Carbon dioxide and ammonia emissions during composting of mixed paper, yard waste and food waste

The objective of the work was to provide a method to predict CO2 and NH3 yields during composting of the biodegradable fraction of municipal solid wastes (MSW). The compostable portion of MSW was simulated using three principal biodegradable components, namely mixed paper wastes, yard wastes and food wastes. Twelve laboratory runs were carried out at thermophilic temperatures based on the principles of mixture experimental and full factorial designs. Seeded mixed paper (MXP), seeded yard waste (YW) and seeded food waste (FW), each composted individually, produced 150, 220 and 370 g CO2-C, and 2.0, 4.4 and 34 g NH3-N per dry kg of initial substrate, respectively. Several experimental runs were also carried out with different mixtures of these three substrates. The effect of seeding was insignificant during composting of food wastes and yard wastes, while seeding was necessary for composting of mixed paper. Polynomial equations were developed to predict CO2 and NH3 (in amounts of mass per dry kg of MSW) from mixtures of MSW. No interactions among components were found to be significant when predicting CO2 yields, while the interaction of food wastes and mixed paper was found to be significant when predicting NH3 yields.     

Mesozooplankton community structure in offshore and coastal waters of the Ionian Sea (eastern Mediterranean) during mixed and stratified conditions

Depth-stratified samples, collected during a period where the water column was vertically mixed (March 2000) and a period of thermal stratification (September 2000), were analyzed in order to investigate the horizontal and vertical distribution patterns and composition of mesozooplankton, especially copepod species assemblages, in a pelagic (Ionian Sea) and a coastal area (Patraikos Gulf) of the eastern Mediterranean. Total mesozooplankton abundance and biomass were significantly lower in the highly oligotrophic offshore waters of the Ionian Sea when compared to the semi-enclosed Patraikos Gulf during both seasons. Small-sized copepods dominated the mesozooplankton community. An ‘offshore’ and a ‘coastal’ copepod assemblage were defined in the surface layer (0–50 m) only during March when differences in environmental conditions (i.e., temperature, salinity and fluorescence) were strong between the two areas. Copepod vertical community structure in offshore waters differed between sampling months. In March one assemblage (0–200 m) was mainly identified, while in September three distinct assemblages (0–50, 50–100 and 100–200 m) were observed, related to different vertical distribution patterns of the various copepod species. A pronounced seasonal change of the dominant copepods was evident in the surface layer, where strong differences in hydrological properties were observed from March to September. Below this layer, the copepod community was relatively stable showing decreasing seasonal differences with increasing depth.     

Photochemical behavior of chlorsulfuronR in water and in adsorbed phase

The photochemistry of the herbicide chlorsulfuron^R (2-chloro-N-[[4-methoxy-6-methyl-1.3.5-triazinyl-2-amino]carbonyl]benzene sulfonamide) was investigated in methanol, distilled water, natural creek-water, on silica gel and on montmorillonit surfaces. The rate of degradation was determined in outdoor and indoor experiments simulating tropospheric conditions (λ>290 nm). Two major photoproducts were identified in all cases.     

Beitrag zum verhalten von octachlorstyrol bei uv-bestrahlung

Octachlorostyrene was irradiated with wavelengths λ > 230 nm using n-hexane, acetone, methanol and methanol/water as solvents. Heptachlorostyrene and two isomers of hexachlorostyrene were identified as main products of the photochemical reaction. Minor amounts of pentachlorostyrene and tetrachlorostyrene were also found by GC/MS. Total degradation is effected by continued irradiation.     

Reaktion von Pendimethalin in Lösung bei UV-bestrahlung

Pendimethalin (I) decomposed in hexane, methanol and aqueous methanol upon irradiation with UV-light (λ > 290 nm) to form “polar” products. The main products formed are the dinitroaniline (II) and the isomers mono-nitroanilines (III). Kinetic studies indicate that the photodegradation of pendimethalin is strongly dependent of solvent and concentration.     

Green Synthesis of Silver Nanoparticles and Study of Their Antimicrobial Properties

One of the major disadvantages of polymers when used in food-contact applications is that they are very susceptible to microbial attack. On the other hand, silver nanoparticles have received increased attention as novel antimicrobial agents. Therefore, the introduction of silver nanoparticles into conventional polymers results in new materials with improved properties. In this investigation, colloidal silver nanoparticles using an environmentally friendly procedure were synthesized. An aqueous solution of AgNO₃ was used as a silver precursor with ‘green’ reducing agents either different types of honey, or β-d-glucose. In the first case, different pH values, as well as the addition of poly(ethylene glycol), PEG were studied, while in the latter, the effect of reduction time in the presence of PEG with various average molecular weights was examined. Properties of the nanoparticles were measured using X-Ray diffraction, UV–Vis and FTIR spectroscopy. Using honey it seems that spherical particles are produced with the smaller average particle size obtained at pH 8.5. Use of honey has the advantage of being a natural product, although its main drawback is that its composition varies and it cannot be predefined to result in reproducible results. Use of β-d-glucose results in stable silver nanoparticles with small average particle size after 24 h reduction. The addition of low molecular weight PEG seems to be beneficial in the production of stable nanoparticles. Finally, the antimicrobial activity of the nanoparticles produced was investigated at different concentrations on both Gram positive and negative bacteria, such as Bacillus cereus, Bacillus subtilis, Escherichia coli and Staphylococcus aureus.     

Thermal degradation characteristics and products obtained after pyrolysis of specific polymers found in Waste Electrical and Electronic Equipment

Modern societies strongly support the recycling practices over simple waste accumulation due to environmental harm caused. In the framework of sustainable recycling of plastics from WEEE, pyrolysis is proposed here as a means of obtaining secondary value-added products. The aim of this study was to investigate the thermal degradation and the products obtained after pyrolysis of specific polymers found in the plastic part of WEEE, using thermogravimetric analysis and a pyrolizer equipped with a GC/MS. Polymers studied include ABS, HIPS, PC and a blend having a composition similar to that appearing in WEEE. It was found that, PC shows greater heat endurance compared to the other polymers, whereas ABS depolymerizes in three-steps. The existence of several polymers in the blend results in synergistic effects which decrease the onset and final temperature of degradation. Moreover, the fragmentation occurred in the pyrolyzer, at certain temperatures, resulted in a great variety of compounds, depending on the polymer type, such as monomers, aromatic products, phenolic compounds and hydrocarbons. The main conclusion from this investigation is that pyrolysis could be an effective method for the sustainable recycling of the plastic part of WEEE resulting in a mixture of chemicals with varying composition but being excellent to be used as fuel retrieved from secondary recycling sources.

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