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Journal of Environmental Science and Technology
eISSN: 2077-2181
pISSN: 1994-7887

Editor-in-Chief:  Mohamed Abdul Rahman Elwakil
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Research Article
Effect of Concentrations of Bacterial Consortia in Culture Medium from Wastewater in Microbial Fuel Cells
Rita Arbianti, Tania Surya Utami, Astry Eka Citrasari and Heri Hermansyah
Background and Objective: Microbial fuel cells (MFCs) are technology by which electricity is generated from microbes. Electricity can be generated by MFCs by using wastewater as a substrate. Bacterial consortia from wastewater have been widely used in MFCs. Bacteria degrade substrates, resulting in a difference in potential, which in turn generates electricity. This research aimed to analyze the potential of bacterial consortia and identify the best number of additional bacterial consortia cultured in nutrient broth containing tempeh wastewater as the primary glucose source. Materials and Methods: In this study, used wastewater from tempeh production with different concentrations of bacterial consortia in culture medium (0, 0.4, 1 and 10%). Voltage was recorded with a digital multimeter instrument for 50 h. Bacterial growth was assessed every 3 h at 486 nm with a spectrophotometer UV-Vis. The COD of tempeh wastewater was analyzed before and after the experiment with COD kits and heating it on a COD Digester Block for 2 h at 150°C. Statistical analysis method used in this study is monothetic analysis or one-factor-at-a-time method. Results: The study indicates that the nutrients present in tempeh wastewater can be used as an effective energy source for MFCs using bacterial consortia as a biocatalyst. Conclusion: The optimum voltage and power density generated was up to 291.1 mV and 66.33 mW m–2 following 1% culture medium and its coulombic efficiency reached 4.48%. In addition to generating electricity, MFCs can remove chemical oxygen demand (COD). The highest COD removal valuereaches 42.97% when 10% of culture was used.
Research Article
Ecological Risks of Contaminated Lead and the Potential Health Risks among School Children in Makassar Coastal Area, Indonesia
Anwar Mallongi, Ruslan La Ane and Agus Bintara Birawida
Background and Objective: Distribution of lead for certainty of their suitability for consumption and other domestic uses from the sea water, bottom sediment, biota for Anadara trapezia sp. and crab were widely polluted the coastal area of Makassar. This research aimed to investigate the lead (Pb) accumulation both in aquatic and terrestrial habitats and assess the potential ecological risks and the potential health risks among school children in Makassar coastal area. Materials and Methods: Water column, sediment, shellfish (Anadara trapezia sp. and crab) soil and snack food samples were collected in one time collection. Then, in terrestrial surface soil and snack food sold was collected in the school children. Those samples were analyzed using varian AA240FS atomic absorption spectrophotometer. In addition, the ecological risks assessment was determined using ecological hazard quotient from EPA formulation. Data was also analyzed by one-way analysis of variance ANOVA (p<0.05) using SPSS. Results: Results revealed that the lead distribution concentration in aquatic in water column, sediment, shells and crab were ranged from 0.12-0.21 mg L–1, 6.03-8.00 mg kg–1 dry weight (d.w) and 1.22-2.90 mg kg–1 wet weight (w.w), 1.02-2.91 mg kg–1 w.w, respectively whereas in the terrestrial of surface soil and school snack were ranged from 5.00-37.40 mg kg–1 dw and 0.01-0.90 mg kg–1, respectively. The magnitude values of ecological risks for water column, sediment and surface soil were in the range of 3.0-4.4, 0.16-0.22 and from 0.6-1.1, respectively. Conclusion: Most values have been exceeded the limit standard or ecological risks >1 for potential ecological risk which is hazardous and potentially not safe for consumption for the long period of Pb contamination seafood.
Research Article
Assessment of Dissolved and Particulate Polycyclic Aromatic Hydrocarbons (PAHs) and their Nitro Derivatives (NPAHs) in the Mediterranean Sea Surface Waters along Alexandria Coast
Hossam F. Nassar
Background and Objective: Polycyclic aromatic hydrocarbons (PAHs) and their derivatives are widely diffused organic pollutant to the environment because of their semi-volatile characteristics. These pollutants are carcinogenic and/or mutagenic and have to be intensively regulated and monitored. In this research studied the dissolved and particulate PAH and NPAHs (nitro-polycyclic aromatic hydrocarbons) concentrations in the Mediterranean sea water along Alexandria coast. Materials and Methods: Samples were collected from three different sites (Alex1, Alex2 and Alex3) representing different activities in the sampling area. HPLC with fluorescence detection was used for PAHs detection, whereas, HPLC with chemiluminescence detection was used for NPAHs detection. Results: The measured concentration levels of dissolved PAHs and NPAHs were ranged from (230.5-704.1) ng L–1, respectively, while those for particulate PAHs and NPAHs were ranged from (79.1-288.5) ng L–1, respectively. Molecular diagnostic ratios were calculated to identify the sources of emissions of such compounds. Results indicated a major contributor of the pyrolytic and sewage discharge contamination particularly at sites (Alex2 and Alex3) with a mixed petrogenic pattern from urban runoff inputs and frequent oil spills at site (Alex1). Conclusion: PAHs and NPAHs total concentration levels at the three sampling stations in the Mediterranean Sea along Alexandria coast followed the order: Alex1> Alex2> Alex3.
Research Article
Effect of Adding Nitrate on the Performance of a Reactor in an Immersed Bacterial Bed Used for Anaerobic Treatment of Domestic Wastewater
Aboubacar Sylla, Fatima Ezzahara Aboussabiq, Najwa Hassou, Jamal Amine, Omar Assobhei and Samira Etahiri
Background and Objective: The difficulty of sanitizing wastewater as it arises acutely in small communities, rural areas etc., requires that appropriate solutions be taken. The discharge of raw wastewater into the wild in Morocco accounts for nearly 54% on the coastline, reflecting the impact of a lack of hygiene and sanitation for the population and the environment. To improve the treatment of wastewater in rural areas that lack sanitation systems, the aim of this study was to introduce 2 anaerobic bioreactors in a pilot wastewater denitrification process to determine if those bioreactors could help decrease the chemical oxygen demand and nitrate levels in the wastewater. Materials and Methods: During operation, the decanted primary effluent separately supplied the 2 anaerobic bioreactors (hereinafter "bioreactor 1" and "bioreactor 2": The bioreactor 1 was fed with external nitrate plus the nitrate present naturally in the primary effluent, whereas, the bioreactor 2 was just fed with nitrate from the primary effluent) with an ascending flow. This allowed the annual average organic loading rate (chemical oxygen demand) of 0.652 g/day to be applied to the bioreactors. The primary effluent nitrate load applied to the bioreactors ranged from 1.94×10–3-14×1.10–3 g/day. In addition, 600 mg L–1 of nitrate was added in the bioreactor 1 treatment throughout the experiment at a 6 h hydraulic retention time. Data was statistically analyzed by one-way ANOVA using SPSS. Results: The overall organic loading rate in effluents treated with bioreactor 1 was 0.036 g m–3 day, a 72.16% reduction and 0.064 g m–3 day, a 48.9% reduction, for ARIBB 2. An average nitrate reduction performance of 80.31% was observed for bioreactor 1 and 42.81% for bioreactor 2 at the end of the experiment in June. Conclusion: The bioreactor 1 with nitrate addition showed better performance than the nitrate-free bioreactor 2, compared with the different chemical oxygen demand (COD) loads and environmental conditions. The relatively low cost of external nitrate facilitates access to the process.
Research Article
Characterization of Radon Concentration and Annual Effective Dose of Soil Surrounding a Refinery Area, Ras Tanura, Saudi Arabia
Fatimh Alshahri, Atef El-Taher and Abd Elmoniem Ahmed Elzain
Background and Objective: Oil refineries process and shipping of petroleum contaminate the environment due to leakage of waste materials containing naturally occurring radionuclides. Radon decays from radium which may content in the waste. Therefore, the present work dealt with measuring soil gas radon concentration, surface and mass exhalation rates from soil samples surrounding a refinery area in Ras Tanura city, Saudi Arabia. Materials and Methods: The measurements were carried out using CR-39 detectors. After etching process, all detectors were automatically counted using scanning and readout system and theoretical calculations were done to find the radon concentration, radon surface and mass exhalation rates and Dose estimation. Results: The soil gas radon concentration ranged from 6.02±0.8 to 927±101 Bq m–3 with an average value of 120±14 Bq m–3. The surface and mass exhalation rates were found to be ranging from 2.65-409 mBq m–2 h and from 0.04-8.31 mBq kg–1 h with an average of 53.4 mBq m–2 h and 1.08 mBq kg–1 h, respectively and the effective dose rate ranged from 0.15-23.4 mSv/y with an average of 3.02 mSv/y. A good positive correlation coefficients were observed between radon concentration and surface and mass radon exhalation rate of soil samples. The obtained results compared with other findings from local and worldwide locations. Conclusion: The obtained results were found to be within the recommended limits. This study could be useful as a baseline data for monitoring and evaluation radon exposure in soil around the residential area nearby refinery area in Arabian Gulf region.
Research Article
Modeling of Extreme Rainfall Recurrence Time by Using Point Process Models
Nurtiti Sunusi, E.T. Herdiani and Nirwan
Background and Objective: Period of extreme rainfall recurrence in certain location becomes a very interesting thing to be studied. In agriculture, uncertain emergence affects many things. The calendar of cropping pattern is closely related to the prediction of recurrence time of extreme rainfall. This study aimed to construct the mathematical model to find the time of extreme rainfall recurrence through point process modeling. Methodology: The assumption used in this study was the waiting time until the subsequent occurrence of subsequent rain follows the inverse Gaussian and the log normal distribution. To estimate the parameters model, the moment method was used. Results: The time of recurrence of subsequent extreme rainfall can be determined by calculating the length of waiting time since the last extreme rain event. Conclusion: The expected waiting time until the subsequent occurrence of the next rain, does not depends on the time difference since the appearance of the extreme last rainfall.
Research Article
Geochemical and Bacteriological Analyses of Water Resources Prone to Contamination from Solid Waste Dumpsites in Imo State, Southeastern Nigeria
Ejiogu Blessing Chikaodili, Opara Alexander Iheanyichukwu, Nwofor Okechukwu Kelechi and Nwosu Eugene Ikechukwu
Background and Objective: Geochemical and bacteriological analysis of water resources within some selected dumpsites in Imo State, Southeastern Nigeria was carried out to detect possible leachate contamination from the open dumpsites. The main objective was to determine the quality and potability of the water resources of the study area. Materials and Methods: A total of sixteen borehole and stream water samples were used in addition to four leachate samples collected within the dumpsites. Chemical analysis of the samples was carried out using standard procedures with the heavy metals analyzed using the atomic absorption spectroscopy (AAS), while bacterial analysis was carried out using the membrane filter technique. Descriptive statistical techniques including the mean and standard deviation of geochemical and bacteriological parameters were employed for statistical analysis. Results: The results of the study revealed that the concentrations in mg L–1 of Na+2, Mg+2, Ca+2, CO3–2 and HCO3‾ ions for both groundwater and surface samples have mean values of 4.65, 18.1, 87.67, 119 and 83.5 mg L–1, respectively. Iron (Fe+2), potassium (K+ ), nitrate (NO3‾) and lead (Pb+2) concentrations in the water samples were above the WHO 2010 permissible limits and ranged from 0.05-2.2, 0-23.3, 0.04-343 and 0–7 mg L–1, respectively. Bacteriological analysis revealed average values of 537, 215, 86 and 32 CFU/100 mL for total bacterial count, total coliform count, total faecal count and total E. coli, respectively indicating possible bacteriological contamination of the water resources in the vicinity of the dumpsites. Two dominant hydro geochemical facies (water types) were identified in the study area which included the Ca-Mg-Cl and Ca-SO4 water types. Conclusion: It was concluded that the high concentrations of potassium, nitrate, iron, lead and high occurrence of bacteria in the water resources of the study area indicate possible anthropogenic contamination from the nearby dumpsites. It was therefore, recommend that a better waste management approach be adopted for environmental protection and sustainability.

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