function of initial composition of water, precipitation, land use and the natural geology of the area. Activities, natural and anthropogenic, affect the regional ground water quantity and quality to a great extent. In this context, we have conducted an assessment of the ground water quality of Kaliveli and its surroundings. Geospatial models have been constructed using GIS to identify areas with poor ground water quality. A total of 41 sampling stations, distributed around the lake, were monitored periodically for one year. The pH, EC and other several essential parameters were analyzed and the results have been discussed with respect to the drinking and irrigation water quality criteria of BIS.

Synthesis and Antitubercular Activity of Some Novel Schiff’s Bases of 2-Amino-5-Aryl-1, 3, 4-Oxadiazoles

Rajak Harish and Gupta Arun Kumar

Current scenario greatly demands some newer classes of drugs due to ever increasing problem of resistance in the treatment of tuberculosis, especially multidrug-resistant tuberculosis. With this aim twenty schiff bases of 2-amino-5-aryl-1,3,4-oxadiazoles have been synthesized for their antitubercular activity. The structures of the compounds were confirmed by elemental analysis, IR and 13C-NMR spectral data. The antitubercular1 properties of the compounds were investigated using Microplate Alamar Blue Assay (MABA) against Mycobacterium tuberculosis strain H37Rv at the single concentration, 6.25 mg/ml. On critical observation of structures of the synthesized oxadiazoles, it can be concluded that all the compounds showing appreciable activity have –NO2 group in one or both of the aromatic rings, which might be responsible for imparting considerable toxicity to the compounds, resulting in the antitubercular activity.

Metal Analysis of Pulp: ICP-AES, XRF and ISE Methods and their on-line Feasibility

Sillanpää Mika and Rämö Jaakko

This study summarizes the performance of three analytical methods. ICP-AES, XRF and ISE have been studied in pulp matrix with the aim of finding out their feasibility for on-line analysis.

Fluorescence Studies of Catacondensed Aromatic Hydrocarbons and Correlation of Spectra-Structural Features

Barghouthi Samira and Walwil Abdalla M.

The chemical and spectral relationships between the studied aromatic systems are observed based on the free-electron model that could be used to classify spectra of condensed aromatic hydrocarbons. Some suggested catacondensed compounds are naphthalene (two benzene rings), anthracene (three linear benzene rings), phenanthrene (three benzene rings (angled)), acridine (three linear benzene rings with nitrogen) and triphenylene (four benzene rings, one central and three peripheral). The most interesting aspect would be to compare fluorescence excitation spectra with fluorescence emission and to explain cases of mirror images spectra (such as anthracene) versus those that are not mirror images (such as phenanthrene).

Oil Spill Trajectory Simulation and Coastal Sensitivity Risk Mapping

Pradhan Biswajeet and Assilzadeh Hamid

This paper deals with detection of oil spill areas from Radarsat images for the Tanjung Piai coast of Strait of Malacca and subsequently model those spilled areas to generate coastal sensitivity index maps for the study area. Spill areas were classified based on their chemical composition and were extracted from satellite images supported with field surveys. Maps of the topography, land cover were constructed from the spatial data sets in GIS. Bathymetry map, shoreline sensitivity, socioeconomic, biological, wind and sea current data were extracted from various resources and modeled in GIS for oil spill trajectory simulation analysis. An oil spill simulation model was developed as a way to find the suitable solution for emergency response and management in case of any future spill occurs in the study area. Remote sensing, GIS and other geomatic systems can be employed to mitigate the age-old problems of information availability and timeliness, data management and synoptic inventory of natural resources when an oil spill caused by accident or human error. This paper describes application of remote sensing and GIS for detecting, mapping, evaluating and modeling of spills in sea environments in order to reduce responding time and qualify the decision making process in contingency planning.

Review Paper: Alternative Filter Media for Roughing Filters

.Nkwonta O.I. and Ochieng G.M.

Roughing filters can be considered as a major pre-treatment process for wastewater, since they efficiently separate fine solids particles over prolonged periods without addition of chemicals. Roughing filtration does not need constant operator attention, making them an appropriate technology for water treatment. This study summarizes and evaluates modifications to roughing filtration technology which may address these limitations without compromising the simplicity of the treatment process. Successful modifications include broken burnt bricks, charcoal, coconut fibre, limestone and plastic materials as filter media. In this modification, the filter material should have a large specific surface to enhance the sedimentation process taking place in the roughing filter and high porosity to allow the accumulation of the separated solids. The paper also reviews the various filter media that enable this technology to be applied more widely than would have been appropriate two decades ago

An Introduction to Thermodynamic Modeling, Thermal Analysis and Calorimetry

Mojumdar S. C., Prasad R., Sun L., Venart J. E. S., Eichhorn S. H., Iqbal M., Elkamel A., Madhurambal G., Meenakshisundaram S., Varshney K. G., Verenkar V. M. S., Jona E., Janotka I., Ray A. and Chowdhury B.

Thermodynamic modelling is a powerful tool for predicting and understanding the behaviour of various systems. There are many thermoanalytical techniques such as thermogravimetric analysis (TGA), high resolution thermogravimetric analysis (Hi-ResTM TGA), derivative thermogravimetry (DTG), differential thermal analysis (DTA), calorimetry, differential scanning calorimetry (DSC), modulated differential scanning calorimetry (MDSC), dynamic mechnical analysis (DMA), thermomechanical analysis (TMA), thermodilatometry (TD), dielectric thermal analysis (DEA), optical transmittance thermal analysis (OTTA), evolved gas analysis (EGA), m-thermal analysis (mTA), isothermal pressure transducer analysis (ITPTA), transient thermal analysis (TTA) and thermal conductivity (k). Simultaneous thermal analysis (STA) is ideal for investigating issues such as the glass transition of modified glasses, binder burnout, dehydration of ceramic materials or decomposition behaviour of inorganic building materials, also with gas analysis. Thermodynamic modeling and various thermoanalytical techniques and their applications from medicine to construction have been discussed in this paper.