Perspectives on Biological Treatment of Sanitary Landfill Leachate

Landfilling, one of the prevailing worldwide waste management strategies, is presented together with its benefits and environmental risks. Aside from biogas, another non-avoidable product of landfilling is landfill leachate, which usually contains a variety of potentially hazardous inorganic and organic compounds. It can be treated by different physico-chemical and biological methods and their combinations. The composition and characteristics of landfill leachate are presented from the aspect of biotreatability. The treatment with activated sludge, mainly consisting of bacterial cultures under aerobic and anaerobic conditions in various reactor systems, is explained, including an extensive literature review. The potential of fungi and their extracellular enzymes for treatment of municipal landfill leachates is also presented, with a detailed review of the landfill leachate treatment studies. The future perspectives of biological treatment are also discussed

Biodegradation Kinetics of Phenol, 2,4,6-Trichlorophenol and Pentachlorophenol with ligninolytic enzymes from Dichomitus Squalens

Biodegradation of phenol, 2,4,6-trichlorophenol and pentachlorophenol was investigated using Dichomitus squalens cultivation media filtrates with initial laccase and manganese peroxidase activities of 1000 U L-1 and 300 U L-1, respectively. Decomposition of all three biocides was studied at T = 28 °C, pH = 4.5 and initial concentrations around 6 mg L-1 and the kinetics evaluated on the basis of the time course of the biocide concentration data. Integral analysis revealed 1st order reaction for all three pollutants and the corresponding reaction rate constants and initial concentrations for phenol, 2,4,6-TCP and PCP were estimated from linearized experimental data. The rate equations obtained allow estimation of the times necessary for a particular biocide conversion. The toxicity of reactants and products to the bacterium Vibrio fischeri before and after 48-hours degradation showed that the products were less toxic than the reactants in all three cases. The initial solutions of the three toxic substances caused 54 - 62 % inhibition of the bacterium Vibrio fischeri, while after 48 hours of degradation, 57 % reduction in the toxicity of phenol, 50 % reduction of 2,4,6-TCP and 29 % reduction of PCP was achieved.Â

Biosorpcija olova u laboratorijskoj koloni s nasutim slojem imobilizirane biomase gljive Rhizopus nigricans u obliku peleta: matematički model i pokusi

The biosorption of lead ions from aqueous solution on a self-immobilized Rhizopus nigricans biomass has been studied. Experiments were performed in a laboratory scale packed bed column at different liquid flow rates and biosorbent bed heights. Recorded experimental breakthrough curves were compared to those predicted by a mathematical model, which was developed to simulate a packed bed biosorption process by a soft, self-immobilized fungal biosorbent. In the range of examined experimental conditions, the biomass characteristics such as pellet porosity and biosorption capacity substantially affected the predicted response curve. General correlations for the estimation of the intra-pellet effective diffusivity, the external mass transfer coefficient, as well as axial dispersion were successfully applied in this biological system with specific mechanical properties. Under the experimental conditions, mass transfer is controlled by the external film resistance, while the intra-pellet mass transfer resistance, as well as the effect of axial dispersion, can be neglected. A new parameter α, the fraction of active biomass, with an average value of α=0.7, was introduced to take into account the specific biomass characteristics, and consequently the observed non-ideal liquid flow through the bed of fungal pellets.Ispitivana je biosorpcija iona olova iz vodene otopine na imobiliziranu biomasu gljive Rhizopus nigricans. Pokusi su provedeni u laboratorijskoj koloni s nasutim slojem, pri različitom protoku vodene otopine i visini sloja biosorbenta. Krivulje su proboja uspoređene s krivuljama izračunatim pomoću matematičkoga modela, razvijenog za simulaciju adsorpcije na pelete meke biomase gljive. Na izračunatu su krivulju znatno utjecali poroznost i adsorpcijski kapacitet biomase. U tom su biološkom sustavu specifičnih mehaničkih svojstava uspješno primijenjene općenite korelacije radi procjene stvarne difuzivnosti i koeficijenta prijenosa tvari unutar peleta, te koeficijenta aksijalne disperzije. Pri eksperimentalnim je uvjetima prijenos tvari kontroliran otporom unutar ovojnice peleta, dok se otpor unutar samoga peleta i aksijalna disperzija mogu lako zanemariti. U model je uveden novi parameter α, koji je dio aktivne biomase, a iznosi 0,7. Tako su uzete u obzir specifične značajke biomase te neidealan protok vodene otopine kroz sloj peleta gljiva

Lead Biosorption by Self-Immobilized Rhizopus nigricans Pellets in a Laboratory Scale Packed Bed Column: Mathematical Model and Experiment

The biosorption of lead ions from aqueous solution on a self-immobilized Rhizopus nigricans biomass has been studied. Experiments were performed in a laboratory scale packed bed column at different liquid flow rates and biosorbent bed heights. Recorded experimental breakthrough curves were compared to those predicted by a mathematical model, which was developed to simulate a packed bed biosorption process by a soft, self-immobilized fungal biosorbent. In the range of examined experimental conditions, the biomass characteristics such as pellet porosity and biosorption capacity substantially affected the predicted response curve. General correlations for the estimation of the intra-pellet effective diffusivity, the external mass transfer coefficient, as well as axial dispersion were successfully applied in this biological system with specific mechanical properties. Under the experimental conditions, mass transfer is controlled by the external film resistance, while the intra-pellet mass transfer resistance, as well as the effect of axial dispersion, can be neglected. A new parameter α, the fraction of active biomass, with an average value of α=0.7, was introduced to take into account the specific biomass characteristics, and consequently the observed non-ideal liquid flow through the bed of fungal pellets

Optimization of Ligninolytic Enzyme Activity and Production Rate with Ceriporiopsis subvermispora for Application in Bioremediation by Varying Submerged Media Composition and Growth Immobilization Support

Response surface methodology (central composite design of experiments) was employed to simultaneously optimize enzyme production and productivities of two ligninolytic enzymes produced by Ceriporiopsis subvermispora. Concentrations of glucose, ammonium tartrate and Polysorbate 80 were varied to establish the optimal composition of liquid media (OLM), where the highest experimentally obtained activities and productivities were 41 U L−1 and 16 U L−1 day−1 for laccase (Lac), and 193 U L−1 and 80 U L−1 day−1 for manganese peroxidase (MnP). Considering culture growth in OLM on various types of immobilization support, the best results were obtained with 1 cm beech wood cubes (BWCM). Enzyme activities in culture filtrate were 152 U L−1 for Lac and 58 U L−1 for MnP, since the chemical composition of this immobilization material induced higher Lac activity. Lower enzyme activities were obtained with polyurethane foam. Culture filtrates of OLM and BWCM were applied for dye decolorization. Remazol Brilliant Blue R (RBBR) was decolorized faster and more efficiently than Copper(II)phthalocyanine (CuP) with BWCM (80% and 60%), since Lac played a crucial role. Decolorization of CuP was initially faster than that of RBBR, due to higher MnP activities in OLM. The extent of decolorization after 14 h was 60% for both dyes

Biodegradation Kinetics of Phenol, 2,4,6-Trichlorophenol and Pentachlorophenol with ligninolytic enzymes from Dichomitus Squalens

Biodegradation of phenol, 2,4,6-trichlorophenol and pentachlorophenol was investigated using Dichomitus squalens cultivation media filtrates with initial laccase and manganese peroxidase activities of 1000 U L-1 and 300 U L-1, respectively. Decomposition of all three biocides was studied at T = 28 °C, pH = 4.5 and initial concentrations around 6 mg L-1 and the kinetics evaluated on the basis of the time course of the biocide concentration data. Integral analysis revealed 1st order reaction for all three pollutants and the corresponding reaction rate constants and initial concentrations for phenol, 2,4,6-TCP and PCP were estimated from linearized experimental data. The rate equations obtained allow estimation of the times necessary for a particular biocide conversion. The toxicity of reactants and products to the bacterium Vibrio fischeri before and after 48-hours degradation showed that the products were less toxic than the reactants in all three cases. The initial solutions of the three toxic substances caused 54 - 62 % inhibition of the bacterium Vibrio fischeri, while after 48 hours of degradation, 57 % reduction in the toxicity of phenol, 50 % reduction of 2,4,6-TCP and 29 % reduction of PCP was achieved.Â

Biosorpcija olova u laboratorijskoj koloni s nasutim slojem imobilizirane biomase gljive Rhizopus nigricans u obliku peleta: matematički model i pokusi

The biosorption of lead ions from aqueous solution on a self-immobilized Rhizopus nigricans biomass has been studied. Experiments were performed in a laboratory scale packed bed column at different liquid flow rates and biosorbent bed heights. Recorded experimental breakthrough curves were compared to those predicted by a mathematical model, which was developed to simulate a packed bed biosorption process by a soft, self-immobilized fungal biosorbent. In the range of examined experimental conditions, the biomass characteristics such as pellet porosity and biosorption capacity substantially affected the predicted response curve. General correlations for the estimation of the intra-pellet effective diffusivity, the external mass transfer coefficient, as well as axial dispersion were successfully applied in this biological system with specific mechanical properties. Under the experimental conditions, mass transfer is controlled by the external film resistance, while the intra-pellet mass transfer resistance, as well as the effect of axial dispersion, can be neglected. A new parameter α, the fraction of active biomass, with an average value of α=0.7, was introduced to take into account the specific biomass characteristics, and consequently the observed non-ideal liquid flow through the bed of fungal pellets.Ispitivana je biosorpcija iona olova iz vodene otopine na imobiliziranu biomasu gljive Rhizopus nigricans. Pokusi su provedeni u laboratorijskoj koloni s nasutim slojem, pri različitom protoku vodene otopine i visini sloja biosorbenta. Krivulje su proboja uspoređene s krivuljama izračunatim pomoću matematičkoga modela, razvijenog za simulaciju adsorpcije na pelete meke biomase gljive. Na izračunatu su krivulju znatno utjecali poroznost i adsorpcijski kapacitet biomase. U tom su biološkom sustavu specifičnih mehaničkih svojstava uspješno primijenjene općenite korelacije radi procjene stvarne difuzivnosti i koeficijenta prijenosa tvari unutar peleta, te koeficijenta aksijalne disperzije. Pri eksperimentalnim je uvjetima prijenos tvari kontroliran otporom unutar ovojnice peleta, dok se otpor unutar samoga peleta i aksijalna disperzija mogu lako zanemariti. U model je uveden novi parameter α, koji je dio aktivne biomase, a iznosi 0,7. Tako su uzete u obzir specifične značajke biomase te neidealan protok vodene otopine kroz sloj peleta gljiva

Interpretation of Experimental Results for Vancomycin Adsorption on Polymeric Resins in a Fixed Bed Column by Mathematical Modeling with Independently Estimated Parameters

A mathematical model of the continuous fixed-bed column adsorption process for isolation of the glycopeptide antibiotic vancomycin, which is an active ingredient in pharmaceutical drugs, from a fermentation broth filtrate on two different polymeric adsorbent resins (Amberlite XAD16N and 1600N) was developed and validated by laboratory-scale experiments. The model was utilized for the prediction of breakthrough curves and, consequently, dynamic adsorption capacities by the application of independently determined adsorption equilibrium and intraparticle kinetic data obtained from batch experiments and hydrodynamic parameters in order to analyze the column performance. The application of structural adsorption/desorption kinetics, taking into account the resin particle size distribution, improved agreement between the calculated and measured data much more than by varying the effect of external mass transfer. A parametric sensitivity analysis of the model was also performed. The study showed that the use of XAD1600N is advantageous in terms of process economics, as the dynamic adsorption capacity is ∼2.5–3.0 times higher, compared to that for XAD16N

Interpretation of Experimental Results for Vancomycin Adsorption on Polymeric Resins in a Fixed Bed Column by Mathematical Modeling with Independently Estimated Parameters

A mathematical model of the continuous fixed-bed column adsorption process for isolation of the glycopeptide antibiotic vancomycin, which is an active ingredient in pharmaceutical drugs, from a fermentation broth filtrate on two different polymeric adsorbent resins (Amberlite XAD16N and 1600N) was developed and validated by laboratory-scale experiments. The model was utilized for the prediction of breakthrough curves and, consequently, dynamic adsorption capacities by the application of independently determined adsorption equilibrium and intraparticle kinetic data obtained from batch experiments and hydrodynamic parameters in order to analyze the column performance. The application of structural adsorption/desorption kinetics, taking into account the resin particle size distribution, improved agreement between the calculated and measured data much more than by varying the effect of external mass transfer. A parametric sensitivity analysis of the model was also performed. The study showed that the use of XAD1600N is advantageous in terms of process economics, as the dynamic adsorption capacity is ∼2.5–3.0 times higher, compared to that for XAD16N