Klaus Fricke

Quality, Physical Characteristics, Nutrient Content, Heavy Metals and Organic Chemicals in Biogenic Waste Compost

Data from an extensive survey of composts produced from biogenic waste were analyzed. Average heavy metals contents can be classified as low. Due to their valuable characteristics to crops and soils, the composts can be utilized in all facets of plant production. However, the addition of biocompost as a mixing component of substratum production might be limited by increased salt contents. It is recommended that standardized methods be developed for the separate collection and processing methods of biocompost to minimize the introduction and content of organic trace contaminants in composts.

Biodegradation of Organic Matter During Mechanical Biological Treatment of MSW

The German Technical Guideline for Municipal Solid Waste (TASI) stipulates criteria for waste to be landfilled in order to minimize environmental hazards and landfill maintenance. One of these requirements is an ignition loss of less than five percent dm (dry matter). Only waste which has been incinerated can comply with this criterion, and subsequently be landfilled. Experts agree that the ignition loss alone is not suitable to predict reactions in a landfill. Therefore, other methods of assessing biological activity of processed MSW in a landfill are presented and discussed. It was found that respiration activity was most appropriate for such an assessment at this stage. From available data, it was concluded that processed MSW is fit for landfilling if the respiration activity is below 5 mg O2/g dm over a period of 96 hours.

Compost quality: Physical characteristics, nutrient content, heavy metals and organic chemicals

Bio‐ and yard waste composts show a high standard of quality. Due to their valuable characteristics it is possible to utilize them in plant production. Average heavy metal contents of bio‐ and yard waste composts is low. Nevertheless, the results presented reveal that nine biocomposts do not comply with the requirements necessary to obtain the “seal of approval for quality compost”;. A first check of the data suggests that soil contamination of geological, respectively pedological origin, is responsible for limit violation. Other limit violations are due to increased soil contaminant levels, caused by anthropogenic activities. Increased heavy metal contents in two more composts is likely due for above average degree of undesirable materials in the separately collected organic refuse. Dioxins can be found ubiquitously in the environment, consequently therefore in composting raw material and in the end product. According to current knowledge, levels of PCDD/F found in bio‐ and greencompost can be classified...

Technology and undesirable components on compost of separately collected organic wastes

Abstract The pilot-project “Green Garbage Can” included the separate collection and composting of biogenic wastes from households, gardens and industries in a city of 18 000 inhabitants. The aim of the project was a reduction of the total amount of wastes and the production of compost of better quality as compared with the previously produced municipal-waste compost (+ slurry). A decentralized system with low-cost technology was established, which allowed processing of biogenic waste under controlled conditions. The results demonstrate that under practical conditions, controlled composting will lead to a final product of better quality, with regard to the contents of undesirable components. Environmental pollution owing to run-off or odour can be minimized using appropriate technologies.

Nutrient value and utilization of biogenic compost in plant production

Abstract The nutrient value of biogenic waste compost (BWC) for plant production was determined by chemical analyses and in a field experiment with kohlrabi (Brassica oleracea Gongylods). The results showed favourable nutrient contents of BWC and indicated that it can be used successfully, directly or in combination with chopped bark in various fields of plant production.

Spatial variability of nitrous oxide and methane emissions from an MBT landfill in operation: Strong N2O hotspots at the working face

Mechanical biological treatment (MBT) is an effective technique, which removes organic carbon from municipal solid waste (MSW) prior to deposition. Thereby, methane (CH4) production in the landfill is strongly mitigated. However, direct measurements of greenhouse gas emissions from full-scale MBT landfills have not been conducted so far. Thus, CH4 and nitrous oxide (N2O) emissions from a German MBT landfill in operation as well as their concentrations in the landfill gas (LFG) were measured. High N2O emissions of 20-200gCO2eq.m(-2)h(-1) magnitude (up to 428mgNm(-2)h(-1)) were observed within 20m of the working face. CH4 emissions were highest at the landfill zone located at a distance of 30-40m from the working face, where they reached about 10gCO2eq.m(-2)h(-1). The MBT material in this area has been deposited several weeks earlier. Maximum LFG concentration for N2O was 24.000ppmv in material below the emission hotspot. At a depth of 50cm from the landfill surface a strong negative correlation between N2O and CH4 concentrations was observed. From this and from the distribution pattern of extractable ammonium, nitrite, and nitrate it has been concluded that strong N2O production is associated with nitrification activity and the occurrence of nitrite and nitrate, which is initiated by oxygen input during waste deposition. Therefore, CH4 mitigation measures, which often employ aeration, could result in a net increase of GHG emissions due to increased N2O emissions, especially at MBT landfills.

Microelectromechanical vibration sensor with optical interconnects

A resonant vibration sensor realized using silicon micromachining for wear monitoring of rotating machinery is described. It comprises a mechanical resonator, piezoresistive bridge, and components for fiber-optical signal readout by an infrared light-emitting diode. The performance of the microsystem is demonstrated by its static and dynamical behavior. The results confirm that the described sensor has the potential for on-line vibration control of rotating machinery operated under the conditions of industrial production.

Energy efficiency of substance and energy recovery of selected waste fractions

In order to reduce the ecological impact of resource exploitation, the EU calls for sustainable options to increase the efficiency and productivity of the utilization of natural resources. This target can only be achieved by considering resource recovery from waste comprehensively. However, waste management measures have to be investigated critically and all aspects of substance-related recycling and energy recovery have to be carefully balanced. This article compares recovery methods for selected waste fractions with regard to their energy efficiency. Whether material recycling or energy recovery is the most energy efficient solution, is a question of particular relevance with regard to the following waste fractions: paper and cardboard, plastics and biowaste and also indirectly metals. For the described material categories material recycling has advantages compared to energy recovery. In accordance with the improved energy efficiency of substance opposed to energy recovery, substance-related recycling causes lower emissions of green house gases. For the fractions paper and cardboard, plastics, biowaste and metals it becomes apparent, that intensification of the separate collection systems in combination with a more intensive use of sorting technologies can increase the extent of material recycling. Collection and sorting systems must be coordinated. The objective of the overall system must be to achieve an optimum of the highest possible recovery rates in combination with a high quality of recyclables. The energy efficiency of substance related recycling of biowaste can be increased by intensifying the use of anaerobic technologies. In order to increase the energy efficiency of the overall system, the energy efficiencies of energy recovery plants must be increased so that the waste unsuitable for substance recycling is recycled or treated with the highest possible energy yield.

Removal of nitrogen from MBT residues by leachate recirculation in combination with intermittent aeration.

Mechanical–biological treatment (MBT) techniques have been used to reduce the emission potential of waste before placement in landfills for a couple of years, especially in Europe. The main focus of MBT is on the reduction of native organic substances and not on nitrogen compounds. As a result, the concentrations of organic substances in leachate from MBT landfills are considerably reduced in comparison to leachates from municipal solid waste landfills, while the ammonia nitrogen concentrations remain at a high level. From the stabilization of old landfills it is well known that recirculation of leachate and supplementary aeration can reduce emissions to an acceptable level in a comparatively short time. In a series of laboratory-scale tests the efficiency of this technique for MBT residues was investigated under different boundary conditions. While the effect of leachate recirculation is also well known for MBT residues, the additional aeration has so far not been investigated. The results show that this technique has only a limited influence on the reduction of organic carbon compounds. In view of nitrogen compounds, only the additional aeration during recirculation shows a strong effect on the quality of leachate, in which the concentrations of ammonium and total nitrogen are reduced by more than 90%. The results indicate that by using simple techniques the long-term emission behavior of MBT residues can be quickly reduced to an acceptable level.

Micromachined resonator for cavitation sensing

Abstract A micromachined spring-mass resonator is investigated with respect to its response on short impacts. The resulting amplitude spectrum is dominated by resonances which are related to bending and torsional vibration modes of the resonator. The amplitude ratio of these modes which depends on the direction of excitation is used to monitor at high sensitivity characteristic parts of complex solid-borne sound spectra of machines. For example, the solid-borne sound emitted by a rolling bearing as well as by a centrifugal pump under different conditions of operation was investigated. The results obtained with the pump show that cavitation can be detected—an effect which may cause severe damage to the pump body due to material erosion.