Two yeast strains are enriched and isolated from industrial refinery wastewater. These strains we... more Two yeast strains are enriched and isolated from industrial refinery wastewater. These strains were observed for their ability to utilize several classes of petroleum hydrocarbons substrates, such as n-alkanes and aromatic hydrocarbons as a sole carbon source. Phylogenetic analysis based on the D1/D2 variable domain and the ITS-region sequences indicated that strains HC1 and HC4 were members of the genera Candida and Trichosporon, respectively. The mechanism of hydrocarbon uptaking by yeast, Candida, and Trichosporon has been studied by means of the kinetic analysis of hydrocarbons-degrading yeasts growth and substrate assimilation. Biodegradation capacity and biomass quantity were daily measured during twelve days by gravimetric analysis and gas chromatography coupled with mass spectrometry techniques. Removal of n-alkanes indicated a strong ability of hydrocarbon biodegradation by the isolated yeast strains. These two strains grew on long-chain n-alkane, diesel oil, and crude oil ...
Background: This study aimed to investigate the effects of bacterial lipase on biogas production ... more Background: This study aimed to investigate the effects of bacterial lipase on biogas production of anaerobic codigestion of slaughterhouse wastewater (SHWW) and hydrolyzed grease (HG). A neutrophilic Staphylococcus xylosus strain exhibiting lipolytic activity was used to perform microbial hydrolysis pretreatment of poultry slaughterhouse lipid rich waste. Results: Optimum proportion of hydrolyzed grease was evaluated by determining biochemical methane potential. A high biogas production was observed in batch containing a mixture of slaughterhouse composed of 75% SHWW and 25% hydrolyzed grease leading to a biogas yield of 0.6 L/g COD introduced. Fixed bed reactor (FBR) results confirmed that the proportion of 25% of hydrolyzed grease gives the optimum condition for the digester performance. Biogas production was significantly high until an organic loading rate (OLR) of 2 g COD/L. d. Conclusion: This study indicates that the use of biological pre-treatment and FBR for the co-digestion of SHWW and hydrolyzed grease is feasible and effective.
Research was undertaken to investigate whether low, medium or high molecular-mass polyphenolics w... more Research was undertaken to investigate whether low, medium or high molecular-mass polyphenolics were the most problematic compounds for olive mill wastewater (OMW) biotreatments. For this reason, three polyphenolic fractions were isolated by ultrafiltration of crude OMW and characterized by GC/MS and gel filtration analysis. When P. chrysosporium was cultivated in the presence of F1 polyphenolic fraction (F1 B 8 kDa), the decolorization/depolymerization was high. However, a very weak decolorization/depolymerization of the F3 fraction (F3 \60 kDa) was observed. Lignin peroxidase (LiP) was detected as traces for the F1 fraction and undetected in the case of F3 one. Moreover, increasing the molecular-mass of aromatics led to decreases in levels of depolymerization and COD removal by P. chrysosporium cultures. The use of a lignin peroxidase induction medium has a positive effect on the high molecular-mass fraction decolorization and a high degree of decolorization paralleled the appearance of LiP activity in the extracellular fluid. By comparison to the synthetic medium used, LiP production was delayed in the presence of F1 fraction but strongly inhibited (80% loss) in the presence of F3 fraction. The F1 fraction was well degraded aerobically by P. putida DSM3932 (pWWO) and A. eutrophus DSM 4057 (pJP3) or an activated sludge consortium while F3 resisted degradation by the OMW-acclimated activated sludge. Moreover, continuous anaerobic biomethanization experiments conducted in parallel with the different fractions showed that at the same hydraulic retention time (26 days), the F1 fraction was bioconverted into methane at high yield while F3 fraction was poorly biodegraded.
Landfill leachate (LFL) collected from the controlled discharge of Jebel Chakir in Tunisia was tr... more Landfill leachate (LFL) collected from the controlled discharge of Jebel Chakir in Tunisia was treated without any physical or chemical pretreatment in an anaerobic membrane bioreactor (AnMBR). The organic loading rate (OLR) in the AnMBR was gradually increased from 1 g COD l −1 d −1 to an average of 6.27 g COD l −1 d −1. At the highest OLR, the biogas production was more than 3 volumes of biogas per volume of the bioreactor. The volatile suspended solids (VSSs) reached a value of approximately 3 g l −1 in the bioreactor. At stable conditions, the treatment efficiency was high with an average COD reduction of 90% and biogas yield of 0.46 l biogas per g COD removed.
Young landfill leachates (LFL) collected from Djebel Chekir (Tunisia) discharge area were found t... more Young landfill leachates (LFL) collected from Djebel Chekir (Tunisia) discharge area were found to be highly loaded with organic matter, ammonia, salts, heavy metals, phenols and hydrocarbons. Despite the possibility of their biodegradability, they represent a threat to the environment and show some resistance to conventional wastewater treatment processes. For these reasons, this study attempted to develop a biological process for the treatment of LFL using selected strains of Trametes trogii, Phanerochaete chrysosporium, Lentinus tigrinus and Aspergillus niger. Experiments were undertaken at different concentrations of the effluent up to 100%. COD removal efficiencies for P. chrysosporium, T. trogii and L. tigrinus were of 68, 79 and 90%, respectively, when LFL underwent a two-fold dilution. COD abatements were accompanied with an important enzyme secretion and a high reduction in the toxicity, expressed as percent bioluminescence inhibition (%BI<20%). Above 50% of LFL, the effluent was toxic to these strains and caused growth inhibition indicating the sensitivity of these strains to concentrated LFL. Comparatively to the other tested strains, A. niger showed to tolerate raw LFL since it grew at 100% of LFL. However, this strain is inefficient in removing phenols and hydrocarbons. Consequently, toxicity abatement was very low (%BI>70%).
Water environment research : a research publication of the Water Environment Federation, 2017
A full-scale study has been conducted to assess the bioaugmentation efficiency of trickling fil... more A full-scale study has been conducted to assess the bioaugmentation efficiency of trickling filter process to treat petrochemical wastewater from a lubricant industry recycling waste oils. During 45 weeks, the organic loading rate (OLR) in the trickling filter was increased stepwise from 0.9 to 4 kg of chemical oxygen demand (COD)/(m3·day) at the end of the upgrading period as the flow rate (FR) reached the value of 30 m3/day. The removal, obtained in terms of percentage, for COD ranged from 60 to 84.5 and greater than 98 for total n-alkane (TNA), while those of total kjeldahl nitrogen (TKN) and total phosphor (TP) were about 32 and 55, respectively. The analytical profile index (API) of trickling biofilm has confirmed that 5 strains are closely related to Acinobacter junii, Stenotrophomonas maltophilia, Vibrio vulnificus, Vibrio metschnikovi, Pseudomona slulzeri and Trichosporon spp2.
Anaerobic digestion is an environmentally sustainable technology for converting a variety of orga... more Anaerobic digestion is an environmentally sustainable technology for converting a variety of organic solid feedstocks to energy in the form of methane. To improve methane yield, the digestion of more than one waste is commonly applied. This study aimed to investigate the dry anaerobic co-digestion (TS of 20%) of vegetable wastes (VW) and animal manures (cow manure (CM) and poultry manure (PM)) through conducting biochemical methane potential (BMP) assays at different substrate to inoculum (S/I) ratio. Fractionation and fluorescence analyses showed that organic matter of VW was less accessible and less complex compared to that of CM and PM. The highest methane yields of mono-digestion experiments were registered with S/I 0.5. Best results of methane yield were observed by the co-digestion of VW and CM (284 mL/g VS), which was about 2.3-fold higher than that of VW mono-fermentation. This finding was confirmed at a laboratory-scale leach bed reactor. Result showed an increase of biogas yield from 220 to 445 mL/g VS, during mono and co-digestion, respectively. The co-digestion of VW and CM mixture led to the enhancement of both methane yield and digestate quality in comparison to mono-digestion.
Soils are perplexing combinations of minerals, water, air, natural matter, and innumerable living... more Soils are perplexing combinations of minerals, water, air, natural matter, and innumerable living beings that are the rotting survives from once living things. Soils fill in as media for development of a wide range of plants. We can say soil is an important ingredient of agriculture. There are a few sorts of soils and each kind of soil can have various types of highlights and various types of yields develop on various sorts of soils. We must know which type of our soil is go better in our soil. We can apply AI procedures to group soil and to anticipate the yield reasonable.
Organic matter amendments have been proposed as a means to enhance soil carbon stocks on degraded... more Organic matter amendments have been proposed as a means to enhance soil carbon stocks on degraded soils particularly under arid climate. Soil organic carbon (SOC) plays a critical role in terrestrial carbon cycling and is central to preserving soil quality. The effects of biowastes compost (BWC) on soil carbon storage were investigated. Besides, changes in soil organic matter (SOM) and even soil organic carbon (SOC) in BWC amended soils following different applications were studied. The added BWC quantities were as followed: BWC/Soil (weight/weight (w/w) respectively: 1/8, 1/4 and 1/2). The different BWC amended soils were assessed during 180 days under arid ambient conditions and in comparison with control soil. Results showed a significant increase in SOM and SOC with relation to BWC quantities applied. This increase was relatively clear up to 120 days, after which a decrease in SOM and SOC levels were observed. Furthermore, results showed improved microbiological activities of the amended soils in comparison with the control soil. This was reflected by the raise of the amended soils respirometric activities as cumulative C-CO2 in function of incubation time and also in terms of specific respiration expressed as C-CO2/SOC ratios.
Phosphate ore processing wastewater (WWPP) from the Gafsa phosphate region of Tunisia was charact... more Phosphate ore processing wastewater (WWPP) from the Gafsa phosphate region of Tunisia was characterized. The WWPP had a very high turbidity, an almost neutral or slightly alkaline pH, and high salinity. The average chemical and biochemical oxygen demands (COD and BOD) met wastewater discharge standards, but the COD/BOD5 (4.34) significantly exceeded biodegradability values. Total nitrogen, residual phosphorus, and some others chemical constituents exceeded wastewater discharge standards. Microbiological enumeration showed that the effluents were very low in microflora. Untreated WWPP and diluted (WWPP/4) inhibited bioluminescence of Vibrio fischeri by 76 and 45%, respectively. The WWPP had a phytotoxicity rate of 20–70%, respectively, for alfalfa and tomato seeds. Adding the effluent to soil for 60 days reduced the residual phytotoxicity of the WWPP-irrigated soil to about 15 and 34%, respectively, for tomato and alfalfa seeds.ZusammenfassungAbwasser der Phosphatgesteinsverarbeitung in der Gafsa-Phosphatregion in Tunesien wurde charakterisiert. Das Abwasser hatte eine sehr hohe Trübung, nahezu neutrale bis schwach alkalische pH-Werte und eine hohe Salinität. Der durchschnittliche chemische und biochemische Sauerstoffbedarf (CSB und BSB5) entsprach den Abwasserableitungsstandards. Jedoch überstieg das Verhältnis CSB/BSB5 (4,34) signifikant die Werte für biologische Abbaubarkeit. Gesamtstickstoff, Phosphor und andere chemische Wasserinhaltsstoffe überschritten die Abwasserableitungsstandards. Zählungen der Mikroorganismen ergaben, dass die Besiedlung mit Mikroorganismen sehr gering war. Unbehandeltes Abwasser der Phosphatgesteinsverarbeitung hemmte die Biolumineszenz von Vibrio fischeri zu 75% und verdünntes (1:4) Abwasser der Phosphatgesteinsverarbeitung zu 45%. Das Abwasser der Phosphatgesteinsverarbeitung hatte eine Phytotoxizität von 20 bis 70% bei Samen von Alfagras und Tomaten. Die Wechselwirkung des Abwassers der Phosphatgesteinsverarbeitung mit Boden für 60 Tage verringerte die Phytotoxizität bei Tomaten- und Alfagrassamen auf 15% bzw. 34%, wenn der Boden mit Abwasser der Phosphatgesteinsverarbeitung bewässert wurde.ResumenSe caracterizó el agua residual proveniente del procesamiento de mineral fosfatado (WWPP) en la región Gafsa de Túnez. WWPP tenía una muy alta turbidez, un pH casi neutro o ligeramente alcalino y una alta salinidad. Las demandas química y bioquímica de oxígeno (COD y BOD), en promedio, cumplieron los estándares para agua de descarga pero COD/BOD5 (4,34) excedieron significativamente los valores de biodegradabilidad. El nitrógeno total, el fósforo residual y algunos otros constituyentes químicos excedieron los estándares para agua de descarga. El conteo microbiológico mostró que los efluentes tuvieron baja microflora. Tanto WWPP como su dilución (WWPP/4) inhibieron la bioluminiscencia de Vibrio fischeri en 76% y 45%, respectivamente. WWPP tiene una tasa de fitotoxicidad de 20 a 70% para semillas de alfalfa y de tomate, respectivamente. El agregado del efluente al suelo por 60 días redujo la fitotoxicidad residual del suelo irrigado con WWPP en 15% y 34% para semillas de tomate y de alfalfa, respectivamente.突尼斯磷矿加工废水及毒理特征研究了突尼斯Gafsa磷矿区矿石加工废水(WWPP)的特征。磷矿石加工废水以浊度高、中~微碱性和矿化度高为特征。磷矿石加工废水的平均化学需氧量(COD)和生物需氧量(BOD)都满足废水排放标准,但是它们的比值COD/BOD (4.34)却严重超出生物降解能力。磷矿石加工废水的总氮、残余磷和某些其它化学成分也超过废水排放标准。微生物枚举分析显示磷矿石加工废水的微生物群落数量非常少。未处理的和四倍稀释(WWPP/4)的磷矿加工废水对Vibrio fischeri荧光抑制分别达76%和45%。磷矿石废水对苜蓿(alfalfa)种子和番茄(tomato)种子的植物毒性分别为20%和70%。磷矿加工废水排放至土壤中60天后可减小磷矿加工废水灌溉土壤对苜蓿种子和番茄残种子植物毒性的15%和34%。
A continuously stirred tank bioreactor (CSTR) was used to optimize feasible and reliable bioproce... more A continuously stirred tank bioreactor (CSTR) was used to optimize feasible and reliable bioprocess system in order to treat hydrocarbon-rich industrial wastewaters. A successful bioremediation was developed by an efficient acclimatized microbial consortium. After an experimental period of 225 days, the process was shown to be highly efficient in decontaminating the wastewater. The performance of the bioaugmented reactor was demonstrated by the reduction of COD rates up to 95%. The residual total petroleum hydrocarbon (TPH) decreased from 320 mg TPH l −1 to 8 mg TPH l −1. Analysis using gas chromatography-mass spectrometry (GC-MS) identified 26 hydrocarbons. The use of the mixed cultures demonstrated high degradation performance for hydrocarbons range n-alkanes (C10-C35). Six microbial isolates from the CSTR were characterized and species identification was confirmed by sequencing the 16S rRNA genes. The partial 16S rRNA gene sequences demonstrated that 5 strains were closely related to Aeromonas punctata (Aeromonas caviae), Bacillus cereus, Ochrobactrum intermedium, Stenotrophomonas maltophilia and Rhodococcus sp. The 6th isolate was affiliated to genera Achromobacter. Besides, the treated wastewater could be considered as non toxic according to the phytotoxicity test since the germination index of Lepidium sativum ranged between 57 and 95%. The treatment provided satisfactory results and presents a feasible technology for the treatment of hydrocarbon-rich wastewater from petrochemical industries and petroleum refineries.
The petrochemical industry generates series of liquid and solid wastes containing large amounts o... more The petrochemical industry generates series of liquid and solid wastes containing large amounts of priority pollutants during the petroleum-refining process. These residues must be treated through depuration processes. The bioremediation process, presenting countless advantages in relation to other processes employed, is an evolving method for the removal and the transformation of many environmental pollutants including those produced by the petroleum industry. In a first step, a continuously stirred tank bioreactor (CSTR) was used to optimize feasible and reliable bioprocess system for successful bioremediation of industrial effluent and to develop an efficient microbial consortium for the degradation of petroleum hydrocarbons. After an experimental period of 175 days, the process was shown to be highly efficient in decontaminating the wastewater. The performance of the bio augmented reactor was demonstrated by the reduction of COD rates up to 95%. Six microbial isolates from the CSTR were characterized and species identification was confirmed by sequencing the 16 S rRNA genes. Besides, the treated wastewater could be considered as non toxic according to the micro-toxicity test. In a second step, bioremediation of a refinery soil containing hydrocarbons climate was investigated. The objective of this study was to assess the ability of bioremediation technique in the presence of the acclimatized consortium to reduce the total petroleum hydrocarbon (TPH) content in the contaminated soil. Results clearly demonstrated that an enhanced bioremediation was carried when the acclimatized bacterial consortium was added to the hydrocarbons contaminated soil. The proposed bioremediation technology has proved significantly higher hydrocarbons removal efficiencies. TPH analysis showed that 50% of the hydrocarbons were eliminated during the first 15 days of bio remediation. TPH removal reached 96% at the end of the treatment. Further, GC/MS profile has proved that the acclimatized bacterial consortium could effectively remove the medium- and long-chain alkanes in the contaminated soil such as the alkanes were undetectable after a 30-day of incubation period. In a third step, a Halomonas sp. strain C2SS100 had been isolated and characterized from Sercina petroleum reservoir. The strain had shown potential hydrocarbon degradation under halophilic condition (100 g 1−1 NaCl). During growth on n-Hexadecane (C16), C2SS100 produced biosurfactant that could solubilise phenanthrene, a three-ring aromatic hydrocarbon. The halophilic character of this bacterium could add further advantages for its use in marine and saline environments-oil bioremediation.
To test the potential use of Phanerochaete chrysosporium and other white-rot fungi to detoxify ol... more To test the potential use of Phanerochaete chrysosporium and other white-rot fungi to detoxify olive mill wastewaters (OMW) in the presence of a complex activated sludge. To combine the aerobic with anaerobic treatment to optimize the conversion of OMW in biogas. A 25-l air lift reactor was used to pretreat OMW by white-rot fungi. Detoxification of the OMW was monitored by size exclusion HPLC analysis, chemical oxygen demand (COD)/biological oxygen demand (BOD(5)) ratio evolution, and bioluminescence toxicity test. Anaerobic treatment of OMW was performed in a 12-l anaerobic filter reactor. Efficiency of the treatment was evaluated by organic matter removal, and biogas production. By comparison with the pretreatment by activated sludge only, the bioaugmentation with Phanerochaete chrysosporium or Trametes versicolor led to high removal of organic matter, decreased the COD/BOD(5) ratio and the toxicity. The subsequent anaerobic digestion of the OMW pretreated with activated sludge-white-rot fungi showed higher biomethanization yields than that pretreated with activated sludge only. Higher loading rates (7 g COD l(-1) day(-1)) were reached without any acidification or inhibition of biomethanization. The use of white-rot fungi, even in the presence of complex biological consortia to detoxify OMW, proved to be possible and made the anaerobic digestion of OMW for methane production feasible. The use of fungi for OMW reuse and energy production could be adapted to industrial applications.
Liquid-liquid extraction was used in order to recover phenolic compounds from centrifuged olive m... more Liquid-liquid extraction was used in order to recover phenolic compounds from centrifuged olive mill wastewater (OMW), a polluting byproduct of olive oil production process, and to reduce their toxicity for a subsequent aerobic or anaerobic digestion. Phenolic compounds were identified in untreated and treated OMW by gas chromatography coupled to mass spectrometry (GC-MS). The experimental results of ethyl acetate extraction showed that the monomers recovery efficiency was over 90%. This pre-treatment resulted in the removal of the major LMM phenolic compounds and a small part of HMM polyphenols. The aerobic treatment of the exhausted OMW fraction removed 78.7% of the soluble COD. In the case of anaerobic digestion at OLR ranged from 1 to 3.5 g COD l −1 day −1 , methanisation process exhibited high methane yield as 0.3 l CH 4 produced per g COD introduced and high COD removal (80%). However, a disruption of the process was observed when the OLR was increased to 4.5 g COD l −1 day −1. A pre-treatment by electro-coagulation resulted in decreasing the toxicity and enhancing the performance of methanisation operated at higher OLR from 4 to 7.5 g COD l −1 day −1 .
A continuously stirred tank bioreactor (CSTR) was used to optimize feasible and reliable bioproce... more A continuously stirred tank bioreactor (CSTR) was used to optimize feasible and reliable bioprocess system in order to treat hydrocarbon-rich industrial wastewaters. A successful bioremediation was developed by an efficient acclimatized microbial consortium. After an experimental period of 225 days, the process was shown to be highly efficient in decontaminating the wastewater. The performance of the bioaugmented reactor was demonstrated by the reduction of COD rates up to 95%. The residual total petroleum hydrocarbon (TPH) decreased from 320 mg TPH l −1 to 8 mg TPH l −1. Analysis using gas chromatography-mass spectrometry (GC-MS) identified 26 hydrocarbons. The use of the mixed cultures demonstrated high degradation performance for hydrocarbons range n-alkanes (C10-C35). Six microbial isolates from the CSTR were characterized and species identification was confirmed by sequencing the 16S rRNA genes. The partial 16S rRNA gene sequences demonstrated that 5 strains were closely related to Aeromonas punctata (Aeromonas caviae), Bacillus cereus, Ochrobactrum intermedium, Stenotrophomonas maltophilia and Rhodococcus sp. The 6th isolate was affiliated to genera Achromobacter. Besides, the treated wastewater could be considered as non toxic according to the phytotoxicity test since the germination index of Lepidium sativum ranged between 57 and 95%. The treatment provided satisfactory results and presents a feasible technology for the treatment of hydrocarbon-rich wastewater from petrochemical industries and petroleum refineries.
Journal of Chemical Technology & Biotechnology, 2013
ABSTRACT BACKGROUND: Bioaugmentation is a promising technology to clean up sites contaminated by ... more ABSTRACT BACKGROUND: Bioaugmentation is a promising technology to clean up sites contaminated by the petrochemical industry. The paper reports on the bioremediation of a refinery soil containing hydrocarbons in a semi-arid climate and its impact on the soil microbial community. Two trial plots were established in autumn 2008 to compare two sets of conditions. The first trial is a control (contaminated soil with indigenous microorganismes) and the second is a trial where an acclimatized bacterial consortium was added. RESULTS: The proposed bioremediation technology resulted in significantly higher hydrocarbons removal efficiencies than the control. The total amount of petroleum hydrocarbon (TPH) was decreased from 63.4 mg g −1 to 2.5 mg g −1 at the end of the treatment. The treated soil could be considered non-phytotoxic since the germination index of Lepidium sativum ranged between 80 and 115%. Further, a GC/MS profile proved that the acclimatized bacterial consortium could effectively remove medium-and long-chain alkanes in the contaminated soil after a 30-day treatment period. Microbial community analysis (16S rRNA and Denaturing Gradient Gel Electrophoresis (DGGE) fingerprints) confirmed the dominance of hydrocarbon degrading genera such as actinobacteria and gamma-proteobacteria phyla. CONCLUSION: These results show that bioaugmentation may be a suitable tool for the remediation of soil contaminated with petroleum hydrocarbons.
Effects of the untreated olive mill wastewater (UOMW) and the bioaugmented olive mill wastewater ... more Effects of the untreated olive mill wastewater (UOMW) and the bioaugmented olive mill wastewater (BOMW) with the fungus Phanerochaete chrysosporium (P. chrysosporium) for the amendment of soil were investigated. Results showed that UOMW inhibited the soil ...
Two yeast strains are enriched and isolated from industrial refinery wastewater. These strains we... more Two yeast strains are enriched and isolated from industrial refinery wastewater. These strains were observed for their ability to utilize several classes of petroleum hydrocarbons substrates, such as n-alkanes and aromatic hydrocarbons as a sole carbon source. Phylogenetic analysis based on the D1/D2 variable domain and the ITS-region sequences indicated that strains HC1 and HC4 were members of the genera Candida and Trichosporon, respectively. The mechanism of hydrocarbon uptaking by yeast, Candida, and Trichosporon has been studied by means of the kinetic analysis of hydrocarbons-degrading yeasts growth and substrate assimilation. Biodegradation capacity and biomass quantity were daily measured during twelve days by gravimetric analysis and gas chromatography coupled with mass spectrometry techniques. Removal of n-alkanes indicated a strong ability of hydrocarbon biodegradation by the isolated yeast strains. These two strains grew on long-chain n-alkane, diesel oil, and crude oil ...
Background: This study aimed to investigate the effects of bacterial lipase on biogas production ... more Background: This study aimed to investigate the effects of bacterial lipase on biogas production of anaerobic codigestion of slaughterhouse wastewater (SHWW) and hydrolyzed grease (HG). A neutrophilic Staphylococcus xylosus strain exhibiting lipolytic activity was used to perform microbial hydrolysis pretreatment of poultry slaughterhouse lipid rich waste. Results: Optimum proportion of hydrolyzed grease was evaluated by determining biochemical methane potential. A high biogas production was observed in batch containing a mixture of slaughterhouse composed of 75% SHWW and 25% hydrolyzed grease leading to a biogas yield of 0.6 L/g COD introduced. Fixed bed reactor (FBR) results confirmed that the proportion of 25% of hydrolyzed grease gives the optimum condition for the digester performance. Biogas production was significantly high until an organic loading rate (OLR) of 2 g COD/L. d. Conclusion: This study indicates that the use of biological pre-treatment and FBR for the co-digestion of SHWW and hydrolyzed grease is feasible and effective.
Research was undertaken to investigate whether low, medium or high molecular-mass polyphenolics w... more Research was undertaken to investigate whether low, medium or high molecular-mass polyphenolics were the most problematic compounds for olive mill wastewater (OMW) biotreatments. For this reason, three polyphenolic fractions were isolated by ultrafiltration of crude OMW and characterized by GC/MS and gel filtration analysis. When P. chrysosporium was cultivated in the presence of F1 polyphenolic fraction (F1 B 8 kDa), the decolorization/depolymerization was high. However, a very weak decolorization/depolymerization of the F3 fraction (F3 \60 kDa) was observed. Lignin peroxidase (LiP) was detected as traces for the F1 fraction and undetected in the case of F3 one. Moreover, increasing the molecular-mass of aromatics led to decreases in levels of depolymerization and COD removal by P. chrysosporium cultures. The use of a lignin peroxidase induction medium has a positive effect on the high molecular-mass fraction decolorization and a high degree of decolorization paralleled the appearance of LiP activity in the extracellular fluid. By comparison to the synthetic medium used, LiP production was delayed in the presence of F1 fraction but strongly inhibited (80% loss) in the presence of F3 fraction. The F1 fraction was well degraded aerobically by P. putida DSM3932 (pWWO) and A. eutrophus DSM 4057 (pJP3) or an activated sludge consortium while F3 resisted degradation by the OMW-acclimated activated sludge. Moreover, continuous anaerobic biomethanization experiments conducted in parallel with the different fractions showed that at the same hydraulic retention time (26 days), the F1 fraction was bioconverted into methane at high yield while F3 fraction was poorly biodegraded.
Landfill leachate (LFL) collected from the controlled discharge of Jebel Chakir in Tunisia was tr... more Landfill leachate (LFL) collected from the controlled discharge of Jebel Chakir in Tunisia was treated without any physical or chemical pretreatment in an anaerobic membrane bioreactor (AnMBR). The organic loading rate (OLR) in the AnMBR was gradually increased from 1 g COD l −1 d −1 to an average of 6.27 g COD l −1 d −1. At the highest OLR, the biogas production was more than 3 volumes of biogas per volume of the bioreactor. The volatile suspended solids (VSSs) reached a value of approximately 3 g l −1 in the bioreactor. At stable conditions, the treatment efficiency was high with an average COD reduction of 90% and biogas yield of 0.46 l biogas per g COD removed.
Young landfill leachates (LFL) collected from Djebel Chekir (Tunisia) discharge area were found t... more Young landfill leachates (LFL) collected from Djebel Chekir (Tunisia) discharge area were found to be highly loaded with organic matter, ammonia, salts, heavy metals, phenols and hydrocarbons. Despite the possibility of their biodegradability, they represent a threat to the environment and show some resistance to conventional wastewater treatment processes. For these reasons, this study attempted to develop a biological process for the treatment of LFL using selected strains of Trametes trogii, Phanerochaete chrysosporium, Lentinus tigrinus and Aspergillus niger. Experiments were undertaken at different concentrations of the effluent up to 100%. COD removal efficiencies for P. chrysosporium, T. trogii and L. tigrinus were of 68, 79 and 90%, respectively, when LFL underwent a two-fold dilution. COD abatements were accompanied with an important enzyme secretion and a high reduction in the toxicity, expressed as percent bioluminescence inhibition (%BI<20%). Above 50% of LFL, the effluent was toxic to these strains and caused growth inhibition indicating the sensitivity of these strains to concentrated LFL. Comparatively to the other tested strains, A. niger showed to tolerate raw LFL since it grew at 100% of LFL. However, this strain is inefficient in removing phenols and hydrocarbons. Consequently, toxicity abatement was very low (%BI>70%).
Water environment research : a research publication of the Water Environment Federation, 2017
A full-scale study has been conducted to assess the bioaugmentation efficiency of trickling fil... more A full-scale study has been conducted to assess the bioaugmentation efficiency of trickling filter process to treat petrochemical wastewater from a lubricant industry recycling waste oils. During 45 weeks, the organic loading rate (OLR) in the trickling filter was increased stepwise from 0.9 to 4 kg of chemical oxygen demand (COD)/(m3·day) at the end of the upgrading period as the flow rate (FR) reached the value of 30 m3/day. The removal, obtained in terms of percentage, for COD ranged from 60 to 84.5 and greater than 98 for total n-alkane (TNA), while those of total kjeldahl nitrogen (TKN) and total phosphor (TP) were about 32 and 55, respectively. The analytical profile index (API) of trickling biofilm has confirmed that 5 strains are closely related to Acinobacter junii, Stenotrophomonas maltophilia, Vibrio vulnificus, Vibrio metschnikovi, Pseudomona slulzeri and Trichosporon spp2.
Anaerobic digestion is an environmentally sustainable technology for converting a variety of orga... more Anaerobic digestion is an environmentally sustainable technology for converting a variety of organic solid feedstocks to energy in the form of methane. To improve methane yield, the digestion of more than one waste is commonly applied. This study aimed to investigate the dry anaerobic co-digestion (TS of 20%) of vegetable wastes (VW) and animal manures (cow manure (CM) and poultry manure (PM)) through conducting biochemical methane potential (BMP) assays at different substrate to inoculum (S/I) ratio. Fractionation and fluorescence analyses showed that organic matter of VW was less accessible and less complex compared to that of CM and PM. The highest methane yields of mono-digestion experiments were registered with S/I 0.5. Best results of methane yield were observed by the co-digestion of VW and CM (284 mL/g VS), which was about 2.3-fold higher than that of VW mono-fermentation. This finding was confirmed at a laboratory-scale leach bed reactor. Result showed an increase of biogas yield from 220 to 445 mL/g VS, during mono and co-digestion, respectively. The co-digestion of VW and CM mixture led to the enhancement of both methane yield and digestate quality in comparison to mono-digestion.
Soils are perplexing combinations of minerals, water, air, natural matter, and innumerable living... more Soils are perplexing combinations of minerals, water, air, natural matter, and innumerable living beings that are the rotting survives from once living things. Soils fill in as media for development of a wide range of plants. We can say soil is an important ingredient of agriculture. There are a few sorts of soils and each kind of soil can have various types of highlights and various types of yields develop on various sorts of soils. We must know which type of our soil is go better in our soil. We can apply AI procedures to group soil and to anticipate the yield reasonable.
Organic matter amendments have been proposed as a means to enhance soil carbon stocks on degraded... more Organic matter amendments have been proposed as a means to enhance soil carbon stocks on degraded soils particularly under arid climate. Soil organic carbon (SOC) plays a critical role in terrestrial carbon cycling and is central to preserving soil quality. The effects of biowastes compost (BWC) on soil carbon storage were investigated. Besides, changes in soil organic matter (SOM) and even soil organic carbon (SOC) in BWC amended soils following different applications were studied. The added BWC quantities were as followed: BWC/Soil (weight/weight (w/w) respectively: 1/8, 1/4 and 1/2). The different BWC amended soils were assessed during 180 days under arid ambient conditions and in comparison with control soil. Results showed a significant increase in SOM and SOC with relation to BWC quantities applied. This increase was relatively clear up to 120 days, after which a decrease in SOM and SOC levels were observed. Furthermore, results showed improved microbiological activities of the amended soils in comparison with the control soil. This was reflected by the raise of the amended soils respirometric activities as cumulative C-CO2 in function of incubation time and also in terms of specific respiration expressed as C-CO2/SOC ratios.
Phosphate ore processing wastewater (WWPP) from the Gafsa phosphate region of Tunisia was charact... more Phosphate ore processing wastewater (WWPP) from the Gafsa phosphate region of Tunisia was characterized. The WWPP had a very high turbidity, an almost neutral or slightly alkaline pH, and high salinity. The average chemical and biochemical oxygen demands (COD and BOD) met wastewater discharge standards, but the COD/BOD5 (4.34) significantly exceeded biodegradability values. Total nitrogen, residual phosphorus, and some others chemical constituents exceeded wastewater discharge standards. Microbiological enumeration showed that the effluents were very low in microflora. Untreated WWPP and diluted (WWPP/4) inhibited bioluminescence of Vibrio fischeri by 76 and 45%, respectively. The WWPP had a phytotoxicity rate of 20–70%, respectively, for alfalfa and tomato seeds. Adding the effluent to soil for 60 days reduced the residual phytotoxicity of the WWPP-irrigated soil to about 15 and 34%, respectively, for tomato and alfalfa seeds.ZusammenfassungAbwasser der Phosphatgesteinsverarbeitung in der Gafsa-Phosphatregion in Tunesien wurde charakterisiert. Das Abwasser hatte eine sehr hohe Trübung, nahezu neutrale bis schwach alkalische pH-Werte und eine hohe Salinität. Der durchschnittliche chemische und biochemische Sauerstoffbedarf (CSB und BSB5) entsprach den Abwasserableitungsstandards. Jedoch überstieg das Verhältnis CSB/BSB5 (4,34) signifikant die Werte für biologische Abbaubarkeit. Gesamtstickstoff, Phosphor und andere chemische Wasserinhaltsstoffe überschritten die Abwasserableitungsstandards. Zählungen der Mikroorganismen ergaben, dass die Besiedlung mit Mikroorganismen sehr gering war. Unbehandeltes Abwasser der Phosphatgesteinsverarbeitung hemmte die Biolumineszenz von Vibrio fischeri zu 75% und verdünntes (1:4) Abwasser der Phosphatgesteinsverarbeitung zu 45%. Das Abwasser der Phosphatgesteinsverarbeitung hatte eine Phytotoxizität von 20 bis 70% bei Samen von Alfagras und Tomaten. Die Wechselwirkung des Abwassers der Phosphatgesteinsverarbeitung mit Boden für 60 Tage verringerte die Phytotoxizität bei Tomaten- und Alfagrassamen auf 15% bzw. 34%, wenn der Boden mit Abwasser der Phosphatgesteinsverarbeitung bewässert wurde.ResumenSe caracterizó el agua residual proveniente del procesamiento de mineral fosfatado (WWPP) en la región Gafsa de Túnez. WWPP tenía una muy alta turbidez, un pH casi neutro o ligeramente alcalino y una alta salinidad. Las demandas química y bioquímica de oxígeno (COD y BOD), en promedio, cumplieron los estándares para agua de descarga pero COD/BOD5 (4,34) excedieron significativamente los valores de biodegradabilidad. El nitrógeno total, el fósforo residual y algunos otros constituyentes químicos excedieron los estándares para agua de descarga. El conteo microbiológico mostró que los efluentes tuvieron baja microflora. Tanto WWPP como su dilución (WWPP/4) inhibieron la bioluminiscencia de Vibrio fischeri en 76% y 45%, respectivamente. WWPP tiene una tasa de fitotoxicidad de 20 a 70% para semillas de alfalfa y de tomate, respectivamente. El agregado del efluente al suelo por 60 días redujo la fitotoxicidad residual del suelo irrigado con WWPP en 15% y 34% para semillas de tomate y de alfalfa, respectivamente.突尼斯磷矿加工废水及毒理特征研究了突尼斯Gafsa磷矿区矿石加工废水(WWPP)的特征。磷矿石加工废水以浊度高、中~微碱性和矿化度高为特征。磷矿石加工废水的平均化学需氧量(COD)和生物需氧量(BOD)都满足废水排放标准,但是它们的比值COD/BOD (4.34)却严重超出生物降解能力。磷矿石加工废水的总氮、残余磷和某些其它化学成分也超过废水排放标准。微生物枚举分析显示磷矿石加工废水的微生物群落数量非常少。未处理的和四倍稀释(WWPP/4)的磷矿加工废水对Vibrio fischeri荧光抑制分别达76%和45%。磷矿石废水对苜蓿(alfalfa)种子和番茄(tomato)种子的植物毒性分别为20%和70%。磷矿加工废水排放至土壤中60天后可减小磷矿加工废水灌溉土壤对苜蓿种子和番茄残种子植物毒性的15%和34%。
A continuously stirred tank bioreactor (CSTR) was used to optimize feasible and reliable bioproce... more A continuously stirred tank bioreactor (CSTR) was used to optimize feasible and reliable bioprocess system in order to treat hydrocarbon-rich industrial wastewaters. A successful bioremediation was developed by an efficient acclimatized microbial consortium. After an experimental period of 225 days, the process was shown to be highly efficient in decontaminating the wastewater. The performance of the bioaugmented reactor was demonstrated by the reduction of COD rates up to 95%. The residual total petroleum hydrocarbon (TPH) decreased from 320 mg TPH l −1 to 8 mg TPH l −1. Analysis using gas chromatography-mass spectrometry (GC-MS) identified 26 hydrocarbons. The use of the mixed cultures demonstrated high degradation performance for hydrocarbons range n-alkanes (C10-C35). Six microbial isolates from the CSTR were characterized and species identification was confirmed by sequencing the 16S rRNA genes. The partial 16S rRNA gene sequences demonstrated that 5 strains were closely related to Aeromonas punctata (Aeromonas caviae), Bacillus cereus, Ochrobactrum intermedium, Stenotrophomonas maltophilia and Rhodococcus sp. The 6th isolate was affiliated to genera Achromobacter. Besides, the treated wastewater could be considered as non toxic according to the phytotoxicity test since the germination index of Lepidium sativum ranged between 57 and 95%. The treatment provided satisfactory results and presents a feasible technology for the treatment of hydrocarbon-rich wastewater from petrochemical industries and petroleum refineries.
The petrochemical industry generates series of liquid and solid wastes containing large amounts o... more The petrochemical industry generates series of liquid and solid wastes containing large amounts of priority pollutants during the petroleum-refining process. These residues must be treated through depuration processes. The bioremediation process, presenting countless advantages in relation to other processes employed, is an evolving method for the removal and the transformation of many environmental pollutants including those produced by the petroleum industry. In a first step, a continuously stirred tank bioreactor (CSTR) was used to optimize feasible and reliable bioprocess system for successful bioremediation of industrial effluent and to develop an efficient microbial consortium for the degradation of petroleum hydrocarbons. After an experimental period of 175 days, the process was shown to be highly efficient in decontaminating the wastewater. The performance of the bio augmented reactor was demonstrated by the reduction of COD rates up to 95%. Six microbial isolates from the CSTR were characterized and species identification was confirmed by sequencing the 16 S rRNA genes. Besides, the treated wastewater could be considered as non toxic according to the micro-toxicity test. In a second step, bioremediation of a refinery soil containing hydrocarbons climate was investigated. The objective of this study was to assess the ability of bioremediation technique in the presence of the acclimatized consortium to reduce the total petroleum hydrocarbon (TPH) content in the contaminated soil. Results clearly demonstrated that an enhanced bioremediation was carried when the acclimatized bacterial consortium was added to the hydrocarbons contaminated soil. The proposed bioremediation technology has proved significantly higher hydrocarbons removal efficiencies. TPH analysis showed that 50% of the hydrocarbons were eliminated during the first 15 days of bio remediation. TPH removal reached 96% at the end of the treatment. Further, GC/MS profile has proved that the acclimatized bacterial consortium could effectively remove the medium- and long-chain alkanes in the contaminated soil such as the alkanes were undetectable after a 30-day of incubation period. In a third step, a Halomonas sp. strain C2SS100 had been isolated and characterized from Sercina petroleum reservoir. The strain had shown potential hydrocarbon degradation under halophilic condition (100 g 1−1 NaCl). During growth on n-Hexadecane (C16), C2SS100 produced biosurfactant that could solubilise phenanthrene, a three-ring aromatic hydrocarbon. The halophilic character of this bacterium could add further advantages for its use in marine and saline environments-oil bioremediation.
To test the potential use of Phanerochaete chrysosporium and other white-rot fungi to detoxify ol... more To test the potential use of Phanerochaete chrysosporium and other white-rot fungi to detoxify olive mill wastewaters (OMW) in the presence of a complex activated sludge. To combine the aerobic with anaerobic treatment to optimize the conversion of OMW in biogas. A 25-l air lift reactor was used to pretreat OMW by white-rot fungi. Detoxification of the OMW was monitored by size exclusion HPLC analysis, chemical oxygen demand (COD)/biological oxygen demand (BOD(5)) ratio evolution, and bioluminescence toxicity test. Anaerobic treatment of OMW was performed in a 12-l anaerobic filter reactor. Efficiency of the treatment was evaluated by organic matter removal, and biogas production. By comparison with the pretreatment by activated sludge only, the bioaugmentation with Phanerochaete chrysosporium or Trametes versicolor led to high removal of organic matter, decreased the COD/BOD(5) ratio and the toxicity. The subsequent anaerobic digestion of the OMW pretreated with activated sludge-white-rot fungi showed higher biomethanization yields than that pretreated with activated sludge only. Higher loading rates (7 g COD l(-1) day(-1)) were reached without any acidification or inhibition of biomethanization. The use of white-rot fungi, even in the presence of complex biological consortia to detoxify OMW, proved to be possible and made the anaerobic digestion of OMW for methane production feasible. The use of fungi for OMW reuse and energy production could be adapted to industrial applications.
Liquid-liquid extraction was used in order to recover phenolic compounds from centrifuged olive m... more Liquid-liquid extraction was used in order to recover phenolic compounds from centrifuged olive mill wastewater (OMW), a polluting byproduct of olive oil production process, and to reduce their toxicity for a subsequent aerobic or anaerobic digestion. Phenolic compounds were identified in untreated and treated OMW by gas chromatography coupled to mass spectrometry (GC-MS). The experimental results of ethyl acetate extraction showed that the monomers recovery efficiency was over 90%. This pre-treatment resulted in the removal of the major LMM phenolic compounds and a small part of HMM polyphenols. The aerobic treatment of the exhausted OMW fraction removed 78.7% of the soluble COD. In the case of anaerobic digestion at OLR ranged from 1 to 3.5 g COD l −1 day −1 , methanisation process exhibited high methane yield as 0.3 l CH 4 produced per g COD introduced and high COD removal (80%). However, a disruption of the process was observed when the OLR was increased to 4.5 g COD l −1 day −1. A pre-treatment by electro-coagulation resulted in decreasing the toxicity and enhancing the performance of methanisation operated at higher OLR from 4 to 7.5 g COD l −1 day −1 .
A continuously stirred tank bioreactor (CSTR) was used to optimize feasible and reliable bioproce... more A continuously stirred tank bioreactor (CSTR) was used to optimize feasible and reliable bioprocess system in order to treat hydrocarbon-rich industrial wastewaters. A successful bioremediation was developed by an efficient acclimatized microbial consortium. After an experimental period of 225 days, the process was shown to be highly efficient in decontaminating the wastewater. The performance of the bioaugmented reactor was demonstrated by the reduction of COD rates up to 95%. The residual total petroleum hydrocarbon (TPH) decreased from 320 mg TPH l −1 to 8 mg TPH l −1. Analysis using gas chromatography-mass spectrometry (GC-MS) identified 26 hydrocarbons. The use of the mixed cultures demonstrated high degradation performance for hydrocarbons range n-alkanes (C10-C35). Six microbial isolates from the CSTR were characterized and species identification was confirmed by sequencing the 16S rRNA genes. The partial 16S rRNA gene sequences demonstrated that 5 strains were closely related to Aeromonas punctata (Aeromonas caviae), Bacillus cereus, Ochrobactrum intermedium, Stenotrophomonas maltophilia and Rhodococcus sp. The 6th isolate was affiliated to genera Achromobacter. Besides, the treated wastewater could be considered as non toxic according to the phytotoxicity test since the germination index of Lepidium sativum ranged between 57 and 95%. The treatment provided satisfactory results and presents a feasible technology for the treatment of hydrocarbon-rich wastewater from petrochemical industries and petroleum refineries.
Journal of Chemical Technology & Biotechnology, 2013
ABSTRACT BACKGROUND: Bioaugmentation is a promising technology to clean up sites contaminated by ... more ABSTRACT BACKGROUND: Bioaugmentation is a promising technology to clean up sites contaminated by the petrochemical industry. The paper reports on the bioremediation of a refinery soil containing hydrocarbons in a semi-arid climate and its impact on the soil microbial community. Two trial plots were established in autumn 2008 to compare two sets of conditions. The first trial is a control (contaminated soil with indigenous microorganismes) and the second is a trial where an acclimatized bacterial consortium was added. RESULTS: The proposed bioremediation technology resulted in significantly higher hydrocarbons removal efficiencies than the control. The total amount of petroleum hydrocarbon (TPH) was decreased from 63.4 mg g −1 to 2.5 mg g −1 at the end of the treatment. The treated soil could be considered non-phytotoxic since the germination index of Lepidium sativum ranged between 80 and 115%. Further, a GC/MS profile proved that the acclimatized bacterial consortium could effectively remove medium-and long-chain alkanes in the contaminated soil after a 30-day treatment period. Microbial community analysis (16S rRNA and Denaturing Gradient Gel Electrophoresis (DGGE) fingerprints) confirmed the dominance of hydrocarbon degrading genera such as actinobacteria and gamma-proteobacteria phyla. CONCLUSION: These results show that bioaugmentation may be a suitable tool for the remediation of soil contaminated with petroleum hydrocarbons.
Effects of the untreated olive mill wastewater (UOMW) and the bioaugmented olive mill wastewater ... more Effects of the untreated olive mill wastewater (UOMW) and the bioaugmented olive mill wastewater (BOMW) with the fungus Phanerochaete chrysosporium (P. chrysosporium) for the amendment of soil were investigated. Results showed that UOMW inhibited the soil ...
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