Environmental Engineering
M. Mambwe; K. K. Kalebaila; T. Johnson
Abstract
Crude oil continues to impact many nations as it is among the major sources of fuel. Its role in making life in modern societies comfortable cannot be overemphasized as it is readily available and easy to use. Contamination resulting from its use in industries such as mining, transportation and ...
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Crude oil continues to impact many nations as it is among the major sources of fuel. Its role in making life in modern societies comfortable cannot be overemphasized as it is readily available and easy to use. Contamination resulting from its use in industries such as mining, transportation and petroleum especially soil contamination cannot be overlooked. Soil pollution resulting from oil contamination can be seen as being among the twenty-first-century vulnerabilities because if not well taken care of the consequences can be devastating. Soil contamination is of interest in most societies because it affects both the environment and humans. This review highlights common sources of soil pollution and their effects, oil waste disposal methods, soil remediation techniques that are well established and those still in their infancy. Such techniques include bioremediation such as phytoremediation and landfarming, where percent removal of contaminated soils was reported from 68% to 89 % in 40 days to 1 year, respectively; physical methods such as excavation and incineration (75-86% removal); chemical methods such as oxidation (48 % by Fenton process); and photocatalysis (67% using titanium dioxide). The choice of remediation in mining, transportation and petroleum industries depends on the urgency and hazardous effects of the pollutant. In Zambia, Mopani Copper Mines uses landfarming as a means to mitigate large amounts of soil contaminated with oil wastes, but the process is slow. In the proposed research, photocatalysis coupled with adsorption of oil on clay will be used to assess the effectiveness of this emerging technology to quicken the degradation of oil in soils. Clay will be incorporated with metal ions and with hydrophobic groups to enhance light absorption and oil-clay interaction, respectively. Photochemical remediation techniques for remediation of soils polluted with oil have attracted considerable interest as the processes are reported to enhance the degradation of oils in soil compared to the biological and physical methods. The extent of photo-degradation of oil waste will be evaluated using the Soxhlet technique by determining the percent residual oil. The importance of remediating contaminated soil in any nation cannot be overemphasized as consequences of not remediating this precious resource might be devastating. Since economic development through industrialization will continue, there is need to constantly improve on methods of mitigating the impact of wastes on the environment, especially in developing countries, where engineering of cheap, nontoxic materials for soil remediation is paramount.
D. Sivakumar
Abstract
Taguchi L9 orthogonal array was implemented to select optimum values of process parameters and to attain the maximum removal of pollutants and power generation from dairy industry wastewater using double chambered salt bridge microbial fuel cell. The maximum chemical oxygen demand reduction, current, ...
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Taguchi L9 orthogonal array was implemented to select optimum values of process parameters and to attain the maximum removal of pollutants and power generation from dairy industry wastewater using double chambered salt bridge microbial fuel cell. The maximum chemical oxygen demand reduction, current, voltage, power, current density and power density in double chambered salt bridge microbial fuel cell from dairy industry wastewater was found to be 86.30 %, 16.10 mA, 886.34 mV, 14.27 mW, 1219.69 mA/m2 and 1081.06 mW/m2 respectively for the optimum value of 1M NaCl concentration, 10 % agar concentration and 0.10 m salt bridge length. Double chambered salt bridge microbial fuel cell was not only removed chemical oxygen demand and produced power, but it also removed other pollutants at the maximum level against the best optimum value of process parameters from the dairy industry wastewater. The proposed regression model was used to select the right combination of process parameters for obtaining a maximum reduction of pollutants and simultaneous power production from the dairy industry wastewater.
A.C. Affam
Abstract
Conventional steam activation pyrolysis of waste materials such as oil palm kernel shell for production of biochar was investigated using central composite design. Conventional steam activation was carried out via an initial carbonization of oil palm kernel shell to obtain biochar and thereafter steam ...
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Conventional steam activation pyrolysis of waste materials such as oil palm kernel shell for production of biochar was investigated using central composite design. Conventional steam activation was carried out via an initial carbonization of oil palm kernel shell to obtain biochar and thereafter steam activation of the biochar using the conventional heating to produce activated carbon. Additionally, removal of chemical oxygen demand and colour was studied alongside the production. Optimum yield was obtained at about 90 min and 725oC. Out of the time duration, 80 min was for carbonation and 10 min was for steam activation. Further extension of time was not significant whereas increasing temperature was able to increase the pores found on the biochar. Under the optimum condition, fixed carbon was 19.39%, chemical oxygen demand and colour removal were 32.02 and 61.15%, respectively at 90 min adsorption time. However, when time was extended to 120 min, chemical oxygen demand (48.2%) and colour (94.19%) removal were achieved. The Brunauer–Emmett–Teller surface area and micropore area of the oil palm kernel shell based activated carbon was 620.45 m2/g and 550.4 m2/g, respectively. The conventional steam activation is an effective method that can be employed in production of activated carbon from waste oil palm kernel shell.
S. Antwi-Akomea; B. Fei-Baffoe; E.J.D. Belford; M. Borigu
Abstract
The present study investigated the coupling effect of biodegradation and media filtration in treating hydrocarbon contaminated water. The study recorded reductions in total petroleum hydrocarbon, total dissolved solids, turbidity and microbial load. The study was essentially a simulated pump and treat ...
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The present study investigated the coupling effect of biodegradation and media filtration in treating hydrocarbon contaminated water. The study recorded reductions in total petroleum hydrocarbon, total dissolved solids, turbidity and microbial load. The study was essentially a simulated pump and treat process that involved the pumping of hydrocarbon contaminated water for treatment in a locally designed multi-stage bioreactor incorporated with media filtration. A mixed consortium of hydrocarbon-eating microbes was applied in the study. Hydrocarbon-eating microbes were isolated from hydrocarbon contaminated soils obtained from selected mechanic workshops. Bamboo chips and coconut husk chips were applied as support media for microbial attachment within the bioreactor compartment of the treatment setup. Applied support media were approximately 2-4 cm in size. Media filters applied comprised three locally manufactured candle filters two of which were respectively impregnated with granular activated charcoal and sand. The coupling effect of biodegradation and media filtration recorded over 99 % (> 8.7 mg/L) total petroleum hydrocarbon removal. Microbial load reduction ranged from 3.57±0.11E+20 to 7.45±0.26E+20 Colony forming unit/mL, total dissolved solids reduction from 30.00±5.66 to 131.00±0.00 mg/L and turbidity reduction from 39.00±1.41 to 123.50±0.71 nephelometric turbidity units. Biodegradation accounted for 69.70±0.63 and 90.72±2.36 % total petroleum hydrocarbon removal respectively for bamboo chips and coconut husk chips.
M. Shahriari Moghadam; N. Safaei; G.H. Ebrahimipour
Abstract
Phenol is an environmental pollutant present in industrial wastewaters such as refineries, coal processing and petrochemicals products. In this study three phenol degrading bacteria from Arak Petrochemical Complex effluent were isolated which consume phenol. Molecular analysis was used to identify bacteria ...
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Phenol is an environmental pollutant present in industrial wastewaters such as refineries, coal processing and petrochemicals products. In this study three phenol degrading bacteria from Arak Petrochemical Complex effluent were isolated which consume phenol. Molecular analysis was used to identify bacteria and isolated bacteria were identified as Rhodococcus pyridinivorans (NS1), Advenella faeciporci (NS2) and Pseudomonas aeroginosa (NS3). Among the isolated strains, NS1 had the highest ability to degrade phenol. In order to observe the best yield in phenol biodegradation using NS1, optimization was performed using one factor at a time of experimental design to investigate the effect of four factors, including pH, temperature, phosphate and urea concentration. The optimal biodegradation condition through or tho pathway was pH = 8, urea = 1 g/L, temperature = 30°C and K2HPO4 = 0.5 g/L. Under the suggested condition, a biodegradation efficiency of 100% was achieved. Moreover, NS1 has shown growth and phenol degradation in concentrations between 250 to 2000 mg/L. In a nutshell, the results revealed thatphenol efficiently consumed by NS1 as the sole carbon source. Obviously, the isolate strain may be seen as an important tool in the bioremediation of wastewater effluent, petrochemical complex.
H.M. Nasir; A. Azmi; A.Z. Aris; S.M. Praveena
Abstract
Heavy metal contamination in the environment could cause harmful effects both to human health and aquatic life. Numerous remediation methods had been developed to encounter with the contamination problem prior to degrade, decrease and to purify the contaminated water at minimal concentration as low as ...
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Heavy metal contamination in the environment could cause harmful effects both to human health and aquatic life. Numerous remediation methods had been developed to encounter with the contamination problem prior to degrade, decrease and to purify the contaminated water at minimal concentration as low as possible. Therefore, in current study, commercialized chicken eggshells and hybrid Akar Putra chicken eggshells were conducted in batch experiment to testify the capabilities of bio-sorbent materials in iron (II) ion removal from aqueous solution at optimized level of dosage and equilibrium contact time. The optimum condition for iron (II) removal for commercialized chicken eggshells and hybrid Akar Putra chicken eggshells bio-sorbents reached at 0.30 g with optimum contact time of 50 minutes and 91.83% and 91.07% of removal percentage with 0.60 g at 40 minutes. The final concentration from both bio-sorbents is achieved below than drinking water guideline (0.30 mg/L), 0.1635 mg/L and 0.1785 mg/L, respectively. The isotherm adsorption results showed it fitted better in Langmuir Isotherm Model than in Freundlich Isotherm Model, however with weak bonding, which could not held onto the heavy metal ions in long time period. In brief, commercialized chicken eggshells and hybrid Akar Putra chicken eggshells have considerable potential in removing heavy metal in aqueous solution. The selection of the bio-sorbent materials is more favorable as it reduces dependency towards chemical usage in water treatment which could have complied with drinking water guideline that can be obtained easily, abundance in amount, cheap and biodegradable.
D. Sivakumar
Abstract
The isolated fungi species of different kinds from chromium contaminated soil sites located in Nagalkeni, Chennai were used for reducing chromium(VI) in a tannery industry wastewater of Nagalkeni, Chennai. The experiments were conducted to know biosorption potential of isolated fungi species for ...
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The isolated fungi species of different kinds from chromium contaminated soil sites located in Nagalkeni, Chennai were used for reducing chromium(VI) in a tannery industry wastewater of Nagalkeni, Chennai. The experiments were conducted to know biosorption potential of isolated fungi species for removing chromium(VI) in a tannery industry wastewater against the different pH, fungi biomass and chromium(VI) concentration (dilution ratio). The results of this study indicated that the order of maximum removal of chromium(VI) by an isolated fungi species at an optimum pH of 3, fungi biomass of 4g andan initial chromium(VI) concentration of 18.125 mg/L (dilution ratio 4)is A. niger > A. flavus > A. fumigatus > A. nidulans > A. heteromorphus > A. foetidus > A. viridinutans. This study found that the maximum removal of chromium(VI) was achieved by Aspergillus niger (96.3 %) than other fungi species at chromium(VI) concentration of 18.125 mg/Lin a tannery industry wastewater. The chromium removal from tannery industry wastewater was validated by checking chromium removal in an aqueous solution and by checking the removal efficiency of other parameters in a tannery industry wastewater using same isolated A. niger. Biosorption model was proposed to simulate the experimental condition for removing chromium(VI) in a tannery industry wastewater by all isolated fungi species. The R2 and values of the proposed model predicted that the proposed biosorption model is very much useful for predicting the trend of reduction potential of chromium(VI) in a tannery industry wastewater by all isolated fungi species. This study suggested that one could select the type of fungi species, ion concentration level, selection of treatment period, quantity of biomass to be used, and pH level of the medium, to achieve the highest reduction of any toxic metals from any contaminated water, wastewater and soil environment.