Odour measurement

Gostelow, P. and S.A. Parsons (2000), Sewage treatment works odour measurement, Water Sci. Tech., 41(6), 33-40. 

Odour nuisance is a particular problem associated with handling and disposal of organic sludges and manures. Recently COST 681 established a sub-group (as part of Working Party 1) to review the methods used for odour measurement in various countries with the aim of promoting greater harmonisation. Involvement in this Workshop is part of the activity. 

The sub-group is also preparing an inventory of European organisations and scientists actively involved in research on environmental odour measurement and control. A bibliography of recent publications in this field will also be prepared for a COST 681 Symposium to be held in Rome in October 1985. 

New sludge/manure processing techniques sludge and manure handling economics odour measurement and control sludge characterisation. 

The topic of odours and odour measurement has been on the programme of the COST 68 activity since the early days. Initially, under COST 68, some studies were made of methods of assessing sludge stability 11 and these included odour assessment but little further co-ordinated work was done until the establishment in 1984 of a sub-group on odours as part of the activity of Working Party 1 of COST 681. 

Odour measurement and control is just one of the many aspects of the treatment and use of organic sludges and liquid animal wastes considered within the COST 681 coordination activity. But it is a very important aspect and one which is receiving particular... 

Odour measurement techniques under trial with ADAS in the UK Investigation of the effect of pig fattening house dust on some odorous... 

To agree to standardise odour measurement techniques to enable quantitative measurements of emission rates of odour from different livestock production systems. 

Recent publications lead to the conclusion that ammonia contributes to the effects of acid precipitation. The main source of ammonia is animal production and regions with a high animal density are expected to have a high emission of ammonia. Because it is a volatile compound research workers in the field of odour measurement and odour control have the best knowledge and the best tools to study ammonia emissions. A proposal is made for the main goals of a research program. 

Sometimes it is considered to be important as a factor in odour measurement techniques. 

A second case of the use of ammonia for odour measurement is reported by van Harreveld (3). 

An important topic of this workshop is Odour measurement . The two cases I described in which ammonia was just an aid in odour measurement are an illustration of the fact that usually ammonia is considered as just one of the volatile compounds in the air from stables, but not as a severe problem. Recent publications have shown that ammonia emissions from stables and from manure are a problem as serious as the odour emissions. 

WHY A COMBINATION OF ODOUR—MEASUREMENT AND MEASUREMENT OF AMMONIA VOLATILIZATION ... 

This method for determination of ammonia losses is inaccurate and gives no information on the factors playing a role in this proces. Specialists in odour measurement techniques have the tools for a much more accurate measurement. In determining the losses over short periods they can look for correlations with the circumstances. This is the first step in contioling this ammonia losses. 

Comparison of olfactometric odour measurement and chemical odour measurement... 

BERNARD, F. (1984). Simplified methods of odour measurement Industrial application and interest for administrative control. Proc. Int. Symp., Soc. Beige de Filtr. (eds.), 25-27 April 1984, Louvain-La-Neuve, Belgium, pp. 139-150. 

Three experimental standards for olfactometric measurement were available and are compared in this review namely from France, the F.R.G. and the Netherlands. Moreover the guide for odour measurement from the Warren Spring Laboratory is considered as a guideline. 

In the Netherlands only a number of boundary conditions are published. Therefore it is not possible to compare all the details. This is also beyond the goal of this review. We want to ask attention for the need of further international standardization or harmonisaof odour measurement techniques in order to enable exchange of knowledge and experiences. 

Assessment and Effects of Odours—Measurement of Annoyance by Means of... 

The following summery can be given. Odour measurements with olfactometers is only a small part of the whole field of odour determination in ambient air and the measurement of odour nuisance must be approached in the near future with appropriate urgency. 

It is known that odour detection thresholds measured by different types of olfactometer can vary substantially. Not unreasonably, there are well-intentioned calls for standardisation of odour measurements , possibly as the basis for odour emission regulations, and so it might be useful to express some cautionary views. 

In order to assist the industry in establishing suitable odour reducing processes, odour measurements are performed at our institute. Olfactometry is useful for objective evaluation of odour levels and for characterization of certain odours, often in combination with gas chromatography. 

The humidity of outlet air must also be taken into consideration. Problems may occur when hot outlet air is sampled at low temperatures. In most such cases sampling is impossible without special arrangements. Such conditions are present during odour measurements in fish meal plants with combustion as the odour reducing method. 

DRAVNIEKS, A. and PROKOP, W.H. (1973). Source emission odour measurement by a dynamic forced choice triangle olfactometer. Air Poll. Control Assoc. Paper, 73-... 

Odour measurements in agriculture have been conducted by the Institute of Agricultural Engineering for a number of years. During this time various olfactometers have been used. It was found that the airflow of the olfactometer is one of the major parameters effecting the results. Futhermore frequent calibration of the olfactometers in use is advisable. 

As the pig house odour research continued, it became clear that the one observer procedure is time consuming. Only two odour measurements per day were possible. Futhermore, panel members observed a stress which was caused by the noise of the olfactometers. Therefore it was decided to order a set of three double sniffing port low noise olfacometers at the University of Utrecht. The Psychological Laboratory of this university had some experience in the construction of olfactometers. The flowrate was set at 10 1/min arbitrary. 

After a considerable construction time the olfactometers became available for use. With these olfactometers and a recently created sniffing room at the IMAG premises, the poultry house odour research was repeated with a panel of eight observers. The necessary diluting air was obtained from a rotary vane compressor. Filtration of the compressed air was applied. The experimental procedures made it possible to use all panel members at the time. As a result, two experimenters were able to complete four odour measurements per day. 

In case of an odour measurement the inhaled air is supposed to be equal to the air delivered by the olfactometer. However if flowrates of the olfactometer are not equal to the respiration level, additional air from the experimental room will be used (see figure 2). Since it is a good practice to keep an experimental room free from odour contamination the additional air can be considered as diluting air. In that case the final dilution of the odour sample is higher than calculated. The result may be negative response in cases where a positive response should occur. An increase of the olfactometer flowrate will replace unaccounted diluting air by accounted air thus making the final dilution is closer to the desired dilution. 

The accurate dilution of odorous gas is a prerequisite for odour measurement using an olfactometer. 

MANNEBECK, H. (1974) A practical portable method of odour measurement. In Proc. 1974 Cornell Agric. Waste Management Conf., 291-294... 

Odour measurements were made on routine ex-works sludges collected from sludge holding tanks at three sewage treatment works. Odour potential was measured using the standard method (see 3.1). Investigations carried out were comparisons of -... 

The concept of Odour Potential has already shown its usefulness in assessing the right time to spread sludge, and incomparing various sludge stabilisation methods. These results have been achieved without the manpower requirements of an extensive site survey and without the necessity of transporting equipment for olfactometry and makes good use of people expert in odour measurement. 

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