Solid waste generation prediction model framework using socioeconomic and demographic factors with real-time MSW collection data.

This article proposes a framework for developing predictive models of end-of-life product flows, highlighting the importance of conducting thorough analyses before developing waste management and end-of-life product flow strategies. The framework emphasizes the importance of recognizing the nature and quality of the available data and finding a balance between model development time and detail requirements. It is designed to adapt to source material heterogeneity and address varying data availability scenarios, such as the presence or absence of radio frequency identification chips. A case study for the city of Gatineau is presented, showcasing the framework's application through agent-based simulation models in a geographic information systems environment. The study focuses on creating models of municipal solid waste generation based on socioeconomic and demographic factors and collection data to accurately predict the quantity and quality of waste streams, enabling municipalities to assess the environmental impact of their waste management strategies.

Parametrized regionalization of paper recycling life-cycle assessment.

Recycling is a commonly acknowledged strategy to reduce the environmental impacts linked to primary resource exploitation. Large regional variations can be observed in recycling processes' parameters, like efficiency, energy mix and treatment of rejects. Life-cycle assessment (LCA) is widely used to evaluate the environmental impacts of recycling processes, but existing studies are neither harmonized nor sufficient to provide a comprehensive geographical and technological coverage of recycling processes. The purpose of this research is to develop an efficient and iterative approach for the parametrized generation of semi-automated regionalized life-cycle inventories that take into account technological and geographical variabilities in the recycling sector. The regionalization framework is then applied to create a parametrized paper recycling regionalization tool. This tool is used in the results section to compare the national climate change impacts of recycling three paper grades. Results show a significant global warming impact variability between countries for recycled graphic paper (0.36 to 2.25 kg CO2-Eq/kg wastepaper recycled), newsprint (0.27 to 1.84 kg CO2-Eq/kg wastepaper recycled) and corrugated cardboard (0.28 to 1.68 kg CO2-Eq/kg wastepaper recycled) productions. A regionalized LCA of the international recycling of the mixed wastepaper exported from Quebec's (Canada) sorting centers is also performed with the tool and compared to the non-regionalized mixed wastepaper recycling process available in the ecoinvent database. Only nine midpoint ReCiPe impact categories remain environmentally advantageous compared to virgin paper production when applying the regionalization methodology, compared to sixteen when using the ecoinvent process, illustrating how regionalization can substantially influence LCA results.

Mixed modeling approach for mechanical sorting processes based on physical properties of municipal solid waste.

Material recovery facilities (MFRs) play an important role in today's waste management systems to maximize recycling efficiency for several waste materials. These facilities face multiple challenges, often due to a poor understanding of the mechanisms occurring within the sorting equipment. Improving modeling techniques of these unit operations appear to be a promising opportunity to mitigates these challenges. Mechanical sorting efficiency of municipal solid waste is often predicted from simple transfer coefficients, which are obtained for a specific set of operating conditions of the sorting equipment and sorting sequence configuration. When these transfer coefficients are used in situations that are different to those in which they were obtained, poor predictions can be expected. To overcome these limitations, a new predictive tool, based on the integration of mechanistic models and transfer coefficients, is presented. Mechanistic models are developed only for the most influential unit operations in a MRF, in order to predict their sorting efficiency based on the physical phenomena occurring. Integration of these models with the use of transfer coefficients for the other unit operations allows the entire predictive tool to remain as simple as possible while providing high prediction accuracy and flexibility. The use of the tool is validated with a real case study of a material recovery facility. Results indicate a good prediction of the mass flows of the facility. Moreover, a new modeling technique is proposed for the representation of a ballistic separator based on the shape factor of the waste items.

Physical properties of recyclable materials and implications for resource recovery.

Mechanical sorting plays a pivotal role in current municipal solid waste management systems for resource recovery. However, material recovery facilities, generally face several challenges in meeting quality standards for multiple waste fractions. Improving these facilities requires a better understanding of municipal solid waste physical characteristics, since they are directly targeted by mechanical sorting unit operations. Three waste physical properties (bulk density, particle size and shape factor) were characterized for several recyclable materials. Narrow ranges of densities were observed for similar waste materials, while the particle size distributions were found to vary widely. Statistical parameters were determined for these two properties. A novel approach, based on the void fraction of a waste item, is proposed to quantify the shape factor. Potential applications of the characterization results for improving mechanical sorting are demonstrated through the analysis of the recovery of corrugated cardboards and multilayer cardboards in a material recovery facility.

Particle size analysis of municipal solid waste for treatment process modeling.

Several unit operations used in municipal solid waste (MSW) processing facilities are based on physical properties of the waste materials, such as particle size, density and shape. Reliable expressions describing particle size distribution (PSD) of the different waste components present in MSW are not readily available in the context of process modeling. In this study, the characterization data for household wastes and construction and demolition (C&D) wastes were analysed with the purpose of selecting the most representative PSD expression for these waste streams. The Rosin-Rammler distribution was identified over the log-normal and the gamma distributions as the best-fitting PSD for the waste samples. This was demonstrated for both raw and processed waste samples. Parameters were derived and validated for every category of MSW materials considered in the characterization. A model for mixed household waste PSD was developed based on the summation of Rosin-Rammler expressions corresponding to each category of waste materials, as the composition was determined to be the main factor influencing particle size. A simplified model was also derived for mixed waste as a bimodal distribution since two main modes were observed in household waste - one for the "organic" fraction and one for the "inorganic" fraction.

Oxidative torrefaction of biomass residues and densification of torrefied sawdust to pellets.

Oxidative torrefaction of sawdust with a carrier gas containing 3-6% O(2) was investigated in a TG and a fluidized bed reactor, with the properties of the torrefied sawdust and pellets compared with traditional torrefaction without any O(2), as well as the dry raw material. It is found that the oxidative torrefaction process produced torrefied sawdust and pellets of similar properties as normally torrefied sawdust and corresponding pellets, especially on the density, energy consumption for pelletization, higher heating value and energy yield. For moisture absorption and hardness of the torrefied pellets, the oxidative torrefaction process showed slightly poor but negligible performance. Therefore, it is feasible to use oxygen laden combustion flue gases as the carrier gas for torrefaction of biomass. Besides, torrefied sawdust can be made into dense and strong pellets of high hydrophobicity at a higher die temperature than normally used in the production of traditional control pellets.

Torrefaction of sawdust in a fluidized bed reactor.

In the present work, stable fluidization of sawdust was achieved in a bench fluidized bed with an inclined orifice distributor without inert bed materials. A solids circulation pattern was established in the bed without the presence of slugging and channeling. The effects of treatment severity and weight loss on the solid product properties were identified. The decomposition of hemicelluloses was found to be responsible for the significant changes of chemical, physical and mechanical properties of the torrefied sawdust, including energy content, particle size distribution and moisture absorption capacity. The hydrophobicity of the torrefied sawdust was improved over the raw sawdust with a reduction of around 40 wt.% in saturated water uptake rate, and enhanced with increasing the treatment severity due to the decomposition of hemicelluloses which are rich in hydroxyl groups. The results in this study provided the basis for torrefaction in fluidized bed reactors.

Dysbindin-1 in dorsolateral prefrontal cortex of schizophrenia cases is reduced in an isoform-specific manner unrelated to dysbindin-1 mRNA expression.

DTNBP1 (dystrobrevin binding protein 1) remains a top candidate gene in schizophrenia. Reduced expression of this gene and of its encoded protein, dysbindin-1, have been reported in the brains of schizophrenia cases. It has not been established, however, if the protein reductions encompass all dysbindin-1 isoforms or if they are associated with decreased DTNBP1 gene expression. Using a matched pairs design in which each of 28 Caucasian schizophrenia cases was matched in age and sex to a normal Caucasian control, Western blotting of whole-tissue lysates of dorsolateral prefrontal cortex (DLPFC) revealed significant reductions in dysbindin-1C (but not in dysbindin-1A or -1B) in schizophrenia (P = 0.022). These reductions occurred without any significant change in levels of the encoding transcript in the same tissue samples and in the absence of the only DTNBP1 risk haplotype for schizophrenia reported in the USA. Indeed, no significant correlations were found between case-control differences in any dysbindin-1 isoform and the case-control differences in its encoding mRNA. Consequently, the mean 60% decrease in dysbindin-1C observed in 71% of our case-control pairs appears to reflect abnormalities in mRNA translation and/or processes promoting dysbindin-1C degradation (e.g. oxidative stress, phosphorylation and/or ubiquitination). Given the predominantly post-synaptic localization of dysbindin-1C and known post-synaptic effects of dysbindin-1 reductions in the rodent equivalent of the DLPFC, the present findings suggest that decreased dysbindin-1C in the DLPFC may contribute to the cognitive deficits of schizophrenia by promoting NMDA receptor hypofunction in fast-spiking interneurons.

Parasite age-intensity relationships in red-spotted newts: does immune memory influence salamander disease dynamics?

Acquired immune memory in vertebrates influences transmission and persistence of infections, with consequences for parasite dynamics at both the individual and population levels. The potential impact of acquired immunity is of particular interest for salamanders, whose acquired immune systems are thought to be less effective than those of frogs and other tetrapods. One way to examine the importance of acquired immunity to parasite dynamics at the population level is by examining the relationship between host age and parasite infection intensity. Acquired immunity reduces infection rates in older animals, causing decreased parasite intensity in older age classes and leading to curvilinear age-intensity relationships for persistent parasites and convex age-intensity relationships for transient parasites. We used age-intensity relationships to look for the signature of acquired immunity for 12 parasite taxa of red-spotted newts (Notophthalmus viridescens), using data from a 2-year parasitological survey of six newt populations. We estimated ages from snout-vent length (SVL) based on the relationship between SVL and skeletochronologically-derived ages in a subset of newts. We found evidence of acquired immunity to two parasite taxa, bacterial pathogens and the protist Amphibiocystidium viridescens, whose convex age-intensity relationships could not be easily explained by alternative mechanisms. Our results suggest that the acquired immune response of newts is sufficient to influence the dynamics of at least some parasites.

A Study of the interaction of HEK-293 cells with streamline chelating adsorbent in expanded bed operation.

Expanded bed adsorption (EBA) is an efficient protein purification process reducing time and steps of downstream processing (DSP) since nonclarified culture media can be processed directly without prior treatments such as filtration or centrifugation. However, cells and debris can interact with the adsorbent and affect bed stability as well as purification performance. To optimize EBA operating conditions these biomass/adsorbent interactions have to be understood and characterized. The adsorption of Human Embryonic Kidney cells (HEK 293) on unprimed and nickel-primed metal affinity adsorbent was studied in a closed loop EBA setup. With the unprimed adsorbent, the overall level of interaction observed was nonsignificant. With the nickel-primed adsorbent and an initial cell concentration ranging from 0.08 x 10(6) to 0.2 x 10(6) cells/mL, biomass/adsorbent interaction was found to be moderate and the adsorption apparent first-order kinetic rate constant was determined to be k = 0.009 to 0.011 min(-1).

Analysis of secondary metabolites from eschscholtzia californica by high-performance liquid chromatography.

A rapid and precise analytical HPLC method has been developed for screening the major benzophenanthridine alkaloids produced by cell cultures of Eschscholtzia califomica, namely, sanguinarine, chelirubine, macarpine, chelerythrine and chelilutine. Separation was achieved on a C18, reversed-phase column with gradient elution using acetonitrile and 50 mM phosphoric acid. Detection was performed by both fluorescence (lambda(ex) 330 nm, lambda(em) 570 nm) and photodiode array, leading to good selectivity and precision in determining peak purity. A simple and quick sample preparation protocol was elaborated involving a methanolic extraction for the measurement of intracellular concentrations of the alkaloids and a solid phase extraction for their quantification in culture medium. Owing to the non-availability of commercially standards, a method for the purification of chelirubine, macar pine and chelilutine by semi-preparative HPLC was developed. Coupled together, the isolation method and the analytical method were highly reliable for screening the alkaloids of interest produced by E. califomica.

Pyrene mineralization capacity increases with compost maturity.

Experiments were conducted to determine the effects of composting or simple addition of compost to the mineralization of n-hexadecane, pyrene and benzo(a)pyrene in soil. Soil (contaminated or clean) was composted with maple leaves and alfalfa. Samples from different composting phases were spiked with radiolabeled and cold n-hexadecane, pyrene or benzo(a)pyrene, placed in aerated microcosms at different temperatures, and monitored for mineralization. It was determined that neither composting nor the addition of compost had any effect on n-alkane or benzo(a)pyrene mineralization. In contrast, the pyrene mineralization rate increased dramatically with the amount of time that soil had been composted. Highest pyrene mineralization rates and extents (more than 60% after 20 days) were obtained when pyrene was in contact with composted soil from the curing stage. Neither thermophiles (55 degrees C) nor fungi were responsible for pyrene mineralization.

Modeling of scale-down effects on the hydrodynamics of expanded bed adsorption columns.

Expanded-bed adsorption (EBA) is a technique for primary recovery of proteins starting from unclarified broths. This process combines centrifugation, concentration, filtration, and initial capturing of the proteins in a single step. An expanded bed (EB) is comparable to a packed bed in terms of separation performance but its hydrodynamics are that of a fluidized bed. Downstream process development involving EBA is normally carried out in small columns to minimize time and costs. Our purpose here is to characterize the hydrodynamics of expanded beds of different diameters, to develop scaling parameters that can be reliably used to predict separation efficiency of larger EBA columns. A hydrodynamic model has been developed which takes into account the radial liquid velocity profile in the column. The scale-down effect can be characterized in terms of apparent axial dispersion, D(axl,app), and plate number, N(EB), adapted for expanded bed. The model is in good agreement with experimental results obtained from 1- and 5-cm column diameters with buffer solutions of different viscosities. The model and the experiments show an increase of apparent axial dispersion with an increase in column diameter. Furthermore, the apparent axial dispersion is affected by an increase in liquid velocity and viscosity. Supported by visual observations and predictions from the model, it was concluded that operating conditions (liquid viscosity and superficial velocity) resulting in a bed-void fraction between 0.7 and 0.75 would provide the optimal separation efficiency in terms of N(EB).