Reduction of fuel side costs due to biomass co-combustion.

The feasibility and influence of co-combustion of woody biomass on the fuel side costs is discussed for three hard coal power plants located in Berlin, Germany. Fuel side costs are defined as the costs resulting from flue gas cleaning and by-products. To have reliable data, co-firing tests were conducted in two power plants (i.

Carbon speciation in ash, residual waste and contaminated soil by thermal and chemical analyses.

Carbon in waste can occur as inorganic (IC), organic (OC) and elemental carbon (EC) each having distinct chemical properties and possible environmental effects. In this study, carbon speciation was performed using thermogravimetric analysis (TGA), chemical degradation tests and the standard total organic carbon (TOC) measurement procedures in three types of waste materials (bottom ash, residual waste and contaminated soil). Over 50% of the total carbon (TC) in all studied materials (72% in ash and residual waste, and 59% in soil) was biologically non-reactive or EC as determined by thermogravimetric analyses.

Accelerated carbonation of steel slags in a landfill cover construction.

Steel slags from high-alloyed tool steel production were used in a full scale cover construction of a municipal solid waste (MSW) landfill. In order to study the long-term stability of the steel slags within the final cover, a laboratory experiment was performed. The effect on the ageing process, due to i.

Hydraulic conductivity of fly ash-sewage sludge mixes for use in landfill cover liners.

Secondary materials could help meeting the increasing demand of landfill cover liner materials. In this study, the effect of compaction energy, water content, ash ratio, freezing, drying and biological activity on the hydraulic conductivity of two fly ash-sewage sludge mixes was investigated using a 2(7-1) fractional factorial design. The aim was to identify the factors that influence hydraulic conductivity, to quantify their effects and to assess how a sufficiently low hydraulic conductivity can be achieved.

Wet extraction of heavy metals and chloride from MSWI and straw combustion fly ashes.

Fly ash residues from combustion often do not meet the criteria neither for reuse as construction materials nor landfilling as non-hazardous waste, mainly because of the high concentration of heavy metals and chlorides. This work aimed to technically evaluate an innovative wet treatment process for the extraction of chloride (Cl(-)), cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) from fly ashes from a municipal solid waste incineration (MSWI) plant and from a straw combustion (SC) facility. Factors investigated were liquid/solid (L/S) ratio, full carbonation (CO(2) treatment), influence of pH and leaching time, using a two-level full factorial design.

Mobility of organic carbon from incineration residues.

Dissolved organic carbon (DOC) may affect the transport of pollutants from incineration residues when landfilled or used in geotechnical construction. The leaching of dissolved organic carbon (DOC) from municipal solid waste incineration (MSWI) bottom ash and air pollution control residue (APC) from the incineration of waste wood was investigated. Factors affecting the mobility of DOC were studied in a reduced 2(6-1) experimental design.

Toxicity of leachate from bottom ash in a road construction.

A test road constructed with municipal solid waste incineration (MSWI) bottom ash was monitored over a period of 36 months. Using chemical and toxicological characterisation, the environmental impact of leachates from bottom ash was evaluated and compared with leachates from gravel used as reference. Initial leaching of Cl, Cu, K, Na, NH4-N and TOC from bottom ash was of major concern.

The effect of isosaccharinic acid (ISA) on the mobilization of metals in municipal solid waste incineration (MSWI) dry scrubber residue.

Co-landfilling of incineration ash and cellulose might facilitate the alkaline degradation of cellulose. A major degradation product is isosaccharinic acid (ISA), a complexing agent for metals. The impact of ISA on the mobility of Pb, Zn, Cr, Cu and Cd from a municipal solid waste incineration dry scrubber residue was studied at laboratory using a reduced 2(5-1) factorial design.

Demobilisation of critical contaminants in four typical waste-to-energy ashes by carbonation.

Two bottom ashes, one air pollution control (APC) residue and one fly ash from three different Swedish municipal solid waste incineration (MSWI) plants were characterised regarding the leaching of environmentally relevant components. Characterisation was performed using a diffusion tank leaching test. The impact of carbonation on the release of eight critical components, i.

Quantification of the effects of environmental leaching factors on emissions from bottom ash in road construction.

The re-use of bottom ash in road construction necessitates a tool to predict the impact of trace metals on the surroundings over the lifetime of the road. The aim of this work was to quantify the effect of environmental factors that are supposed to influence leaching, so as to suggest guidelines in developing a leaching procedure for the testing of incineration residues re-used in road constructions. The effects of pH, L/S (liquid-to-solid ratio), leaching time, and leaching atmosphere on the leachate concentrations of Cd, Cr, Cu, Ni, Pb, and Zn were studied using a two-level full factorial design.

Evaluation and prediction of emissions from a road built with bottom ash from municipal solid waste incineration (MSWI).

In autumn 2001, a full-scale test road was built with municipal solid waste incineration (MSWI) bottom ash at the Dåvamyran landfill, Umeå, Northern Sweden. Leachates were collected from asphalted sections with either bottom ash or gravel as filling material. In this research, 12 months of ash leachate sampling were evaluated with respect to emissions of contaminants such as trace metals and chlorides (Cl).

Sequestration of metals in carbonated municipal solid waste incineration (MSWI) fly ash.

Waste management is in need of a reliable and economical treatment method for metals in fly ashes from municipal solid waste incineration (MSWI). However, no state-of-the-art technique has gained wide acceptance yet. This paper is a synthesis of five elsewhere published investigations covering a project which aimed to assess the possibilities and limitations of adding carbon dioxide (CO2) to fly ash as a stabilization method.

Solidification with water as a treatment method for air pollution control residues.

The process of solidification with water was studied on air pollution control (APC) residues from incineration of refuse-derived fuel (RDF) regarding mechanical strength and leaching behaviour of solidified material. Factorial design in two levels was applied to investigate the impact of water addition, time, and temperature to mechanical strength of solidified material. Factors time and temperature, as well as the interaction between the addition of water and time significantly (alpha=0.

Effect of electric arc vitrification of bottom ash on the mobility and fate of metals.

Increasing amounts of municipal solid waste incineration (MSWI) residues are treated prior to landfilling or reuse. In Japan, electric arc melting is used for bottom ash vitrification that generates a glasslike slag. The objective of this paper was to assess this pretreatment technique with respect to its effect on metal mobility and metal content.

[Dynamic force measurement in implantation of total endoprostheses of the hip joint].

The forces within the femoral shaft have been studied in preparation for the total hip replacement. The experimental device consisted of a personal computer connected with a digital enhanced measurement system which converted the data, that was received from the strain gauges, mounted on the femur. The bitochanter hip replacement designed by Ecke was used as an example of a press fit endoprosthesis which is anchored cementless.

[Effect of form elasticity of the prosthesis shaft in response to stress of the proximal femur].

Uncemented hip prostheses are characterized by a variable design of the stem. In these investigations, nine different prostheses were studied according to the model of a standard bone (Kunststoffnormfemur). After preparation of the cavity of the prostheses with original instruments and after its implantation, strain gauges were placed at 16 certain points.

[Diagnosis and therapy of metastasis-induced pathologic fractures].

Improved survival rates of cancer patients have led to an increase in the incidence of metastatic disease of the bone. Normal load and minimal trauma may result in pathological fractures. The malignant diseases most commonly diagnosed were breast cancer, bronchial carcinoma and hypernephroma.

[Post-traumatic lesion of the distal radioulnar joint with disordered forearm pronation].

Within a period of 14 years in 27 cases operative correction of a traumatic lesion of the distal radioulnar joint has been performed at the University Clinic of Giessen. The follow-up of our results is to be confined to the last ten cases; all efforts to evaluate the outcome of 17 joints having been operated on previously unfortunately have proved to be unfeasible. Different types of corrective operative procedures have been accomplished.

[Bridging tension band fixation in the reconstruction of ruptured amphiarthrosis of the pelvic girdle].

Two different surgical techniques to treat rupture of the symphysis or the sacroiliac joint, which were introduced at the beginning of the seventies and were modified later, are presented in regards to their methodology and their results. In a lot of cases after surgery they enable a normal spring-suspension of the pelvis.

[Biomechanical studies of various forms of symphysis banding].

The banding operation with polydioxanone cord for pelvis stabilization after accidental symphysis rupture is altogether reliable. Nevertheless in some cases we saw later on non satisfying reduction results in the "pelvis-half-joints"--especially in intense dislocation of the iliosacral amphiarthrosis. For improving the stability we investigated the stiffness character of some different methods with four PDS cords varied by four and six drilling holes.

[Rupture of the amphiarthrosis of the pelvic girdle].

So-called over-bridging tension band fixations are presented with special respect to their surgical procedures, development to technique, operative approaches, experimental findings gathered from 83 human pelves explanted post-mortally and clinical results. PDS band fixation has shown to guarantee approximately the same stability as comparable procedures offering in any case an immediate ease of bedside care and the possibility of physical exercise in bed. A slight postoperative elongation of the PDS band is sometimes seen on the X-ray as a small step in the outlines of the symphysis, but so far has been of no importance in our cases of treatment.

[Bone stress. A hitherto neglected factor in hip endoprosthesis design].

Growing interest in hip endoprostheses is giving rise to new ideas on form and materials, although it is not precisely known what forces the proximal femur is subject to. To find out more about these forces, we made computerized analyses of the stresses on some different types of prostheses in an artificial standardized femur. The E-module amounts to about 14,000 N/mm.

[Follow-up studies and results of dorsal stabilization of unstable spinal fractures].

Temporary dorsal plate spondylodesis with transpedunclar screwing has proved successful in the therapy of recent unstable injuries to the spine. This method allows a considerable reconstruction and stabilization of the vertebral body as well as an early mobilization of the patient. The mobility of the spine will not be essentially reduced if the spondylodesis plates are removed early, i.

[Torsion forces of the proximal femur following implantation of a hip prostheses].

Growing interest in hip endoprosthesis is inducing a lot of ideas for formgiving, without having cleared the adequate strength to the proximale femur. To know more about these forces, we made computerized tension-analyses of some different types of prosthesis in a normed artificial femur. Measurement of press- and tensile tensions on one hand and the torsion-tensions on the other hand showed some enhanced forces which might be the reason for slackening of hip endoprosthesis.