International Journal of Environmental Science and Technology

Laboratory and pilot testing of electrocoagulation for removing scale-forming species from industrial process waters

M. C. Schulz; J. C. Baygents; *J. Farrell

This study investigated the performance of electrocoagulation using iron and aluminum electrodes for removing silica, calcium and magnesium from cooling tower blowdown and reverse osmosis reject waters. Experiments were conducted at both the bench and pilot scales to determine the levels of target species removal as a function of the coagulant dose. At the bench scale, aluminum removed the target compounds from both cooling tower blowdown and reverse osmosis reject more efficiently than iron. A 2 mM aluminum dose removed 80 % of the silica and 20 to 40 % of the calcium and magnesium. The same iron dose removed only 60 % of the silica and 10 to 20 % of the calcium and magnesium. When operated with iron electrodes, pilot unit performance was comparable to that of the bench unit, which suggests that such systems can be scaled-up on the basis of coagulant dose. However, when operated with aluminum electrodes the pilot unit underperformed the bench unit due to fouling of the electrode surfaces after a few hours of operation. This result was completely unexpected based on the short-term experiments performed using the bench unit.

Relationship between geomorphology and contamination with weathered hydrocarbons in an old river Levee/Marsh association

1*R. H. Adams, 2D. Olán-Castro, 1F. J. Guzmán-Osorio, 1I. J. Díaz-Ramírez

A site evaluation was made for a low-lying property in an old river levee/marsh association, used marginally for cattle raising, which was contaminated due to historical practices. Contamination was related to geomorphology: the lowest areas contained 79 % of the contaminated samples. Other contaminated samples were all rear access roads (probable intentional dumping). There were no samples in the higher, levee areas away from roads with hydrocarbon concentrations above 3,000 mg/kg. Medium and high impact levels, corresponding to average hydrocarbon concentrations of 13,400 mg/kg and 109,700 mg/kg, respectively, were found in 28 % and 27 % of the property area. The medium impact level was predicted to have a reduced pasture production potential of ~ 50 % while at the high impact level practically no pasture production was predicted. Toxicological risk to cattle is present in only 12 % of the sample points although almost all of these are in very marshy areas not apt for cattle raising. Because the hydrocarbons at this tropical site are very weathered, acute toxicity was not related to hydrocarbon concentration. Although slightly more than half of the property has hydrocarbon concentrations above the permissible limit, only about one-third of the contaminated area is apt for cattle raising. This study, based on hydrocarbon distribution related to site geomorphology, soil toxicity bioassay, risk assessment to cattle and evaluation of pasture production allowed to made a more accurate assessment and definition of future use of the site. These criteria could be used for diagnostic studies of sites with similar tropical conditions.

Removal of bisphenol A from aqueous solution by hydrophobic sorption of hemimicelles

1*R. Gong; 1J. Liang; 2J. Chen; 3F. Huang

In this work, the hydrophobic sorption of hemimicelles was proposed as an innovative method for removing bisphenol A from aqueous solution with esterified carboxyl cotton as sorbent and cetyl trimethyl ammonium bromide as cationic surfactant. In order to optimize the sorption process, the effect of sorbent dose, initial pH, surfactant dose, sorbate concentration, contact time and temperature was investigated in batch system. The maximum value of bisphenol A removal appeared in the pH range 4-10. The bisphenol A removal ratio came up to the maximum value beyond 12 time of surfactant/bisphenol A. The isothermal data of bisphenol A sorption conformed well to the Langmuir model and the maximum sorption capacity (Qm) of esterified carboxyl cotton for bisphenol A was 87.72 mg/g. The bisphenol A removal equilibrium was reached within about 4 h and the removal process could be described by the pseudo-second-order kinetic model. The thermodynamic study indicated that the bisphenol A sorption process was spontaneous and exothermic.

Chlorinated volatile organic compounds found near the water surface of heavily polluted rivers

*D. F. Juang; C. H. Lee; S. C. Hsueh

The objectives of this study were to identify the chlorinated volatile organic compounds near the water surface of two heavily polluted rivers in the south of Taiwan and compare their concentration distributions. Air samples were collected seasonally at the upstream, midstream and downstream water surfaces of each river and the chlorinated volatile organic compounds were analyzed qualitatively and quantitatively by gas chromatography and electron capture detector. Totally, twelve kinds of chlorinated volatile organic compounds were found at the water surfaces of both rivers and many of them were reported to be carcinogenic or probably carcinogenic to human. The results showed that each chlorinated volatile organic compound had its own distribution pattern and no good correlation of chlorinated volatile organic compounds between both rivers was obtained. The chlorinated volatile organic compounds identified at the river water surface of Fong Shan Stream showed much higher concentration than those of Chuen-Tsen River. Several chlorinated volatile organic compounds, including chlorodibromomethane, hexachlorobutadiene, 1,1,2,2-tetrachloroethene and 1,2-dibromo-3-chloropropane were found with much higher concentration (mean concentrations of 124.5 µg/m3, 334.5 µg/m3, 92.2 µg/m3, 268.4 µg/m3, respectively) at the water surface of Fong Shan Stream in some seasons (especially spring and summer, summer and winter, spring and winter, spring and summer, respectively) and they were reported to be possibly carcinogenic to human. Therefore, it may be concluded that the people living close to Fong Shan Stream possibly had higher health risks due to the release of VOCs from the heavily polluted river.

The influence of picocyanobacterial photosynthesis on calcite precipitation

1*I. B. M. Kosamu; 2M. Obst

This study assessed the role of picocyanobacterial photosynthesis in the induction of calcite precipitation. It aimed at establishing whether photosynthetic uptake of bicarbonate by Synechoccoccus cells leads to calcite nucleation. The precipitation of calcite was initiated by addition of previously washed cyanobacterial cells of Synechococcus strain PCC 7942 to solutions of calcium carbonate at different saturation levels with respect to calcite. Precipitation experiments were performed under controlled laboratory conditions in two set-ups: one in which photosynthesis was inhibited using a herbicide called Diuron and the other one in which photosynthesis was taking place. During the experiments, a pH meter monitored the pH and ion selective electrodes monitored concentrations of carbonate and calcium ions. The morphology of the precipitated crystals was analysed using Scanning Electron Microscopy. When the kinetics of calcium carbonate nucleation by the Synechococcus cells were compared for the two sets of experiments, there were very little differences. In fact, the induction times for precipitation reactions with photosynthesis were shorter due to the uptake of carbon dioxide. It is therefore ‘ concluded that photosynthesis does not directly influence the nucleation of calcite at the surface of Synechococcus cells with sufficient supply of carbon dioxide, i.e. cells took up carbon dioxide and not bicarbonate.The microscopic observations, however, provided some evidence that picocyanobacterial cell walls act as a template for calcite nucleation.

Anisotropy and bedding effects on the hydro geological regime in a confined aquifer to design an appropriate dewatering system

1*A. Aryafar; 2F. Doulati Ardejani

Prediction of groundwater inflow into mining excavations is very important in order to design an effective dewatering system to keep the mine workings dry and create prolonged cone of depression. The effects of anisotropy ratio and bedding on the hydraulic head and drawdown curves of a dewatering test carried out in a fully penetrating well in a confined aquifer have been investigated. An existing numerical finite element model has been used to perform the simulations. The results of the numerical model are compared to those from analytical Jacob and Lohman solution for estimating hydraulic heads and drawdown curves. It was found that the anisotropy ratio and bedding should not have a significant effect on drawdown and the quantity of inflow into a confined aquifer. It was further found that taking the simultaneous effects of anisotropy and bedding into account reduces the differences in the results of analytical and numerical methods. Comparison of the field data and model predictions showed that, the modelling results for a three layer anisotropic aquifer fit well to the field data than those results obtained for a single layer aquifer and the relative error decreased from 4.81 % to 2.98 %.

Effects of chromium on seed germination, root elongation and coleoptile growth in six pulses

*R. Jun; T. Ling; Z. Guanghua

The ecotoxicological effects of Cr2+ on germination and early seedling growth of six pulses were investigated. Seeds of these plants were exposed to seven different concentrations of Cr (0-3.2 mM). The results indicated that root elongation and coleoptile growth of six pulse plants were more sensitive than seed germination for measurement of the toxic of Cr2+ pollutions. Different species show different levels of tolerance to Cr2+ pollution. Lablab purpureus and Glycine max are the most sensitive to Cr2+, their germination percentage, root and coleoptile length were significantly lower than other tested species, by contrast, Lathyrus odoratus and Dumasia villosa are the most resist species, their germination and seedling growth almost were not influenced by Cr2+ pollution significantly comparing the control. There were significantly negatively correlations between seedling growth and increasing concentration of Cr2+ for Glycine max, Vigna radiate and Lablab purpureus. The significantly negative correlations between germination and increasing concentration of Cr2+ were shown for Glycine max, Vigna radiate and V. angularis.

A satellite based assessment of the impact of urban expansion around a lagoon

*M. Cetin

This paper examines the coastal regional trends in urbanization processes using remotely sensed images around the Kucukcekmece Lagoon as a case study, located in the western part of Istanbul, Turkey. Throughout the examination process, the coastline changes are determined for a long-term period. To achieve this goal, post-classification comparison method is applied to the CORONA and LANDSAT TM satellite images of 1963, 1987 and 2005. In order to identify the land use changes, common landscape structures in the region were distinguished as water, green and open land, urban and industrial areas. Due to the mix up of land-cover types between urban and industrial areas, the classified images are integrated with geographic information system data obtained from visual interpretation of the enhanced images and auxiliary data sets. The results of the change analyses in coastal region showed that important alterations are taking place in the area due to the unplanned urban and industrial expansions that has irreversibly changed the physical features of the Kucukcekmece Lagoon. According to image classification results, the urban land use area increased from 2 % of total area in 1963 to 38 % in 1987 and 46 % in 2005, most of which converted from agricultural and greenlands. At the same time, the ecological impact of the loss of specific land covers is highlighted based on the results of the land use changes and the previous scientific applications. Furthermore, some recommendations are given to planners, decision makers and politicians to maintain the sustainable coastal ecosystem management.

Risk assessment of workers exposed to noise pollution in a textile plant

1*M. Mohammadi Roozbahani, 2P. Nassiri, 3P. Jafari Shalkouhi

In order to assess the risks associated with worker's hearing loss, due to exposure to noise pollution, at the Boroujerd Textile Factory a cross sectional study was conducted. 60 workers from the Spinning and Weaving workshops and official staff were randomly selected as case and control groups and their hearing were tested by audiometry. The audiometric results revealed that amongst workers being exposed to the noise pollution in the Spinning and Weaving Workshops there is a distinct increase in the number of cases of hearing loss at high frequencies. There also appears to be a slight bias towards hearing loss in the left ear, in preference to the right in addition, those who have worked for longer than 16 years are subjected to hearing loss even at low frequencies conversely, the office workers (the control group) seem to suffer little or no hearing loss at low frequencies at all, but after approximately 10 years of service there may be some hearing loss, but only at higher frequencies, which could be attributed to presbycusis. Also, the t-test (statistical hypothesis test) results verified the significant difference among both groups at high frequencies. The questionnaire results indicated that workers feel symptoms such as headache, no sense centralization, excitement, nervousness, vertigo. Hence, controlling procedures seem to be essential to protect workers from noise disorders.

Preliminary investigation of chloramphenicol in fish, water and sediment from freshwater aquaculture pond

1X. W. Lu; 1*Z. Dang; 1C. Yang

Analytical methods of chloramphenicol in the aquaculture environment have been developed using high-performance liquid chromatography and liquid chromatography-tandem mass spectrometry. The contents of chloramphenicol were determined using high-performance liquid chromatography for sediment and liquid chromatography-tandem mass spectrometry for fish and water collected from a freshwater aquaculture pond in China. Chloramphenicol in the water and sediment were 112.3 ng/L and 0.1957 mg/kg, respectively. The chloramphenicol residues in 3 kinds of fish, including carp, chub and grass carp were different. Only the muscle and head of grass carp were under the minimum required performance limit (0.3 ìg/kg) and were safe to eat. The chloramphenicol in other tissues of grass carp, carp and chub exceeded the minimum required performance limit. The highest content of chloramphenicol was in the branchia of carp and the lowest was in the head of grass carp. The results showed the chloramphenicol in the aquaculture environment was serious, although the government of China had banned the use of chloramphenicol in aquaculture a few years ago.

Environmental impact assessment framework by integrating scientific analysis and subjective perception

C. C. Chen

Environmental impact assessment is widely recognized as an effective tool for supporting the sustainable development of the environment through policy, plan and program decision-making processes. Traditional approach of environmental impact assessment generally focuses on scientific analysis and neglects subjective utilities on the project development. This paper proposes a framework of environmental impact assessment process by integrating subjective perception and scientific analysis. This framework suggests that environmental impacts and their consequent effects are analyzed and calculated based on the inventory analysis, but the non-market loss arising from the construction of the sensitive facility is estimated by contingent valuation method and the relative importance of affecting groups in affecting the ongoing of project development is evaluated by analytical hierarchy process. Eventually, a mathematical model is presented to determine the optimal compensation amount under a targeted refusal rate. Also, a case example is presented to illustrate this approach that integrates the objectively scientific assessment for potentially environmental impacts and individual subjective perception on the non-market value of environmental damages arising from the project development.

Degradation of 2, 4, 6-trinitotoluene in aqueous solution by ozonation and multi-stage ozonation biological treatment

G. El Diwani; *Sh. El Rafie; S. Hawash

The objective of this study was to explore the extent of 2,4,6-trinitrotoluene synthetic solution and red water mineralization by comparing conventional direct ozonation and multi-stage ozonation-biological treatment process. The alkaline hydrolysis was used for remediation 2, 4, 6-trinitrotoluene and red water at pH = 10.9. Nevertheless, the hydroxyl radicals would be generated by ozone decomposition with ozone dose of 0.177 g/L. The samples were subjected to chemical oxygen demand and total organic carbon analysis to monitor pollutants removal. The rate of 2, 4, 6-trinitrotoluene and red water pollutants degradation were quantified using high performance liquid chromatography. 2, 4, 6-trinitrotoluene synthetic solution resulted 55.5 % chemical oxygen demand removal by 3 h direct ozonation. Following direct ozonation the biological treatment twenty four hours chemical oxygen demand reached 98.9 % and 98.7 % removal using humic acid and river water 1 % ( v/v) inoculation singly and respectively. Conventional direct ozonation showed non significant change in total organic carbon degradation. While on using multi-stage ozone-biological treatment process where humic acid and/or river water were used as inoculums singly and respectively, total organic carbon fulfilled 73 % and 98.3 % removal. The process was one hour direct ozonation and followed by three days multi-stage ozone-biological treatment. In multi-stage ozone-biological treatment process, ozonation was effective to decompose total organic carbon and to produce biodegradable dissolved organic carbon easily removed by ozone oxidation up to 98.3 % in 2,4,6-trinitrotoluene synthetic solution. Pollutants removal achieved 99 % in authentic red water effluent using river inoculation 1 % (v/v) in 5 days. Nuclear Magnetic Resonance and Fourier Transformation Infra Red methods were performed to confirm types of pollutants content in red water.

Evaluating the effectiveness of a hybrid sorbent resin in removing fluoride from water

1M. Rahmani Boldaji; 2*A. H. Mahvi; 1S. Dobaradaran; 1S. S. Hosseini

In some regions of the world, the concentration of fluoride in groundwater is high. To reduce the amount of fluoride to acceptable drinking water standard, it is highly recommended to treat the water. Fluoride adsorption in aqueous solution by a hybrid resin was studied in this research because of its functional groups likeness with goethite. Kinetic data showed that F adsorption was rapid in the beginning and maximum uptake occurred in within 10 min and equilibrium reached within 100 min. The experimental results showed that fluoride adsorption was influenced by pH of solution and optimum operating pH was in the range of 3 to 5.5. Langmuir model was applicable to the present study and F ions were exchanged with hydroxide ions in nano-scaled structure on the surface of sorbent. This adsorbent with 61 % efficiency is suitable for the regions where F concentration is less than 4 mg/L.

Linearized and non-linearized isotherm models comparative study on adsorption of aqueous phenol solution in soil

*B. Subramanyam; A. Das

Use of native soil in adsorption of phenol from industrial wastewater has been one of the attractive option for dephenolation, especially in view of low cost and ease in accessibility, as well as scope for regeneration (or, at least reuse). However, an effective usage of the adsorbent necessitates a deeper understanding of the adsorption characteristics. Most of the study of adsorption characteristics are confined to analysis of mono- and bi- parametric isotherm models (and rarely, linearized multi-parametric isotherm models), due to the difficulties in solving higher parametric models, as well as fairly satisfying results by lower-parametric models. In the present study, adsorption batch studies were carried out using a naturally and widely available common soil of south India (namely, Adhanur soil), for removal of phenol from the aqueous solution, with an explicit objective of comparison of linear and non-linear regression methods for finding variation in isotherm coefficients and fitness of the models. Six linearized isotherm models (including four linearized Langmuir models) and three non-linear isotherm model were discussed in this paper, and their coefficients were estimated. Although all the studied isotherm models showed fairly good fit to the experimental data, but Redlich-Peterson isotherm was found to be the best representative for phenol-sorption on the used soil adsorbent. Besides, it was observed that to determine the isotherm parameters non-linear isotherm models were found to be the best representative of adsorption characteristics, than their linearized counter-parts.

Heavy metal characterization of waste portable rechargeable batteries used in mobile phones

1*I. C. Nnorom; 2O. Osibanjo

Ten brands of spent portable rechargeable batteries used in mobile phones (lithium-ion and nickel metal hydride) were collected and disassembled and the battery electrode and printed wiring board prepared using the EPA Method 3050B. The metal concentrations were determined by atomic absorption spectrometry. The mean (± standard deviation) concentrations and range of cobalt, chromium, nickel and cadmium in the battery electrodes were 361284±32281mg/kg (range 20870-575330 mg/kg); 25.3 ± 4.6 mg/kg (7.9-149 mg/kg); 75272 ± 14630 mg/kg (3589-266607 mg/kg) and 2.8 ± 0.6 mg/kg (0.2- 16.3 mg/kg), respectively. Similarly, the mean values of cobalt, chromium, nickel and cadmium in the PWB were 564 ± 165 mg/kg (56.1-4068mg/kg); 28.1 ± 4.0 mg/kg (ND-97.2 mg/kg); 735 ± 188 mg/kg (22.7-2727 mg/kg) and 1.8 ± 0.3 mg/kg (ND-7.2 mg/kg), respectively. The Li-ion battery electrodes contained significantly higher levels of cobalt (p < 0.01) whereas, the NiMH battery contained significantly higher nickel (P < 0.01). All the results for the cobalt and nickel levels in the battery electrodes exceeded the toxicity threshold limit concentration used in the toxicity characterization of solid wastes (cobalt, 8000 mg/kg; nickel , 2000 mg/kg). In fact, the mean cobalt level of the battery electrode is about 45 times the toxicity threshold limit concentration limit for cobalt while the mean nickel result is about 38 times the toxicity threshold limit concentration. Spent portable rechargeable batteries should be handled as toxic materials that require special treatment. Implementation of a well-coordinated management strategy for spent batteries is urgently required to check the dissipation of large doses of toxic heavy metals and rare earth into the environment.

Spatial distribution and assemblage structure of macrobenthos in a tidal creek in relation to industrial activities

1*N. Mooraki; 2A. Esmaeli Sari; 3M. Soltani; 4T. Valinassab

The impact of petrochemical special economic zone activities on the health status of Jafari Creek was studied by assessing the changes in macroinvertebrate assemblages in nine sites during September 2006- January 2008. The relationship between spatial pattern of macroinvertebrate assemblages and ambient factors (i.e. water temperature, salinity, pH, dissolved oxygen, sediment grain size distribution, sediment organic content, heavy metals contents) was measured. Background enrichment indices, contamination factor and contamination degree, were used to assess the health status in the study area based on nickel, lead, cadmium and mercury contents of the sediments. The macrobenthic communities had a low diversity and were dominated by opportunistic taxa. The BIO-ENV analysis identified salinity, dissolved oxygen, pH and silt/clay content of sediments as the major environmental variables influencing the infaunal pattern. This suggests that management should attempt to ensure minimal disturbance to environmental variables underlying the spatial variation in macroinvertebrate assemblages. Background enrichment indices showed that the health of Jafari Creek has declined over time due to the constant discharge of heavy metals to the Creek system. These indices also identified a significant degree of pollution in the study area. The decrease in the ecological potential of Jafari Creek was best highlighted by the alteration in macrobenthic assemblages.

Determination of lead, naphthalene, phenanthrene, anthracene and pyrene in street dust

1*A. C. Durán; 2A. González

Street dust is a potential source of lead exposure to humans, however scarce information about the pollution levels with lead and polyromatic hydrocarbons exists in Venezuela, limiting the appropriate evaluation of the levels of risk of the people. This work was aimed in the determination of the concentrations of lead, naphtalene, anthracene, phenanthrene and pyrene in the street dust of the most transited avenues and streets of Maracay city. Thirty street dust samples were collected at the streets and avenues, troll and bus main station. Lead was determined by atomic absorption spectrometry after acid digestion (Pb-total), also the fractions of lead soluble in 1 M MgCl2 and 0.5 M ammonium acetate (pH = 7) were quantified. The polyaromatic hydrocarbons concentrations were determined by capillary gas chromatography equipped with a flame ionization detector. The Pb-total ranged between 734 and 11.439 ìg/g with the higher values at the most transited streets and avenues. About 60 % of samples exhibited concentrations between 1.000 and 2.500 ìg/g, similar to the values reported in the literature for soils of urban areas. The fraction of lead soluble in magnesium accounted for less than 3 % of Pb-Total, while the 0.5 M ammonium acetate solution represented more than the 75 % of the total loads of the pollutant. The most contaminated samples were those taken at the toll with concentrations of 695.5 and 252.1 ìg/g phenanthrene and anthracene were the most abundant, while at the bus station all compounds were detected.

Determination of cadmium and lead in human milk

1*E. Rahimi; 2M. Hashemi; 3Z. Torki Baghbadorani

The objectives of this study were to determine cadmium and lead concentrations in the breast milk of healthy lactating women who were living in Zarrinshahr, an industrial area of Iran and to investigate the effect of mother's age, parity and smoking habits in families living in the vicinity of areas contaminated with heavy metals. Cadmium and lead concentrations were determined by graphite furnace atomic absorption spectrometry in 44 milk samples from healthy lactating women collected on first to sixth postpartum week. Accuracy of the analysis was checked by various methods including the use of reference material. The mean ± standard deviation of cadmium and lead concentrations in human milk were 2.44 ± 1.47 ìg/L (range 0.62 - 6.32 ìg/L) and 10.39 ± 4.72 ìg/L (range 3.18-24.67 ìg/L), respectively. There was a positive correlation between the concentrations of lead in milk samples and mother's age and parity (P < 0.05). Also the concentration of cadmium in breast milk significantly increased (P < 0.05) in mothers who were actively and/or passively exposed to smoking. The results of this study showed that lead and cadmium concentrations in milk samples from lactating women in Zarrinshahr were high. This can be a major public health hazard for the inhabitants living in this industrial region of Iran.

Correlation between the chemical structure of biodiesel and its physical properties

*A. A. Refaat

Biodiesel is a renewable, biodegradable, environmentally benign, energy efficient, substitution fuel which can fulfill energy security needs without sacrificing engine's operational performance. Thus it provides a feasible solution to the twin crises of fossil fuel depletion and environmental degradation. The properties of the various individual fatty esters that comprise biodiesel determine the overall properties of the biodiesel fuel. In turn, the properties of the various fatty esters are determined by the structural features of the fatty acid and the alcohol moieties that comprise a fatty ester. Better understanding of the structure-physical property relationships in fatty acid esters is of particular importance when choosing vegetable oils that will give the desired biodiesel quality. By having accurate knowledge of the influence of the molecular structure on the properties determined, the composition of the oils and the alcohol used can both be selected to give the optimal performance. In this paper the relationship between the chemical structure and physical properties of vegetable oil esters is reviewed and engineering fatty acid profiles to optimize biodiesel fuel characteristics is highlighted.

Issues affecting British honey bee biodiversity and the need for conservation of this important ecological component

*A. G. S. Cuthbertson and M. A. Brown