Final Report Summary - ODOURCOB (OdourCOB - Odour Characterization of Odorants from Biosolids) The aim of the project OdourCOB was to identify the major contributing chemical species possess odour - odorants produced from wastewater biosolids to odour annoyance. In order to achieve this goal biosolids emissions from municipal wastewater treatment plants (WWTPs) located in Australia and Poland were characterized to determine the olfactory impact of odours. In that research thermal desorption gas chromatography-mass spectrometry with an odour detection port (TD-GC-MS/ODP), TD-GC with a sulfur chemiluminescense detector (TD-GC-SCD), a gold film H2S analyser, TD-GC with a nitrogen chemiluminescense detector (TD-GC-NCD) and a comprehensive two-dimensional gas chromatography quadrupole-time-of-flight mass spectrometry (GCxGC-MS-QTOF) systems were used for separation, isolation and identification of compounds from biosolids emissions. The combine analytical, sensorial and data analysis techniques were enabled to establishment the specific odour fingerprints for biosolids emission. The researcher was going to determine relationship between chemical composition and odour character. It assumed to confirm the hypotheses: 1. Odorous emissions from wastewater biosolids are composed of a complex mixture of odorants.2. The identification of odour annoyance of wastewater biosolids can be achieved by taking into account odorant quality characters and intensity.3. There are a number of key odorants whose formation can be related to the operational and biochemical processes.4. GC-MS/ODP technique can characterize odours by allowing a full identification of the volatile compounds presents in the environmental emissions from both chemical and sensory viewpoints.During three years of the project researcher identified volatile organic compounds (VOCs) associated with anaerobically stabilised biosolids, map emissions as the biosolids are stored and to identify sensorially relevant VOCs which have the potential to contribute to nuisance emissions from the biosolids at the wastewater treatment plants. VOCs were measured to identify compounds that could contribute to the overall odour character of nuisance emissions. Compounds emitted varied as the biosolids cakes were stored for a period of 35 days. The range of VOCs identified as the anaerobically stabilised cakes are aged during storage suggests they are present due to a range of factors; biotic and/or abiotic production as well as household or industrial inputs to the sewer catchment. Variations between the types and concentration of compounds emitted from different biosolids emphasises the impact of upstream processes on biosolids emissions.Sensorially important VOCs such as trimethylamine (TMA), acetic acid, limonene and ethyl methyl benzene were identified at levels above their detection thresholds. However, TMA was the only compound to exceed the sulfur compounds being detected with a concentration four orders of magnitude greater than its odour detection threshold.In this work, a GC-MSD/ODP system was used to identify previously unreported odorants in emissions from biosolids, resulting in the identification of 2,4,6-Trichloroanisole (TCA) and 2-Isopropyl-3-methoxypyrazine (IPMP). TCA and IPMP were identified in all analysed samples of dewatered biosolids after anaerobically stabilization process. Intensities levels of TCA do not shown any increasing or decreasing trend as the biosolids were aged, whilst IPMP showing TCA is consistently present in stored biosolid samples. TCA and IPMP seem to be an odorants of importance in biosolids emission due to its low odour threshold and frequent detection by ODP assessors. Moreover, very limited data exist on qualitative analysis of musty type odours. Taking into consideration 36 different biosolids cakes at the different age of storage it could be concluded that due to its intensity and frequency of detection by ODP assessors TCA and IPMP should be consider as odorants of concern in biosolids emission. Thus the identification and quantification of trace amounts of odor-causing compounds such as TCA and IPMP should not be neglected in emission from biosolids. Apart from TCA and IPMP researcher has identified new odorants from biosolids emissions which have not being reported in the literature: Sulfide allyl methyl, Methyl propyl sulfide. Moreover, emissions from 218 biosolids cakes have been analyzed to show the variation between ODP assessors for the identification and intensity assessment of odorous VOCs. The ODP assessors detected 32 different odorous VOCs from biosolids emission. Some of those compounds are still unknown. The frequencies of positive responses and the intensities assigned by each assessor to particular VOCs varied. Moreover, some of odorous VOCs were not detected by all assessors. For example, the geosmin was detected by only two of them. The use of GC-MS/ODP system for the analysis of odorous VOCs could be valuable when analysed by different assessors, allowing a range of responses to specific odorants in a populations to be investigated.To correctly find relationship between odour and chemical composition will be absolutely necessary to find those unknown chemicals. http://opz.is.pw.edu.pl/OdourCOB_website.pdf
