Mechanical properties of Municipal Solid Waste by SDMT

In the paper the results of a geotechnical investigation carried on Municipal Solid Waste (MSW) materials retrieved from the “Cozzo Vuturo” landfill in the Enna area (Sicily, Italy) are reported and analyzed. Mechanical properties were determined both by in situ and laboratory large-scale one dimensional compression tests.While among in situ tests, Dilatomer Marchetti Tests (DMT) is used widely in measuring soil properties, the adoption of the DMT for the measurements of MSW properties has not often been documented in literature. To validate its applicability for the estimation of MSW properties, a comparison between the seismic dilatometer (SDMT) results and the waste properties evaluated by laboratory tests was carried out.Parameters for “fresh” and “degraded waste” have been evaluated. These preliminary results seems to be promising as concerns the assessment of the friction angle of waste and the evaluation of the S-wave in terms of shear wave velocity. Further studies are certainly required to obtain more representative values of the elastic parameters according to the SDMT measurements.     

Rapid discrimination of plastic packaging materials using MIR spectroscopy coupled with independent components analysis (ICA)

Plastic packaging wastes increased considerably in recent decades, raising a major and serious public concern on political, economical and environmental levels. Dealing with this kind of problems is generally done by landfilling and energy recovery. However, these two methods are becoming more and more expensive, hazardous to the public health and the environment. Therefore, recycling is gaining worldwide consideration as a solution to decrease the growing volume of plastic packaging wastes and simultaneously reduce the consumption of oil required to produce virgin resin. Nevertheless, a major shortage is encountered in recycling which is related to the sorting of plastic wastes. In this paper, a feasibility study was performed in order to test the potential of an innovative approach combining mid infrared (MIR) spectroscopy with independent components analysis (ICA), as a simple and fast approach which could achieve high separation rates. This approach (MIR-ICA) gave 100% discrimination rates in the separation of all studied plastics: polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polystyrene (PS) and polylactide (PLA). In addition, some more specific discriminations were obtained separating plastic materials belonging to the same polymer family e.g. high density polyethylene (HDPE) from low density polyethylene (LDPE). High discrimination rates were obtained despite the heterogeneity among samples especially differences in colors, thicknesses and surface textures. The reproducibility of the proposed approach was also tested using two spectrometers with considerable differences in their sensitivities. Discrimination rates were not affected proving that the developed approach could be extrapolated to different spectrometers. MIR combined with ICA is a promising tool for plastic waste separation that can help improve performance in this field; however further technological improvements and developments are required before it can be applied at an industrial level given that all tests presented here were performed under laboratory conditions.     

Environmental policy with collective waste disposal

Centralized collection and disposal is an integral component of waste management strategies for many solid and liquid wastes, and carbon capture and storage is currently being considered for gaseous waste. In this paper we show how collective waste disposal systems introduce essential changes in the design of optimal environmental policy. Absent collective disposal, an optimal environmental policy imposes relatively stringent regulations on polluters in regions where local environmental damage functions are “high”; however, under collective waste disposal, the optimal environmental policy level increases monotonically over distance from the disposal site, and this is true irrespective of the degree of spatial heterogeneity in local environmental damage functions. We characterize the optimal spatial pattern of environmental policy levels under collective waste disposal and identify optimal membership size for waste disposal networks comprised of homogeneous producers.     

Chemometrical analysis of waste water monitoring data from Yantra river basin,Bulgaria

A chemometrical study of waste water data is carried out in order to reveal some new information about the pollution events in Yantra river basin, Bulgaria. Cluster analysis shows that no substantial difference in the behaviour of various sites along the river could be found if all chemical pollutants are simultaneously considered as variables (both for direct and indirect inlet of pollutants). Further, the clustering of the variables indicates a separation between organic and nutrition polluting species. The principal components analysis offered information about the latent factors influencing the data structure. In principle, three to four such latent factors explain over 80% of the total variance of the system. These factors are conditionally named “organic pollution”;, “nutrition pollution”; or “natural”; and are slightly different for the cases of direct and indirect inlet.     

New method for acrylic acid recovery from industrial waste water via esterification with 2-ethyl hexanol

Acrylic acid (AA) is an important component for the production of acrylate polymer. In a typical acrylic manufacturing unit, waste water contains AA in a range of 4–15 wt.% contributes to the high values of chemical oxygen demand. Due to the toxicity of AA to the aquatic organism, this wastewater should be treated before it is discharged to the environment. The waste water could be evaporated before sending to the incineration which was neither economic feasible nor environmental friendly. Esterification of wastewater containing carboxylic acid with alcohol could be a promising method to recover the acid by converting it to ester while purifying the wastewater. In the present study, recovery of AA via esterification with 2-ethyl hexanol (2EH) was investigated. The model industrial wastewater with various concentration of AA (10–100% w/w) was reacted with 2EH to produce 2-ethyl hexyl acrylate (2EHA) in the setups with total reflux and continuously water removal. These Amberlyst-15 (ion exchange resin) catalyzed reactions were carried out under the mass transfer resistance free region. The performance of both systems was compared. The yield for the reactions of the AA solutions with the AA concentrations of 30–80% was enhanced significantly when the reactions were carried out using the second setup. The kinetic data of the esterification of dilute AA was well described by the Eley–Rideal (ER) kinetic model incorporated with a correction factor to consider the catalyst fouling effect and pseudo-homogeneous (PH) kinetic model for the AA polymerization. The findings have shown the potential of recovering AA from the waste water stream via esterification. The concentrated AA solutions or larger amount of inhibitor should be adopted to prevent the catalyst fouling by the deposition of poly-acrylic acid on the catalyst surface.     

Characterization of chlorine and heavy metals for the potential recycling of bottom ash from municipal solid waste incinerators as cement additives

Bottom ash is an inevitable by-product from municipal solid waste (MSW) incineration plants. Recycling it as additives for cement production is a promising disposal method. However, the heavy metals and chlorine are the main limiting factors because of the potential environmental risks and corrosion of cement kilns. Therefore, investigating heavy metal and chlorine characteristics of bottom ash is the significant prerequisite of its reuse in cement industries. In this study, a correlative analysis was conducted to evaluate the effect of the MSW components and collection mode on the heavy metal and chlorine characteristics in bottom ash. The chemical speciation of insoluble chlorine was also investigated by synchrotron X-ray diffraction analysis. The results showed that industrial waste was the main source of heavy metals, especially Cr and Pb, in bottom ash. The higher contents of plastics and kitchen waste lead to the higher chlorine level (0.6 wt.%–0.7 wt.%) of the bottom ash. The insoluble chlorine in the MSW incineration bottom ash existed primarily as AlOCl, which was produced under the high temperature (1250°C) in incinerators.

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Adapting to new policy environment – past pattern and future trend in us-sino waste plastic trade flow

Plastics are one of the most used materials in human activities, where consumer consumption and industrial production together has imposed vast rise in demand for this material in last century. While plastic is ideally derived from crude oil as a primary source from manufacturers’ perspective, varying crude oil prices are driving manufacturers economically to seek for alternative sources for plastics production. Waste plastic recovered from obsolete consumer products thus becomes an economic substitution for virgin plastics, which is further intensified with the possibility of international waste plastic trading. This study focuses on waste plastic trade between the US and mainland China by performing a correlation analysis of trade data. It is suggested in this study that although waste plastics are traded from the US to mainland China in general, as many of us believes, the route is gradually shifting in the past years. With tightening Chinese customs regulations, waste plastic from the US now tends to take a transit in a third destination (Hong Kong SAR for instance) for preliminary treatment to bypass Chinese customs inspection. Such phenomenon is worth noting, as a complication in waste plastic trading route hinders waste plastic transboundary movement monitoring. Furthermore, it will have adverse consequent consumer, industrial, and environmental impacts. It is thus necessary for national competent authorities to strengthen cooperative study and communication capacity in the future as a response to the changing waste plastic trade pattern.     

制糖废水用于农田灌溉的效果研究

制糖废水富含适宜农作物生长的有机质及营养元素成分,可以作为农业的补充用水,并可以节约能源。节约化肥,提高作物产量,提高土壤肥力。从保护环境的角度看,这是一项极具推广价值和长远意义的工作。对废水用于农田灌溉的不良影响,可通过严格控制灌溉水质、结合作物需求采用合理科学的灌溉制度及灌溉技术等加以解决。     

Influence of construction and demolition waste management on the environmental impact of buildings

The purpose of this study is to quantify comparable environmental impacts within a Life Cycle Analysis (LCA) perspective, for buildings in which the first (Materials) and last (End of Life) life cycle stages are adjusted to several waste/material management options. Unlike most LCAs, the approach is “top-down” rather than “bottom-up”, which usually involves large amounts of data and the use of specific software applications. This approach is considered appropriate for a limited but expedient LCA designed to compare the environmental impacts of different life cycle options.Present results, based on real buildings measurements and demolition contractor activities, show that shallow, superficial, selective demolition may not result in reduced environmental impacts. Calculations actually show an increase (generally less than 5%) in most impact categories for the Materials and End of Life stages because of extra transportation needs. However, core material separation in demolition operations and its recycling and/or reuse does bring environmental benefits. A reduction of around 77% has been estimated in the climate change impact category, 57% in acidification potential and 81% in the summer smog impact (for the life cycle stages referred).     

Simultaneous sampling of PCDD/PCDF inside the combustion chamber and on four boiler levels of a waste incineration plant

At a MSWI (municipal solid waste incinerator) plant PCDD/PCDF samples (gasphase and particulates) were taken simultaneously be a shock-freezing method in the incinerator combustion chamber at approx. 800°C and in four sampling sections in the boiler at about 490°C, 370°C, 330°C and 270°C. In this way PCDD/PCDF-formation in the flow through the boiler was determined. Two data sets were evaluated. A considerable PCDD/PCDF-formation had occurred already at boiler temperatures of about 490°C; the highest concentration, however, was found at the end of the boiler at about 300°C. The accompanying measuring program of plant parameters made the calculation of the PCDD/PCDF mass flows possible, which allowed the inclusion of the PCDD/PCDF-content in the ESP dust in the mass flow calculations.