DEVELOPING APPROPRIATE TECHNOLOGY FOR SMALL SCALE SHALLOW LANDFILL - THE MID AUCHENCARROCH LANDFILL RESEARCH FACILITY Crispin Wingfield-Hayes
Abstract In the majority of developed countries landfill is by far the most common waste disposal route for controlled waste. Transportation costs to major sites from rural and remote communities are usually prohibitive, necessitating small scale shallow landfill sites. These are not widely accepted as feasible options, with the inherent problems of low technology and low quantities of waste. The Mid Auchencarroch Landfill Research facility has shown through its first phase, that methanogenesis can be established and sustained in shallow landfill, and further that the waste can be manipulated in several ways to optimise the methanogenic processes at work. The second phase is currently attempting to establish optimisation techniques with a view to promoting gas utilisation from small scale landfill, and achieving stabilisation at an accelerated rate. This work aims to show the benefits of maintaining rural and remote landfill as an asset to the community, given that the appropriate levels of technology and cost are achieved. Key Words: Shallow landfill; appropriate technology; methane; bioreactor; rural; agricultural diversification
MASS BALANCE AND HEAVY METALS DISTRIBUTION IN MUNICIPAL SOLID WASTE INCINERATION Binner S. Galeotti L,Lombardi F, Mogensen E, Sirini P.
ABSTRACT Incineration plants are recognized as a valid and efficient technology to treat Municipal Solid Wastes (MSW), particularly when they are part of integrated treatment plants. Waste incineration reduces the waste volume and weight, thus saving space on the landfill; also the end products are hygienized by transforming organic matter into water and carbon dioxide (CO2); it is also possible to recover steam and/or energy. The main environmental impact in an incineration plant is due to the residues of the process (solid, liquid and gaseous emissions). Consequently waste incineration can gain public acceptance only if the concentration of low volatile organic compounds and the elution stability of heavy metals can be guaranteed. The characteristics of the residue depend on many factors such as composition of municipal solid wastes, properties of the individual metals, incineration technology and operating conditions of the incinerator. In the present work, the mass balance and the transfer of some heavy metals in a Danish full scale incineration plant (combined grate and rotary kiln furnace, boiler, filter bag) were tested. The elemental analysis and leaching test data of solid residues were also evaluated. The obtained results confirm the high efficiency of the examined incineration plant. That is confirmed by the heavy metals distribution, in relation to their lithophilic or volatile behavior. The results of the leaching test show the reduced associated environmental risk associated to the slags (about 87% by weight of the solid residues), while they confirm the necessity to dispose of fly ashes in a landfill with a high level of environmental protection. Keywords: Incineration, mass balance, heavy metals, slags, fly ashes, leaching test
USE OF A COMPUTER MODEL TO GENERATE SOLID WASTE DISPOSAL ALTERNATIVES Shoou-Yuh Chang and Zhi Li
ABSTRACT A model utilizing a modeling-to-generate-alternatives (MGA) approach for generating solid waste management (SWM) alternatives is presented in this study. The goal of this study is to create a computer program for the preliminary design of SWM systems. The program can be used to determine the least cost treatment and disposal system for a given SWM problem, and generate a set of alternatives that are widely 'different' with respect to treatment processes. Therefore, a wide range of technical alternatives and possible effects can be analyzed. A Bounded Implicit Enumeration (BIE) technique is first applied to produce a set of SWM systems within a specified cost constraint. The Pairwise Difference (PWD) approach is then used to rank the alternatives and screen out designs which employ similar treatment processes. The information and cost data collected on SWM processes, disposal methods, and costs for City of Greensboro, NC are compiled and used to demonstrate how the model can be used in practice. The results of this study show that the model developed is capable of generating SWM systems that are different from each other and cost no more than a specified percent above the lowest cost design. Key Words: Solid waste management, Mathematical model, Optimization, Systems approach, Generating alternatives
BEHAVIOR OF FIBER CONCRETE COMPOSITES USING RECYCLED STEEL SHAVINGS Abdullah KEYVANI S.
ABSTRACT Steel shavings or chips are long, narrow steel strips, 0.1-1.0 mm in thickness, 1-3 mm in width and have a rough surface, toothed edges and twisted section. They are produced by milling or drilling machines in assembly plants and steel forming workshops. These chips or steel shavings have very high tensile and shear strengths, and are much harder than original steel. Steel shavings have different shapes according to the machining process. However, the important point is the quantity of these materials which can be found in the heavy industrial sites. Also, these materials are waste materials, and therefore can usually be obtained without any charge. By cutting these chips into the desirable length, steel fibers can be obtained. Steel fiber reinforced concrete as a composite material has many applications and using steel shavings as steel fibers for concrete reinforcement is a new practical method of recycling waste solid materials in the concrete industry. The results of experiments showed that steel fiber reinforced concrete using recycled steel shavings results in a 94% increase in ultimate flexural strength, 113% increase in ultimate tensile strength, 62% increase in ultimate splitting strength, 80% increase in ultimate shear strength and a flexural toughness index of more than 800% compared to these in unreinforced concrete. Key Words: Waste steel shavings, chips, steel fiber, aspect ratio, roughness, hardness, bonding, pulling-out, rupture, toughness, fracture behavior, flexural toughness index.
IMMOBILIZATION OF HEAVY METALS FROM MSW INCINERATOR ASH VIA USE OF SOREL CEMENT Slavomira Macakova
ABSTRACT In the autumn of 1993, a research program was initiated in Slovakia to employ a by-product from a magnesium processing plant, Sorel cement, to stabilize fly ash originating from municipal waste incinerators. Sorel cement is a combination of magnesium oxide and chloride, currently a by-product of magnesium operations. The resulting product is mechanically strong and also passes environmental testing by the Slovak Waste Extraction Test and also EPA extraction testing. The potential therefore exists to combine two industrial wastes into one to make a stable, strong, and environmentally acceptable material which, if not suitable for construction, can readily be managed without risk. Key Words: Incinerator ash; fixation; immobilization; heavy metals; sorel cement
LANDFILL CLOSURE PLANS AND POST - CLOSURE CARE- COVER DESIGN AND MAINTENANCE T.Viraraghavan, V. Mahendraker and D. J. Mihial
ABSTRACT When the approved or licensed design capacity of a landfill is exhausted, it must be closed in an environmentally acceptable manner. A landfill closure plan should be developed at the design stage of the landfill or during the site development phase to comply with environmental controls during closure and post-closure periods as per the local, provincial and federal regulations. This paper examines the closure options for landfills especially the characteristics of landfill covers. The specific functions of the individual layers in the cover, as well as their design, and constructional aspects are discussed. The closure plan for the City of Regina landfill is reviewed in detail in respect of its cover design. Keywords: Landfill; Closure; Post-closure care; Landfill gas; Leachate |
