Use of non-thermal plasma and UV-light for removal of odour from sludge treatment

Non-thermal plasma (NTP) systems can be used for abatement of odour nuisances. Odour reductions are achieved by radical-initiated oxidation and dust collection in the plasma reactor. For some emissions a sequence of NTP followed by UV-light can improve the odour reduction further. This study was conducted to evaluate the efficiency of NTP technology combined with UV-light towards odour emissions from sludge treatment. Air from a pilot sludge dryer was treated with a pilot NTP and a UV unit. The effect of using an acid scrubber upstream the NTP system was also tested. Thermal desorption gas chromatography and mass spectrometry (TD-GC/MS) was used to analyse samples taken from the inlet and the outlet of the NTP system. The TD-GC/MS used was also equipped with a sniffing port that made it possible to record odour-active compounds eluting from the column. Relative amounts of odour-active compounds in the inlet and the outlet flow from the NTP system were compared. Bag samples from inlet and outlet were also separately analysed by an external lab and by two operators using a one-man olfactometer, a modified NasalRanger(TM). These results indicated a significant odour removal efficiency of 70-90% depending on the settings and combinations of abatement equipment.

How reliable are odour assessments?

This paper will demonstrate the differences found in odour test results, when odour sampling is performed at the same sources by two different consultants. By examining two case studies, this paper will highlight that the difference between the results can be significant. Both studies are based on odour sampling programs determining the odour removal efficiency of odour control units installed at two different facilities: a pet food facility and an oil/grease recycling facility. The first study is based on odour measurements at the inlet and outlet of the unit installed by Applied Plasma Physics AS at the pet food facility. Odour assessments were performed by two separate consultants at the same time. The second study is based on testing of the odour removal effectiveness of two units: a scrubber and a biofilter at an oil/grease recycling facility. During this study two odour sampling programs were performed by two consultants at different times, but under the same process conditions. This paper will show how varying results can play a role in choosing the adequate odour control technologies. The final results suggest that although, an odour control unit may appear to be insufficient, it actually is successful at removing the odours.

X-Ray induced radiation damage in taurine: a combined X-ray diffraction and Raman study

The impact of X-radiation on crystalline taurine has been investigated by time resolved synchrotron X-ray powder and single crystal diffraction and Raman spectroscopy. Multiple data sets have been collected at 120 and 296 K. All the observed effects of radiation, i.e. broadening and shifts of Raman and diffraction lines, a dose dependent irreversible increase in the atomic displacement parameters (ADPs) as well as in one of the unit-cell axes, and an apparent enhancement of electron density in the SO(3) group can be tentatively attributed to primary radical formation predominantly involving the SO(3) group. In secondary reactions molecular species that are distinct from taurine are created in minute quantities, thereby introducing local departure from crystalline order, i.e. enhanced static disorder and a build-up of local strain. Our study provides evidence for ascribing the linear increase in ADPs as well as the expansion of the c axis to the accumulation of foreign species in the crystal, and not to a thermal effect. Once initiated, this process appears to continue also without radiation, however, then at a much reduced rate.

HPLC combined with multiple mass spectrometry (MSn): an alternative for the structure elucidation of compounds and artefacts found in smog chamber samples

Ion trap multiple mass spectrometry combined with high-performance liquid chromatography (online HPLC-MSn) was used to identify carbonyl compounds and artefacts found in air samples of 2-3 L taken during the OH-radical reaction study of cis-3-acetyl-2,2-dimethylcyclobutylethanal (pinonal) or cis-3-acetyl-2,2-dimethylcyclobutylcarbaldehyde (nor-pinonal) in a smog chamber. Carbonyls were transformed into 2,4-dinitrophenylhydrazones. Detection of low picogram quantities was possible. Twenty-eight compounds could be identified based on the presence of structure characteristic fragments, a developed fragmentation scheme, comparison of retention times and a library of MSn spectra of selected carbonyls. Furthermore, the additional elucidation of the sub-structures of sixteen unknowns was possible. Details about the structure elucidation procedure and the formation of the observed fragments are presented.

Measurements of (18)O-Enriched Ozone Isotopomer Abundances Using High-Resolution Fourier Transform Far-IR Spectroscopy

The distribution of ozone isotopomers in ozone mixtures produced by electric discharge in mixtures of (16)O(2) and (18)O(2) at 77 K was measured by high-resolution FTIR spectroscopy. It was of key importance to assess not only the total amount of isotopomers of a certain mass but also the relative amounts of corresponding asymmetric and symmetric ozone species of the same mass given as the ratios [(16)O(16)O(18)O]/[(16)O(18)O(16)O] and [(16)O(18)O(18)O]/[(18)O(16)O(18)O]. For many purposes both ratios have been assumed to have the statistical value 2.00. Pure rotational spectra in the far-IR region (30-100 cm(-1)) were recorded for three different (18)O-enriched ozone mixtures, all at 0.00185 cm(-1) resolution. All the spectra were corrected for thermal emission. Linestrengths for individual lines in a particular spectrum were measured by means of a fitting technique taking into account contributions from all other lines in the spectrum. For this purpose theoretical linestrengths for all six ozone species containing (16)O and (18)O obtained from a quantum-number-dependent dipole operator were used. The ratios between observed and theoretical linestrengths were used to determine the abundances of individual isotopomers in a particular ozone mixture. For one of the ozone samples the abundances of all six ozone species were determined within 1% relative uncertainty. For the three ozone mixtures studied, the ratio between asymmetric and symmetric species of mono-(18)O ozone were determined to 1.99(2), 2.01(2), and 2.10(6). The ratio between asymmetric and symmetric species of di-(18)O ozone were determined to 2.51(4), 2.42(10), and 2.46(3). Copyright 2000 Academic Press.

The High-Resolution Infrared Spectrum of 1,2,4-Triazine Vapor between 550 and 1700 cm(-1)

The Fourier transform gas-phase IR spectrum of 1,2,4-triazine between 550 and 1700 cm(-1) was measured with a resolution of ca. 0.003 cm(-1). Comparing with the liquid-phase IR and Raman spectra and using ab initio predictions, most of the fundamental bands of 1,2,4-triazine below 1600 cm(-1) were assigned. From the high-resolution gas-phase spectra, 12 of the fundamental bands were analyzed by the Watson Hamiltonian model to yield upper state spectroscopic constants. A number of local resonances were identified and explained. From a simultaneous ground state combination difference analysis of four of the bands, a set of ground state rotational and centrifugal distortion constants were obtained. Copyright 1999 Academic Press.

Die sielkundige kontrak: Wedersydse verwagtings tydens die aanvangsfase van militêr-akademiese studies

The psychological contract: Mutual expectations during the join-up phase of military-academical studies. In order to determine the expectations of both the potential students of the Military Academy and the Military Academy itself, Kotter's expectation questionnaire was completed on 66 first year students and staff members of the Military Academy. Significant differences were found between the expectations of the students and the expectations of the organisation (as represented by those as staff members). The results also indicated significant differences between students with high expectations and those with low expectations in respect of work satisfaction and career expectations. Opsomming Ten einde voornemende militêre studente en die Militêre Akademie se verwagtings te bepaal, is 'n verwagtingsvraelys van Kotter op 66 eerstejaarstudente en staflede, verbonde aan die Militêre Akademie, geadministreer. Dit blyk uit die ondersoek dat beduidende verskille tussen studente se verwagtings en die organisasie se verwagtings (soos beliggaam in die van staflede) bestaan en dat daar beduidende verskille tussen studente met hoe verwagtings en studente met lae verwagtings ten opsigte van werkstevredenheid en loopbaanverwagtings bestaan.