Johannes Jager

Compound-specific chlorine isotope analysis: a comparison of gas chromatography/isotope ratio mass spectrometry and gas chromatography/quadrupole mass spectrometry methods in an interlaboratory study.

Chlorine isotope analysis of chlorinated hydrocarbons like trichloroethylene (TCE) is of emerging demand because these species are important environmental pollutants. Continuous flow analysis of noncombusted TCE molecules, either by gas chromatography/isotope ratio mass spectrometry (GC/IRMS) or by GC/quadrupole mass spectrometry (GC/qMS), was recently brought forward as innovative analytical solution. Despite early implementations, a benchmark for routine applications has been missing. This study systematically compared the performance of GC/qMS versus GC/IRMS in six laboratories involving eight different instruments (GC/IRMS, Isoprime and Thermo MAT-253; GC/qMS, Agilent 5973N, two Agilent 5975C, two Thermo DSQII, and one Thermo DSQI). Calibrations of (37)Cl/(35)Cl instrument data against the international SMOC scale (Standard Mean Ocean Chloride) deviated between instruments and over time. Therefore, at least two calibration standards are required to obtain true differences between samples. Amount dependency of δ(37)Cl was pronounced for some instruments, but could be eliminated by corrections, or by adjusting amplitudes of standards and samples. Precision decreased in the order GC/IRMS (1σ ≈ 0.1‰), to GC/qMS (1σ ≈ 0.2-0.5‰ for Agilent GC/qMS and 1σ ≈ 0.2-0.9‰ for Thermo GC/qMS). Nonetheless, δ(37)Cl values between laboratories showed good agreement when the same external standards were used. These results lend confidence to the methods and may serve as a benchmark for future applications.

Odour monitoring by the combination of sensors and neural networks

Abstract The treatment of waste is always combined with odour emission which can be annoying to people living near waste treatment plants. To identify and evaluate these odour emissions, different methods are used. The most frequently applied “measuring instrument” is the human nose. However, various factors, e.g. form on the day, make assessment difficult. Therefore, it is necessary to develop a measuring method which is objective and efficient. One example is a combination of sensors and neural networks. With this device, called an “Electronic Nose”, it is not only possible to identify odour, but all kinds of substances, depending on the selectivities of the sensors, can be detected and monitored. With reference to the characteristic patterns of defined emission situations, process control is possible in order to classify the emitting parts of a plant.

PCDD/PCDF balance of different municipal waste management methods

Abstract An inventory of different methods of managing municipal waste show not only incineration and disposal, but recycling techniques like composting or material recycling for e.g. metals are facing comparable dioxin problems. This result will have consequences in the public discussion about dioxin problems in waste management. A comprehensive solution for this problem cannot be achieved by end-of-the-pipe-techniques (e.g. dioxin filters in MWI), but has to go to the roots: the input of dioxins and precursor substances into waste management.

Formation of chlorinated and brominated dioxins and other organohalogen compounds at the pilot incineration plant VERONA

Experiments were conducted at the VERONA pilot plant, an incineration plant with stationary grate and separate post-combustion chamber, using wood and propane as basic combustible materials and with controlled dosage of various bromine-, chlorine- and copper-containing compounds. The behaviour of the following compounds was studied in the combustion chamber, after the post-combustion chamber and after the heat exchanger: polychlorinated phenols (PCPh), polybrominated phenols (PBrPh), polychlorinated benzenes (PCBz), polybrominated benzenes (PBrBz), polychlorinated dioxins and furans (PCDD/F) and polybrominated dioxins and furans (PBDD/F). The bromine co-incineration leaded to very high bromophenol concentrations after the post-combustion chamber. The formation of brominated and mixed-halogenated phenols and the further reaction to halogenated dioxins is apparently a relevant reaction mechanism for dioxin formation in processes involving bromine. This assumption is supported by the high formation rates of PBDD/F found in the heat exchanger, which were 4-20 times higher than those of PCDD/F. Moreover, the strong correlations found between the formation rates of PCPh, PCBz and PCDD/F in the heat exchanger indicate that in addition considerable new formation of dioxins takes place through de novo synthesis. Experiments involving the variation of primary operational parameters and fuel properties have shown that the quality of post-combustion plays a much greater role than the other parameters. Furthermore, it became apparent that the congeners of the chlorophenols and of the chlorobenzenes, measured in various incineration stages, do not correlate closely with the dioxin concentrations after the heat exchanger.

Distribution of PCDD/PCDF and other organochlorine compounds in different municipal solid waste fractions

Abstract The authors prepared 70 analyses of four waste fractions of samples taken in 1980 (A = paper + cardboards; B = Plastics, wood, leather, textile etc.; C = fine debris 8 mm), due to their content of PCDD/PCDF, and other organochlorine compounds. PCDD/PCDF contamination in I-TE was 18.3 - 383 pg/g (fraction A), 29.1 - 1370 pg/g (fraction B), 8 - 468 pg/g (fraction C) and 7.4 - 100 pg/g (fraction D). The average PCDD/PCDF content in I-TE of the analytical waste amounted to 104 pg/g, of the wet total waste to 50.2 pg/g. Patterns and possible input factors are discussed.

Behaviour of PCDD/F under pyrolysis conditions

Results are reported for the behaviour of PCDD/F during the pyrolysis process. Investigations were performed at a rotary kiln operating as a disposal facility as well as in a laboratory-scale batch reactor. The amount of input PCDD concentration and the operating conditions seemed not to have an impact on the PCDD mass balance. In both cases about half the input amount was found in the pyrolysis products. Contrary to that, formation rates and distribution of the generated furans depended largely on the operating conditions and the input composition.

Determination and reduction of PCDD/F emissions from wood burning facilities

Seven wood burning facilities were analyzed for their emissions of PCDD/F and other parameters while the input was varied. PCDD/F emission concentrations ranged from 0.004 to 9.820 ng I-TEQ/Nm3, with the majority of values > 0.1 ng I-TEQ/Nm3, even if the input was untreated wood. Highest concentrations occurred after addition of halogenated materials (NH4Cl hardened or PVC coated plywood) to the input. Using typical input materials, facilities with smaller thermal capacity ( 1 MW) emitted 0.07 to 0.5 μg I-TEQ/h. Using treated input materials, emission freights of smaller facilities reached 1.6 μg I-TEQ/h, while the large plants released up to 7.2 μg I-TEQ/h.

Practical concepts to minimize the emission of halogenated organic compounds from municipal solid waste incinerators

Abstract The authors present their research findings at four different municipal waste incinerators (MWIs) concerning generation and release of dioxins and furans. The analytical results of the following design and operation conditions are described: “cold blowing”, flue gas cooling and “soot blowing”. In addition, input variation test results are presented. Consequences for reducing the emission of halogenated dioxins and furans are discussed.

PCDD/F, PCB, chlorobenzene and chlorophenol emissions of a Municipal Solid Waste Incineration plant (MSWI) — variation within a five day routine performance and influence of Mg(OH)2-addition

Abstract PCDD/F concentration in clean gas ranged from 1.88 to 7.76 ng l-TEQ/Nm 3 and varied for a factor of 4.1 during routine operation. During performance with Mg(OH) 2 addition, clean gas concentrations ranged from 5.06 to 8.19 ng I-TEQ/Nm 3 and varied for a factor of 1.6. Mg(OH) 2 addition seemed to increase emissions concentrations of PCDD/F (I-TEQ), PCB and chlorobenzenes, but not chlorophenols, while inorganic acid parameters (HCl, HF, SO 2 ) are reduced, as expected. In addition, conclusions concerning the reliability of single emission measurements are drawn.

Extraction of medium chain fatty acids from organic municipal waste and subsequent production of bio-based fuels.

This paper provides an overview on investigations for a new technology to generate bio-based fuel additives from bio-waste. The investigations are taking place at the composting plant in Darmstadt-Kranichstein (Germany). The aim is to explore the potential of bio-waste as feedstock in producing different bio-based products (or bio-based fuels). For this investigation, a facultative anaerobic process is to be integrated into the normal aerobic waste treatment process for composting. The bio-waste is to be treated in four steps to produce biofuels. The first step is the facultative anaerobic treatment of the waste in a rotting box namely percolate to generate a fatty-acid rich liquid fraction. The Hydrolysis takes place in the rotting box during the waste treatment. The organic compounds are then dissolved and transferred into the waste liquid phase. Browne et al. (2013) describes the hydrolysis as an enzymatically degradation of high solid substrates to soluble products which are further degraded to volatile fatty acids (VFA). This is confirmed by analytical tests done on the liquid fraction. After the percolation, volatile and medium chain fatty acids are found in the liquid phase. Concentrations of fatty acids between 8.0 and 31.5 were detected depending on the nature of the input material. In the second step, a fermentation process will be initiated to produce additional fatty acids. Existing microorganism mass is activated to degrade the organic components that are still remaining in the percolate. After fermentation the quantity of fatty acids in four investigated reactors increased 3-5 times. While fermentation mainly non-polar fatty acids (pentanoic to octanoic acid) are build. Next to the fermentation process, a chain-elongation step is arranged by adding ethanol to the fatty acid rich percolate. While these investigations a chain-elongation of mainly fatty acids with pair numbers of carbon atoms (acetate, butanoic and hexanoic acid) are demonstrated. After these three pre-treatments, the percolate is brought to a refinery to extract the non-polar fatty acids using bio-diesel, which was generated from used kitchen oil at the refinery. The extraction tests in the lab have proved that the efficiency of the liquid-liquid-extraction is directly linked with the chain length and polarity of the fatty acids. By using a non-polar bio-diesel mainly the non-polar fatty acids, like pentanoic to octanoic acid, are extracted. After extraction, the bio-diesel enriched with the fatty acids is esterified. As a result bio-diesel with a lower viscosity than usual is produced. The fatty acids remaining in the percolate after the extraction can be used in another fermentation process to generate biogas.