SciCombinator

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Journal: Waste management & research : the journal of the International Solid Wastes and Public Cleansing Association, ISWA

28

The construction industry is one of the biggest and most active sectors of the European Union (EU), consuming more raw materials and energy than any other economic activity. Furthermore, construction waste is the commonest waste produced in the EU. Current EU legislation sets out to implement construction and demolition waste (CDW) prevention and recycling measures. However it lacks tools to accelerate the development of a sector as bound by tradition as the building industry. The main objective of the present study was to determine indicators to estimate the amount of CDW generated on site both globally and by waste stream. CDW generation was estimated for six specific sectors: new residential construction, new non-residential construction, residential demolition, non-residential demolition, residential refurbishment, and non-residential refurbishment. The data needed to develop the indicators was collected through an exhaustive survey of previous international studies. The indicators determined suggest that the average composition of waste generated on site is mostly concrete and ceramic materials. Specifically for new residential and new non-residential construction the production of concrete waste in buildings with a reinforced concrete structure lies between 17.8 and 32.9 kg m(-2) and between 18.3 and 40.1 kg m(-2), respectively. For the residential and non-residential demolition sectors the production of this waste stream in buildings with a reinforced concrete structure varies from 492 to 840 kg m(-2) and from 401 to 768 kg/m(-2), respectively. For the residential and non-residential refurbishment sectors the production of concrete waste in buildings lies between 18.9 and 45.9 kg/m(-2) and between 18.9 and 191.2 kg/m(-2), respectively.

Concepts: European Union, Construction, Building, Waste, Fire protection, Occupancy, Reinforced concrete, Demolition waste

28

This work presents the enforcement performance of recent Haulien County, Taiwan municipal solid waste (MSW) recycling management programs. These programs include: Mandatory Refuse Sorting and Recycling, Diverse Bulk Waste Reuse, Pay-as-you-Discharge, Total Food Waste Recycling, Restricted Use on Plastic Shopping Bags & Plastic Tableware, Recycling Fund Management, and Ash Reuse. These programs provide incentives to reduce the MSW quantity growth rate. It was found that the recycled material fraction of MSW generated in 2001 was from 6.8%, but was 32.4% in 2010 and will increase stably by 2-5% yearly in the near future. Survey data for the last few years show that only 2.68% (based on total MSW generated) of food waste was collected in 2001. However, food waste was up to 9.7 % in 2010 after the Total Food Waste Recycling program was implemented. The reutilization rate of bottom ash was 20% in 2005 and up to 65% in 2010 owing to Ash Reuse Program enforcement. A quantified index, the Total Recycle Index, was proposed to evaluate MSW management program performance. The demonstrated county will move toward a zero waste society in 2015 if the Total Recycle Index approaches 1.00. Exact management with available programs can lead to slow-growing waste volume and recovery of all MSW.

Concepts: Waste management, Reuse, Recycling, Incineration, Waste, Waste picker, Waste hierarchy, Waste management concepts

28

The present study investigated the utilization of an industrial by-product, lignite fly ash, in oil pollution treatment, with the further potential profit of energy production. The properties of lignite fly ash, such as fine particle size, porosity, hydrophobic character, combined with the properties, such as high porosity and low specific gravity, of an agricultural by-product, namely sawdust, resulted in an effective oil-sorbent material. The materials were mixed either in the dry state or in aqueous solution. The oil sorption behaviour of the fly ash-sawdust mixtures was investigated in both marine and dry environments. Mixtures containing fly ash and 15-25% w/w sawdust performed better than each material alone when added to oil spills in a marine environment, as they formed a cohesive semi-solid phase, adsorbing almost no water, floating on the water surface and allowing total oil removal. For the clean-up of an oil spill 0.5 mm thick with surface area 1000 m(2), 225-255 kg of lignite fly ash can be utilized with the addition of 15-25% w/w sawdust. Fly ash-sawdust mixtures have also proved efficient for oil spill clean-up on land, since their oil sorption capacity in dry conditions was at least 0.6-1.4 g oil g(-1) mixture. The higher calorific value of the resultant oil-fly ash-sawdust mixtures increased up to that of bituminous coal and oil and exceeded that of lignite, thereby encouraging their utilization as alternative fuels especially in the cement industry, suggesting that the remaining ash can contribute in clinker production.

Concepts: Energy, Water, Petroleum, Mediterranean Sea, Coal, Exxon Valdez oil spill, Oil spill, Bituminous coal

27

The disposal of municipal waste in landfills may pose an environmental problem because the product of the decomposition of these residues generates large volumes of leachate, which may present high toxicity. The aim of this study was to assess the toxic and genotoxic effects of a sample of untreated leachate in fish (Leporinus obtusidens) and onions (Allium cepa). The leachate was collected in a landfill located in the region of Vale do Rio dos Sinos, southern Brazil. The fish were exposed to raw leachate, at concentrations of 0.5%, 1.0%, 5%, 10% and 20% for 6 days, while the bulbs of A. cepa were exposed to concentrations of 5%, 10%, 25%, 50% and 100% for 48 h. For fish, the concentrations of 5%, 10% and 20% were lethal, thus indicating high toxicity; however, sublethal concentrations (0.5% and 1.0%) showed no genotoxicity by micronucleus test when compared with the control group. In the bioassays involving onions, high toxicity was observed, with significant reduction of root growth and mitotic index in bulbs exposed to the 100% concentration of the leachate. An increase in the frequency of chromosome abnormalities in the A. cepa root cells in anaphase-telophase was observed in accordance with the increase in the concentration of leachate (5%, 10%, 25% and 50%), with values significantly greater than the control, at the highest concentration. The results showed that the leachate contains toxic and genotoxic substances, thus representing a major source of environmental pollution if not handled properly.

Concepts: Toxicology, Pollution, Garlic, Allium, Root, Leachate, Landfill, Onion

27

This study aimed to determine the content of fossil carbon in waste combusted in Sweden by using four different methods at seven geographically spread combustion plants. In total, the measurement campaign included 42 solid samples, 21 flue gas samples, 3 sorting analyses and 2 investigations using the balance method. The fossil carbon content in the solid samples and in the flue gas samples was determined using (14)C-analysis. From the analyses it was concluded that about a third of the carbon in mixed Swedish waste (municipal solid waste and industrial waste collected at Swedish industry sites) is fossil. The two other methods (the balance method and calculations from sorting analyses), based on assumptions and calculations, gave similar results in the plants in which they were used. Furthermore, the results indicate that the difference between samples containing as much as 80% industrial waste and samples consisting of solely municipal solid waste was not as large as expected. Besides investigating the fossil content of the waste, the project was also established to investigate the usability of various methods. However, it is difficult to directly compare the different methods used in this project because besides the estimation of emitted fossil carbon the methods provide other information, which is valuable to the plant owner. Therefore, the choice of method can also be controlled by factors other than direct determination of the fossil fuel emissions when considering implementation in the combustion plants.

Concepts: Carbon dioxide, Petroleum, Fossil fuel, Waste, Flue gas emissions from fossil fuel combustion

27

The technology used in the manufacturing of televisions and monitors has been changing in recent years. Monitors with liquid crystal displays (LCD) emerged in the market with the aim of replacing cathode ray tube monitors. As a result, the disposal of this type of product, which is already very high, will increase. Thus, without accurate knowledge of the components and materials present in an LCD monitor, the recycling of materials, such as mercury, thermoplastic polymers, glasses, metals and precious metals amongst others, is not only performed, but allows contamination of soil, water and air with the liberation of toxic compounds present in this type of waste when disposed of improperly. Therefore, the objective of this study was to disassemble and characterize the materials in this type of waste, identify the composition, amount and form to enable, in further work, the development of recycling routes. After various tests and analyses, it was observed that an LCD display can be recycled, provided that precautions are taken. Levels of lead, fluoride and copper are above those permitted by the Brazilian law, characterizing this residue as having a high pollution potential. The materials present in printed circuit boards (base and precious metals)-thermoplastics, such as polyethylene terephthalate, acrylic, acrylonitrile butadiene styrene and polycarbonate and metals, such as steel and aluminum, and a layer of indium (in the internal face of the glass)-are components that make a point in terms of their potential for recycling.

Concepts: Liquid crystal display, Recycling, Liquid crystal, Thermoplastic, Acrylonitrile butadiene styrene, Polyethylene terephthalate, Printed circuit board, Cathode ray tube

27

Despite their importance in urban drainage systems, gully pot internal processes have received little scientific study. Therefore, gully pot contents were examined to gain a basic understanding of these processes and to establish the decomposition characteristics of the contents ex situ. Moisture content, organic matter content, enzyme activity and pH were measured to investigate seasonal and geographical effects, in addition to a 5-week composting trial to determine the rate and characteristics of decomposition. Little difference was observed in the content processes, especially between seasons, and the composting trial illustrated organic content decreased at an average rate of 0.1 g of organic matter per 13 g of organic matter per day. The results from this study indicate an as yet unknown initial decomposition rate. Activity monitored between gully pots also suggests they are relatively similar systems across space and time; enabling gully contents to be evaluated universally in future research.

Concepts: Time, Scientific method, Enzyme, PH, Space, Humus, Decomposition, Sustainable urban drainage systems

27

This study focuses on the issues related to the waste management in river ports in general and, particularly, in ports on the river Danube’s flow through Serbia. The ports of Apatin, Bezdan, Backa Palanka, Novi Sad, Belgrade, Smederevo, Veliko Gradiste, Prahovo and Kladovo were analyzed. The input data (number of watercrafts, passengers and crew members) were obtained from harbor authorities for the period 2005-2009. The quantities of solid waste generated on both cruise and cargo ships are considered in this article. As there is no strategy for waste treatment in the ports in Serbia, these data are extremely valuable for further design of equipment for waste treatment and collection. Trends in data were analyzed and regression models were used to predict the waste quantities in each port in next 3 years. The obtained trends could be utilized as the basis for the calculation of the equipment capacities for waste selection, collection, storage and treatment. The results presented in this study establish the need for an organized management system for this type of waste, as well as suggest where the terminals for collection, storage and treatment of solid waste from ships should be located.

Concepts: Serbia, Waste, Danube, Syrmia, Vojvodina, Novi Sad, Belgrade, Ba ka

27

Municipal solid waste management (MSWM) is an important, practical and challenging environmental subject. The processes of a MSWM system include household collection, transportation, treatment, material recycling, compost and disposal. A regional program of MSWM is more complicated owing to the involvement of multi-municipality and multi-facility issues. Therefore, an effective decision support system capable of solving regional MSWM problems is necessary for decision-makers. This article employs linear programming techniques to establish a MSWM decision support system (MSWM-DSS) that is able to determine the least costs of regional MSWM strategies. The results of investigating a real-world case in central Taiwan indicate that a regional program is more economical and efficient. For the redeployment of MSW streams, the relatively least cost of operation for the MSWM system can still be achieved through the re-estimation of the MSWM-DSS. This tool and results are useful for MSWM policy-making in central Taiwan.

Concepts: Decision theory, Waste management, Decision support system, Recycling, Waste-to-energy, Waste, Decision engineering, Compost

27

Composting facilities in Thailand have faced various operational problems, resulting in the emission of odours, incomplete digestion of waste organics, and higher than desired costs. Composting technologies imported from developed countries tend to be sized for larger communities and are otherwise not suited for the rural communities that comprise more than 80% of all communities in Thailand. This article addresses the research and development of a novel composting technology aimed at filling this observed need. The study was divided into two parts: (1) the development of a new composting technology and fabrication of a prototype configuration of equipment; and (2) scale-up and study on a pilot-scale using real rubbish. The proposed technology, called ‘serial self-turning reactor (STR)’, entailed a vertical flow composting system that consisted of a set of aerobic reactors stacked on a set of gravity fed turning units. In-vessel bioreactor technology enables the operator to control composting conditions. The researchers found that a tower-like STR results in flexibility in size scale and waste processing residence time. The pilot-scale experiments showed that the proposed system can produce good quality compost while consuming comparatively little energy and occupying a compact space, compared to traditional land-intensive windrow composting facilities.

Concepts: Developed country, Research, Waste management, Recycling, Innovation, Composting, Vermicompost, In-vessel composting