Showing papers in "American Journal of Environmental Sciences in 2008"

Application of Moving Bed Biofilm Process for Biological Organics and Nutrients Removal from Municipal Wastewater

Abstract: In this study, experiments have been conducted to evaluate the organics and nutrients removal from synthetic wastewater by a laboratory scale moving bed biofilm process. For nutrients removal, moving bed biofilm process has been applied in series with anaerobic, anoxic and aerobic units in four separate reactors. Moving bed biofilm reactors were operated continuously at different loading rates of nitrogen and Phosphorus. During optimum conditions, close to complete nitrification with average ammonium removal efficiency of 99.72% occurred in the aerobic reactor. In the aerobic reactor, the average specific nitrification rate was 1.8 g NOx-N kg VSS −1 h −1 . The results of the average effluent soluble COD concentration from each reactor showed that denitrification process in the second anoxic reactor consumed most of the biodegradable organic matter. As seen from the results, denitrification rate has increased with increasing NOx-N loading in the second anoxic reactor. The aerobic phosphate removal rate showed a good correlation to the anaerobic phosphate release rate. Moreover, phosphate removal rate showed a strong correlation to the phosphate loading rate in the aerobic reactor. In optimum conditions, the average SCOD, total nitrogen and phosphorus removal efficiencies were 96.9, 84.6 and 95.8%, respectively. This study showed that the moving bed biofilm process could be used as an ideal and efficient option for the total nutrient removal from municipal wastewater.

Organochlorine Pesticide Residues in Fish Samples from Lagos Lagoon, Nigeria

Abstract: The organochlorine pesticide (OCPs) residues were measured in three species of fish Tilapia zilli (Red belly Tilapia), Ethmalosa fimbriata (Bonga Shad) and Chrysichthys nigrodigitatus (Catfish). These fish species are a significant part of the diet of residents of Lagos Nigeria. The organochlorine pesticides analyzed include DDT(pp'1,1,1-trichloro-2,2-bis-(4-chlorophenyl) ethane), DDD, DDE (pp 1,1-dichloro-2, 2-bis-(4-chlorophenyl) ethylene, HCH (gamma 1,2,3,4,5,6-hexachlorocylohexane, HCB (hexachlorobenzene),Dieldrin (1,2,3,4,10,10-hexachloro-6,7-epoxy-1,4,4a,5,6,7,8,8a octahydro-1,4,5,8 dimethanonaphthalene) and transnonachlor. The analysis was done using Gas Chromatograph with Electron Capture Detector. The mean concentration of OCPs ranged from 0.01-8.92 ppm. The concentration of the OCPs (except for HCHs) in fish samples in this study were below the extraneous residue limit of 5 ppm, set by the codex alimentarious commission of FAO-WHO-1997. However, the concentrations were higher than those detected during previous studies of fish samples from Lake Victoria, Uganda in Africa. Also the levels were quite high when compared with the allowable Federal Environmental Protection Agency (FEPA), now Federal Ministry of Environment limit and can be harmful if the trend is not checked. The study also showed that concentration of OCPs were higher in adult, than in Juvenile of most of the fish and there was no correlation observed between fat content and total concentration of OCPs.

Chemical Contaminants and Toxicity of Ganga River Sediment from Up and Down Stream Area at Kanpur

Abstract: The objective of this study was the sediment quality assessment of Ganga River at Kanpur city where effluents from tannery industries are discharged. Sediment samples from upstream and downstream area were collected and analyzed for trace metals and toxicity bioassay. Among various trace metals examined Cr in downstream sediment was 30-fold higher than in upstream sediment and its concentration was above the probable effect level. In general trace metals in the downstream sediment were found higher compared to reported earlier. Seed germination bioassay revealed negligible effect on the growth of root but the shoot growth was stunted in seeds exposed to downstream sediments. Trace metals determined in sediment elutriate showed poor elution of metals in aqueous phase but elutriates exerted toxic effects on both root and shoot growth, suggesting presence of other bioavailable toxic factor associated with sediment. The study revealed that seed germination bioassay may be used to differentiate contaminated and uncontaminated sediment.

Environmental performance of the milling process of Malaysian palm oil using the life cycle assessment approach.

Abstract: Malaysia is currently the world leader in the production and export of palm oil. This study has a gate to gate system boundary. The inventory data collection starts at the oil palm fresh fruit bunch hoppers when the fresh fruit bunch is received at the mill up till the production of the crude palm oil in the storage tanks at the mill. The plantation phase and land use for the production of oil palm fresh fruit bunch is not included in this system boundary. This gate to gate case study of 12 mills identifies the potential impacts associated with the production of palm oil using the life cycle assessment approach and evaluates opportunities to overcome the potential impacts. Most of the impact categories show savings rather than impact. Within the system boundary there are only two main parameters that are causing the potential impacts to the environment; they are the Palm Oil Mill Effluent (POME) followed by the boiler ash. The impact categories that the POME contributes to are under the Respiratory Organics and Climate Change. Both these impact categories are related to air emissions. The main air emission from the POME ponds during the anaerobic digestion is the biogas which consists of methane, carbon dioxide and traces of hydrogen sulfide. An alternate scenario was conducted to see how the impact will be if the biogas was harvested and used as energy and the results shows that when the biogas is harvested, the impact from the POME is removed. The other significant impact is the boiler ash. This is the ash that is produced when the biomass is burnt in the boiler. This potential impact contributes to the ecotoxicity impact category. This is mainly because of the disposal of this ash which in most cases was used for land application in the roads leading to the mil or in the plantations. If the parameters causing these two potential impacts are curbed, then this will be a further plus point for the Malaysian oil palm industry which is already avoiding fossil fuel based energy and chemical use for processing.

Geochemical Distribution of Trace Metals and Assessment of Anthropogenic Pollution in Sediments of Old Nakagawa River, Tokyo, Japan

Abstract: The geochemical distributions of cadmium (Cd), copper (Cu), chromium (Cr), lead (Pb) and zinc (Zn) were examined in sediments collected from Old Nakagawa River (NR), Tokyo, Japan. A widely used 5-step sequential extraction procedure was employed for the fractionation of the metals and the concentrations were measured in the liquid extracts by inductively coupled plasma mass spectrometry (ICP-MS). The association of Cd (76-98%) and Zn (48-67%) were found highest with AEC (adsorbed/exchangeable/carbonate) phase, Cu (45-60%) and Pb (44-73%) with amorphous Fe oxyhydroxide phase and the maximum fractionation of Cr was in both crystalline Fe oxide (12-60%) and amorphous Fe oxyhydroxide phase (15-60%). For retention by amorphous Fe oxyhydroxide minerals, the observed stoichiometric gradient was: 1.52 for Cu, 1.23 for Pb, 2.25 for Cr and 3.09 for Zn. Corresponding values for association with crystalline oxides and sulphides and organics were an order of magnitude greater than those for amorphous oxyhydroxide, indicating a greater affinity of trace metals for these phases. The total concentration ranges of Cd, Cr, Cu, Pb and Zn in NR sediments were 2.86-16.95, 551.7-3953.1, 340.6-1565.3, 136.9-385.9 and 931.4-3650.1 µg g-1, respectively. The observed order of potential trace metal mobility in the aquatic system was: Cd>Zn>Pb>Cu>Cr. Organic carbon contents in sediment samples were comparatively high (mean 5.48%) and the X-ray diffraction (XRD) study detected the presence of several clay minerals, those are likely to be major host of trace metals in sediments. The sediments of NR was considered to be polluted on the basis of unpolluted sediments and geochemical background values with respect to Cd, Cr, Cu, Pb and Zn. According to the enrichment factors (EFc), most of the sites have several times higher values of trace metals than the standard. The study revealed that the pollution in sediments of NR could be linked to anthropogenic activities such as industrialization, urbanization, deposition of industrial wastes and others.

Sulfur Recovery from Acid Gas Using the Claus Process and High Temperature Air Combustion (HiTAC) Technology

Abstract: Sulfur-bearing compounds are very detrimental to the environment and to industrial process equipment. They are often obtained or formed as a by-product of separation and thermal processing of fuels containing sulfur, such as coal, crude oil and natural gas. The two sulfur compounds, which need special attention, are: hydrogen sulfide (H2S) and sulfur dioxide (SO2). H2S is a highly corrosive gas with a foul smell. SO2 is a toxic gas responsible for acid rain formation and equipment corrosion. Various methods of reducing pollutants containing sulfur are described in this paper, with a focus on the modified Claus process, enhanced by the use of High Temperature Air Combustion (HiTAC) technology in the Claus furnace. The Claus process has been known and used in the industry for over 100 years. It involves thermal oxidation of hydrogen sulfide and its reaction with sulfur dioxide to form sulfur and water vapor. This process is equilibrium-limited and usually achieves efficiencies in the range of 94-97%, which have been regarded as acceptable in the past years. Nowadays strict air pollution regulations regarding hydrogen sulfide and sulfur dioxide emissions call for nearly 100% efficiency, which can only be achieved with process modifications. High temperature air combustion technology or otherwise called flameless (or colorless) combustion is proposed here for application in Claus furnaces, especially those employing lean acid gas streams, which cannot be burned without the use of auxiliary fuel or oxygen enrichment under standard conditions. With the use of HiTAC it has been shown, however, that fuel-lean, Low Calorific Value (LCV) fuels can be burned with very uniform thermal fields without the need for fuel enrichment or oxygen addition. The uniform temperature distribution favors clean and efficient burning with an additional advantage of significant reduction of NOx, CO and hydrocarbon emission.

Influence of Ionizing Radiation on Antioxidant Enzymes in Three Species of Trigonella

Abstract: The response of three species of Trigonella, namely, Trigonella stellata, Trigonella hamosa and Trigonella anguina to gamma irradiation stress was investigated with respect to antioxidant enzyme induction. When dry seeds were subjected to gamma rays (0, 40, 60, 80, 100 Krad) from a cobalt source 60Co at a dose rate of 233.5 rad/ min, a dose dependent increase in the activities of ascorbate peroxidase (APOX), superoxide dismutase (SOD) and glutathione reductase (GR) was observed in both shoots and roots of the studied species. On the contrary, catalase activity was repressed, particularly at the higher applied doses. Shoots were more significantly affected by irradiation than roots. The three species differed in their radio-sensitivity with respect to the characters concerned. Changes in the activity of the key antioxidant enzymes which confer tolerance to irradiation stress were discussed.

Performance Evaluation of a Waste Stabilization Pond in a Rural Area in Egypt

Abstract: The performance evaluation of the waste stabilization pond (WSP) as a model of domestic wastewater treatment unit in rural area was carried out. The unit comprised of anaerobic, facultative and maturation ponds in two series. The effluents of WSP which are discharged in the drain had the BOD reduced to 109-245 mg L -1 (Mean = 145.3 mg L -1 , 50.65% removal), while the COD was reduced to 221-400 mg L -1 (Mean = 289 mg L -1 , 48.95% removal) and the total suspended solids (TSS) were reduced to 118-190 mg L -1 (Mean = 157.8 mg L -1 , 44.3% removal). The reduction percentages of total coliform (TC), faecal coliform (FC), E.coli, faecal streptococci (FS), salmonellae and Listeria were 98.8, 95.6, 79.4, 96.8, 97.9 and 89.5% respectively. Also, the removal percentages of coliphage and infectious rotaviruses were 49.03 and 99.66% respectively. Identical sequences of rotaviruses VP-6 detected in the final effluent of the pond and the drain were observed. Euglena variables and Chlamydomonas reinhardii were predominant in anaerobic, facultative and maturation effluents. It has been noticed that pollution affected species diversity of zooplankton; the number of species in facultative pond was 8 species because of high pollution level, whereas in maturation pond increased to 21 species. Also, pollution in anaerobic pond increased density of ciliates (Protozoa) which are known to be bio-indicators of organic pollution. The percent removal of ciliates in the maturation pond was 70%. It is recommended to make some modifications in the design to increase the efficiency of WSP.

Phytoplankton Diversity as Indicator of Water Quality for Fish Cultivation

Abstract: Waste water fed fisheries are a common feature in different parts of the world. Yet not all work as efficiently as those operating at East Calcutta Wetland for more than 70 years now. The objective of this study is to unravel the reason for the markedly greater efficiency of the Bheris in fish production compared to other water bodies like rain water ponds or sewage fed fish ponds elsewhere. The study indicates that plankton growth could be an important factor responsible for greater fish production in the Bheris. The architecture of the Bheri itself acts as a facilitator in the process. It is proposed that planktons can act as biomarker for water quality assessment in fish production.

Environmental Impact Assessment for Potential Continuous Processes for the Production of Carbon Nanotubes

Abstract: As an emerging discipline, nanotechnology has the potential to improve environmental sustainability through its application in pollution prevention, treatment, remediation, etc. One challenging issue in the growth of nanotechnology is how to produce purified carbon nanotubes (CNT) in commercial quantities at affordable price and with low environmental impacts. A detailed assessment of such a manufacturing process from both economic and environmental aspects at the design phase will benefit both the industry and the society. In this work, an LCA type of environmental impact assessment is conducted for the conceptual design of two catalytic, chemical vapor deposition processes (CNT-PFR and CNT-FBR) used for continuous large-scale production of CNT. The core of both processes is a high-temperature catalytic reactor. Mineral acids are used in the purification steps, from which liquid and solid wastes are generated and must be treated before discharge. Based on the simulation results, the environmental impacts of each process are calculated. The results provide vital information that can be used during the design phase of these processes for better decision-making.

Review of Malaysian agricultural policies with regards to sustainability.

Abstract: The new scientific knowledge coupled with concerns for the environmental, economic and social aspects of agriculture brought Malaysian agriculture into a state of transition. The need for reviewing Malaysian agricultural policies has arisen due to that fact that current agricultural practices in the country are found to be related to environmental, economic and social problems. This study is an effort to review the current Malaysian agricultural policies with regards to sustainability. The Third National Agricultural Policy (3NAP), which is the latest one and relevant secondary materials have primarily been reviewed to substantiate our arguments in this paper. The study, however, argues that the latest Malaysian agricultural policies are compatible with the standards of sustainable agriculture, but the current agricultural practices in the country differ, to some extent, from sustainability principles. The study ends up with some concluding remarks.

Traditional Aquaculture Practice at East Calcutta Wetland: The Safety Assessment

Abstract: The current study is on East Calcutta Wetland (ECW) which is a model for multi-use resource recovery system with activities like pisciculture and agriculture. The entire city's soluble waste is disposed into the raw sewage canals which finally drains into the shallow, flat bottom fish ponds called Bheri. These sewage fed fisheries act simultaneously for the purification process like removal of heavy metals, coliform reduction as well as fish production at a commercial scale. The fishes from these Bheri are analyzed for the extent of metal accumulation in them as compared with those collected from the fresh water ponds around Calcutta. This comparative study was done to access the risk involved, if any, in fish cultivation and its subsequent consumption from these wastewater fed fisheries. Two types of commonly consumed fishes were chosen for the study namely Labeo rohita and Cirrhinus mrigala. Analysis of elements like P, S, Cl, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr and Pb was done by Energy Dispersive X Ray Fluorescence (EDXRF) in order to quantify the level of accumulation. The analysis inferred that elements like Cr, Cu, Rb, Pb shows accumulation in substantial amount in both type of fishes collected from the sewage fed as well as freshwater sources. The uptake of these fishes by human population thereby causes the consumption of these elements in relatively higher level as compared to the Recommended Dietary Allowance (RDA). Thus consumption of waste water cultivated fishes pose no additional health hazard. The accumulation of these metals in fishes from both Bheri as well as fresh water pond put forth a plausible action of diverse microscopic population and certain geochemical factors acting beneath the phenomenon of sedimentation as well as biomagnification of metal in the fish pond and their subsequent uptake in the aquatic food chain.

Prediction of the Daily Mean PM10 Concentrations Using Linear Models

Abstract: The performance of five linear models to predict the daily mean PM10 concentrations was compared. The linear models proposed were: (i) multiple linear regression; (ii) principal component regression; (iii) independent component regression; (iv) quantile regression; and (v) partial least squares regression. The study was based on data from an urban site in Oporto Metropolitan Area and the analysed period was from January 2003 to December 2005. The linear models were evaluated with two datasets of different sizes belonging to the analysed period. Environmental data (SO2, CO, NO, NO2 and PM10 concentrations) and meteorological data (temperature, relative humidity and wind speed) were used as PM10 predictors.During the training step, quantile regression presented the lowest residual errors for the two datasets. Independent component regression was the worst model using the larger dataset. Multiple linear regression, principal component regression and partial least squares regression presented similar results for both datasets. During the test step, independent component regression and quantile regression showed bad performance, while multiple linear regression, principal component regression and partial least squares regression presented similar results using the larger dataset. For the smaller dataset, the models that remove the correlation of the variables (principal component regression, independent component regression and partial least squares regression) presented better results than multiple linear regression and quantile regression. Independent component regression was the linear model with the lowest value of residual error. Concluding, the dataset size is also an important parameter for the evaluation of the models concerning the prediction of variables. The prediction of the daily mean PM10 concentrations was more efficient when using independent component regression for the smaller dataset and partial least squares regression for the larger datasets.

A Preliminary Investigation into the Environmental Awareness of the Omani Public and their Willingness to Protect the Environment

Abstract: This study was conducted with the objective of evaluating the present status of environmental awareness of Omani citizens and their willingness to contribute to environmental protection. The focus of the study was to investigate the Omani public’s level of knowledge about general basic and current local and international environmental issues and to find out their environmental attitudes and behaviors towards their environment. This information was gathered through a survey questionnaire with its structure constructed for this purpose. The survey questionnaire consisted of various current topics regarding the environment. It was primarily designed to assess the level of residents’ environmental awareness from three aspects: environmental knowledge, environmental attitudes, and environmental behaviors. This questionnaire was administered to 425 respondents who were evenly distributed among all areas of the entire Muscat governorate in Oman during January 2007. The results of the survey showed that the basic environmental knowledge of the public was generally lacking, whereas their local and international environmental knowledge were found to be higher. In contrast, the study found that the public had a higher level of environmental attitudes and behaviors, but also noted that the public achieved a higher score in their environmental attitudes than in their environmental behaviors. The results of the survey and recommendations of the study are hoped to be used in the evaluation of the effectiveness of the current public awareness strategies and programmes and in the design future programmes by government authorities and civil service groups.

Evolution of Biochemical Parameters during Composting of Various Wastes Compost

Abstract: In Tunisia the most treatment waste is landfill (50% of wastes were land filled) and only 5% are composted. And since our soil become more and more poor in organic matter, green waste can be a significant source of organic matter; in parallel we cited the domestic waste and dead posodonia collected from beaches. All these wastes coming from various origins can be exploited to produce stable compost able to correct the deficiency of soil. Exploiting waste could lead at different quality of mature compost. We are not interested in only the quality of the mature compost but we are interested in the time of the composting cycle. The goals of this study were to characterize the maturity and the sanitary quality of compost in relation with the feed stock source (green waste (C1), green waste mixed with Posidonia (C2) and municipal solid waste (C3). The results obtained showed that the duration of the cycle of composting depends on the nature of the substrate. The longest cycle (200 days) was observed with the feed stock source C3. The C/N ratios ranged between 22 and 27 at the beginning of the cycle of composting and decreased notably during time of composting. NH4-N decreased over the progress cycle and at the end of composting progress, all wastes presented a content of NH4-N not exceeding the maximal value recommended for mature compost (400 mg kg-1). The CO2 released by C1 was of approximately 6000 mg C-CO2 DM kg-1 at the start of the cycle and it reached at the end of the cycle of composting 2300 mg C-CO2 DM kg-1. Nevertheless, the deshydrogenase activity (DHA) recorded was important during the thermophilous phase at the level of the three piles C1, C2 and C3, where it reached the respective values of 5.9; 6.2 and 4 TPFS/TPF/g of DM. Maturity stage showed the values of 0.3; 0.8 and 0.4 TPFS/TPF/g of DM, respectively. Salmonella appeared only at the level of the piles C2 et C3 at the beginning of composting. After 40th days composting these bacteria are not detected. Staphylocoques were not detected at the level of the two piles C1 and C2. The number of these bacteria was important in the compost C3, where it fluctuated between 103 and 105 bacteria g-1 of dry matter. Statistical analyses showed that the compost of municipal solid waste C3 presented a value of salinity (6.8 g Kg-1 of DM) higher than those obtained at the level of the other studied piles 2.6 g kg-1 of DM for C1; 4 g Kg-1 of DM for C2). We also noted that the compost C2 was relatively rich in P (2.17%/ of DM) and MgO (2.62% of DM) as compared with the two other studied piles which contain a percentage of MgO of 0. 73 in C1 pile and 0. 8 in C3 pile. Although important heavy metals contents determined in the three studied composts were lower than the levels indicated by the standards of the European Union.

Use of Barley for the Purification of Aquaculture Wastewater in a Hydroponics System

Abstract: Barley was examined for its ability to remove nutrients from aquaculture wastewater. The effects of seed sterilization using ethanol and bleach and seed density on germination and plant growth were investigated. Surface sterilization of barley seeds had a negative impact on germination. Increasing the ethanol concentration and/or the bleach concentration reduced the germination percentage. Barley seeds were first germinated in water in the hydroponics system. The seedlings then received wastewater from an aquaculture system stocked with Arctic charr. During the experiment, the crops grew rapidly and fairly uniformly and showed no signs of mineral deficiency or disease. The average crop height at harvest was 25.5 cm and the yield varied from 25 to 59 t haˉ1, depending on the seed density. The hydroponically grown barley was able to significantly reduce the pollution load of the aquaculture wastewater. The TS, COD, NH4+-N, NO2--N, NO3--N, and PO43--P reductions ranged from 52.7 to 60.5%, from 72.9 to 83.1%, from 76.0 to 76.0%, from 97.6 to 99.2%, from 76.9 to 81.6% and from 87.1 to 95.1%, respectively. However, the effluent produced from the hydroponics system had slightly higher levels of TS (420-485 mg Lˉ1) than the 480 mg Lˉ1 recommended for aquatic animals. A sedimentation/filtration unit should be added to the hydroponics system.

Valorization of Drinking Water Treatment Sludges as Raw Materials to Produce Concrete and Mortar

Abstract: The purpose of this work was to assess the technical feasibility to valorize sludges, generated and stored at the Los Berros drinking water facility (PPLB), as raw material to produce building products (mortar and concrete) for the construction industry. The experimental study was divided into three stages: 1) sampling and characterization of PPLB sludges to determine their potential as raw material (sand substitute and supplementary cementing materials) to produce mortar and concrete; 2) production and characterization of specimens, using sludge in different weight ratios of mixtures with cement, lime, commercial mortar and plaster to prepare mortars and concretes and 3) comparison of compressive strength and drying contraction values between each specimen and the Mexican criteria to build mortars and concretes. The characterization results of the PPLB sludges showed that these residues could be used as a sand substitute in mortar and concrete formulations, since they were mainly comprised of this material (46.83%). The specimens prepared with a) the binary formulations, sludge-cement and sludge-mortar (90-10%) and b) the ternary formulation, sludge-lime-cement (90-5-5%), gave the best results (ranging from 130 to 150 kg cm-2) of the compressive strength test. The compressive strength values of these formulations were higher than those of equivalent mortar (types I, II and III) and cement mixtures (125 kg cm-2) prepared according to the Mexican complementary technical criteria to design and build masonry. These cementing properties exhibited by the PPLB sludges might be associated to their high content of aluminum and silicon oxides, 31.98 and 33.23%, respectively. Thus, calcium silicate (the main carrier strength in hardened cement) can be produced from lime hydration of cement with the active silica present in the sludge. Considering all these results, the PPLB sludges present a high feasibility for being valorized as raw materials (supplementary cementing material and sand substitute) to produce building products for the construction industry.

Assessing the Effect of a Dumpsite to Groundwater Quality in Payatas, Philippines

Abstract: The study assessed and compared the groundwater quality of 14 selected wells continuously used in the with (Payatas) and without dumpsite (Holy Spirit) areas at the Payatas estate, Philippines. Water quality monitoring and analyses of the bio-physico-chemical variables (pH, Total Suspended Solids (TSS), Total Dissolved Solids (TDS), total coliform, conductivity, salinity, nitrate-nitrogen, sulfate, color, total chromium, total lead and total cadmium) were carried out for six consecutive months, from April to September 2003, covering both dry and wet seasons. Results showed most of the groundwater quality variables in both the with and without dumpsite areas of the Payatas estate were within the normal Philippine water quality standards except for the observed high levels of TDS, TSS and total coliform and low pH levels. No significant differences were observed for nitrate- nitrogen, total cadmium, total lead, total chromium and total coliform in both the with and without dumpsite areas. TDS, conductivity, salinity and sulfate concentrations in the with dumpsite groundwater sources were significantly different compared to those in the without dumpsite areas. Continuous water quality monitoring is encouraged to effectively analyze the impact of dumpsites on the environment and human health.

Sulfur Dioxide (SO2) Accumulation in Soil and Plant's Leaves around an Oil Refinery: A Case Study from Saudi Arabia

Abstract: The accumulative levels of SO2 in soil and plant's leaves around an oil refinery were monitored. Four different sites around the refinery area were chosen; west, south east, north east and the northern side. The refinery southern side was not accessible. In addition to the soil samples, leaves samples of the dominant plants species Myoporum pictum were randomly collected from all sites. Highly significant levels of sulfate were found in soil and plant leaves samples at all sites compared to the control. The highest level of sulfate in soil (9,000 ± 1200 μg g-1) and plant's leaves (65,774 ± 320 μg g-1) were found in the southern east side. This high content of sulfate indicates high levels of air contamination with SO2 around the refinery which negatively effects the environment and public health at this populated area.

Analysis and Optimization of Carbon Dioxide Emission Mitigation Options in the Cement Industry

Abstract: The cement industry is responsible for approximately 5% of global anthropogenic carbon dioxide emissions emitting nearly 900 kg of CO2 for every 1000 kg of cement produced. Effective control strategies to mitigate these emissions are discussed and a mathematical programming model able to suggest the best cost effective strategy is outlined. Control costs consisting of operating and investment costs along with the efficiency of control options are taken into account in the model. A representative case study from the cement industry was considered in order to illustrate the use of the model in giving optimal control strategies. Efficiency improvement measures were found to be effective options for reduction targets up to 10 %. The model suggested that fuel switching and carbon capture must be considered at reduction targets higher than 10%. The cost of cement production was shown to increase dramatically with an increase in reduction target.

Exponential smoothing method of base flow separation and its impact on continuous loss estimates

Abstract: The calculation of loss is vital for design flood estimation models and in order to estimate continuing loss (CL), proportional loss (PL) and volumetric runoff coefficient, the surface runoff has to be separated from the total given in a stream flow hydrograph. To obtain the volume of surface runoff from the streamflow hydrograph, baseflow separation becomes necessary and in this paper a few base flow separation methods are explored and an appropriate method selected to assess to impact of baseflow on loss estimates. The process of separation requires a base flow separation coefficient and this coefficient (�) is selected from individual study catchments from 3 to 5 rainfall streamflow events of the same catchments based on sensitivity analysis. The selectedvalue of individual catchments is then applied to other rainfall streamflow events of a given catchment. It has been observed that a small degree of error in the selection ofvalue does not seem to affect the estimates of the CL, PL or runoff coefficient. Hence, the more practical base flow separation method used in this paper may be applied to other rural catchments for baseflow separation in design loss studies.

Total Emissions from Flaring in Kuwait Oilfields

Abstract: Kuwait is a major oil producing country and its economy directly depends on its export of crude and refined products. Kuwait Oil Company (KOC) is responsible for all exploration and production of crude oil in Kuwait. These activities result in the emission of gaseous pollutants to the atmosphere, particularly from the flaring of undesirable product and excess gases. For environmental and resource conservation reasons, KOC is required to minimize the amount of gas flared in order to control and reduce the emissions of major pollutants in the State of Kuwait and neighbors countries. In the present study the total emissions of primary pollutants associated from flaring activities from Kuwait oil field have been estimated. An inventory records the annual emissions of air pollutants: NOX, SO2, CO, CO2, Methane and non-methane, Volatile Organic Compounds (VOC): resulting from oil production operations in the Kuwait Oil Fields. The emissions are generated from various point sources and aggregated to have total pollutants load of ambient air. Emissions of flaring pollutants are associated with all operations in Oil fields, Gathering Centers (GC), Boaster Stations (BS), Tank areas and other oil production related activities. The objective of this work was to obtain an accurate estimation of the total flare emission from oil production activities thereby aiding the effective planning of mitigation strategies to control and reduce the pollution from crude related operation.

Calibration and Simultaneous Monitoring of Soil Water Content and Salinity with Capacitance and Four-electrode Probes

Abstract: Non-destructive monitoring of soil water content (W) and the electrical conductivity of the soil solution (ECw) has been desired for environmental evaluation and sustainable agriculture. Dielectric probes and four-electrode probes are widely used for the non-destructive determination of W and the soil bulk electrical conductivity (ECb), respectively. Since the output of dielectric probes is affected by soil salinity, the calibration for the effect is indispensable for accurate determination of W. Meanwhile, four-electrode probes require the W value for determination of ECw from ECb. We present an empirical calibration method for the salinity dependence of commercial capacitance moisture probes. A four-electrode probe was also calibrated to investigate the possibility of simultaneous monitoring of W and ECw by combining each calibration equation for capacitance and four-electrode probes. A laboratory experiment was conducted using a sandy soil to obtain probe outputs at various W (air-dry-near-saturation) and ECw (0-31.9 dS m-1). The output of the capacitance probe exhibited strong, nonlinear dependence on ECw. The root mean square error (RMSE) between actual W and calculated W using the linear functions provided by the manufacturer was at a maximum of 0.162 m3 m-3. A calibration equation, describing the probe output as a function of W and ECw, was developed using curve fitting approach. The RMSE between the actual and calibrated W by this equation was at a maximum of 0.011 m3 m-3. The output of the four-electrode probe (ECb) was also expressed as a function of W and ECw. The calibration equations for each probe were combined and solved for W and ECw. Although both W and ECw were determined with acceptable accuracy, the combined calibration equation had multiple solutions for W. Development of the method to select optimal solutions will be needed for the practical application of this probe combination.

Heavy Metal Mobility in Polluted Soils: Effect of Different Treatments

Abstract: The effects of biosolid compost and phytoremediation applied on the leaching of cadmium, copper, lead and zinc, through the different horizons of a superficially polluted soil were determined. The soil was from the Province of Buenos Aires, Argentina. It was contaminated with cadmium copper, lead and zinc. Leaching columns were used with three different horizons: A: 0.12 m A horizon, B: 0.12 m horizon A+0.15 Bt horizon and C: 0.12 m A horizon+0.15 m Bt horizon+0.13 m BC horizon. The treatments were (1). Witness (contaminated soil), (2). contaminated soil+plants (Plant), (3). contaminated soil+50 Mg has-1 biosolid compost (Compost) and (4). contaminated soil+50 Mg has-1 biosolid compost+plants (Compost-Plant). The leached ones were gathered after incorporating to the columns the following volumes of water A: 1000 mL, B: 1200 mL and C: 2000 mL. Leachates were obtained out after harvesting vegetal material. It was found that horizon Bt presents a barrier to metal leaching. Both concentration of clay and type of clay appears to immobilize heavy metals in those soils. The clay content over 40% and/or 53.4 g smectite g-1 soils reduce the heavy metal leaching. The application of organic amendment or occurrence of plant eventually used in remediation techniques did not influence on the leaching of metals.

Histogram of Intensity Feature Extraction for Automatic Plastic Bottle Recycling System Using Machine Vision

Abstract: Currently, many recycling activities adopt manual sorting for plastic recycling that relies on plant personnel who visually identify and pick plastic bottles as they travel along the conveyor belt. These bottles are then sorted into the respective containers. Manual sorting may not be a suitable option for recycling facilities of high throughput. It has also been noted that the high turnover among sorting line workers had caused difficulties in achieving consistency in the plastic separation process. As a result, an intelligent system for automated sorting is greatly needed to replace manual sorting system. The core components of machine vision for this intelligent sorting system is the image recognition and classification. In this research, the overall plastic bottle sorting system is described. Additionally, the feature extraction algorithm used is discussed in detail since it is the core component of the overall system that determines the success rate. The performance of the proposed feature extractions were evaluated in terms of classification accuracy and result obtained showed an accuracy of more than 80%.

Total SO2 Emissions from Power Stations and Evaluation of their Impact in Kuwait Using a Gaussian Plume Dispersion Model

Abstract: In Kuwait, most of the power stations use fuel oil as the prime source of energy. The sulphur content (S%) of the fuel used as well as other factors have a direct impact on the ground level concentration of sulphur dioxide (SO2) released by power stations into the atmosphere. The SO2 ground level concentration has to meet the environmental standards set by Kuwait Environment Public Authority (KEPA). In this communication we present results obtained using the Industrial Sources Complex Short Term (ISCST3) model to calculate the SO2 concentration resulting from existing power stations in Kuwait assuming zero background SO2 concentration and entire reliance on Heavy Fuel Oil. 1, 2, 3 and 4S% scenarios were simulated for three emission cycle cases. The computed annual SO2 concentrations were always less than KEPA standards for all scenarios. The daily SO2 concentrations were within KEPA standards for 1S% but violated KEPA standards for higher S%. In general, the concentrations obtained from the combined hourly and seasonal cycle were the lowest and those obtained from the no cycle case were the highest. The comparison between the results of the three cycles revealed that the violation times cannot be solely attributed to the increase in emissions and the meteorological conditions have to be taken into consideration.

Desalination of Saline Sludges Using Ion-Exchange Column with Zeolite

Abstract: A flushing process followed by a zeolite based ion-exchange process were developed for the treatment of saline sludges from oil and gas exploration sites. The particle size distribution of sludge sample indicated the presence of very fine sand and clay. The electrical conductivity of the sludge was 42.2 dS m-1 indicating very saline sludge and the Cation Exchange Capacity (CEC) was 40 cmoL kg-1 which was very suitable for ion-exchange process. A 500 g sample of saline sludge (containing CaCl2:MgCl2:NaCl ratio as 1:1.16:36.61) was washed using demineralized water in a mixed reactor and the sludge was allowed to settle for 36 h. The optimal number of washes was determined to be two washes with an overall salt removal efficiency of 94.47%. The treated sludge contained 515 mg salt kg-1 sludge (or 0.05% w w-1) and was suitable for agricultural application. The washwater was passed through a Mountain Stronach zeolite (chabazite) based ion-exchange column for salt reduction. The sodium salt removal efficiency was 75.34%. This was increased to 99.79% when using two ion-exchange columns. The Ca and Mg ions were under regulatory limits and required no further treatment. The final salt concentration in the wash water was 314.0 mg L-1 which was below the limits established by the Canadian Guidelines. For complete removal of total salts, a series of ion-exchange columns with different zeolites (for removal of NaCl, MgCl2 and CaCl2) will be required.

Salinity, Temperature and Turbidity Structure in the Suva Lagoon, Fiji

Abstract: The city of Suva is home to nearly a quarter of the population of the Fiji thereby placing a lot of anthropogenic pressure on its lagoon. The Suva lagoon (comprising of Suva Harbour and Laucala Bay) has been subject to substantial sediment inputs generated by erosion and human activities. Freshwater input into the lagoon comes predominantly from the Rewa River, the largest fluvial system in the country. The high sedimentary load from the Rewa River, especially during the wet-warm period (November-April), has a strong impact on the lagoon. In addition, there are local sources of pollutant input into the lagoon via the Vatuwaqa River and the Kinoya Sewage Treatment Plant, which discharges effluents into the lagoon and degrades the marine environment. The salinity, temperature and turbidity in the Suva lagoon are some important parameters for water quality which are continuously changing with the seasons and need to be studied because they are efficient indicators of variations in the lagoon and can transform the marine ecosystem. Several field trips were undertaken in the Suva lagoon to collect hydrographical data to study the water properties in the lagoon. Results obtained showed that the salinity near the head of Laucala Bay during the wet-warm period was below 24.8 psu and was 33.7 psu during the dry-cool period (May - October). The temperature range during the wet-warm period was between 28.0-30.5°C and between 24.5-25.5°C during the dry-cool period. The turbidity was always above 3.0 FTU near the river mouths. The field results show that the variations of CTD measurements are dependent predominantly on the river discharge, while the dominant wind regime is the southeast trade winds.

Behaviour of Main Microbiological Parameters And of Enteric Microorganisms During the Composting of Municipal Solid Wastes and Sewage Sludge in A Semi-Industrial Composting Plant

Abstract: This study was focused on the microbiological aspects of composting and on the behaviour of main prevalent microbial communities (non-pathogenic and selected pathogenic bacteria) during the composting process of municipal solid wastes and sewage sludge in a semi-industrial composting plant. Results showed that the dehydrogenase activity and Biomass C / Biomass N ratio showed a noticeable increase in the two windrows W1 (100% of municipal solid wastes) and W2 (60% of municipal solid wastes and 40% of dried sewage sludge) during the thermophilic phase (≥45°C for 100 days) and marked a high microbial activity during this period of the composting process. During the thermophilic phase, the removal of faecal indicator bacteria is in order of 2 Ulog10, and a total absence of Staphylococcus aureus and Salmonella was observed. The re-emergence of faecal indicator bacteria at the end of the composting progress (cooling step) could constitute a major problem for the agricultural use of compost.

A screen for Benzo(a)pyrene in Fish Samples From Crude Oil Polluted Environments

Abstract: Several studies have shown that exposure to Benzo(a)pyrene increases the risk of cancer. In this study several fish samples from Niger the Delta region of Nigeria were screened for the presence of Benzo(a)pyrene. The study was carried out using Gas chromatograph coupled to a mass spectrometry detector. Benzo(a)pyrenes in the samples were identified through both retention time match with authentic standards and simultaneous maximization of several major ions from GC/MS data. Perylene-d12 was used as the internal standard for quantitation. Concentration of benzo(a)pyrene in the samples ranged from 1.47 to 10.53 µg/kg which is more than WHO recommended maximum allowable concentration. Therefore this study concludes that the population is at an elevated risk of cancer of occurrence.