Assessment of the environmental impact of management measures for the biodegradable fraction of municipal solid waste in São Paulo City

There is increasing concern about landfilling of biodegradable wastes. Therefore, biological treatment processes such as composting and biogasification have been considered as alternative strategies for managing those wastes. In this work, life cycle assessment was employed to compare the environmental impacts of landfilling, composting, and biological treatment of municipal solid waste in S?o Paulo City, Brazil. Energy consumption, recovered resources, and emissions to air and water were quantified and analyzed in terms of their potential contribution to global warming, acidification, and nutrient enrichment impact. The results demonstrated that processes that require high levels of energy consumption, such as wastewater treatment, play an important role in the outcome of environmental impact potentials. It was found that the landfilling of all waste is generally the worst strategy from an environmental point of view. However, significant reductions in the resulting impacts can be accomplished through biogasification and composting of the biodegradable fraction. Regarding composting, the application of a biofilter for gas treatment reduced significantly the gaseous emissions.     

Can We Decode the Messages of Activated Sludge Through the Respirograms?

Wastewater contains varieties of carbonaceous and nitrogenous compounds that undergo complicated biodegradation processes in wastewater treatment plants. How these different compounds are degraded by activated sludge in aerobic conditions is still a mystery. Researchers have been trying to interpret it using the oxygen uptake rate (OUR) derived from the respirograms of respective substrates. Several models have been proposed to interpret the substrate removal mechanisms using the experimental observations. Have we succeeded in understanding the messages by activated sludge correctly using these models? In this paper, the distinctive nature of the respirograms when activated sludge is fed with different substrates and the biokinetic models that have been developed to explain the substrate removal mechanisms using derived OUR profiles are reviewed. In addition, a sensitivity study was conducted on the recently evolved simultaneous storage and growth model to investigate the influence of key parameters on OUR profiles during the biodegradation process.     

Influence of regulation on the productivity of waste utilities. What can we learn with the Portuguese experience?

This paper examines the merits and the perverse effects of quality of service regulation in the performance of urban waste services when implemented alone and compares the performance of different economic regulatory methods. By means of a productivity analysis, we investigate the influence of a five-year period of regulation on the performance of Portuguese urban waste utilities using an unbalanced panel data for the period 2001-2008. Different non-parametric methods were applied to estimate the productivity change, all leading to similar outcomes. We observed a tendency of productivity decline in the urban waste utilities and concluded that in spite of the unequivocal improvements in the quality of service induced by sunshine regulation, more should be done as far as economic regulation is concerned. We also found that the use of sunshine regulation together with low incentive economic regulatory methods is not positive, leading to overinvestment rather than to value for money.     

The introduction of recycled-aggregate concrete specifications in Japan and the research into the freezing–thawing resistance of recycled-aggregate concrete

Journal of Material Cycles and Waste Management - In Japan, recycled concrete aggregate (RCA) and recycled-aggregate concrete (RAC) are standardized in the Japanese Industrial Standards (JIS) A...     

The Impact of the Macaíba Components Addition on the Biodegradation Acceleration of Poly (Ɛ-Caprolactone) (PCL)

Journal of Polymers and the Environment - Nowadays, there is a need to obtain eco-friendly materials, especially plastics that are responsible for most of the environmental pollution. In this...     

A Methodology to Identify the Releasing of the Amide-Containing β-Glucan from the Usnea Lichen: A Spectroscopic Study

Journal of Polymers and the Environment - Polymer fractions from a biological matrix have been well-characterized by vibrational spectroscopy, XPS, CP/MAS 13C NMR, MALDI-TOF mass...     

Classification of the sugarcane residues and their characteristics—an environmental assessment of mortar with addition of sugarcane residues

Journal of Material Cycles and Waste Management - The use of agro-residue in resource-limited regions can be a smart way for civil construction to reduce costs, reduce emissions of pollutant gases...     

Emission of trace organics from municipal solid waste incinerators—rationale of national guidelines in the Federal Republic of Germany

In the Federal Republic of Germany a working party has developed recommendations for dealing with the dioxin problems posed by waste incineration. According to these recommendations limit values for dioxin emissions are neither necessary nor practical. However, from the point of view of preventive environmental protection, dioxin emissions should be further reduced as far as is possible with present-day technology. The TA Luft (Technical Instructions for Maintaining Air Quality) contains stipulations and advice on this. The most significant of the solid residues from waste incinerators are the filter ashes as they have a high dioxin content. The working party of Under (states) has compiled a catalogue of recommendations for the disposal of filter ashes. The transport of solid residues from solid waste incinerators is controlled under the Abfallgesetz (Waste Act) and regulations passed in connection with this act and under the Gefahrgutverordnung Strasse—GGVS (Regulation on the transport of dangerous freight by road). The latter stipulates at what level of dioxin certain transport conditions must be respected. The new Gefahrstoffverordnung-GefStoffV (Regulation on dangerous substances) prohibits substances containing dioxin in concentrations above a certain level from being placed on the market. It does not apply to residues from solid waste incinerators.     

How are WEEE doing? A global review of the management of electrical and electronic wastes

This paper presents and critically analyses the current waste electrical and electronic equipment (WEEE) management practices in various countries and regions. Global trends in (i) the quantities and composition of WEEE; and (ii) the various strategies and practices adopted by selected countries to handle, regulate and prevent WEEE are comprehensively examined. The findings indicate that for (i), the quantities of WEEE generated are high and/or on the increase. IT and telecommunications equipment seem to be the dominant WEEE being generated, at least in terms of numbers, in Africa, in the poorer regions of Asia and in Latin/South America. However, the paper contends that the reported figures on quantities of WEEE generated may be grossly underestimated. For (ii), with the notable exception of Europe, many countries seem to be lacking or are slow in initiating, drafting and adopting WEEE regulations. Handling of WEEE in developing countries is typified by high rate of repair and reuse within a largely informal recycling sector. In both developed and developing nations, the landfilling of WEEE is still a concern. It has been established that stockpiling of unwanted electrical and electronic products is common in both the USA and less developed economies. The paper also identifies and discusses four common priority areas for WEEE across the globe, namely: (i) resource depletion; (ii) ethical concerns; (iii) health and environmental issues; and (iv) WEEE takeback strategies. Further, the paper discusses the future perspectives on WEEE generation, treatment, prevention and regulation. Four key conclusions are drawn from this review: global amounts of WEEE will continue unabated for some time due to emergence of new technologies and affordable electronics; informal recycling in developing nations has the potential of making a valuable contribution if their operations can be changed with strict safety standards as a priority; the pace of initiating and enacting WEEE specific legislation is very slow across the globe and in some cases non-existent; and globally, there is need for more accurate and current data on amounts and types of WEEE generated.     

Chronic toxicity of the ‘water-soluble fraction’ of Norman Wells crude oil to juvenile fish

Young rainbow trout were exposed to Norman Wells crude oil for periods as long as 55 d. Mortality was light for the first few days, but it continued throughout exposure with more rapid and increased mortality at the higher exposure levels. The mortality was generally exacerbated by the presence of oil dispersants Corexit 7664 or 9600. Fish surviving the 55-day experiment showed severe fin erosion and apparent ‘flooding’, since mean body water content was increased from about 84% to over 90%. We hypothesize that the oil affected the ability of the fish to regulate their water content.     

Comparison of the Effect of Plasticizers on PHBV—and Organoclay—Based Biodegradable Polymer Nanocomposites

The aim of this work was to evaluate the effect of different plasticizers on the morphology, crystallization, and mechanical properties of poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV)/organomodified montmorillonite (OMt) nanocomposites. We investigated three different plasticizers: dioctyl phthalate (DOP), a commonly used additive in the polymer industry, and two natural and biodegradable plasticizers: epoxidized soybean oil (ESO) and triethyl citrate (TEC). The nanocomposites with 3 wt% OMt were obtained by melt processing in an internal mixer. The plasticizers were used alone or in combination with clay in a concentration of 10 wt%. X-ray diffraction and scanning electron microscopy results revealed a partially intercalated structure. The degree of crystallinity was higher for all of the samples compared to neat PHBV, although the melting temperature decreased with the use of plasticizers combined with OMt. The impact strength results were dependent on the interaction between the components of the system. Triethyl citrate was the most effective plasticizer due to its more pronounced interaction with the PHBV matrix, which yielded improvements in processing conditions and PHBV’s flexibility and impact properties.     

Lysimeter Experiments to Investigate the Fate of Chemicals in Soils – Comparison of Five Different Lysimeter Systems

Several lysimeter scenarios and approaches exist to study the fate of agro-chemicals or contaminants from deposition in soil columns. In many systems just transport and leaching of the parent compound is followed, in some systems the leaching and transport of the metabolites is investigated as well. In more sophisticated lysimeter systems the volatilization and also the mineralization of the applied chemicals can be additionally monitored. Depending on the lysimeter system used and on the fact whether the applied chemicals are ¹⁴C-labeled or not, different results and various interpretations of the results might be achieved. Different lysimeter systems are described in this paper and a real dataset of a specific lysimeter experiment was transferred and evaluated in a virtual approach in the different lysimeter systems in order to show the advantages and disadvantages of the various systems.     

Influence of Processing Additives on the Degradation of Melt-Pressed Films of Poly(ε-Caprolactone) and Poly(Lactic Acid)

Melt-pressed films of polycaprolactone (PCL) and poly(lactic acid) (PLA) with processing additives, CaCO₃, SiO₂, and erucamide, were subjected to pure fungal cultures Aspergillus fumigatus and Penicillium simplicissimum and to composting. The PCL films showed a rapid weight loss with a minor reduction in the molecular weight after 45 days in A. fumigatus. The addition of SiO₂ to PCL increased the rate of (bio)erosion in A. fumigatus and in compost. The use of a slip additive, erucamide, was shown to modify the properties of the film surface without decreasing the rate of bio(erosion). Both the rate of weight loss and the rate of molecular weight reduction of PCL increased with decreasing film thickness. The addition of CaCO₃ to PLA significantly reduced the thermal degradation during processing, but it also reduced the rate of the subsequent (bio)degradation in the pure fungal cultures. PLA without additives and PLA containing SiO₂ exhibited the fastest (bio)degradation, followed by PLA with CaCO₃. The degradation of the PLA films was initially governed by chemical hydrolysis, followed by an acceleration of the weight change and of the molecular weight reduction. PLA film subjected to composting exhibits a rapid decrease in molecular weight, which then remains unchanged during the measurement period, probably because of crystallization.     

Formation of Reactive Gaseous Mercury in the Arctic: Evidence of Oxidation of Hg° to Gas-Phase Hg-II Compounds after Arctic Sunrise

We have measured total gaseous mercury concentrations(Hg°) at Point Barrow, Alaska since September 1998 in aneffort to determine the geographic extent and reaction mechanismof the so-called mercury depletion events (MDE) previouslyreported in the high Arctic at Alert, Canada. Hg° has beensampled now for nearly 2 years at Barrow. In September, 1999, webegan making the first automated measurements of reactive gaseousmercury (RGM) attempted in the Arctic, along with measurements ofHg accumulation in snowpack to determine the fate of the depleted Hg°. During the fall and early winter, Hg°and RGM exhibit only minor variation, Hg° remaining within10% of global background, near 1.6–1.8 ng m^-3. The MDEperiods are quite different, however; within days of Arcticsunrise in January, Hg° exhibits major variations from themean, rapidly dropping as low as 0.05 ng m^-3 and then cyclingback to typical levels, sometimes exceeding global background. These events continue throughout Arctic spring, then end abruptlyfollowing snowmelt, in early June. Prior to Arctic sunrise, RGMremains near detection (<2 pg m^-3), but after sunriseincreases dramatically (to levels as high as 900 pg/m³) insynchrony with the depletion of Hg°. Both phenomenaexhibit a strong diel cycle, in parallel with UV-B. We concludethat MDE's involve rapid in-air oxidation of Hg° to aspecies of RGM by photochemically-driven reactions, probablyinvolving the same reactive bromine and chlorine compoundsinvolved in ozone destruction. Sharp increases in Hg in thesurface snowpack after sunrise coincident with periods of peakRGM suggest surface accumulation of the RGM by dry deposition.     

The in situ treatment of PFAS within porewater at the air–water interface of a PFAS source zone

The treatment of per- and polyfluoroalkyl substances (PFAS) within groundwater is an emerging topic, with various technologies being researched and tested. Currently, PFAS-impacted groundwater is typically treated ex situ using sorptive media such as activated carbon and ion exchange resin. Proven in situ remedial approaches for groundwater have been limited to colloidal activated carbon (CAC) injected into aquifers downgradient of the source zones. However, treatment of groundwater within the source zones has not been shown to be feasible to date. This study evaluated the use of CAC to treat dissolved PFAS at the air–water interface within the PFAS source zone. Studies have shown that PFAS tends to preferentially accumulate at the air–water interface due to the chemical properties of the various PFAS. This accumulation can act as a long-term source for PFAS, thus making downgradient treatment of groundwater a long-term requirement. A solution of CAC was injected at the air–water interface within the source zone at a site with PFAS contamination using direct push technology. A dense injection grid that targeted the interface between the air and groundwater was used to deliver the CAC. Concentrations of PFAS within the porewater and groundwater were collected using a series of nine lysimeters installed within the vadose and saturated water columns. A total of six PFAS were detected in the porewater and groundwater including perfluorobutanoic acid (PFBA), perfluoropentanoic acid (PFPeA), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), and perfluorononanoic acid (PFNA). Detectable concentrations of PFAS within the pore and groundwater before treatment ranged from values greater than 300 µg/L for PFPeA to less than 3 µg/L for PFNA. Following the injection of the CAC, monitoring of the porewater and groundwater for PFAS was conducted approximately 3, 6, 9, 12, and 18 months postinjection. The results indicated that the PFAS within the porewater and groundwater at and near the air–water interface was effectively attenuated over the 1.5-year monitoring program, with PFAS concentrations being below the method detection limits of approximately 10 ng/L, with the exception of PFPeA, which was detected within the porewater during the 18-month sampling event at concentrations of up to 55 ng/L. PFPeA is a five carbon-chained PFAS that has been shown to have a lower affinity for sorption onto activated carbon compared to the longer carbon-chained PFAS such as PFOA. Examination of aquifer cores in the zone of injection indicated that the total organic carbon concentration of the aquifer increased by five orders of magnitude postinjection, with 97% of the samples collected within the target injection area containing activated carbon, indicating that the CAC was successfully delivered into the source zone.     

University students’ awareness of e-waste and its disposal practices in Pakistan: a construction of the conceptual framework

Journal of Material Cycles and Waste Management - Pakistan is among the few countries generating and receiving enormous e-waste, which posits a threat to its&nbsp;future generations. A...     

A Study of the Photocatalytic Oxidation of Humic Acid on Anatase and Mixed-phase Anatase–Rutile TiO2 Nanoparticles

In this study, slurry photocatalytic oxidation process was investigated for natural organic matter removal from aqueous humic acid solutions by using different titanium dioxide (TiO₂) under UV-A irradiation. Bench scale experimental studies were conducted at different humic acid concentration at the range of 10–50 mg/L and different pH. Anatase and mixed-phase anatase–rutile TiO₂ nano particles used in the photocatalytic reactor. The results were evaluated in terms of the parameters that are specific to organic matter content such as dissolved organic carbon concentration, ultraviolet absorbance at 254 nm (UV₂₅₄), specific ultaviolet absorbance at 254 nm, and color (VIS₄₀₀). It was observed that increasing humic acid concentration decreases photocatalytic degradation efficiency. The reactivity of the mixed-phase anatase–rutile (Degussa P-25) TiO₂ was greater than individual anatase particles and the highest efficiency was observed at pH 3 for anatase TiO₂.     

Effect of Matrix–Particle Interfacial Adhesion on the Mechanical Properties of Poly(lactic acid)/Wood-Flour Micro-Composites

The influence of interfacial matrix/particle adhesion on the mechanical properties of poly(lactic acid) (PLA) micro-composites was investigated. The tensile strength of PLA/wood-flour micro-composites is almost independent of wood-flour content, suggesting only weak adhesion exists between the PLA matrix and the wood-flour particles. The addition of wood-flour resulted in an increase of up to 95% in the tensile modulus, in comparison with pure PLA, which showed a more resilient matrix. The addition of a coupling agent, methylenediphenyl-diisocyanate (MDI) to the composition resulted in an increase in tensile strength and tensile modulus of the micro-composites, of 10 and 135%, respectively, indicating enhanced matrix–particle interfacial adhesion. SEM and electron probe microanalysis provided evidence of improved interfacial adhesion between PLA and wood-flour particles from the addition of MDI. In contrast, addition of PEAA resulted in a micro-composite displaying substantially reduced tensile strength, up to 35% and a slightly increased in impact strength, up to 15%, consistent with the introduction of the rubbery PEAA component into the polymeric matrix. No evidence for increased matrix–particle adhesion was found for the PLA/wood-flour micro-composites containing PEAA.     

Chemical Recycling of PLA: A Great Opportunity Towards the Sustainable Development?

This work aims at analyzing the energy efficiency of the chemical recycling process of polylactic acid (PLA) and its sustainability from an environmental point of view. The results show that the production of lactic acid from chemical depolymerization of PLA is preferable, from an energy point of view, to the production of lactic acid by glucose fermentation. The study also shows that the environmental footprint of the analyzed process is larger than that of the PLA mechanical recycling.     

The effect of moisture regimes on the anaerobic degradation of municipal solid waste from Metepec (México)

The State of México, situated in central México, has a population of about 14 million, distributed in approximately 125 counties. Solid waste management represents a serious and ongoing pressure to local authorities. The final disposal site ("El Socavón") does not comply with minimum environmental requirements as no liners or leachate management infrastructure are available. Consequently, leachate composition or the effects of rain water input on municipal solid waste degradation are largely unknown. The aim of this work was to monitor the anaerobic degradation of municipal solid waste (MSW), simulating the water addition due to rainfall, under two different moisture content regimes (70% and 80% humidity). The study was carried out using bioreactors in both laboratory and pilot scales. The variation of organic matter and pH was followed in the solid matrix of the MSW. The leachate produced was used to estimate the field capacity of the MSW and to determine the pH, COD, BOD and heavy metals. Some leachate parameters were found to be within permitted limits, but further research is needed in order to analyze the leachate from lower layers of the disposal site ("El Socavón").